Topic Editors

Department of Chemistry, University of Patras, 26504 Patras, Greece
Pharmacy Program, Department of Health Sciences, University of Nicosia, CY-1700 Nicosia, Cyprus
Institute for Advanced Energy Technologies "Nicola Giordano" ITAE, Italian National Research Council (CNR), 98126 Messina, Italy
Institute for Advanced Energy Technologies "Nicola Giordano" ITAE, Italian National Research Council (CNR), 98126 Messina, Italy

Synthesis, Characterization and Performance of Materials for a Sustainable Future

Abstract submission deadline
closed (30 September 2022)
Manuscript submission deadline
closed (31 December 2022)
Viewed by
250453

Topic Information

Dear Colleagues,

We are pleased to invite you, along with the members of your research group, to contribute to the forthcoming Topic “Synthesis, Characterization and Performance of Materials for a Sustainable Future” by MDPI. Today, sustainability represents the key factor for economic progress in compliance with social advancement and environmental protection, driving innovation in materials, processes and technologies. Therefore, starting from the need for innovative chemical formulations for advanced (nano)materials, inorganic/organic/coordination compounds, porous composites, hybrid/multifunctional or nanostructured supported systems, this Topic aims at collecting recent progresses, challenges and opportunities for the application of functional materials in different fields, including catalysis, photocatalysis, electronics, optics, energy and environment, according to green chemistry and green engineering concepts, eco-efficiency, industrial ecology and sustainable processes from an environment and economic point of view. In this respect, a more rational use of natural sources and solid wastes is to be addressed, as well as the application of novel synthetic procedures for energy saving. Specific attention is also to be paid on the potential of modeling as an analytical tool for matching peculiar structure–reactivity relationships of materials, pointing out mechanistic clues controlling their behavior in processes of industrial interest. Relevant subject areas to be covered in this Topic span from material-to-application including:

  • Production of green hydrogen;
  • Purification of gaseous streams from industrial processes;
  • Power-to-gas approaches;
  • CCUS strategies to reach net zero or negative GHG emissions;
  • Synthesis of sustainable chemicals and fuels; o Conversion of biomass and wastes to added value products;
  • Treatment of air, water and soil pollution.

Review articles surveying recent research trends, original research articles, high-quality research notes or short communications are to be preferentially delivered to the following journals: Catalysts, Materials, Nanomaterials, Polymers and Sustainability. We hope that you will be able to accept this invitation and join to the on-going success of this outstanding Topic.

Dr. John Vakros
Dr. Evroula Hapeshi
Dr. Catia Cannilla
Dr. Giuseppe Bonura
Topic Editors

Keywords

  • green hydrogen
  • power-to-gas
  • CCUS
  • CO2 conversion
  • carbon neutral processes
  • oxidation processes
  • hydrogenation processes
  • biofuel production
  • sustainable materials
  • smart materials
  • membrane technology
  • nanomaterials
  • hybrid catalysts
  • photocatalysts
  • biomass conversion
  • solid wastes
  • pollutant degradation
  • water pollution
  • soil pollution

Participating Journals

Journal Name Impact Factor CiteScore Launched Year First Decision (median) APC
Catalysts
catalysts
3.9 6.3 2011 14.3 Days CHF 2700
Materials
materials
3.4 5.2 2008 13.9 Days CHF 2600
Nanomaterials
nanomaterials
5.3 7.4 2010 13.6 Days CHF 2900
Polymers
polymers
5.0 6.6 2009 13.7 Days CHF 2700
Sustainability
sustainability
3.9 5.8 2009 18.8 Days CHF 2400

Preprints.org is a multidiscipline platform providing preprint service that is dedicated to sharing your research from the start and empowering your research journey.

MDPI Topics is cooperating with Preprints.org and has built a direct connection between MDPI journals and Preprints.org. Authors are encouraged to enjoy the benefits by posting a preprint at Preprints.org prior to publication:

  1. Immediately share your ideas ahead of publication and establish your research priority;
  2. Protect your idea from being stolen with this time-stamped preprint article;
  3. Enhance the exposure and impact of your research;
  4. Receive feedback from your peers in advance;
  5. Have it indexed in Web of Science (Preprint Citation Index), Google Scholar, Crossref, SHARE, PrePubMed, Scilit and Europe PMC.

Published Papers (105 papers)

Order results
Result details
Journals
Select all
Export citation of selected articles as:
3 pages, 168 KiB  
Editorial
Synthesis, Characterization and Performance of Materials for a Sustainable Future
by John Vakros, Evroula Hapeshi, Catia Cannilla and Giuseppe Bonura
Sustainability 2024, 16(1), 368; https://doi.org/10.3390/su16010368 - 31 Dec 2023
Viewed by 799
Abstract
The commonly applied resource management strategies are rarely characterized by medium–long term sustainability, but an indispensable and urgent shift is necessary according to a circular economy approach that includes actions aimed at saving and reusing resources [...] Full article
7 pages, 201 KiB  
Editorial
Synthesis, Characterization and Performance of Materials for a Sustainable Future
by John Vakros, Evroula Hapeshi, Catia Cannilla and Giuseppe Bonura
Polymers 2024, 16(1), 124; https://doi.org/10.3390/polym16010124 - 29 Dec 2023
Viewed by 526
Abstract
The current era has been defined as “The Plastic Era”, considering that over the past 50 years the role and importance of polymeric materials in our economy has steadily grown, reaching a production of around a few hundred million tons per year which [...] Read more.
The current era has been defined as “The Plastic Era”, considering that over the past 50 years the role and importance of polymeric materials in our economy has steadily grown, reaching a production of around a few hundred million tons per year which may even double in the next 20 years [...] Full article
8 pages, 242 KiB  
Editorial
Synthesis, Characterization and Performance of Materials for a Sustainable Future
by John Vakros, Evroula Hapeshi, Catia Cannilla and Giuseppe Bonura
Nanomaterials 2023, 13(13), 1929; https://doi.org/10.3390/nano13131929 - 25 Jun 2023
Cited by 1 | Viewed by 786
Abstract
Today, sustainability represents the key factor for economic progress in compliance with social advancement and environmental protection, driving innovation in materials, processes and technologies [...] Full article
21 pages, 6125 KiB  
Article
Influence of the Nature of Aminoalcohol on ZnO Films Formed by Sol-Gel Methods
by Anna Vilà, Alberto Gómez-Núñez, Xavier Alcobé, Sergi Palacios, Teo Puig Walz and Concepción López
Nanomaterials 2023, 13(6), 1057; https://doi.org/10.3390/nano13061057 - 15 Mar 2023
Cited by 4 | Viewed by 1455
Abstract
Here we present comparative studies of: (i) the formation of ZnO thin films via the sol-gel method using zinc acetate dihydrate (ZAD), 2-methoxyethanol (ME) as solvent, and the aminoalcohols (AA): ethanolamine, (S)-(+)-2-amino-1-propanol, (S)-(+)-2-amino-3-methyl-1-butanol, 2-aminophenol, and aminobenzyl alcohol, and (ii) [...] Read more.
Here we present comparative studies of: (i) the formation of ZnO thin films via the sol-gel method using zinc acetate dihydrate (ZAD), 2-methoxyethanol (ME) as solvent, and the aminoalcohols (AA): ethanolamine, (S)-(+)-2-amino-1-propanol, (S)-(+)-2-amino-3-methyl-1-butanol, 2-aminophenol, and aminobenzyl alcohol, and (ii) elemental analyses, infrared spectroscopy, X-ray diffraction, scanning electron microscopy, absorption and emission spectra of films obtained after deposition by drop coating on glass surface, and thermal treatments at 300, 400, 500 and 600 °C. The results obtained provide conclusive evidences of the influence of the AA used (aliphatic vs. aromatic) on the ink stability (prior to deposition), and on the composition, structures, morphologies, and properties of films after calcination, in particular, those due to the different substituents, H, Me, or iPr, and to the presence or the absence of a –CH2 unit. Aliphatic films, more stable and purer than aromatic ones, contained the ZnO wurtzite form for all annealing temperatures, while the cubic sphalerite (zinc-blende) form was also detected after using aromatic AAs. Films having frayed fibers or quartered layers or uniform yarns evolved to “neuron-like” patterns. UV and photoluminescence studies revealed that these AAs also affect the optical band gap, the structural defects, and photo-optical properties of the films. Full article
Show Figures

Graphical abstract

14 pages, 2485 KiB  
Article
Piezo-Enhanced Photocatalytic Activity of the Electrospun Fibrous Magnetic PVDF/BiFeO3 Membrane
by Farid Orudzhev, Dinara Sobola, Shikhgasan Ramazanov, Klára Částková, Nikola Papež, Daud A. Selimov, Magomed Abdurakhmanov, Abdulatip Shuaibov, Alina Rabadanova, Rashid Gulakhmedov and Vladimír Holcman
Polymers 2023, 15(1), 246; https://doi.org/10.3390/polym15010246 - 03 Jan 2023
Cited by 12 | Viewed by 3270
Abstract
Creating stimulus-sensitive smart catalysts capable of decomposing organic dyes with high efficiency is a critical task in ecology. Combining the advantages of photoactive piezoelectric nanomaterials and ferroelectric polymers can effectively solve this problem by collecting mechanical vibrations and light energy. Using the electrospinning [...] Read more.
Creating stimulus-sensitive smart catalysts capable of decomposing organic dyes with high efficiency is a critical task in ecology. Combining the advantages of photoactive piezoelectric nanomaterials and ferroelectric polymers can effectively solve this problem by collecting mechanical vibrations and light energy. Using the electrospinning method, we synthesized hybrid polymer-inorganic nanocomposite fiber membranes based on polyvinylidene fluoride (PVDF) and bismuth ferrite (BFO). The samples were studied by scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FTIR), total transmittance and diffuse reflectance, X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), vibrating-sample magnetometer (VSM), and piezopotential measurements. It has been demonstrated that the addition of BFO leads to an increase in the proportion of the polar phase from 86.5% to 96.1% due to the surface ion–dipole interaction. It is shown that the composite exhibits anisotropy of magnetic properties depending on the orientation of the magnetic field. The results of piezo-photocatalytic experiments showed that under the combined action of ultrasonic treatment and irradiation with both visible and UV light, the reaction rate increased in comparison with photolysis, sonolysis, and piezocatalysis. Moreover, for PVDF/BFO, which does not exhibit photocatalytic activity, under the combined action of light and ultrasound, the reaction rate increases by about 3× under UV irradiation and by about 6× under visible light irradiation. This behavior is explained by the piezoelectric potential and the narrowing of the band gap of the composite due to mechanical stress caused by the ultrasound. Full article
Show Figures

Graphical abstract

14 pages, 2411 KiB  
Article
Evaporative and Wicking Functionalities at Hot Airflows of Laser Nano-/Microstructured Ti-6Al-4V Material
by Ranran Fang, Zhonglin Pan, Jiangen Zheng, Xiaofa Wang, Rui Li, Chen Yang, Lianrui Deng and Anatoliy Y. Vorobyev
Nanomaterials 2023, 13(1), 218; https://doi.org/10.3390/nano13010218 - 03 Jan 2023
Cited by 3 | Viewed by 1654
Abstract
A novel multifunctional material with efficient wicking and evaporative functionalities was fabricated using hierarchical surface nano-/microstructuring by femtosecond laser micromachining. The created material exhibits excellent multifunctional performance. Our experiments in a wind tunnel demonstrate its good wicking and evaporative functionalities under the conditions [...] Read more.
A novel multifunctional material with efficient wicking and evaporative functionalities was fabricated using hierarchical surface nano-/microstructuring by femtosecond laser micromachining. The created material exhibits excellent multifunctional performance. Our experiments in a wind tunnel demonstrate its good wicking and evaporative functionalities under the conditions of high-temperature airflows. An important finding of this work is the significantly enhanced evaporation rate of the created material compared with the free water surface. The obtained results provide a platform for the practical implementation of Maisotsenko-cycle cooling technologies for substantially increasing efficiency in power generation, thermal management, and other evaporation-based technologies. The developed multifunctional material demonstrates long-lasting wicking and evaporative functionalities that are resistant to degradation under high-temperature airflows, indicating its suitability for practical applications. Full article
Show Figures

Figure 1

21 pages, 5451 KiB  
Article
Reinforcement of Calcareous Sands by Stimulation of Native Microorganisms Induced Mineralization
by Gangqiang Shen, Shiyu Liu, Yuhan He, Muzhi Pan, Jin Yu and Yanyan Cai
Materials 2023, 16(1), 251; https://doi.org/10.3390/ma16010251 - 27 Dec 2022
Cited by 1 | Viewed by 1349
Abstract
Calcareous sand is a special soil formed by the accumulation of carbonate fragments. Its compressibility is caused by a high void ratio and breakable particles. Because of its high carbonate content and weak cementation, its load-bearing capacity is limited. In this study, the [...] Read more.
Calcareous sand is a special soil formed by the accumulation of carbonate fragments. Its compressibility is caused by a high void ratio and breakable particles. Because of its high carbonate content and weak cementation, its load-bearing capacity is limited. In this study, the optimal stimulation solution was obtained with response surface methodology. Then, the effect of reinforcing calcareous sand was analysed with unconfined compressive strength (UCS) tests, calcium carbonate content tests, microscopy and microbial community analyses. The components and concentrations of the optimal stimulation solution were as follows: sodium acetate (38.00 mM), ammonium chloride (124.24 mM), yeast extract (0.46 g/L), urea (333 mM), and nickel chloride (0.01 mM), and the pH was 8.75. After the calcareous sand was treated with the optimal stimulation scheme, the urease activity was 6.1891 mM urea/min, the calcium carbonate production was 8.40%, and the UCS was 770 kPa, which constituted increases of 71.41%, 35.40%, and 83.33%, respectively, compared with the initial scheme. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses showed that calcium carbonate crystals were formed between the particles of the calcareous sand after the reaction, and the calcium carbonate crystals were mainly calcite. Urease-producing microorganisms became the dominant species in calcareous sand after treatment. This study showed that biostimulation-induced mineralization is feasible for reinforcing calcareous sand. Full article
Show Figures

Figure 1

20 pages, 2062 KiB  
Article
Screening of Raw and Modified Biochars from Food Processing Wastes for the Removal of Phosphates, Nitrates, and Ammonia from Water
by Styliani E. Biliani, John Vakros and Ioannis D. Manariotis
Sustainability 2022, 14(24), 16483; https://doi.org/10.3390/su142416483 - 09 Dec 2022
Cited by 4 | Viewed by 1248
Abstract
The aim of this work was to compare the performance of biochar from various food processing wastes of different origin for the removal of different nutrients from water. Eggshells (EGS), rice husk (RH), and coffee biochars were pyrolyzed at 400 and 800 °C [...] Read more.
The aim of this work was to compare the performance of biochar from various food processing wastes of different origin for the removal of different nutrients from water. Eggshells (EGS), rice husk (RH), and coffee biochars were pyrolyzed at 400 and 800 °C and were examined for the removal of phosphates, nitrates, and ammonia nitrogen. The raw materials were also modified with magnesium chloride in order to investigate their sorption behavior. The highest sorption capacity (qmax) for phosphates and ammonium was observed with EGS pyrolyzed at 800 °C and was 11.45 mg PO43−-P/g and 11.59 mg NH3-N/g, while the highest nitrates sorption capacity was observed with the magnesium-modified RH pyrolyzed at 800 °C (5.24 mg NO3-N). The modified EGS biochars pyrolyzed at 800 °C had almost the half the sorption capacity for phosphates and nitrates compared to the unmodified materials. The modification of RH pyrolyzed at 800 °C resulted in higher sorption capacity by 34 and 158% for phosphates and ammonium, respectively. The coffee raw and modified biochars were less efficient in nutrient removal compared to the other materials. The specific surface area values of the biochars examined is not a decisive factor for nutrient sorption. The reaction between magnesium and calcium (for the eggshell samples) ions with phosphates is responsible for the higher sorption efficiency. On the other hand, the presence of magnesium and calcium ions has a detrimental effect on the sorption of NH3-N. Full article
Show Figures

Figure 1

15 pages, 4383 KiB  
Article
Atomic-Level Sn Doping Effect in Ga2O3 Films Using Plasma-Enhanced Atomic Layer Deposition
by Yi Shen, Hong-Ping Ma, Lin Gu, Jie Zhang, Wei Huang, Jing-Tao Zhu and Qing-Chun Zhang
Nanomaterials 2022, 12(23), 4256; https://doi.org/10.3390/nano12234256 - 30 Nov 2022
Cited by 7 | Viewed by 1898
Abstract
In this work, the atomic level doping of Sn into Ga2O3 films was successfully deposited by using a plasma-enhanced atomic layer deposition method. Here, we systematically studied the changes in the chemical state, microstructure evolution, optical properties, energy band alignment, [...] Read more.
In this work, the atomic level doping of Sn into Ga2O3 films was successfully deposited by using a plasma-enhanced atomic layer deposition method. Here, we systematically studied the changes in the chemical state, microstructure evolution, optical properties, energy band alignment, and electrical properties for various configurations of the Sn-doped Ga2O3 films. The results indicated that all the films have high transparency with an average transmittance of above 90% over ultraviolet and visible light wavelengths. X-ray reflectivity and spectroscopic ellipsometry measurement indicated that the Sn doping level affects the density, refractive index, and extinction coefficient. In particular, the chemical microstructure and energy band structure for the Sn-doped Ga2O3 films were analyzed and discussed in detail. With an increase in the Sn content, the ratio of Sn–O bonding increases, but by contrast, the proportion of the oxygen vacancies decreases. The reduction in the oxygen vacancy content leads to an increase in the valence band maximum, but the energy bandgap decreases from 4.73 to 4.31 eV. Moreover, with the increase in Sn content, the breakdown mode transformed the hard breakdown into the soft breakdown. The C-V characteristics proved that the Sn-doped Ga2O3 films have large permittivity. These studies offer a foundation and a systematical analysis for assisting the design and application of Ga2O3 film-based transparent devices. Full article
Show Figures

Figure 1

20 pages, 5049 KiB  
Article
Solid Features Modification by the Reactor Selection and US Support during Reactive Crystallization
by Magdalena Stec and Piotr Maria Synowiec
Materials 2022, 15(21), 7419; https://doi.org/10.3390/ma15217419 - 22 Oct 2022
Viewed by 1144
Abstract
The use of materials requires adjusting their features to current applications/needs. In crystallization, the production methods leading directly to the product with pre-determined characteristics are being sought. The research focuses on the abilities of “shaping” the solid product (CSD, shape, form, etc.) and [...] Read more.
The use of materials requires adjusting their features to current applications/needs. In crystallization, the production methods leading directly to the product with pre-determined characteristics are being sought. The research focuses on the abilities of “shaping” the solid product (CSD, shape, form, etc.) and is based on experimental work carried out in the ultrasound (US)-assisted Koflo static mixer (STM). As the model reaction calcium fluoride precipitation has been used as a “common denominator” that complements the previous authors’ studies, providing comprehensive knowledge and a more general look at the mentioned problem. It has been shown that it is possible to obtain crystals with the desired characteristics; however, one should be aware of the used reactors’ limitations. The conscious selection of operating conditions, as well as US parameters (if they are used), is also essential. It has been revealed that the introduction of US to the STM only affects the turbulence intensity, but it doesn’t change the mixing profile. The kinetics of crystallization remain unchanged, but crystals are subjected to greater attrition. In the stirred tank reactors, one might significantly improve the homogeneity of the unit mixing distribution by the selection of the relative input power εrel and, thus, affect the kinetics of crystallization. Full article
Show Figures

Figure 1

17 pages, 2201 KiB  
Article
Influence of Quaternary Ammonium Salt Functionalized Chitosan Additive as Sustainable Filler for High-Density Polyethylene Composites
by Maria José G. de Araújo, Francivandi C. Barbosa, Marcus Vinícius L. Fook, Suédina Maria L. Silva and Itamara F. Leite
Materials 2022, 15(21), 7418; https://doi.org/10.3390/ma15217418 - 22 Oct 2022
Cited by 2 | Viewed by 1123
Abstract
In this study, an antimicrobial packaging material was successfully developed with blends of high-density polyethylene (HDPE) and chitosan (CS) made by melt processing. In the different HDPE/CS composites, the CS content effect (up to 40%), and the addition of quaternary ammonium salt functionalized [...] Read more.
In this study, an antimicrobial packaging material was successfully developed with blends of high-density polyethylene (HDPE) and chitosan (CS) made by melt processing. In the different HDPE/CS composites, the CS content effect (up to 40%), and the addition of quaternary ammonium salt functionalized chitosan (CS-CTAB) as an additive were evaluated by X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analyses (TG), tensile strength, scanning electron microscopy (SEM) and antimicrobial activity. When analyzing the effect of the additive in the different HDPE/CS composites, it was observed that the compositions with 10 and 20 %wt of chitosan showed better elongation values (~13% and 10%) as well as a higher decomposition temperature at 20% mass loss (T20) varying from (321–332 °C and 302–312 °C), respectively, in relation to the other compositions, regardless of the type of additive used, it acted as an antimicrobial agent, promoting inhibition of microbial growth against the strains gram-positive and gram-negative used in this work, making the different HDPE/CS composites suitable candidates for use in food packaging. Full article
Show Figures

Figure 1

23 pages, 6684 KiB  
Review
Covalent Organic Frameworks with Ionic Liquid-Moieties (ILCOFs): Structures, Synthesis, and CO2 Conversion
by Ruina Zhang, Zekai Zhang, Quanli Ke, Bing Zhou, Guokai Cui and Hanfeng Lu
Nanomaterials 2022, 12(20), 3615; https://doi.org/10.3390/nano12203615 - 15 Oct 2022
Cited by 8 | Viewed by 3225
Abstract
CO2, an acidic gas, is usually emitted from the combustion of fossil fuels and leads to the formation of acid rain and greenhouse effects. CO2 can be used to produce kinds of value-added chemicals from a viewpoint based on carbon [...] Read more.
CO2, an acidic gas, is usually emitted from the combustion of fossil fuels and leads to the formation of acid rain and greenhouse effects. CO2 can be used to produce kinds of value-added chemicals from a viewpoint based on carbon capture, utilization, and storage (CCUS). With the combination of unique structures and properties of ionic liquids (ILs) and covalent organic frameworks (COFs), covalent organic frameworks with ionic liquid-moieties (ILCOFs) have been developed as a kind of novel and efficient sorbent, catalyst, and electrolyte since 2016. In this critical review, we first focus on the structures and synthesis of different kinds of ILCOFs materials, including ILCOFs with IL moieties located on the main linkers, on the nodes, and on the side chains. We then discuss the ILCOFs for CO2 capture and conversion, including the reduction and cycloaddition of CO2. Finally, future directions and prospects for ILCOFs are outlined. This review is beneficial for academic researchers in obtaining an overall understanding of ILCOFs and their application of CO2 conversion. This work will open a door to develop novel ILCOFs materials for the capture, separation, and utilization of other typical acid, basic, or neutral gases such as SO2, H2S, NOx, NH3, and so on. Full article
Show Figures

Graphical abstract

18 pages, 5102 KiB  
Article
Biosynthesis, Characterization, Evaluation, and Shelf-Life Study of Silver Nanoparticles against Cotton Bollworm, Helicoverpa armigera (Hubner) (Noctuidae: Lepidoptera)
by M.M. Anees, S.B. Patil, D.N. Kambrekar, S.S. Chandrashekhar and Shamarao Jahagirdar
Nanomaterials 2022, 12(19), 3511; https://doi.org/10.3390/nano12193511 - 08 Oct 2022
Cited by 5 | Viewed by 1699
Abstract
Nanoparticles provide a promising and alternative platform of eco-friendly technologies that encompasses better cost-resilient remedies against one of the most economically harnessing insect pests of cotton. The main goal of this research was to provide a better management strategy through biologically synthesizing (sunlight [...] Read more.
Nanoparticles provide a promising and alternative platform of eco-friendly technologies that encompasses better cost-resilient remedies against one of the most economically harnessing insect pests of cotton. The main goal of this research was to provide a better management strategy through biologically synthesizing (sunlight exposure method) green nanoparticles from leaf extracts of Azadirachta indica and Pongamia pinnata and proving their bioefficacy on H. armigera (2nd instar). Characterization of bio-synthesized silver nanoparticles was carried out using UV-Visible spectroscopy for confirming the formation of nanoparticles, a Particle Size Analyzer (PSA) for determining the size/distribution of particles, and a Scanning Electron Microscope (SEM) for analyzing the surface topology of nanoparticles. The results obtained from PSA analysis showed that A. indica and P. pinnata-based silver nanoparticles had an average diameter of 61.70 nm and 68.80, respectively. Topographical images obtained from SEM proved that most of the green synthesized silver nanoparticles were spherical in shape. A. indica-based silver nanoparticles were found to be comparatively more efficient and have higher insecticidal activity compared to P. pinnata-based nanoparticles. A. indica-based AgNPs recorded larval mortality of 60.00 to 93.33 percent at the concentrations of 500 to 2000 ppm, followed by P. pinnata-based nanoparticles, with 60.00 to 90.00 percent larval mortality. Shelf-life studies revealed that A. indica-based AgNPs had the maximum negative zeta potential of −58.96 mV and could be stored for three months without losing bioefficacy and up to six months with negligible reduction in bioefficacy. Symptoms caused by silver nanoparticles were leakage of body fluids, sluggishness, inactiveness, brittleness, etc. Full article
Show Figures

Figure 1

19 pages, 6404 KiB  
Article
A Novel ZnO Nanoparticles Enhanced Surfactant Based Viscoelastic Fluid Systems for Fracturing under High Temperature and High Shear Rate Conditions: Synthesis, Rheometric Analysis, and Fluid Model Derivation
by Mahesh Chandra Patel, Mohammed Abdalla Ayoub, Anas Mohammed Hassan and Mazlin Bt Idress
Polymers 2022, 14(19), 4023; https://doi.org/10.3390/polym14194023 - 26 Sep 2022
Cited by 9 | Viewed by 1608
Abstract
Surfactant-based viscoelastic (SBVE) fluids are innovative nonpolymeric non-newtonian fluid compositions that have recently gained much attention from the oil industry. SBVE can replace traditional polymeric fracturing fluid composition by mitigating problems arising during and after hydraulic fracturing operations are performed. In this study, [...] Read more.
Surfactant-based viscoelastic (SBVE) fluids are innovative nonpolymeric non-newtonian fluid compositions that have recently gained much attention from the oil industry. SBVE can replace traditional polymeric fracturing fluid composition by mitigating problems arising during and after hydraulic fracturing operations are performed. In this study, SBVE fluid systems which are entangled with worm-like micellar solutions of cationic surfactant: cetrimonium bromide or CTAB and counterion inorganic sodium nitrate salt are synthesized. The salt reagent concentration is optimized by comparing the rheological characteristics of different concentration fluids at 25 °C. The study aims to mitigate the primary issue concerning these SBVE fluids: significant drop in viscosity at high temperature and high shear rate (HTHS) conditions. Hence, the authors synthesized a modified viscoelastic fluid system using ZnO nanoparticle (NPs) additives with a hypothesis of getting fluids with improved rheology. The rheology of optimum fluids of both categories: with (0.6 M NaNO3 concentration fluid) and without (0.8 M NaNO3 concentration fluid) ZnO NPs additives were compared for a range of shear rates from 1 to 500 Sec−1 at different temperatures from 25 °C to 75 °C to visualize modifications in viscosity values after the addition of NPs additives. The rheology in terms of viscosity was higher for the fluid with 1% dispersed ZnO NPs additives at all temperatures for the entire range of shear rate values. Additionally, rheological correlation function models were derived for the synthesized fluids using statistical analysis methods. Subsequently, Herschel–Bulkley models were developed for optimum fluids depending on rheological correlation models. In the last section of the study, the pressure-drop estimation method is described using given group equations for laminar flow in a pipe depending on Herschel–Bulkley-model parameters have been identified for optimum fluids are consistency, flow index and yield stress values. Full article
Show Figures

Graphical abstract

14 pages, 2163 KiB  
Article
Effect of Exogenous Glucose at Different Concentrations on the Formation of Dark-Brown Humic-like Substances in the Maillard Reaction Pathway Based on the Abiotic Condensation of Precursors Involving δ-MnO2
by Nan Wang, Qi Zhang, Wanhong Li, Chengxin Bai, Yan Song, Shuai Wang and Zhijiang Liu
Sustainability 2022, 14(18), 11603; https://doi.org/10.3390/su141811603 - 15 Sep 2022
Cited by 2 | Viewed by 1325
Abstract
The Maillard reaction is a type of nonenzymatic browning process and is an important pathway for the formation of humic-like substances (HLSs). Glucose is one of the three crucial precursors for the Maillard reaction, and a change in glucose concentration can inevitably affect [...] Read more.
The Maillard reaction is a type of nonenzymatic browning process and is an important pathway for the formation of humic-like substances (HLSs). Glucose is one of the three crucial precursors for the Maillard reaction, and a change in glucose concentration can inevitably affect the humification pathway, thereby regulating the composition and quality of HLSs. To verify the scientific hypothesis, the method of liquid shake-flask culture was adopted. Both catechol and glycine with fixed concentrations were added to a phosphate buffer including δ-MnO2, and only the concentration of glucose was adjusted in the sterile culture system. The obtained supernatant fluid and dark-brown residue were collected dynamically through the centrifugation method. The E4/E6 ratio and total organic C (TOC) of the supernatant fluid, the humus composition, and FTIR spectra for the dark-brown residue, and the elemental composition of humic-like acid (HLA) extracted from the dark-brown residue were analyzed to reveal the effect of varying glucose concentrations on the abiotic humification pathways for the Maillard reaction and the characteristics of relevant products under abiotic processes. The results reveal that (1) the exogenous addition of glucose at different concentrations simplifies the molecular structure in the supernatant fluid, and the TOC content is decreased to varying degrees, among which the addition of 0.24 mol/L glucose leads to the formation of simpler organic molecules in the supernatant compared to that for the other treatments, and the addition of 0.03 mol/L glucose shows the largest decrease in TOC content; (2) Under the coexistence of glycine and catechol, CHLA treated with the addition of glucose at different concentrations shows an upward trend in the course of the culture, which is significantly higher than that obtained for the CK control. The addition of 0.12 mol/L glucose results in the largest increase in CHLA. During the culture period, the structure of HLA molecules from each treatment first become complex and then gradually become simpler. Finally, the molecular structure of HLA treated with different concentrations of glucose becomes more complex, but the structure of HLA molecules from the CK control tends to be simplified. The addition of glucose can improve the condensation degree of HLA molecules, among which the addition of 0.12 mol/L glucose shows the most significant effect. With increasing exogenous glucose concentration, the number of N-containing compounds in the HLA molecules further decreases, while the number of O-containing functional groups increases. (3) The greater the concentration of glucose added, the higher the proportion of aromatic C structures in the dark-brown residue. During this process, the Mn-O bond lattice vibration of the δ-MnO2 layered structure is greatly enhanced. The organic molecules in the dark-brown residue and δ-MnO2 are bound to each other through intermolecular hydrogen bonding. The CHLA/CFLA ratio for each treatment increases to varying degrees after the culture period, indicating that the addition of glucose is more conducive to the improvement of humus quality than the CK control, among which the addition of 0.12 mol/L glucose shows the best effect. Full article
Show Figures

Figure 1

12 pages, 3129 KiB  
Article
Cysteine-Mediated Green Synthesis of Copper Sulphide Nanoparticles: Biocompatibility Studies and Characterization as Counter Electrodes
by Luis A. Saona, Jessica L. Campo-Giraldo, Giovanna Anziani-Ostuni, Nicolás Órdenes-Aenishanslins, Felipe A. Venegas, María F. Giordana, Carlos Díaz, Mauricio Isaacs, Denisse Bravo and José M. Pérez-Donoso
Nanomaterials 2022, 12(18), 3194; https://doi.org/10.3390/nano12183194 - 14 Sep 2022
Cited by 5 | Viewed by 1884
Abstract
A one-pot green method for aqueous synthesis of fluorescent copper sulphide nanoparticles (NPs) was developed. The reaction was carried out in borax–citrate buffer at physiological pH, 37 °C, aerobic conditions and using Cu (II) and the biological thiol cysteine. NPs exhibit green fluorescence [...] Read more.
A one-pot green method for aqueous synthesis of fluorescent copper sulphide nanoparticles (NPs) was developed. The reaction was carried out in borax–citrate buffer at physiological pH, 37 °C, aerobic conditions and using Cu (II) and the biological thiol cysteine. NPs exhibit green fluorescence with a peak at 520 nm when excited at 410 nm and an absorbance peak at 410 nm. A size between 8–12 nm was determined by dynamic light scattering and transmission electron microscopy. An interplanar atomic distance of (3.5 ± 0.1) Å and a hexagonal chalcocite crystalline structure (βCh) of Cu2S NPs were also determined (HR-TEM). Furthermore, FTIR analyses revealed a Cu-S bond and the presence of organic molecules on NPs. Regarding toxicity, fluorescent Cu2S NPs display high biocompatibility when tested in cell lines and bacterial strains. Electrocatalytic activity of Cu2S NPs as counter electrodes was evaluated, and the best value of charge transfer resistance (Rct) was obtained with FTO/Cu2S (four layers). Consequently, the performance of biomimetic Cu2S NPs as counter electrodes in photovoltaic devices constructed using different sensitizers (ruthenium dye or CdTe NPs) and electrolytes (S2−/Sn2− or I/I3−) was successfully checked. Altogether, novel characteristics of copper sulfide NPs such as green, simple, and inexpensive production, spectroscopic properties, high biocompatibility, and particularly their electrochemical performance, validate its use in different biotechnological applications. Full article
Show Figures

Graphical abstract

16 pages, 1864 KiB  
Review
The Generation Process, Impurity Removal and High-Value Utilization of Phosphogypsum Material
by Xinfeng Lv and Lan Xiang
Nanomaterials 2022, 12(17), 3021; https://doi.org/10.3390/nano12173021 - 31 Aug 2022
Cited by 16 | Viewed by 2231
Abstract
As phosphogypsum constitutes a large amount of solid waste material, its purification treatment and comprehensive utilization have close connection with economic development and ecological environmental protection. For the moment, the storage quantity of phosphogypsum is still rising as a result of the increasing [...] Read more.
As phosphogypsum constitutes a large amount of solid waste material, its purification treatment and comprehensive utilization have close connection with economic development and ecological environmental protection. For the moment, the storage quantity of phosphogypsum is still rising as a result of the increasing phosphate fertilizer production to meet the food demand in China. This paper summarizes the generation process, impurity removal treatment (physical method, chemical method, heat method), high-value utilization (nanometer calcium sulfate whisker, nanometer calcium carbonate) of phosphogypsum material and some existing problems. It puts forward some views on the challenges in this field and the direction of future development. It is hoped that the investigation and summary in this paper could supply some significant information for the impurity removal and high-value utilization of phosphogypsum material as a contribution to sustainability. Full article
Show Figures

Figure 1

9 pages, 3344 KiB  
Article
A Novel Sustainable Process for Multilayer Graphene Synthesis Using CO2 from Ambient Air
by Matthew Colson, Leandro Alvarez, Stephanie Michelle Soto, Sung Hee Joo, Kai Li, Andrew Lupini, Kashif Nawaz, Ignatius Fomunung, Mbakisya A. Onyango, Michael K. Danquah, Joseph Owino and Sungwoo Yang
Materials 2022, 15(17), 5894; https://doi.org/10.3390/ma15175894 - 26 Aug 2022
Cited by 1 | Viewed by 1788
Abstract
Graphene produced by different methods can present varying physicochemical properties and quality, resulting in a wide range of applications. The implementation of a novel method to synthesize graphene requires characterizations to determine the relevant physicochemical and functional properties for its tailored application. We [...] Read more.
Graphene produced by different methods can present varying physicochemical properties and quality, resulting in a wide range of applications. The implementation of a novel method to synthesize graphene requires characterizations to determine the relevant physicochemical and functional properties for its tailored application. We present a novel method for multilayer graphene synthesis using atmospheric carbon dioxide with characterization. Synthesis begins with carbon dioxide sequestered from air by monoethanolamine dissolution and released into an enclosed vessel. Magnesium is ignited in the presence of the concentrated carbon dioxide, resulting in the formation of graphene flakes. These flakes are separated and enhanced by washing with hydrochloric acid and exfoliation by ammonium sulfate, which is then cycled through a tumble blender and filtrated. Raman spectroscopic characterization, FTIR spectroscopic characterization, XPS spectroscopic characterization, SEM imaging, and TEM imaging indicated that the graphene has fifteen layers with some remnant oxygen-possessing and nitrogen-possessing functional groups. The multilayer graphene flake possessed particle sizes ranging from 2 µm to 80 µm in diameter. BET analysis measured the surface area of the multilayer graphene particles as 330 m2/g, and the pore size distribution indicated about 51% of the pores as having diameters from 0.8 nm to 5 nm. This study demonstrates a novel and scalable method to synthesize multilayer graphene using CO2 from ambient air at 1 g/kWh electricity, potentially allowing for multilayer graphene production by the ton. The approach creates opportunities to synthesize multilayer graphene particles with defined properties through a careful control of the synthesis parameters for tailored applications. Full article
Show Figures

Figure 1

19 pages, 4559 KiB  
Article
Comparison of Pyrene Biodegradation Using Two Types of Marine Bacterial Isolates
by Ismail Marzuki, Khairun Nisaa, Ruzkiah Asaf, Admi Athirah, Mudian Paena, Endang Susianingsih, Nurhidayah Nurhidayah, Ince Ayu Khairana Kadriah, Kamaruddin Kamaruddin, Sahabuddin Sahabuddin, Nurbaya Nurbaya, Early Septiningsih, Herlinah Herlinah, Erfan Andi Hendrajat, Suwardi Suwardi and Andi Ramlan
Sustainability 2022, 14(16), 9890; https://doi.org/10.3390/su14169890 - 10 Aug 2022
Cited by 4 | Viewed by 2021
Abstract
Polycyclic aromatic hydrocarbons (PAHs) contaminants have toxic, carcinogenic, and mutagenic properties. Screening bacteria from different sources capable of carrying out the biodegradation of (PAHs) is essential for mapping and mobilization purposes and applying them to polluted hydrocarbon environments. The study aims to compare [...] Read more.
Polycyclic aromatic hydrocarbons (PAHs) contaminants have toxic, carcinogenic, and mutagenic properties. Screening bacteria from different sources capable of carrying out the biodegradation of (PAHs) is essential for mapping and mobilization purposes and applying them to polluted hydrocarbon environments. The study aims to compare the capacity of PAH biodegradation by two types of bacteria isolated from different sources. The method applied is the interaction between bacterial suspension and pyrene-contaminated waste for 30 days. Biodegradation products in organic compounds were analyzed using gas chromatography/mass spectroscopy (GC/MS) and Fourier transform infrared spectroscopy (FTIR). The analysis results found several indications of the performance of bacterial biodegradation: The capacity of pyrene degradation by Bacillus licheniformis strain ATCC 9789 (Bl) bacteria against pyrene was relatively more dominant than Sphingobacterium sp. strain 21 (Sb) bacteria. The percentage of total bacterial biodegradation for product type Sb was (39.00%), and that of the product of bacterial degradation type Bl (38.29%). The biodegradation products of the test bacteria (Bl and Sb) were relatively similar to pyrene in the form of alcohol and carboxylic acid organic compounds. There was no significant difference in the pyrene biodegradation between Bl and Sb bacteria. Full article
Show Figures

Figure 1

15 pages, 3557 KiB  
Article
Aqueous-Based Synthesis of Photocatalytic Copper Sulfide Using Sulfur Waste as Sulfurizing Agent
by Gabriele Sarapajevaite, Davide Morselli and Kestutis Baltakys
Materials 2022, 15(15), 5253; https://doi.org/10.3390/ma15155253 - 29 Jul 2022
Cited by 1 | Viewed by 1512
Abstract
Most of the copper sulfide synthetic approaches developed until now are still facing issues in their procedure, such as long synthesis duration, high energetic consumption, and high implementation costs. This publication reports a facile and sustainable approach for synthesizing copper sulfides on a [...] Read more.
Most of the copper sulfide synthetic approaches developed until now are still facing issues in their procedure, such as long synthesis duration, high energetic consumption, and high implementation costs. This publication reports a facile and sustainable approach for synthesizing copper sulfides on a large scale. In particular, an industrial by-product of sulfur waste was used as a sulfurizing agent for copper sulfide synthesis in a water medium. The reaction was performed in the hydrothermal environment by following a novel proposed mechanism of copper sulfide formation. The investigation of morphological and optical properties revealed that the target products obtained by using waste possess the resembling properties as the ones synthesized from the most conventional sulfurizing agent. Since the determined band gap of synthesis products varied from 1.72 to 1.81 eV, the photocatalytic properties, triggered under visible light irradiation, were also investigated by degrading the methylene blue as a model pollutant. Importantly, the degradation efficiency of the copper sulfide synthesized from sulfur waste was equivalent to a sample obtained from a reference sulfurizing agent since the value for both samples was 96% in 180 min. This very simple synthetic approach opens up a new way for large-scale sustainable production of visible-light-driven photocatalysts for water purification from organic pollutants. Full article
Show Figures

Figure 1

14 pages, 3642 KiB  
Article
Fabrication and Characterization of Degradable Crop-Straw-Fiber Composite Film Using In Situ Polymerization with Melamine–Urea–Formaldehyde Prepolymer for Agricultural Film Mulching
by Qian Lang, Chuanhao Liu, Xiaoxin Zhu, Chao Zhang, Shengming Zhang, Longhai Li, Shuang Liu and Haitao Chen
Materials 2022, 15(15), 5170; https://doi.org/10.3390/ma15155170 - 26 Jul 2022
Cited by 2 | Viewed by 1532
Abstract
Soil mulch composite films composed of biodegradable materials are being increasingly used in agriculture. In this study, mulch films based on wheat straw fiber and an environmentally friendly modifier were prepared via in situ polymerization and tested as the ridge mulch for crops. [...] Read more.
Soil mulch composite films composed of biodegradable materials are being increasingly used in agriculture. In this study, mulch films based on wheat straw fiber and an environmentally friendly modifier were prepared via in situ polymerization and tested as the ridge mulch for crops. The mechanical properties of the straw fiber film were significantly enhanced by the modification. In particular, the films exhibited a noticeable increase in dry and wet tensile strength from 2.35 to 4.15 and 0.41 to 1.51 kN/m, respectively, with increasing filler content from 0% to 25%. The contact angle of the straw also showed an improvement based on its hydrophilicity. The crystallinity of the modified film was higher than that of the unmodified film and increased with modifier content. The changes in chemical interaction of the straw fiber film were determined by Fourier transform infrared spectroscopy, and the thermal stability of the unmodified film was improved by in situ polymerization. Scanning electron microscopy images indicated that the modifier was uniformly dispersed in the fiber film, resulting in an improvement in its mechanical properties. The modified straw fiber films could be degraded after mulching for approximately 50 days. Overall, the superior properties of the modified straw fiber film lend it great potential for agricultural application. Full article
Show Figures

Figure 1

18 pages, 4488 KiB  
Article
Adsorptive Removal of Naproxen from Water Using Polyhedral Oligomeric Silesquioxane (POSS) Covalent Organic Frameworks (COFs)
by Suleiman Bala, Che Azurahanim Che Abdullah, Mohamed Ibrahim Mohamed Tahir and Mohd Basyaruddin Abdul Rahman
Nanomaterials 2022, 12(14), 2491; https://doi.org/10.3390/nano12142491 - 20 Jul 2022
Cited by 9 | Viewed by 1812
Abstract
Covalent organic frameworks are porous crystalline compounds made up of organic material bonded together by strong reversible covalent bonds (these are novel types of materials which have the processability of extended or repeated structures with high performance, like those of thermosets and thermoplastics [...] Read more.
Covalent organic frameworks are porous crystalline compounds made up of organic material bonded together by strong reversible covalent bonds (these are novel types of materials which have the processability of extended or repeated structures with high performance, like those of thermosets and thermoplastics that produce high surface coverage). These have a long-term effect on an arrangement’s geometry and permeability. These compounds are entirely made up of light elements like H, B, C, N, O and Si. Pharmaceuticals and personal care products (PPCPs) have emerged as a new threatened species. A hazardous substance known as an “emerging toxin,” such as naproxen, is one that has been established or is generated in sufficient amounts in an environment, creating permanent damage to organisms. COF-S7, OAPS and 2-methylanthraquionone(2-MeAQ), and COF-S12, OAPS and terephthalaldehyde (TPA) were effectively synthesized by condensation (solvothermal) via a Schiff base reaction (R1R2C=NR′), with a molar ratio of 1:8 for OAPS to linker (L1 and L2), at a temperature of 125 °C and 100 °C for COF-S7 and COF-S12, respectively. The compounds obtained were assessed using several spectroscopy techniques, which revealed azomethine C=N bonds, aromatic carbon environments via solid 13C and 29Si NMR, the morphological structure and porosity, and the thermostability of these materials. The remedied effluent was investigated, and a substantial execution was noted in the removal ability of the naproxen over synthesized materials, such as 70% and 86% at a contact time of 210 min and 270 min, respectively, at a constant dose of 0.05 g and pH 7. The maximum adsorption abilities of the substances were found to be 35 mg/g and 42 mg/g. The pH result implies that there is stable exclusion with a rise in pH to 9. At pH 9, the drop significance was attained for COF-S7 with the exception of COF-S12, which was detected at pH 11, due to the negative Foster charge, consequent to the repulsion among the synthesized COFs and naproxen solution. From the isotherms acquired (Langmuir and Freundlich), the substances displayed a higher value (close to 1) of correlation coefficient (R2), which showed that the substances fit into the Freundlich isotherm (heterogenous process), and the value of heterogeneity process (n) achieved (less than 1) specifies that the adsorption is a chemical process. Analysis of the as-prepared composites revealed remarkable reusability in the elimination of naproxen by adsorption. Due to its convenience of synthesis, significant adsorption effectiveness, and remarkable reusability, the as-synthesized COFs are expected to be able to be used as potential adsorbents for eliminating AIDs from water. Full article
Show Figures

Graphical abstract

12 pages, 4834 KiB  
Article
Facile Synthesis of Multi-Emission Nitrogen/Boron Co-Doped Carbon Dots from Lignin for Anti-Counterfeiting Printing
by Xuexin Gu, Lingli Zhu, Dekui Shen and Chong Li
Polymers 2022, 14(14), 2779; https://doi.org/10.3390/polym14142779 - 07 Jul 2022
Cited by 12 | Viewed by 2236
Abstract
The transformation of lignin with natural aromatic structure into value-added carbon dots (CDs) achieves a win-win situation for low-cost production of novel nanomaterials and reasonable disposal of biomass waste. However, it remains challenging to produce multi-emission CDs from biomass for advanced applications. Herein, [...] Read more.
The transformation of lignin with natural aromatic structure into value-added carbon dots (CDs) achieves a win-win situation for low-cost production of novel nanomaterials and reasonable disposal of biomass waste. However, it remains challenging to produce multi-emission CDs from biomass for advanced applications. Herein, a green and facile approach to preparing multi-emission CDs from alkali lignin via N and B co-doping is developed. The obtained N and B co-doped CDs (NB-CDs) show multi-emission fluorescence centers at 346, 428 and 514 nm under different excitations. As the doping amount of N and B increases, the fluorescence emission band gradually shifts to 428 and 514 nm, while that at 346 nm decreases. The fluorescence mechanism is explored through the research of the structure, composition and optical performance of NB-CDs in combination with density functional theory (DFT) calculations. It demonstrates that the effect of doping with B-containing functional groups on the fluorescence emission behavior is multivariate, which may be the crucial contribution to the unique multi-emission fluorescence of CDs. The multi-emission NB-CDs with prominent stability are applied for multilevel anti-counterfeiting printing. It provides a promising direction for the sustainable and advanced application of biomass-derived CDs, and the theoretical results highlight a new insight into the deep understanding of the multi-emission fluorescence mechanism. Full article
Show Figures

Figure 1

13 pages, 2889 KiB  
Article
One-Pot Synthesis of LiFePO4/N-Doped C Composite Cathodes for Li-ion Batteries
by Baoquan Zhang, Shuzhong Wang, Lu Liu, Yanhui Li and Jianqiao Yang
Materials 2022, 15(14), 4738; https://doi.org/10.3390/ma15144738 - 06 Jul 2022
Cited by 6 | Viewed by 2179
Abstract
LiFePO4/N-doped C composites with core–shell structures were synthesized by a convenient solvothermal method. Cetyltrimethylammonium bromide (CTAB) and glucose were used as nitrogen and carbon sources, respectively. The growth of LiFePO4 nanocrystals was regulated by CTAB, resulting in an average particle [...] Read more.
LiFePO4/N-doped C composites with core–shell structures were synthesized by a convenient solvothermal method. Cetyltrimethylammonium bromide (CTAB) and glucose were used as nitrogen and carbon sources, respectively. The growth of LiFePO4 nanocrystals was regulated by CTAB, resulting in an average particle size of 143 nm for the LiFePO4/N-doped C. The N atoms existed in the carbon of LiFePO4/N-doped C in the form of pyridinic N and graphitic N. The LiFePO4/N-doped C composites delivered discharge specific capacities of 160.7 mAh·g−1 (0.1 C), 128.4 mAh·g−1 (5 C), and 115.8 mAh·g−1 (10 C). Meanwhile, no capacity attenuation was found after 100 electrochemical cycles at 1 C. N-doping enhanced the capacity performance of the LiFePO4/C cathode, while the core–shell structure enhanced the cycle performance of the cathode. The electrochemical test data showed a synergistic effect between N-doping and core–shell structure on the enhancement of the electrochemical performance of the LiFePO4/C cathode. Full article
Show Figures

Graphical abstract

20 pages, 18198 KiB  
Article
Degradation of 4-Tert-Butylphenol in Water Using Mono-Doped (M1: Mo, W) and Co-Doped (M2-M1: Cu, Co, Zn) Titania Catalysts
by Saule Mergenbayeva, Alisher Kumarov, Timur Sh. Atabaev, Evroula Hapeshi, John Vakros, Dionissios Mantzavinos and Stavros G. Poulopoulos
Nanomaterials 2022, 12(14), 2326; https://doi.org/10.3390/nano12142326 - 06 Jul 2022
Cited by 10 | Viewed by 2029
Abstract
Mono-doped (Mo-TiO2 and W-TiO2) and co-doped TiO2 (Co-Mo-TiO2, Co-W-TiO2, Cu-Mo-TiO2, Cu-W-TiO2, Zn-Mo-TiO2, and Zn-W-TiO2) catalysts were synthesized by simple impregnation methods and tested for the photocatalytic degradation [...] Read more.
Mono-doped (Mo-TiO2 and W-TiO2) and co-doped TiO2 (Co-Mo-TiO2, Co-W-TiO2, Cu-Mo-TiO2, Cu-W-TiO2, Zn-Mo-TiO2, and Zn-W-TiO2) catalysts were synthesized by simple impregnation methods and tested for the photocatalytic degradation of 4-tert-butylphenol in water under UV (365 nm) light irradiation. The catalysts were characterized with various analytical methods. X-ray diffraction (XRD), Raman, Diffuse reflectance (DR) spectroscopies, Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), and Energy dispersive spectroscopy (EDS) were applied to investigate the structure, optical properties, morphology, and elemental composition of the prepared catalysts. The XRD patterns revealed the presence of peaks corresponding to the WO3 in W-TiO2, Co-W-TiO2, Cu-W-TiO2, and Zn-W-TiO2. The co-doping of Cu and Mo to the TiO2 lattice was evidenced by the shift of XRD planes towards higher 2θ values, confirming the lattice distortion. Elemental mapping images confirmed the successful impregnation and uniform distribution of metal particles on the TiO2 surface. Compared to undoped TiO2, Mo-TiO2 and W-TiO2 exhibited a lower energy gap. Further incorporation of Mo-TiO2 with Co or Cu introduced slight changes in energy gap and light absorption characteristics, particularly visible light absorption. In addition, photoluminescence (PL) showed that Cu-Mo-TiO2 has a weaker PL intensity than undoped TiO2. Thus, Cu-Mo-TiO2 showed better catalytic activity than pure TiO2, achieving complete degradation of 4-tert-butylphenol under UV light irradiation after 60 min. The application of Cu-Mo-TiO2 under solar light conditions was also tested, and 70% of 4-tert-butylphenol degradation was achieved within 150 min. Full article
Show Figures

Figure 1

23 pages, 1694 KiB  
Review
Anti-Wear and Anti-Erosive Properties of Polymers and Their Hybrid Composites: A Critical Review of Findings and Needs
by Zaib Un Nisa, Lee Kean Chuan, Beh Hoe Guan, Saba Ayub and Faiz Ahmad
Nanomaterials 2022, 12(13), 2194; https://doi.org/10.3390/nano12132194 - 26 Jun 2022
Cited by 10 | Viewed by 2028
Abstract
Erosion caused by the repeated impact of particles on the surface of a substance is a common wear method resulting in the gradual and continual loss of affected objects. It is a crucial problem in several modern industries because the surfaces of various [...] Read more.
Erosion caused by the repeated impact of particles on the surface of a substance is a common wear method resulting in the gradual and continual loss of affected objects. It is a crucial problem in several modern industries because the surfaces of various products and materials are frequently subjected to destructively erosive situations. Polymers and their hybrid materials are suitable, in powdered form, for use as coatings in several different applications. This review paper aims to provide extensive information on the erosion behaviors of thermoset and thermoplastic neat resin and their hybrid material composites. Specific attention is paid to the influence of the properties of selected materials and to impingement parameters such as the incident angle of the erodent, the impact velocity of the erodent, the nature of the erodent, and the erosion mechanism. The review further extends the information available about the erosion techniques and numerical simulation methods used for wear studies of surfaces. An investigation was carried out to allow researchers to explore the available selection of materials and methods in terms of the conditions and parameters necessary to meet current and future needs and challenges, in technologically advanced industries, relating to the protection of surfaces. During the review, which was conducted on the findings in the literature of the past fifty years, it was noted that the thermoplastic nature of composites is a key component in determining their anti-wear properties; moreover, composites with lower glass transition, higher ductility, and greater crystallinity provide better protection against erosion in advanced surface applications. Full article
Show Figures

Graphical abstract

15 pages, 2743 KiB  
Article
The Removal of a Textile Dye from an Aqueous Solution Using a Biocomposite Adsorbent
by Hana Ferkous, Karima Rouibah, Nour-El-Houda Hammoudi, Manawwer Alam, Chahrazed Djilani, Amel Delimi, Omar Laraba, Krishna Kumar Yadav, Hyun-Jo Ahn, Byong-Hun Jeon and Yacine Benguerba
Polymers 2022, 14(12), 2396; https://doi.org/10.3390/polym14122396 - 13 Jun 2022
Cited by 17 | Viewed by 2137
Abstract
The adsorption mechanisms of methylene blue (MB) onto olive waste (residue) treated with KOH (OR-KOH) and onto an OR-KOH and PEG–silica gel composite (OR-KOH/PEG-SG) at various temperatures were investigated using a combination of experimental analysis and Monte Carlo ab-initio simulations. The effects of [...] Read more.
The adsorption mechanisms of methylene blue (MB) onto olive waste (residue) treated with KOH (OR-KOH) and onto an OR-KOH and PEG–silica gel composite (OR-KOH/PEG-SG) at various temperatures were investigated using a combination of experimental analysis and Monte Carlo ab-initio simulations. The effects of adsorption process variables such as pH, temperature, and starting adsorbate concentration were investigated. The experimental data were fitted to Langmuir and Freundlich models. The maximum adsorption capacities of MB onto OR-KOH and OR-KOH/PEG-SG adsorbents reached values of 504.9 mg/g and 161.44 mg/g, respectively. The experimental FT-IR spectra indicated that electrostatic attraction and hydrogen bond formation were critical for MB adsorption onto the adsorbents generated from olive waste. The energetic analyses performed using Monte Carlo atomistic simulations explained the experimental results of a differential affinity for the investigated adsorbents and confirmed the nature of the interactions between methylene blue and the adsorbents to be van der Waals electrostatic forces. Full article
Show Figures

Figure 1

22 pages, 6337 KiB  
Article
Synthesis and Characterization of Green ZnO@polynaniline/Bentonite Tripartite Structure (G.Zn@PN/BE) as Adsorbent for As (V) Ions: Integration, Steric, and Energetic Properties
by Mohamed Abdel Salam, Mohamed Mokhtar, Soha M. Albukhari, Doaa F. Baamer, Leonardo Palmisano, Mariusz Jaremko and Mostafa R. Abukhadra
Polymers 2022, 14(12), 2329; https://doi.org/10.3390/polym14122329 - 09 Jun 2022
Cited by 36 | Viewed by 2431
Abstract
A green ZnO@polynaniline/bentonite composite (G.Zn@PN/BE) was synthesized as an enhanced adsorbent for As (V) ions. Its adsorption properties were assessed in comparison with the integrated components of bentonite (BE) and polyaniline/bentonite (PN/BE) composites. The G.Zn@PN/BE composite achieved an As (V) retention capacity (213 [...] Read more.
A green ZnO@polynaniline/bentonite composite (G.Zn@PN/BE) was synthesized as an enhanced adsorbent for As (V) ions. Its adsorption properties were assessed in comparison with the integrated components of bentonite (BE) and polyaniline/bentonite (PN/BE) composites. The G.Zn@PN/BE composite achieved an As (V) retention capacity (213 mg/g) higher than BE (72.7 mg/g) and PN/BE (119.8 mg/g). The enhanced capacity of G.Zn@PN/BE was studied using classic (Langmuir) and advanced equilibrium (monolayer model of one energy) models. Considering the steric properties, the structure of G.Zn@PN/BE demonstrated a higher density of active sites (Nm = 109.8 (20 °C), 108.9 (30 °C), and 67.8 mg/g (40 °C)) than BE and PN/BE. This declared the effect of the integration process in inducing the retention capacity by increasing the quantities of the active sites. The number of adsorbed As (V) ions per site (1.76 up to 2.13) signifies the retention of two or three ions per site by a multi-ionic mechanism. The adsorption energies (from −3.07 to −3.26 kJ/mol) suggested physical retention mechanisms (hydrogen bonding and dipole bonding forces). The adsorption energy, internal energy, and free enthalpy reflected the exothermic, feasible, and spontaneous nature of the retention process. The structure is of significant As (V) uptake capacity in the existence of competitive anions or metal ions. Full article
Show Figures

Graphical abstract

13 pages, 5948 KiB  
Article
Influence of Freeze–Thaw Cycles on Physical and Mechanical Properties of Cement-Treated Silty Sand
by Nazerke Sagidullina, Shynggys Abdialim, Jong Kim, Alfrendo Satyanaga and Sung-Woo Moon
Sustainability 2022, 14(12), 7000; https://doi.org/10.3390/su14127000 - 08 Jun 2022
Cited by 11 | Viewed by 1557
Abstract
The problem of weak ground conditions is currently of great interest, as with the rapid development of infrastructure, researchers are trying to cope with the improvement of problematic soil properties to build structures on it. In cold regions, the problem of weak soils [...] Read more.
The problem of weak ground conditions is currently of great interest, as with the rapid development of infrastructure, researchers are trying to cope with the improvement of problematic soil properties to build structures on it. In cold regions, the problem of weak soils is further exacerbated by freeze–thaw cycling. For the improvement of soil properties, the soil stabilization method using ordinary Portland Cement (OPC) is commonly applied, but it produces a significant amount of carbon dioxide emissions. Therefore, the purpose of this research study is to present laboratory testing results for the evaluation of soil treatment using Calcium Sulfoaluminate (CSA) cement that has a lesser carbon footprint. On stabilized soil specimens cured for 3, 7, and 14 days and subjected to freeze–thaw cycles, unconfined compressive strength (UCS) and ultrasonic pulse velocity (UPV) testing were performed. Samples were prepared at optimum moisture content using different cement content, 3%, 5%, and 7%. Applying the results from the UCS test, the strength loss/gain and resilient modulus of treated soil were obtained. The test results show that the strength and pulse velocity values decreased with the increase of freeze–thaw cycles. However, improvement in soil performance can be observed with the increase in cement content. Overall, the use of CSA as a stabilizer for silty sand would be useful to achieve sufficient strength of subgrade. Full article
Show Figures

Figure 1

10 pages, 2578 KiB  
Article
Synthesis of Superhydrophobic Cellulose Stearoyl Ester for Oil/Water Separation
by Qian Yang, Weiyin Su, Jianquan Hu, Yan Xu, Zhong Liu and Lanfeng Hui
Nanomaterials 2022, 12(12), 1964; https://doi.org/10.3390/nano12121964 - 08 Jun 2022
Cited by 7 | Viewed by 1842
Abstract
Developing fluorine-free superhydrophobic and biodegradable materials for oil/water separation has already become an irresistible trend. In this paper, we designed two biopolymer oil/water separation routes based on cellulose stearoyl ester (CSE), which was obtained via the acylation reaction between dissolving pulp and stearoyl [...] Read more.
Developing fluorine-free superhydrophobic and biodegradable materials for oil/water separation has already become an irresistible trend. In this paper, we designed two biopolymer oil/water separation routes based on cellulose stearoyl ester (CSE), which was obtained via the acylation reaction between dissolving pulp and stearoyl chloride homogeneously. The CSE showed a superhydrophobic property, which could selectively adsorb oil from the oil/water mixture. Additionally, the CSE was emulsified with an oxidized starch (OS) solution, and the resulting latex was used to impregnate commercial, filter base paper, finally obtaining a hydrophobic and oleophilic membrane. The SEM revealed the membrane had hierarchical micro/nanostructures, while the water contact angle indicated the low surface energy of the membrane, all of which were attributed to the CSE. The membrane had high strength and long durability due to the addition of OS/CSE, and the separation efficiency was more than 99% even after ten repeated uses. Full article
Show Figures

Graphical abstract

17 pages, 4736 KiB  
Article
An Experimental Investigation on the Thermo-Rheological Behaviors of Lactic Acid-Based Natural Deep Eutectic Solvents
by Yousef Elhamarnah, Mashael AlRasheedi, Wadha AlMarri, Asma AlBadr, Alanoud AlMalki, Nora Mohamed, Izzah Fatima, Mustafa Nasser and Hazim Qiblawey
Materials 2022, 15(11), 4027; https://doi.org/10.3390/ma15114027 - 06 Jun 2022
Cited by 3 | Viewed by 1965
Abstract
The rheological studies of Lactic Acid (LA)-based Natural Deep Eutectic Solvents (NADES) are provided in the present investigation. Those mechanisms were also studied in which three distinct Hydrogen Bond Acceptors (HBAs) of Choline Chloride (ChCl), Betaine (Be), and β-Alanine (β-Al), after being added [...] Read more.
The rheological studies of Lactic Acid (LA)-based Natural Deep Eutectic Solvents (NADES) are provided in the present investigation. Those mechanisms were also studied in which three distinct Hydrogen Bond Acceptors (HBAs) of Choline Chloride (ChCl), Betaine (Be), and β-Alanine (β-Al), after being added to a specific Hydrogen Bond Donor (HBD) at a predefined mole-to-mole ratio of 1:1, affected the rheological properties of the prepared NADES. The alterations in the rheology-related characteristics in association with the mechanical and physical properties indicate the tolerance of the material under various operational conditions in the field and show their potential utilization as environmentally suitable and feasible solvents for industrial applications. In the present research, the viscoelastic properties of the three samples of NADES were assessed along with their shear flow properties. The backward and forward temperature change in the Apparent Viscosity (AV) pattern related to the NADES system was described by a rheogram. Furthermore, the density was determined and compared with the AV while considering the temperature-related factor. On a further note, the viscoelastic characteristics were utilized in describing and investigating the network disturbance on the level of the microstructure of NADES upon frequency sweep. A series of experiments were carried out using Thermogravimetry Analysis (TGA) to investigate the thermo-physical properties to optimize them. The rheological properties of shear flow measurements were analyzed using the Bingham model that is best suited for the AV developed with the shear rate with the dynamic yield stress of three systems. The Bingham model was used to determine the lowest stress necessary to disturb the network structure and commence the flow of LA-based NADES. Overall, the viscoelastic behavior of the LA-based NADES revealed the dissimilarity between their strength and viscosity. In addition, shear flow investigations demonstrated that LA-based NADES systems exhibit non-Newtonian properties and substantial shear-thinning effects equivalent to those of alternative IL sorbents. Assessing the rheological properties of LA-based NADES is crucial for a better understanding the key challenges associated with high viscosity. Defining the transport yield stress requirements for NADES systems under different conditions benefits their future development and potentially opens the door to more challenging applications. Full article
Show Figures

Figure 1

11 pages, 6602 KiB  
Article
Biosynthesis of Platinum Nanoparticles with Cordyceps Flower Extract: Characterization, Antioxidant Activity and Antibacterial Activity
by Ling Liu, Yun Jing, Ailing Guo, Xiaojing Li, Qun Li, Wukang Liu and Xinshuai Zhang
Nanomaterials 2022, 12(11), 1904; https://doi.org/10.3390/nano12111904 - 02 Jun 2022
Cited by 9 | Viewed by 1851
Abstract
The aim of this work is to develop a green route for platinum nanoparticles (PtNPs) biosynthesized using Cordyceps flower extract and to evaluate their antioxidant activity and antibacterial activity. Different characterization techniques were utilized to characterize the biosynthetic PtNPs. The results showed that [...] Read more.
The aim of this work is to develop a green route for platinum nanoparticles (PtNPs) biosynthesized using Cordyceps flower extract and to evaluate their antioxidant activity and antibacterial activity. Different characterization techniques were utilized to characterize the biosynthetic PtNPs. The results showed that PtNPs were spherical particles covered with Cordyceps flower extract. The average particle size of PtNPs in Dynamic Light Scattering was 84.67 ± 5.28 nm, while that of PtNPs in Transmission Electron Microscope was 13.34 ± 4.06 nm. Antioxidant activity of PtNPs was evaluated by DPPH free radical scavenging ability test. The results showed that the antioxidant activity was positively correlated with the concentration of PtNPs, the DPPH scavenging efficiency of PtNPs (0.50–125.00 μg/mL) was 27.77–44.00%. In addition, the morphological changes of four kinds of bacteria (Escherichia coli, Salmonella typhimurium, Bacillus subtilis, Staphylococcus aureus) exposed to PtNPs were observed by scanning electron microscope. The results showed that the antibacterial activity of PtNPs against Gram-negative bacteria was stronger than that of Gram-positive bacteria. Full article
Show Figures

Figure 1

10 pages, 1929 KiB  
Article
Synthesis and Characterization of Nanostructured Multi-Layer Cr/SnO2/NiO/Cr Coatings Prepared via E-Beam Evaporation Technique for Metal-Insulator-Insulator-Metal Diodes
by Sana Abrar, Muhammad Bilal Hanif, Abdulaziz Salem Alghamdi, Abdul Khaliq, K. S. Abdel Halim, Tayyab Subhani, Martin Motola and Abdul Faheem Khan
Materials 2022, 15(11), 3906; https://doi.org/10.3390/ma15113906 - 31 May 2022
Cited by 3 | Viewed by 1938
Abstract
Enhanced non-linearity and asymmetric behavior of the Cr/metal oxide diode is reported, with the addition of two insulator layers of SnO2 and NiO to form the metal-insulator-insulator-metal (MIIM) configuration. Such an MIIM diode shows potential for various applications (rectifiers and electronic equipment) [...] Read more.
Enhanced non-linearity and asymmetric behavior of the Cr/metal oxide diode is reported, with the addition of two insulator layers of SnO2 and NiO to form the metal-insulator-insulator-metal (MIIM) configuration. Such an MIIM diode shows potential for various applications (rectifiers and electronic equipment) which enable the femtosecond fast intoxication in MIIM diodes. In this work, nanostructured multi-layer Cr/SnO2/NiO/Cr coatings were fabricated via e-beam evaporation with the following thicknesses: 150 nm/20 nm/10 nm/150 nm. Coatings were characterized via Rutherford backscattering (RBS), scanning electron microscopy (SEM), and two-probe conductivity testing. RBS confirmed the layered structure and optimal stoichiometry of the coatings. A non-linear and asymmetric behavior at <1.5 V applied bias with the non-linearity maximum of 2.6 V−1 and the maximum sensitivity of 9.0 V−1 at the DC bias point was observed. The promising performance of the coating is due to two insulating layers which enables resonant tunneling and/or step-tunneling. Based on the properties, the present multi-layer coatings can be employed for MIIM application. Full article
Show Figures

Figure 1

18 pages, 6870 KiB  
Article
Effects of Electrolytes on the Electrochemical Impedance Properties of NiPcMWCNTs-Modified Glassy Carbon Electrode
by Sheriff A. Balogun and Omolola E. Fayemi
Nanomaterials 2022, 12(11), 1876; https://doi.org/10.3390/nano12111876 - 30 May 2022
Cited by 8 | Viewed by 2189
Abstract
The supercapacitive properties of synthesized nickel phthalocyanine multiwalled carbon nanotubes nanocomposite on a glassy carbon electrode (NiPcMWCNTs-GCE) in four different electrolytes were investigated. The successful synthesis of the NiPcMWCNTs nanocomposite was confirmed by UV/vis electrode spectroscopy, SEM, TEM, EDX, and XRD techniques. The [...] Read more.
The supercapacitive properties of synthesized nickel phthalocyanine multiwalled carbon nanotubes nanocomposite on a glassy carbon electrode (NiPcMWCNTs-GCE) in four different electrolytes were investigated. The successful synthesis of the NiPcMWCNTs nanocomposite was confirmed by UV/vis electrode spectroscopy, SEM, TEM, EDX, and XRD techniques. The supercapacitive behaviors of the modified electrodes were examined in PBS, H2SO4, Na2SO4, and SAB electrolytes via CV and EIS techniques. The highest specific capacitance of 6.80 F g−1 was achieved for the GCE-NiPcMWCNTs electrode in 5 mM [Fe(CN)6]4−/3− prepared in 0.1 M PBS (pH 7). Charge transfer resistance Rct values of 0.06, 0.36, 0.61, and 1.98 kΩ were obtained for the GCE-NiPcMWCNTs in H2SO4, SAB, Na2SO4, and PBS electrolytes, respectively. Power density values, otherwise known as the “knee” frequency f°, of 21.2, 6.87, 2.22, and 1.68 Hz were also obtained for GCE-NiPcMWCNTs in H2SO4, Na2SO4, PBS, and SAB electrolytes, respectively. GCE-NiPcMWCNTs demonstrated the fastest electron transport capability and the highest power density in H2SO4 compared to the other electrolytes. Hence, GCE-NiPcMWCNTs-modified electrodes had high stability, high energy and power densities, and a large specific capacitance. Full article
Show Figures

Figure 1

13 pages, 3514 KiB  
Article
High Anti-Reflection Large-Scale Cup-Shaped Nano-Pillar Arrays via Thin Film Anodic Aluminum Oxide Replication
by Tangyou Sun, Furong Shui, Xiancui Yang, Zhiping Zhou, Rongqiao Wan, Yun Liu, Cheng Qian, Zhimou Xu, Haiou Li and Wenjing Guo
Nanomaterials 2022, 12(11), 1875; https://doi.org/10.3390/nano12111875 - 30 May 2022
Cited by 5 | Viewed by 1810
Abstract
Surface anti-reflection (AR) with nanometer-scaled texture has shown excellent light trapping performance involving optical devices. In this work, we developed a simple and lithography-free structure replication process to obtain large scale surface cup-shaped nano-pillar (CSNP) arrays for the first time. A method of [...] Read more.
Surface anti-reflection (AR) with nanometer-scaled texture has shown excellent light trapping performance involving optical devices. In this work, we developed a simple and lithography-free structure replication process to obtain large scale surface cup-shaped nano-pillar (CSNP) arrays for the first time. A method of depositing was used for pattern transfer based on PMMA pre-coated through-hole anodic aluminum oxide (AAO) thin film (~500 nm), and eventually, the uniformity of the transferred nanostructures was guaranteed. From the spectrum (250 nm~2000 nm) dependent measurements, the CSNP nanostructured Si showed excellent AR performance when compared with that of the single-polished Si. Moreover, the CSNP was found to be polarization insensitive and less dependent on incidence angles (≤80°) over the whole spectrum. To further prove the excellent antireflective properties of the CSNP structure, thin film solar cell models were built and studied. The maximum value of Jph for CSNP solar cells shows obvious improvement comparing with that of the cylinder, cone and parabola structured ones. Specifically, in comparison with the optimized Si3N4 thin film solar cell, an increment of 54.64% has been achieved for the CSNP thin film solar cell. Full article
Show Figures

Figure 1

20 pages, 40788 KiB  
Article
Synthesis, Characterization and Properties of Soybean Oil-Based Polyurethane
by Qi Xu, Jianwei Lin and Guichang Jiang
Polymers 2022, 14(11), 2201; https://doi.org/10.3390/polym14112201 - 28 May 2022
Cited by 10 | Viewed by 3171
Abstract
At present, the consumption of polyurethane is huge in various industries. As a result, it has become a research hotspot to use environmentally friendly and renewable bio-based raw materials (instead of petroleum-based raw materials) to prepare polyurethane. In this paper, epoxy soybean oil [...] Read more.
At present, the consumption of polyurethane is huge in various industries. As a result, it has become a research hotspot to use environmentally friendly and renewable bio-based raw materials (instead of petroleum-based raw materials) to prepare polyurethane. In this paper, epoxy soybean oil (ESO) was used as raw material, and polyethylene glycol (PEG-600) was used for ring opening. Fourier transform infrared (FT-IR) and proton nuclear magnetic resonance (1H NMR) analysis proved that soybean oil-based polyester polyols was prepared. Soybean oil-based polyurethane (SPU) was synthesized by the reaction of the soybean oil-based polyol with isophorone diisocyanate (IPDI), so as to save energy and protect the environment. The properties of SPU films were adjusted by changing the R value (the molar ration of -NCO/-OH) and the film forming temperature. The chemical structure and properties of the SPU were characterized by FTIR, 1H NMR, gel permeation chromatography (GPC), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The results show that the mechanical strength, water contact angle, microphase separation degree, barrier property, and thermal stability of SPU films gradually increase, while the transparency, oxygen permeability coefficient and moisture permeability coefficient of SPU films gradually decrease with the increase of R value and film forming temperature. Full article
(This article belongs to the Topic Synthesis, Characterization and Performance of Materials for a Sustainable Future)
(This article belongs to the Section Polymer Chemistry)
Show Figures

Graphical abstract

13 pages, 2630 KiB  
Review
Lime Mortar, a Boon to the Environment: Characterization Case Study and Overview
by Abirami Manoharan and C. Umarani
Sustainability 2022, 14(11), 6481; https://doi.org/10.3390/su14116481 - 25 May 2022
Cited by 8 | Viewed by 2659
Abstract
Lime is an ancient construction material that has been utilized throughout the world in various forms, providing stable construction methods in usable conditions. Lime mortar is well known for its low carbon footprint in production and carbon absorption throughout its lifespan as a [...] Read more.
Lime is an ancient construction material that has been utilized throughout the world in various forms, providing stable construction methods in usable conditions. Lime mortar is well known for its low carbon footprint in production and carbon absorption throughout its lifespan as a hardened material. The significant benefits of lime mortar were analyzed and reviewed for further research. Ancient lime constructions need proper maintenance for aesthetic and structural strengthening to preserve this cultural architecture of national pride. Hence, the characterization of ancient mortars is mandatory for renovation work. Here, we studied the various characterization methods available worldwide. We analyzed samples taken from the 1900-year-old Vedapureeswarar Temple of Thiruvothur, Cheyyar, and the 1800-year-old Lakshmi Narasimhar Temple of Parikkal, located in Tamil Nadu. Hardened samples from these two ancient temples were collected and analyzed. The mineralogical characterization of these mortars using SEM, XRF, FTIR and XRD gave immense knowledge of the mortar matrix. Experimental analysis indicated that using natural organic materials in the lime has made the structures more potent and stable. The characterization study provided information on the ratio of mortar mix used, the presence of organic ingredients, and the need for compatible repair materials for proper maintenance of the temple structures. The characterization study furthers the necessary knowledge to provide a compatible repair material and indicates the need for ancient construction technology in the current highly polluted environment. Full article
Show Figures

Figure 1

16 pages, 3737 KiB  
Article
Dendrobium officinale Enzyme Changing the Structure and Behaviors of Chitosan/γ-poly(glutamic acid) Hydrogel for Potential Skin Care
by Mengmeng Wang, Erwei Zhang, Chenrui Yu, Dandan Liu, Shiguang Zhao, Maodong Xu, Xiaofeng Zhao, Wenjin Yue and Guangjun Nie
Polymers 2022, 14(10), 2070; https://doi.org/10.3390/polym14102070 - 19 May 2022
Cited by 5 | Viewed by 1846
Abstract
Hydrogels have been widespreadly used in various fields. But weak toughness has limited their further applications. In this study, Dendrobium officinale enzyme (DOE) was explored to improve chitosan/γ-poly(glutamic acid) (CS/γ-PGA) hydrogel in the structure and properties. The results indicated that DOE with various [...] Read more.
Hydrogels have been widespreadly used in various fields. But weak toughness has limited their further applications. In this study, Dendrobium officinale enzyme (DOE) was explored to improve chitosan/γ-poly(glutamic acid) (CS/γ-PGA) hydrogel in the structure and properties. The results indicated that DOE with various sizes of ingredients can make multiple noncovalent crosslinks with the skeleton network of CS/γ-PGA, significantly changing the self-assembly of CS/γ-PGA/DOE hydrogel to form regular protuberance nanostructures, which exhibits stronger toughness and better behaviors for skin care. Particularly, 4% DOE enhanced the toughness of CS/γ-PGA/DOE hydrogel, increasing it by 116%. Meanwhile, water absorption, antioxygenation, antibacterial behavior and air permeability were increased by 39%, 97%, 27% and 52%. Full article
Show Figures

Graphical abstract

14 pages, 51851 KiB  
Article
Thermal Radiation Shielding and Mechanical Strengthening of Mullite Fiber/SiC Nanowire Aerogels Using In Situ Synthesized SiC Nanowires
by Hui Xu, Xiaolei Li, Zongwei Tong, Baojie Zhang and Huiming Ji
Materials 2022, 15(10), 3522; https://doi.org/10.3390/ma15103522 - 13 May 2022
Cited by 5 | Viewed by 2202
Abstract
Traditional solid nanoparticle aerogels have been unable to meet the requirements of practical application due to their inherent brittleness and poor infrared shielding performance. Herein, combining vacuum impregnation and high-temperature pyrolysis, a novel micro/nano-composite fibrous aerogel was prepared via in situ synthesis of [...] Read more.
Traditional solid nanoparticle aerogels have been unable to meet the requirements of practical application due to their inherent brittleness and poor infrared shielding performance. Herein, combining vacuum impregnation and high-temperature pyrolysis, a novel micro/nano-composite fibrous aerogel was prepared via in situ synthesis of silicon carbide nanowires (SiC NWS) in mullite fiber (MF) preform. During this process, uniformly distributed SiC NWS in the MF preform serve as an enhancement phase and also act as an infrared shielding agent to reduce radiation heat transfer, which can significantly improve the mechanical properties of the mullite fiber/silicon carbide nanowire composite aerogels (MF/SiC NWS). The fabricated MF/SiC NWS exhibited excellent thermal stability (1400 °C), high compressive strength (~0.47 MPa), and outstanding infrared shielding performance (infrared transmittance reduced by ~70%). These superior properties make them appealing for their potential in practical application as high-temperature thermal insulators. Full article
Show Figures

Figure 1

11 pages, 2199 KiB  
Article
Facile Construction and Fabrication of a Superhydrophobic and Super Oleophilic Stainless Steel Mesh for Separation of Water and Oil
by Yinyu Sun, Zhongcheng Ke, Caiyun Shen, Qing Wei, Ruikang Sun, Wei Yang and Zihan Yin
Nanomaterials 2022, 12(10), 1661; https://doi.org/10.3390/nano12101661 - 13 May 2022
Cited by 2 | Viewed by 1735
Abstract
The fluoride-free fabrication of superhydrophobic materials for the separation of oil/water mixtures has received widespread attention because of frequent offshore oil exploration and chemical leakage. In recent years, oil/water separation materials, based on metal meshes, have drawn much attention, with significant advantages in [...] Read more.
The fluoride-free fabrication of superhydrophobic materials for the separation of oil/water mixtures has received widespread attention because of frequent offshore oil exploration and chemical leakage. In recent years, oil/water separation materials, based on metal meshes, have drawn much attention, with significant advantages in terms of their high mechanical strength, easy availability, and long durability. However, it is still challenging to prepare superhydrophobic metal meshes with high-separation capacity, low costs, and high recyclability for dealing with oil–water separation. In this work, a superhydrophobic and super oleophilic stainless steel mesh (SSM) was successfully prepared by anchoring Fe2O3 nanoclusters (Fe2O3-NCs) on SSM via the in-situ flame synthesis method and followed by further modification with octadecyltrimethoxysilane (OTS). The as-prepared SSM with Fe2O3-NCs and OTS (OTS@Fe2O3-NCs@SSM) was confirmed by a field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), energy dispersive spectrometer (EDS), X-ray photoelectron spectrometer (XPS), and X-ray diffractometer (XRD). The oil–water separation capacity of the sample was also measured. The results show that the interlaced and dense Fe2O3-NCs, composed of Fe2O3 nanoparticles, were uniformly coated on the surface of the SSM after the immerging-burning process. Additionally, a compact self-assembled OTS layer with low surface energy is coated on the surface of Fe2O3-NCs@SSM, leading to the formation of OTS@Fe2O3-NCs@SSM. The prepared OTS@Fe2O3-NCs@SSM shows excellent superhydrophobicity, with a water static contact angle of 151.3°. The separation efficiencies of OTS@Fe2O3-NCs@SSM for the mixtures of oil/water are all above 98.5%, except for corn oil/water (97.5%) because of its high viscosity. Moreover, the modified SSM exhibits excellent stability and recyclability. This work provides a facile approach for the preparation of superhydrophobic and super oleophilic metal meshes, which will lead to advancements in their large-scale applications on separating oil/water mixtures. Full article
Show Figures

Graphical abstract

17 pages, 4337 KiB  
Article
Numerical Study of the Optimum Fiber Content of Sealing Grease Using Discrete Element Method
by Xiong Zhou, Yingjie Wei, Yuyou Yang and Pengfei Xu
Materials 2022, 15(10), 3485; https://doi.org/10.3390/ma15103485 - 12 May 2022
Viewed by 1148
Abstract
A sealing grease plays a crucial role in the sealing of shield tails. Its pumpability and pressure sealing resistant sealing performance are greatly affected by the fiber content. In this study, discrete element method models were used to simulate the pressure-resistant tests of [...] Read more.
A sealing grease plays a crucial role in the sealing of shield tails. Its pumpability and pressure sealing resistant sealing performance are greatly affected by the fiber content. In this study, discrete element method models were used to simulate the pressure-resistant tests of sealing grease in order to investigate the influence of viscosity grade and fiber’s aspect ratio on the optimum fiber content of sealing grease. Meanwhile, the rationality of the optimum fiber number determined based on the sealing performance was verified with the unbalanced force and fiber area proportion obtained in the simulation, of which the variation curves with the increasing fiber number were practically identical. The simulation results elucidated that the viscosity of grease had little effect on the optimum fiber content for sealing grease. However, the increase in viscosity can improve the sealing effect, and increasing the fiber’s aspect ratio can reduce the fiber number to reach a specific seal state. Based on the analysis of the total number of fiber spheres for the models with different fiber’s respect ratios, it can be concluded that the sealing grease sample made of the same fiber material and quality can reach the same seal state and seal effect, independent on fiber’s aspect ratio. Full article
Show Figures

Figure 1

12 pages, 2184 KiB  
Article
Stability of Pt-Adsorbed CO on Catalysts for Room Temperature-Oxidation of CO
by Frédéric C. Meunier, Taha Elgayyar, Kassiogé Dembélé and Helena Kaper
Catalysts 2022, 12(5), 532; https://doi.org/10.3390/catal12050532 - 11 May 2022
Cited by 9 | Viewed by 2138
Abstract
A large signal of gas-phase CO overlapping with those of adsorbates is often present when investigating catalysts by operando diffuse reflectance FT-IR spectroscopy. Physically removing CO(g) from the IR cell may lead to a fast decay of adsorbate signals. Our work shows that [...] Read more.
A large signal of gas-phase CO overlapping with those of adsorbates is often present when investigating catalysts by operando diffuse reflectance FT-IR spectroscopy. Physically removing CO(g) from the IR cell may lead to a fast decay of adsorbate signals. Our work shows that carbonyls adsorbed on metallic Pt sites fully vanished in less than 10 min at 30 °C upon removing CO(g) when redox supports were used. In contrast, a broad band assigned to CO adsorbed on oxidized Pt sites was stable. It was concluded that physically removing CO(g) at room temperature during IR analyses will most likely lead to changes in the distribution of CO(ads) and a misrepresentation of the Pt site speciation, misguiding the development of efficient low-temperature CO oxidation catalysts. A tentative representation of the nature of the Pt phases present depending on the feed composition is also proposed. Full article
Show Figures

Graphical abstract

12 pages, 3735 KiB  
Article
Changes in the Structural Composition and Moisture-Adsorption Properties of Mechanically Rolled Bamboo Fibers
by Wenjuan Zhao, Jian Zhang, Wenfu Zhang, Jin Wang and Ge Wang
Materials 2022, 15(10), 3463; https://doi.org/10.3390/ma15103463 - 11 May 2022
Cited by 3 | Viewed by 1626
Abstract
The chemical content, mechanical capability, and dimensional stability of bamboo fibers (BFs) are all directly related to the hygroscopic behavior, which is crucial for industrial applications. To support the utilization of BFs, the structural and chemical composition of BFs with different opening times [...] Read more.
The chemical content, mechanical capability, and dimensional stability of bamboo fibers (BFs) are all directly related to the hygroscopic behavior, which is crucial for industrial applications. To support the utilization of BFs, the structural and chemical composition of BFs with different opening times after mechanical rolling were investigated in this study, and the Guggenheim–Anderson–de Boer (GAB) model was selected to predict their moisture-adsorption properties. The results showed that the length and diameter of the fibers gradually decreased with the increase in the number of openings, and the fibers gradually separated from bundles into single fibers. It was also observed that the treated BFs exhibited different equilibrium moisture contents (EMCs). BFs with a smaller number of openings had a higher hemicellulose content and more exposed parenchyma cells on the fibers, which increased the number of water adsorption sites. As the number of openings increased, the parenchyma cells on the fibers decreased, and the lignin content increased, which reduced the number of fiber moisture-adsorption sites and decreased the EMC of the fibers. Full article
Show Figures

Figure 1

20 pages, 4853 KiB  
Article
A Highly Stable and Sustainable Low-Temperature Selective Absorber: Structural and Ageing Characterisation
by Meryem Farchado, Gema San Vicente, Nuria Germán, César Maffiotte and Ángel Morales
Materials 2022, 15(10), 3427; https://doi.org/10.3390/ma15103427 - 10 May 2022
Cited by 1 | Viewed by 1272
Abstract
Solar absorbers in a three-layer configuration have been prepared by dip-coating onto aluminium substrates. They are constituted by two spinel layers with one silica layer on the top and values of solar absorptance above 0.950 and thermal emittance below 0.04 were obtained. The [...] Read more.
Solar absorbers in a three-layer configuration have been prepared by dip-coating onto aluminium substrates. They are constituted by two spinel layers with one silica layer on the top and values of solar absorptance above 0.950 and thermal emittance below 0.04 were obtained. The effects of using different sintering conditions of the upper silica layer on the optical behaviour and durability tests have been studied. Results obtained in accelerated ageing methods, such as thermal stability tests and condensation tests, clearly show that the proposed selective absorber exhibits excellent thermal stability and very good humidity resistance. The results show that the protective action is due not only to the silica layer but also to the alumina layer produced during the absorber preparation. The phase composition of the individual layers was independently confirmed using X-ray diffraction and corroborated by X-ray Photoelectron Spectroscopy. Spinel-like phases were obtained in both the first and second layers. The ageing study shows that the three-layer configuration proposed has a very high potential, in terms of both durability and optical behaviour, for solar thermal low-temperature applications. Full article
Show Figures

Figure 1

12 pages, 2501 KiB  
Article
Exploration of Zero-Valent Iron Stabilized Calcium–Silicate–Alginate Beads’ Catalytic Activity and Stability for Perchlorate Degradation
by Yu-Kyung Jung, Alam Venugopal Narendra Kumar, Byong-Hun Jeon, Eun Young Kim, Taewoo Yum and Ki-Jung Paeng
Materials 2022, 15(9), 3340; https://doi.org/10.3390/ma15093340 - 06 May 2022
Cited by 3 | Viewed by 1466
Abstract
Perchlorate contamination in groundwater poses a serious threat to human health, owing to its interference with thyroid function. The high solubility and poor adsorption of perchlorate ions make perchlorate degradation a necessary technology in groundwater contaminant removal. Here, we demonstrate the perchlorate degradation [...] Read more.
Perchlorate contamination in groundwater poses a serious threat to human health, owing to its interference with thyroid function. The high solubility and poor adsorption of perchlorate ions make perchlorate degradation a necessary technology in groundwater contaminant removal. Here, we demonstrate the perchlorate degradation by employing nano zero-valent iron (nZVI) embedded in biocompatible silica alginate hybrid beads fabricated using calcium chloride (1 wt%) as a crosslinker. The concentration of precursors (sodium alginate, sodium silicate) for bead formation was standardized by evaluating the thermal stability of beads prepared at different sodium silicate and alginate concentrations. Thermal degradation of silica alginate hybrid samples showed a stepwise weight loss during the thermal sweep, indicating different types of reactions that occur during the degradation process. The formation of the silica alginate hybrid structure was confirmed by FT-IR spectroscopy. Scanning electron microscopy (SEM) data revealed the surface morphology of silica alginate hybrid changes by varying sodium silicate and alginate concentrations. nZVI-loaded alginate–silicate polymer bead (nZVI-ASB) exhibited excellent perchlorate degradation efficiency by degrading 20 ppm of perchlorate within 4 h. Our study also showed the perchlorate degradation efficiency of nZVI-ASB is maximum at neutral pH conditions. Full article
Show Figures

Figure 1

22 pages, 4657 KiB  
Article
Comprehension of the Route for the Synthesis of Co/Fe LDHs via the Method of Coprecipitation with Varying pH
by Chérif Morcos, Alain Seron, Nicolas Maubec, Ioannis Ignatiadis and Stéphanie Betelu
Nanomaterials 2022, 12(9), 1570; https://doi.org/10.3390/nano12091570 - 06 May 2022
Cited by 4 | Viewed by 2020
Abstract
Co/Fe-based layered double hydroxides (LDHs) are among the most promising materials for electrochemical applications, particularly in the development of energy storage devices, such as electrochemical capacitors. They have also been demonstrated to function as energy conversion catalysts in photoelectrochemical applications for CO2 [...] Read more.
Co/Fe-based layered double hydroxides (LDHs) are among the most promising materials for electrochemical applications, particularly in the development of energy storage devices, such as electrochemical capacitors. They have also been demonstrated to function as energy conversion catalysts in photoelectrochemical applications for CO2 conversion into valuable chemicals. Understanding the formation mechanisms of such compounds is therefore of prime interest for further controlling the chemical composition, structure, morphology, and/or reactivity of synthesized materials. In this study, a combination of X-ray diffraction, vibrational and absorption spectroscopies, as well as physical and chemical analyses were used to provide deep insight into the coprecipitation formation mechanisms of Co/Fe-based LDHs under high supersaturation conditions. This procedure consists of adding an alkaline aqueous solution (2.80 M NaOH and 0.78 M Na2CO3) into a cationic solution (0.15 M CoII and 0.05 M FeIII) and varying the pH until the desired pH value is reached. Beginning at pH 2, pH increases induce precipitation of FeIII as ferrihydrite, which is the pristine reactional intermediate. From pH > 2, CoII sorption on ferrihydrite promotes a redox reaction between FeIII of ferrihydrite and the sorbed CoII. The crystallinity of the poorly crystalized ferrihydrite progressively decreases with increasing pH. The combination of such a phenomenon with the hydrolysis of both the sorbed CoIII and free CoII generates pristine hydroxylated FeII/CoIII LDHs at pH 7. Above pH 7, free CoII hydrolysis proceeds, which is responsible for the local dissolution of pristine LDHs and their reprecipitation and then 3D organization into CoII4FeII2CoIII2 LDHs. The progressive incorporation of CoII into the LDH structure is accountable for two phenomena: decreased coulombic attraction between the positive surface-charge sites and the interlayer anions and, concomitantly, the relative redox potential evolution of the redox species, such as when FeII is re-oxidized to FeIII, while CoIII is re-reduced to CoII, returning to a CoII6FeIII2 LDH. The nature of the interlamellar species (OH, HCO3, CO32− and NO3) depends on their mobility and the speciation of anions in response to changing pH. Full article
Show Figures

Figure 1

9 pages, 1144 KiB  
Article
Preparation of Surfactant-Free Nano Oil Particles in Water Using Ultrasonic System and the Mechanism of Emulsion Stability
by Seon-Ae Hwangbo, Seung-Yul Lee, Bu-An Kim and Chang-Kwon Moon
Nanomaterials 2022, 12(9), 1547; https://doi.org/10.3390/nano12091547 - 03 May 2022
Cited by 9 | Viewed by 1752
Abstract
Emulsion technology is widely used in the preparation of cosmetics, pharmaceuticals, drug delivery, and other daily necessities, and surfactants are frequently used to prepare these emulsions because of the lack of reliable surfactant-free emulsification techniques. This is disadvantageous because some surfactants pose health [...] Read more.
Emulsion technology is widely used in the preparation of cosmetics, pharmaceuticals, drug delivery, and other daily necessities, and surfactants are frequently used to prepare these emulsions because of the lack of reliable surfactant-free emulsification techniques. This is disadvantageous because some surfactants pose health hazards, cause environmental pollution, have costly components, and place limitations on process development. In this paper, an efficient method for surfactant-free nano-emulsification is presented. In addition, we discuss the effects of different operating parameters on the oil particle size, as well as the effect of the particle size on the emulsion stability. Specifically, we compared three surfactant-free ultrasonic emulsification technologies (horn, bath, and focused ultrasonic systems). The focused ultrasonic system, which concentrates sound energy at the center of the dispersion system, showed the best performance, producing emulsions with a particle size distribution of 60–400 nm at 400 kHz. In addition, phase separation did not occur despite the lack of surfactants and thickeners, and the emulsion remained stable for seven days. It is expected to be widely used in eco-friendly emulsification processes. Full article
Show Figures

Figure 1

14 pages, 4904 KiB  
Article
Chitosan Catalyzed Novel Piperidinium Dicoumarol: Green Synthesis, X-ray Diffraction, Hirshfeld Surface and DFT Studies
by Mohammad Asad, Muhammad Nadeem Arshad, Mohammed Musthafa T.N. and Abdullah M. Asiri
Polymers 2022, 14(9), 1854; https://doi.org/10.3390/polym14091854 - 30 Apr 2022
Cited by 2 | Viewed by 1603
Abstract
The novel piperidinium dicoumarol has been synthesized by the reaction of 3-formylchromone, 4-hydroxycoumarin, and piperidine under chitosan catalyzed solvent-free green conditions. FT-IR and NMR spectroscopy established the structure of dicoumarol, which was further confirmed by a single X-ray diffraction study. The single diffraction [...] Read more.
The novel piperidinium dicoumarol has been synthesized by the reaction of 3-formylchromone, 4-hydroxycoumarin, and piperidine under chitosan catalyzed solvent-free green conditions. FT-IR and NMR spectroscopy established the structure of dicoumarol, which was further confirmed by a single X-ray diffraction study. The single diffraction study has revealed the hydrogen bonding interactions, which were further validated by Hirshfeld surface analysis. Geometry optimizations of dicoumarol have been performed at the DFT level of theory by the B3LYP acting along with Gaussian 16, revision B.01 to calculate the geometric and electronic structure parameters. Full article
Show Figures

Figure 1

15 pages, 9682 KiB  
Article
Optical Properties of Polyisocyanurate–Polyurethane Aerogels: Study of the Scattering Mechanisms
by Beatriz Merillas, Judith Martín-de León, Fernando Villafañe and Miguel Ángel Rodríguez-Pérez
Nanomaterials 2022, 12(9), 1522; https://doi.org/10.3390/nano12091522 - 30 Apr 2022
Cited by 11 | Viewed by 2024
Abstract
Highly transparent polyisocyanurate–polyurethane (PUR–PIR) aerogels were synthesized, and their optical properties were studied in detail. After determining the density and structural parameters of the manufactured materials, we analyzed their optical transmittance. It was demonstrated that the catalyst content used to produce the aerogels [...] Read more.
Highly transparent polyisocyanurate–polyurethane (PUR–PIR) aerogels were synthesized, and their optical properties were studied in detail. After determining the density and structural parameters of the manufactured materials, we analyzed their optical transmittance. It was demonstrated that the catalyst content used to produce the aerogels can be employed to tune the internal structure and optical properties. The results show that the employment of lower catalyst amounts leads to smaller particles forming the aerogel and concomitantly to higher transmittances, which reach values of 85% (650 nm) due to aerogel particles acting as scattering centers. Thus, it was found that the lower this size, the higher the transmittance. The effect of the sample thickness on the transmittance was studied through the Beer–Lambert law. Finally, the scattering mechanisms involved in the light attenuation were systematically evaluated by measuring a wide range of light wavelengths and determining the transition between Rayleigh and Mie scattering when the particles were larger. Therefore, the optical properties of polyurethane aerogels were studied for the first time, opening a wide range of applications in building and energy sectors such as glazing windows. Full article
Show Figures

Graphical abstract

13 pages, 3739 KiB  
Article
Eu3+- and Tb3+-Based Coordination Complexes of Poly(N-Isopropyl,N-methylacrylamide-stat-N,N-dimethylacrylamide) Copolymer: Synthesis, Characterization and Property
by Jian Li, Guihua Cui, Siyuan Bi, Xu Cui, Yanhui Li, Qian Duan, Toyoji Kakuchi and Yougen Chen
Polymers 2022, 14(9), 1815; https://doi.org/10.3390/polym14091815 - 29 Apr 2022
Cited by 3 | Viewed by 1959
Abstract
This contribution reports the syntheses, structural analyses and properties of europium (Eu3+)- and terbium (Tb3+)-based coordination complexes of poly(N-isopropyl,N-methylacrylamide-stat-N,N-dimethylacrylamide) (poly(iPMAm-stat-DMAm)) copolymer, named as poly-Eu(III) and poly-Tb(III), respectively. In greater [...] Read more.
This contribution reports the syntheses, structural analyses and properties of europium (Eu3+)- and terbium (Tb3+)-based coordination complexes of poly(N-isopropyl,N-methylacrylamide-stat-N,N-dimethylacrylamide) (poly(iPMAm-stat-DMAm)) copolymer, named as poly-Eu(III) and poly-Tb(III), respectively. In greater detail, poly(iPMAm85-stat-DMAm15) is first prepared by random copolymerization of N-isopropyl,N-methylacrylamide (iPMAm) and N,N-dimethylacrylamide (DMAm) via group transfer polymerization (GTP). Next, poly(iPMAm85-stat-DMAm15) is used as the polymer matrix for chelating with Eu3+ and Tb3+ cations at its side amide groups, to produce poly-Eu(III) and poly-Tb(III). Their structural characterizations by FT-IR spectroscopy and XPS confirm the formation of polymeric complexes. The study on their fluorescence emission characteristics and luminescence lifetime demonstrates that Poly-Eu(III) shows four strong emission peaks at 578, 593, 622, and 651 nm, which are responsible for the electron transitions from the excited 5D0 state to the multiplet 7FJ (J = 0, 1, 2, 3) states, respectively, and poly-Tb(III) also displays four emission peaks at 489, 545, 588, and 654 nm, mainly due to the electron transitions of 5D47Fi (i = 6, 5, 4, 3). The luminescence lifetimes of poly-Eu(III) (τpoly-Eu(III)) and poly-Tb(III) (τpoly-Tb(III)) are determined to be 4.57 and 7.50 ms, respectively. In addition, in aqueous solutions, poly-Eu(III) and poly-Tb(III) are found to exhibit thermoresponsivity, with their cloud temperatures (Tcs) locating around 36.4 and 36.8 °C, respectively. Finally, the cytotoxicity study on the human colon carcinoma cells LoVo and DLD1 suggests that the luminescent Eu3+ and Tb3+ in the chelated state with poly(iPMAm-stat-DMAm) show much better biocompatibility and lower toxicity than their inorganic salts. Full article
Show Figures

Figure 1

15 pages, 4488 KiB  
Article
Evaluation of the Radiation Shielding Properties of a Tellurite Glass System Modified with Sodium Oxide
by Khalid I. Hussein, Mohammed S. Alqahtani, Arwa A. Meshawi, Khloud J. Alzahrani, Heba Y. Zahran, Ali M. Alshehri, Ibrahim S. Yahia, Manuela Reben and El Sayed Yousef
Materials 2022, 15(9), 3172; https://doi.org/10.3390/ma15093172 - 27 Apr 2022
Cited by 3 | Viewed by 1536
Abstract
In this study, the X-ray and gamma attenuation characteristics and optical properties of a synthesized tellurite–phosphate–sodium oxide glass system with a composition of (85 − x)TeO2–10P2O5–xNa2O mol% (where x = 15, 20, and 25) were [...] Read more.
In this study, the X-ray and gamma attenuation characteristics and optical properties of a synthesized tellurite–phosphate–sodium oxide glass system with a composition of (85 − x)TeO2–10P2O5–xNa2O mol% (where x = 15, 20, and 25) were evaluated. The glass systems we re fabricated by our research group using quenching melt fabrication. The shielding parameters of as-synthesized systems, such as the mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), effective atomic number (Zeff), half-value layer (HVL), tenth value layer (TVL), mean free path (MFP), and effective electron density (Neff) in a wide energy range between 15 keV and 15 MeV, were estimated using well-known PHY-X/PSD software and recently developed MIKE software. Herein, the optical parameters of prepared glasses, such as molar volume (VM), oxygen molar volume (VO), oxygen packing density (OPD), molar polarizability (αm), molar refractivity (Rm), reflection loss (RL), and metallization (M), were estimated using MIKE software. Furthermore, the shielding performance of the prepared glasses was compared with that of commonly used standard glass shielding materials. The results show that the incorporation of sodium oxide into the matrix TeO2/P2O5 with an optimum concentration can yield a glass system with good shielding performance as well as good optical and physical properties, especially at low photon energy. Full article
Show Figures

Figure 1

24 pages, 9728 KiB  
Article
Ash from Poultry Manure Incineration as a Substitute for Phosphorus Fertiliser
by Magdalena Cempa, Paweł Olszewski, Krzysztof Wierzchowski, Piotr Kucharski and Barbara Białecka
Materials 2022, 15(9), 3023; https://doi.org/10.3390/ma15093023 - 21 Apr 2022
Cited by 5 | Viewed by 1894
Abstract
The goal of the tests was to separate a phosphate concentrate from ash and to assess its fertiliser use efficiency in anthropogenic land. Ash obtained from poultry manure incineration is an interesting fertiliser, as it contains both of the necessary nutrients, i.e., phosphorus [...] Read more.
The goal of the tests was to separate a phosphate concentrate from ash and to assess its fertiliser use efficiency in anthropogenic land. Ash obtained from poultry manure incineration is an interesting fertiliser, as it contains both of the necessary nutrients, i.e., phosphorus and potassium. The ash selected for the tests contained 15.73 wt% P2O5, and 6.75 wt% K2O. CaO also constituted the main component (44.79 wt%). Phosphorus in crystalline form was present as hydroxyapatite and carbonate apatite. The first stage, applied in order to separate a phosphate concentrate from ash, involved a number of physicochemical methods: (i) a method based on grain wettability differences; (ii) a method based on grain density differences; and (iii) methods based on size distribution differences. Wet sieving made it possible to separate a fraction with a P2O5 content of 24.56 wt%. The second stage, applied to assess fertiliser use efficiency, involved cassette tests as well as pot and field cultivation using as fertiliser, the obtained product as well as raw ash and commercial ones. Therefore, the conducted research allowed for the development of a methodology for the management of ash from the incineration of a poultry manure and their use as a substitute for phosphorus fertiliser. The tested material was applied in various doses. Using the obtained phosphate concentrate at a dose of 95 g/m3 resulted in a comparable yield as in the case of the commercial fertiliser at a dose recommended by the producer (75 g/m3). Unprocessed ash had to be used in larger amounts, i.e., 165 g/m3, to have a comparable yield as a commercial fertiliser. Full article
Show Figures

Figure 1

19 pages, 7050 KiB  
Article
Zr-Based Biocomposite Materials as an Alternative for Fluoride Removal, Preparation and Characteristics
by Adriana Robledo-Peralta, Linda Viviana García-Quiñonez, René I. Rodríguez-Beltrán and Liliana Reynoso-Cuevas
Polymers 2022, 14(8), 1575; https://doi.org/10.3390/polym14081575 - 12 Apr 2022
Cited by 6 | Viewed by 2084
Abstract
The development of biocomposite materials used as adsorbents to remove ions in aqueous media has become an attractive option. The biomasses (base materials) are chemically treated and impregnated with metal cations, becoming competitive for fluoride-capture capacity. In this research, Valence orange (Citrus [...] Read more.
The development of biocomposite materials used as adsorbents to remove ions in aqueous media has become an attractive option. The biomasses (base materials) are chemically treated and impregnated with metal cations, becoming competitive for fluoride-capture capacity. In this research, Valence orange (Citrus sinensis) and Red Delicious apple (Malus Domestica) peels were modified by alkaline treatment, carboxylation, and impregnation with zirconium (Zr). These materials were characterized morphologically and structurally to understand the modifications in the treated biomasses and the mechanism of fluoride adsorption. The results show changes in surface area and composition, most notably, an increment in roughness and Zr impregnation of the bioadsorbents. After batch experimentation, the maximum capacity of the materials was determined to be 4.854 and 5.627 mg/g for the orange and apple peel bioadsorbent, respectively, at pH 3.5. The experimental data fitted the Langmuir model, suggesting that chemisorption occurs in monolayers. Finally, the characterization of the bioadsorbents in contact with fluoride allowed the replacement of OH species by fluoride or the formation of hydrogen bonds between them as an adsorption mechanism. Therefore, these bioadsorbents are considered viable and can be studied in a continuous system. Full article
Show Figures

Figure 1

12 pages, 5273 KiB  
Article
Role of Bimetallic Solutions in the Growth and Functionality of Cu-BTC Metal–Organic Framework
by Nishesh Kumar Gupta, Jiyeol Bae and Kwang-Soo Kim
Materials 2022, 15(8), 2804; https://doi.org/10.3390/ma15082804 - 11 Apr 2022
Cited by 4 | Viewed by 2251
Abstract
Bimetallic solutions play a vital role in the growth and functionality of copper trimesate (Cu-BTC) metal–organic frameworks (MOFs). The effect of Ag+, Ca2+, Mn2+, Co2+, and Zn2+ on the growth of Cu-BTC was studied [...] Read more.
Bimetallic solutions play a vital role in the growth and functionality of copper trimesate (Cu-BTC) metal–organic frameworks (MOFs). The effect of Ag+, Ca2+, Mn2+, Co2+, and Zn2+ on the growth of Cu-BTC was studied by fabricating M-Cu-BTC MOFs at room temperature using bimetallic M-Cu solutions. While Ag+ in the MOF had a rod-like morphology and surface properties, divalent cations deteriorated it. Moreover, unconventional Cu+ presence in the MOF formed a new building unit, which was confirmed in all the MOFs. Apart from Ag and Mn, no other MOF showed any presence of secondary cations in the structure. While Ag-Cu-BTC showed an improved H2S uptake capacity, other M-Cu-BTC MOFs had superior organic pollutant adsorption behavior. Thus, we have demonstrated that the physicochemical properties of Cu-BTC could be modified by growing it in bimetallic solutions. Full article
Show Figures

Figure 1

15 pages, 3149 KiB  
Article
Synthesis and Characterization of Cyclodextrin-Based Polyhemiaminal Composites with Enhanced Thermal Stability
by Hoque Mohammed Jabedul, Mitsuo Toda and Nobuyuki Mase
Polymers 2022, 14(8), 1562; https://doi.org/10.3390/polym14081562 - 11 Apr 2022
Cited by 2 | Viewed by 1979
Abstract
Polyhemiaminal (PHA) polymers are a new class of thermosetting polymers that have recently gained attention owing to their high mechanical strength and excellent recycling behavior. However, low thermal stability is a common issue in PHA polymers due to the thermally labile crosslinked knots. [...] Read more.
Polyhemiaminal (PHA) polymers are a new class of thermosetting polymers that have recently gained attention owing to their high mechanical strength and excellent recycling behavior. However, low thermal stability is a common issue in PHA polymers due to the thermally labile crosslinked knots. Herein, crosslinked PHA polymer composites were synthesized by reacting formaldehyde with a precursor solution of 4,4ʹ-oxydianiline (ODA) and cyclodextrins (CDs) (α-, β-, and γ-). The material obtained under optimal conditions (ODA:CD molar ratio of 1:0.5, 37% aqueous solution of formaldehyde (formalin)) exhibited good film formability and high thermal stability with two characteristic decomposition phenomena and a high char yield. The early decomposition of CDs and char formation led to high thermal stability. Time-resolved NMR analysis was conducted to study hemiaminal bond formation via a condensation reaction between ODA and formaldehyde. Furthermore, PHA matrix formation was confirmed by the dissolution of the deposited CD layer in a solution of N-methyl-2-pyrrolidinone containing 8–9 wt.% LiBr at 80 °C and FTIR analysis. Based on the elemental analysis results, PHA network formation was confirmed by considering a single unit of the PHA network with CD composition, including the solvent and water. Full article
Show Figures

Graphical abstract

11 pages, 2101 KiB  
Article
Acid-Assisted Ball Mill Synthesis of Carboxyl-Functional-Group-Modified Prussian Blue as Sodium-Ion Battery Cathode
by Yu Luo, Jiayu Peng, Shengming Yin, Lihong Xue and Youwei Yan
Nanomaterials 2022, 12(8), 1290; https://doi.org/10.3390/nano12081290 - 11 Apr 2022
Cited by 9 | Viewed by 2647
Abstract
Prussian blue attracts the attention of many researchers as a promising candidate for use in sodium-ion battery cathodes due to its open frameworks and high working potential. However, the interstitial water in its crystal structure and its poor electronic conductivity limits its performance [...] Read more.
Prussian blue attracts the attention of many researchers as a promising candidate for use in sodium-ion battery cathodes due to its open frameworks and high working potential. However, the interstitial water in its crystal structure and its poor electronic conductivity limits its performance in practical sodium-ion batteries. Here, acid-assisted ball milling synthesis was employed as a versatile method for the production of surface-modified Prussian blue. With (CH3COO)2Fe being used as the raw material, the Prussian blue produced using ball milling synthesis was modified by the carboxyl functional group on its surface, which resulted in lower interstitial water content and enhanced electrochemical cycling performance. In addition, ball milling synthesis provided the as-prepared Prussian blue with a large surface area, improving its electrochemical rate performance. When used as the cathode of sodium-ion batteries, as-prepared Prussian blue delivered a specific capacity of 145.3 mAh g−1 at 0.2 C and 113.7 mAh g−1 at 1 C, maintaining 54.5% of the initial capacity after 1000 cycles at 1 C (1 C = 170 mA g−1). Furthermore, a solid-state sodium-ion battery was mounted, with as-prepared Prussian blue being employed as the cathode and Na metal as the anode, which delivered a high specific capacity of 128.7 mAh g−1 at 0.2 C. The present study put forward an effective solution to overcome the limitations of Prussian blue for its commercial application. Full article
Show Figures

Graphical abstract

14 pages, 5132 KiB  
Article
Effect of UV Irradiation on the Structural Variation of Metal Oxide-Silica Nanocomposites for Enhanced Removal of Erythromycin at Neutral pH
by Yasaman Ghaffari, Soyoung Beak, Jiyeol Bae, Md Saifuddin and Kwang Soo Kim
Catalysts 2022, 12(4), 424; https://doi.org/10.3390/catal12040424 - 10 Apr 2022
Cited by 6 | Viewed by 2115
Abstract
In this study, the effect of UV treatment on the physicochemical properties and structural variation of metal oxide-silica nanocomposites (Mn2O3-Fe2O3@SiO2) has been investigated. Based on the results, UV irradiation significantly affects the nanocomposite [...] Read more.
In this study, the effect of UV treatment on the physicochemical properties and structural variation of metal oxide-silica nanocomposites (Mn2O3-Fe2O3@SiO2) has been investigated. Based on the results, UV irradiation significantly affects the nanocomposite structure, where SiO2 network reconfiguration, change in surface OH group density, and surface area were observed. Erythromycin (ERY) has been chosen as a module pollutant to compare the performance of the pristine and UV-treated nanocomposites. The pristine nanocomposite had a high adsorption efficiency (99.47%) and photocatalytic activity (99.57%) at neutral pH for ERY in the first cycle, and this efficiency decreased significantly for the multiple cycles. However, different results have been observed for the UV-treated nanocomposite, where it retained its performance for ten consecutive cycles. This enhanced performance is attributed to the structural modifications after UV exposure, where increased surface area, pore volume, and OH group density resulted in an increased number of the possible mechanisms responsible for the adsorption/oxidation of ERY. Moreover, oxidation of adsorbed molecules by UV light after each cycle can also be another reason for enhanced removal. For the first time, the fate of ERY is studied using regenerated nanocomposites after the last cycle. LC/MS/MS results showed that ERY degraded in 20 min, and the produced reaction by-products were adsorbed by nanocomposites. This study could be a foundation research for the practical approaches for the regeneration of nanomaterials and the successful removal of organic pollutants from aquatic environments. Full article
Show Figures

Graphical abstract

10 pages, 1919 KiB  
Article
Electrospun Cellulose-Acetate/Chitosan Fibers for Humic-Acid Removal: Improved Efficiency and Robustness with a Core-Sheath Design
by Yirong Zhang and Yixiang Wang
Nanomaterials 2022, 12(8), 1284; https://doi.org/10.3390/nano12081284 - 09 Apr 2022
Cited by 6 | Viewed by 1983
Abstract
Recycling biomass waste into functional materials has attracted much attention, and a rational structural design can make more effective use of each component. In our previous work, the fabrication of electrospun cellulose-acetate (CA)/chitosan (CS) adsorbents for humic-acid (HA) removal guided by the intermolecular [...] Read more.
Recycling biomass waste into functional materials has attracted much attention, and a rational structural design can make more effective use of each component. In our previous work, the fabrication of electrospun cellulose-acetate (CA)/chitosan (CS) adsorbents for humic-acid (HA) removal guided by the intermolecular interaction mechanism was demonstrated. Herein, a core-sheath structure was designed via one-step co-axial electrospinning, where a mixture of CS and CA was employed as the sheath layer to efficiently adsorb HA, and cellulose nanocrystals (CNCs) derived from waste cotton fabrics were incorporated into the CA core as load-bearing components. Compared to the non-layered electrospun CS/CA fibers, all the CS/CA–CNC fibers with a core-sheath structure exhibited smaller diameters, greater homogeneity, and significantly improved mechanical strength. Meanwhile, their maximum adsorption capacities towards HA had no significant differences. Even after the complete hydrolysis of CA into cellulose, the electrospun fibers maintained the fibrous structures and showed a higher tensile strength while exhibiting an acceptable adsorption capacity towards HA. Therefore, this work demonstrates the importance of rational design in the efficient preparation of functional materials and the feasibility of using electrospun core-sheath fibers derived from biomass wastes for the removal of water contaminants. Full article