Green and Environmentally Sustainable Chemical Processes

Editors


E-Mail Website
Collection Editor
Department of Sciences and Methods for Engineering, University of Modena and Reggio Emilia, Via Amendola 2, 42122 Reggio Emilia, Italy
Interests: green metrics; life cycle assessment; green chemistry; sustainable chemistry
Special Issues, Collections and Topics in MDPI journals

E-Mail Website
Collection Editor
Department of Sciences and Methods for Engineering, University of Modena and Reggio Emilia, Via Amendola 2, 42122 Reggio Emilia, Italy
Interests: life cycle assessment; environmental science; chemical engineering; materials science
Special Issues, Collections and Topics in MDPI journals

E-Mail Website
Collection Editor
1. Process Control Manager, Ceramica Fondovalle S.p.A., Via Rio Piodo 12, Torre Maina, 41053 Modena, Italy
2. Department of Engineering “Enzo Ferrari”, University of Modena and Reggio Emilia, Via Vivarelli 10, 41125 Modena, Italy
Interests: materials science; green materials; green processes; green engineering; ceramic materials; glassy materials; circular economy

E-Mail
Collection Editor
Department of Sciences and Methods for Engineering, University of Modena and Reggio Emilia, Via Amendola 2, 42122 Reggio Emilia, Italy
Interests: life cycle assessment; environmental science; sustainability assessment

Topical Collection Information

Dear Colleagues,

This Topical Collection of ChemEngineering, entitled “Green and Environmentally Sustainable Chemical Processes”, will focus on the publication of original manuscripts and critical reviews aimed at advancing the application of the principles of green chemistry and green engineering to chemical processes performed both at industrial and laboratory scales. Manuscripts devoted, but not limited, to the preparation of organic, inorganic, ceramic, and glassy materials are warmly welcome.

Indeed, pursuing ever-more sustainable development requires chemistry and materials science disciplines to adopt procedures aimed at reducing their associated environmental impacts. However, the quantification of the environmental benefits of the proposed processes over the well-established ones is necessary in order to assess the effective green characteristics of the proposed approaches.

Particularly, the application of well-established green chemistry metrics, environmental sustainability metrics, and/or indicators, to prove and quantify the effective shift of the proposed process in the ecological transition direction, will be the main focus of this Topical Collection, and particular attention will be given to contributions that demonstrate environmentally sustainable advancements with respect to current scenarios, technologies, and processes.

Manuscripts devoted to the proposition of new metrics and indicators will be considered as well.

Dr. Roberto Rosa
Prof. Dr. Anna Maria Ferrari
Dr. Consuelo Mugoni
Dr. Grazia Maria Cappucci
Collection Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the collection website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. ChemEngineering is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • green chemistry
  • green engineering
  • green materials science
  • green chemical processes
  • sustainable materials
  • sustainable chemistry
  • green metrics
  • mass-, energy-, and environmentally based metrics
  • life cycle assessment
  • LCA

Published Papers (13 papers)

2024

Jump to: 2023

17 pages, 2815 KiB  
Article
Magnetic Three-Dimensional Graphene: A Superior Adsorbent for Selective and Sensitive Determination of Nitrite in Water Samples by Ion-Pair Based-Surfactant-Assisted Solid-Phase Extraction Combined with Spectrophotometry
by Mina Vasheghani Farahani, Sajad Karami, Hassan Sereshti, Shokouh Mahpishanian, Somayeh Koupaei Malek and Shahabaldin Rezania
ChemEngineering 2024, 8(3), 47; https://doi.org/10.3390/chemengineering8030047 - 1 May 2024
Viewed by 767
Abstract
A straightforward, fast and efficient analytical method was developed which utilizes a magnetic composite called three-dimensional graphene (3D-G@Fe3O4) as an adsorbent to recover nitrite ions (NO2) from environmental water samples. The investigation into the synthesized adsorbent [...] Read more.
A straightforward, fast and efficient analytical method was developed which utilizes a magnetic composite called three-dimensional graphene (3D-G@Fe3O4) as an adsorbent to recover nitrite ions (NO2) from environmental water samples. The investigation into the synthesized adsorbent contained an examination of its morphology, chemical composition, structural attributes, and magnetic properties. This comprehensive analysis was conducted using various instrumental techniques, including Fourier transform-infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), Raman spectroscopy, X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), Barrett-Joyner-Halenda (BJH), and vibrating sample magnetometry (VSM). The adsorbent surface was activated by adding cetyltrimethylammonium bromide (CTAB) to the sample solution. To improve the selectivity and sensitivity of the method, nitrite ions were reacted with sulfanilic acid and chromotropic acid sequentially. An orange-red azo-dye complex was formed in the presence of nitrite ions with a clear absorbance peak at 514 nm. The effect of the main experimental parameters such as the pH of the sample solution, adsorbent dosage, and CTAB dosage was explored, and the optimization process was performed using a central composite design (CCD). The linear dynamic range (20–100 ng mL−1) was determined under optimal experimental circumstances, yielding a reasonable determination coefficient (R2, 0.9993), a detection limit of 5.12 ng mL−1, an enrichment factor of 167, and precision values of 1.0% intraday and 2.9% inter-day. The methodology successfully identified minute nitrite ions in environmental water samples with relative recoveries that varied between 96.05 and 101.6 ng mL−1. Full article
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16 pages, 1279 KiB  
Review
A Review on Lanthanum-Based Materials for Phosphate Removal
by Sundarakannan Rajendran, A. V. S. L. Sai Bharadwaj, Praveen Barmavatu, Geetha Palani, Herri Trilaksanna, Karthik Kannan and Nagaraj Meenakshisundaram
ChemEngineering 2024, 8(1), 23; https://doi.org/10.3390/chemengineering8010023 - 9 Feb 2024
Viewed by 1616
Abstract
In the past decade, eutrophication and phosphate recovery from surface water have become major issues. Adsorption is an effective method for phosphate removal because of its high efficiency. Even though lanthanum-based compounds are effective at removing phosphate from water, outside factors influence them. [...] Read more.
In the past decade, eutrophication and phosphate recovery from surface water have become major issues. Adsorption is an effective method for phosphate removal because of its high efficiency. Even though lanthanum-based compounds are effective at removing phosphate from water, outside factors influence them. Hence, it is vital to develop and employ cost-effective innovations to fulfill ever-tougher requirements and address the issue of water contamination. Adsorption technology is highly effective in phosphate removal at concentrations from wastewater. This work briefly describes the preparation of lanthanum nano-adsorbents for the removal of phosphate efficiently in water, and phosphate adsorption on La-based adsorbents in various La forms. The work presented in this study offers an outline for future phosphate adsorption studies in La-based adsorbents, resulting in La-based materials with substantial adsorption capacity and strong regeneration capability. Full article
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11 pages, 1445 KiB  
Article
Simulation Process for Allyl Alcohol Production via Deoxydehydration of Glycerol
by Ghadir Assaad, Karen Silva Vargas, Benjamin Katryniok and Marcia Araque
ChemEngineering 2024, 8(1), 10; https://doi.org/10.3390/chemengineering8010010 - 3 Jan 2024
Viewed by 1794
Abstract
A process for the deoxydehydration (DODH) of glycerol to allyl alcohol in 2-hexanol as solvent was modelled with Aspen Plus. Experimental results for the DODH reaction, the liquid vapour equilibria and the catalytic hydrogenation were employed for the development of the model. The [...] Read more.
A process for the deoxydehydration (DODH) of glycerol to allyl alcohol in 2-hexanol as solvent was modelled with Aspen Plus. Experimental results for the DODH reaction, the liquid vapour equilibria and the catalytic hydrogenation were employed for the development of the model. The whole process consists of four subsystems: allyl alcohol production (S1), solvent recovery (S2), allyl alcohol purification (S3) and solvent regeneration (S4). Based on the results of the process model, allyl alcohol with 96% yield and a purity of 99.99% with product loss of only 0.2% was obtained. The optimisation of the energy consumption through an integrated heat exchange network resulted in a net primary energy input of 863.5 kW, which corresponded to a carbon footprint of 1.89 kgCO2/kgAllylOH. Full article
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2023

Jump to: 2024

23 pages, 3762 KiB  
Article
Dynamic and Steady-State Simulation Study for the Stabilization of Natural Gas Condensate and CO2 Removal through Heating and Pressure Reduction
by Mohsin Ehsan, Usman Ali, Farooq Sher, Hafiz M. Abubakar and Muhammad Fazal Ul Basit
ChemEngineering 2023, 7(5), 78; https://doi.org/10.3390/chemengineering7050078 - 29 Aug 2023
Viewed by 1947
Abstract
Stabilization of condensate is a highly energy-consuming process compared to other oil and gas processes. There is a need to reduce this energy consumption. Therefore, the present work aims to simulate the stabilization unit in terms of available energy and on-spec stabilized condensate [...] Read more.
Stabilization of condensate is a highly energy-consuming process compared to other oil and gas processes. There is a need to reduce this energy consumption. Therefore, the present work aims to simulate the stabilization unit in terms of available energy and on-spec stabilized condensate products. Natural gas condensate liquids (NGL) need to be stabilized by eliminating lighter hydrocarbon gases and acid gases before being sent to the refinery. Stabilized NGL has the vapor pressure determined as a Reid vapor pressure of 7 psia, showing that light components did not evolve as a separate gas phase. Stabilization and CO2 removal was performed through the distillation method by heating and pressure reduction using steady state and dynamic simulation through Aspen HYSYS. Different process alterations around the exchanger and column have been studied based on the utilities available for the stabilization and CO2 removal process. Sensitivity studies, including the impact of CO2 concentration, the temperature at the inlet of the stabilizer flash separator, and the dynamic simulation for the PID controller, have been performed to analyze the impact on the process parameters, such as Reid vapor pressure (RVP) and CO2 of the rundown air cooler and heat duties of the exchangers. Actual plant data have been used for the validation of process simulation values for the accuracy of the condensate stabilization unit model. Based on the scenarios analyzed, it can be concluded that the nitrogen stripping method achieved 7 ppmv CO2 and 7 psia RVP in the condensate from the cooler outlet, while a variation of 29 bpd was observed for the stabilized condensate flowrate throughout all scenarios with data validation showing 0.24% discrepancy between Aspen Hysys data and actual plant data. Full article
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11 pages, 1400 KiB  
Article
Influence of the Absolute Pressure of the Extraction System on the Yield and Composition of Corymbia citriodora (Hook.) K.D.Hill and L.A.S.Johnson Leaf Essential Oil Extracted by Steam Distillation
by Juliana de Araujo, Wendel Paulo Silvestre, Gabriel Fernandes Pauletti and Luis Antonio Rezende Muniz
ChemEngineering 2023, 7(4), 67; https://doi.org/10.3390/chemengineering7040067 - 24 Jul 2023
Cited by 3 | Viewed by 1509
Abstract
This study aimed to evaluate the extraction of Corymbia citriodora (Hook.) K.D.Hill and L.A.S.Johnson essential oil by steam distillation under reduced pressure. Yield and composition of the essential oils obtained at different system pressures were analyzed. System pressure had a significant influence on [...] Read more.
This study aimed to evaluate the extraction of Corymbia citriodora (Hook.) K.D.Hill and L.A.S.Johnson essential oil by steam distillation under reduced pressure. Yield and composition of the essential oils obtained at different system pressures were analyzed. System pressure had a significant influence on essential oil yield, resulting in a reduction of 78.6% when the pressure was reduced from 690 Torr to 240 Torr. There were also changes in essential oil composition, with an increase in citronellol content (oxygenated monoterpene). However, the major compound (citronellal) remained at a high content in all tests. Regarding the extracted mass of the major compounds (citronellal, citronellol), there was a significant reduction for all when the system pressure was reduced. Although the reduction in the pressure of the system caused a reduction in oil yield, it was possible to carry out the steps of extraction and purification of the major compound simultaneously. Reduced pressure extraction may decrease process time, increasing its efficiency and reducing costs in the extraction of essential oils. Full article
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12 pages, 2085 KiB  
Article
Development of Mosquito-Repellent Camouflage Fabric Using Eucalyptus Oil with Moringa oleifera Gum
by Faiza Anwar, Mudassar Abbas, Mumtaz Hasan Malik, Amna Aziz Cheema, Suniya Tariq, Warda Afzal and Asfandyar Khan
ChemEngineering 2023, 7(4), 64; https://doi.org/10.3390/chemengineering7040064 - 20 Jul 2023
Cited by 2 | Viewed by 2402
Abstract
Military personnel are exposed to several harsh conditions and mosquitos in mountains and wild forests. Mosquito-repellent textiles can help them to cope with such conditions. The present research work established a sustainable approach for fabricating microcapsules from Eucalyptus oil, Moringa oleifera, and [...] Read more.
Military personnel are exposed to several harsh conditions and mosquitos in mountains and wild forests. Mosquito-repellent textiles can help them to cope with such conditions. The present research work established a sustainable approach for fabricating microcapsules from Eucalyptus oil, Moringa oleifera, and Arabic gum via a complex coacervation method. Moringa oleifera and Arabic gums were utilized as the outer shell of the microcapsules, whereas the core part was made of Eucalyptus oil in different concentrations. The military camouflage-printed polyester/cotton (PC) blended fabric was coated with the as-prepared microcapsules using the pad–dry–cure technique. The surface morphology of the microcapsules was examined using an optical microscope and scanning electron microscope (SEM), and the coated fabric’s mosquito-repellent property was investigated using a specified cage test according to a standard testing protocol. The water absorbency and air permeability of the treated samples were also evaluated in order to learn about the comfort properties. The cage test results revealed that the coated fabric had a good tendency to repel the mosquitoes used in the cage test. In addition, the coated fabric showed significant durability even after several rigorous washing cycles. However, the application of microcapsules to the fabric slightly affected the water absorbency and air permeability of the fabric. This study presents a novel sustainable approach for fabricating microcapsules from the mentioned precursors and their application in the field of textiles, particularly for military purposes. Full article
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13 pages, 21684 KiB  
Article
Waste Management after the Injection Process by Manufacturing Polyamide Products Based on Regranulate
by Danuta Matykiewicz, Tomasz Olszewski and Jacek Andrzejewski
ChemEngineering 2023, 7(3), 51; https://doi.org/10.3390/chemengineering7030051 - 1 Jun 2023
Cited by 1 | Viewed by 1867
Abstract
The aim of the work was to assess the possibility of utilizing the waste generated in the injection molding process for the production of new products based on polyamide 6 reinforced with glass fiber. The manufactured samples were prepared with the addition of [...] Read more.
The aim of the work was to assess the possibility of utilizing the waste generated in the injection molding process for the production of new products based on polyamide 6 reinforced with glass fiber. The manufactured samples were prepared with the addition of 5, 10, 15, and 100 wt.% regrind from the runner system. The impact strength, tensile strength, and hardness of injection products were obtained directly and were assessed after conditioning in distilled water for 24 h. Moreover, the structure of the tested materials was assessed using the FTIR method and their thermal properties using the DSC method. The results of the tests confirm that the addition of regrind up to 15 wt.% to virgin polyamide does not adversely affect its impact strength, tensile strength, and hardness. The water-conditioned materials showed higher values of impact strength but lower values of tensile strength and Young’s modulus at a higher elongation at break. The obtained results are important due to the assumptions of the circular economy and the minimization of the amount of waste and material losses during the injection process. Full article
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35 pages, 20165 KiB  
Article
Effect of the Infill Patterns on the Mechanical and Surface Characteristics of 3D Printing of PLA, PLA+ and PETG Materials
by A. H. Kadhum, Salah Al-Zubaidi and Salah S. Abdulkareem
ChemEngineering 2023, 7(3), 46; https://doi.org/10.3390/chemengineering7030046 - 12 May 2023
Cited by 4 | Viewed by 2778
Abstract
This study aims to evaluate the 3D-printed parts of different materials in terms of the achieved mechanical properties and surface characteristics. Fourteen infill patterns were employed in the 3D printing of polylactic acid (PLA), enhanced polylactic acid (PLA+), and polyethylene terephthalate glycol (PETG) [...] Read more.
This study aims to evaluate the 3D-printed parts of different materials in terms of the achieved mechanical properties and surface characteristics. Fourteen infill patterns were employed in the 3D printing of polylactic acid (PLA), enhanced polylactic acid (PLA+), and polyethylene terephthalate glycol (PETG) materials. The printed specimens’ mechanical properties and surface characteristics were evaluated and discussed. Ultimate tensile strengths, Young’s modulus, and strain at break % were determined as mechanical properties, while average, maximum, and total height of profiles (Ra, Rz, and Rt) were measured as surface characteristics of the produced specimens. The cubic, gyroid, and concentric patterns were found to be the best infill patterns in terms of the mechanical properties of PLA, PLA+, and PETG materials, where maximum ultimate tensile strengths were recorded for these materials: 15.6250, 20.8333, and 16.5483 MPa, respectively. From the other side, the best Ra, Rz, and Rt were achieved with cross, quarter cubic, and concentric patterns of the PLA, PETG, and PLA+ materials, where the best values were (2.832 µm, 8.19 µm, and 17.53), (4.759 µm, 24.113 µm, and 35.216), and (4.234 µm, 30.136 µm, and 31.896), respectively. Full article
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16 pages, 3382 KiB  
Article
Lignin Valorization for Added-Value Chemicals: Kraft Lignin versus Lignin Fractions
by Carina A. E. Costa, Filipa M. Casimiro, Carlos Vega-Aguilar and Alírio E. Rodrigues
ChemEngineering 2023, 7(3), 42; https://doi.org/10.3390/chemengineering7030042 - 1 May 2023
Cited by 4 | Viewed by 2573
Abstract
Lignin is a raw material that can potentially be converted into valuable compounds through depolymerization reactions in addition to its use as a polymer or material. However, the chemical recalcitrance and the heterogeneous composition and structure of lignin make it challenging to establish [...] Read more.
Lignin is a raw material that can potentially be converted into valuable compounds through depolymerization reactions in addition to its use as a polymer or material. However, the chemical recalcitrance and the heterogeneous composition and structure of lignin make it challenging to establish processes that add value to this complex aromatic biopolymer. In this work, solvent fractionation was applied to obtain lignin fractions with a narrowed molecular weight and specific structural characteristics, improving its homogeneity and purity. A kraft lignin was submitted to fractionation using different ratios of acetone, ranging from 60 to 15% v/v, in aqueous mixtures. The composition, structure, and molecular weight of each fraction were studied and their potential applications were evaluated. The most water-soluble fraction has more phenolic OH, less aliphatic OH groups, and shows the lowest content of aryl-ether linkages, which is in accordance with its highest degree of condensation. On the other hand, the insoluble fraction from the mixture with 60% of acetone has the lowest molecular weight and the highest content of inorganic material. Radar plots were applied for lignin fractions evaluation and the fraction with the highest potential (IF 30:70) was submitted to alkaline oxidation with O2. The results were compared with the products yielded from kraft lignin. An increase of about 13 and 19% was found for vanillin and syringaldehyde, respectively, when the fraction IF 30:70 was submitted to oxidation. In conclusion, the proposed fractionation process showed to be an effective method to obtain lignin fractions with specific composition and structural characteristics that could improve its potential as a source of high added-value monomeric phenolic compounds. Full article
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13 pages, 1740 KiB  
Article
A Machine Learning-Based Study of Li+ and Na+ Metal Complexation with Phosphoryl-Containing Ligands for the Selective Extraction of Li+ from Brine
by Natalia Kireeva, Vladimir E. Baulin and Aslan Yu. Tsivadze
ChemEngineering 2023, 7(3), 41; https://doi.org/10.3390/chemengineering7030041 - 1 May 2023
Cited by 2 | Viewed by 1867
Abstract
The growth of technologies concerned with the high demand in lithium (Li) sources dictates the need for technological solutions garnering Li supplies to preserve the sustainability of the processes. The aim of this study was to use a machine learning-based search for phosphoryl-containing [...] Read more.
The growth of technologies concerned with the high demand in lithium (Li) sources dictates the need for technological solutions garnering Li supplies to preserve the sustainability of the processes. The aim of this study was to use a machine learning-based search for phosphoryl-containing podandic ligands, potentially selective for lithium extraction from brine. Based on the experimental data available on the stability constant values of phosphoryl-containing organic ligands with Li+ and Na+ cations at 4:1 THF:CHCl3, candidate di-podandic ligands were proposed, for which the stability constant values (logK) with Li+ and Na+ as well as the corresponding selectivity values were evaluated using machine learning methods (ML). The modelling showed a reasonable predictive performance with the following statistical parameters: the determination coefficient R2= 0.75, 0.87 and 0.83 and root-mean-square error RMSE = 0.485, 0.449 and 0.32 were obtained for the prediction of the stability constant values with Li+ and Na+ cations and Li+/Na+ selectivity values, respectively. This ML-based analysis was complemented by the preliminary estimation of the host–guest complementarity of metal–ligand 1:1 complexes using the HostDesigner software. Full article
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18 pages, 8531 KiB  
Article
Synthesis and Characteristics of Composite Material with a Plant-Based Filler
by Natalia Igorevna Cherkashina, Zoya Vladimirovna Pavlenko, Dar’ya Sergeyevna Matveenko, Semen Nikolayevich Domarev, Dar’ya Vasil’yevna Pushkarskaya and Dar’ya Aleksandrovna Ryzhikh
ChemEngineering 2023, 7(2), 38; https://doi.org/10.3390/chemengineering7020038 - 18 Apr 2023
Cited by 2 | Viewed by 1911
Abstract
The article presents the results of synthesis of polymeric composite material based on epoxy binder and plant-based filler. Pre-dried and powdered wheat straw was used as a plant-based filler. The wheat straw content in the composite varied from 10 to 50 wt.%. Thermal, [...] Read more.
The article presents the results of synthesis of polymeric composite material based on epoxy binder and plant-based filler. Pre-dried and powdered wheat straw was used as a plant-based filler. The wheat straw content in the composite varied from 10 to 50 wt.%. Thermal, mechanical, and surface properties of composites depending on the wheat straw content were researched. In addition, the samples were studied for resistance to corrosive environments. The hydrophobic–hydrophilic surface balance of composites was evaluated, and their free surface energy was studied. Introduction of wheat straw in small amounts (up to 30 wt.%) increases bending strength of polymer from 18.65 ± 1.12 MPa to 22.61 ± 0.91 MPa; when the content is more than 40 wt.%, reduction of strength is observed. Even with a wheat straw powder content of 50 wt.%, the bending strength is 11.52 ± 1.03 MPa, which corresponds to the strength of the construction material. The upper limit of working temperature for the epoxy binder is 306 °C, and for the composite with the wheat straw content of 30 wt.%—264 °C. The surface of the pure polymer shows a hydrophilic character. The average value of the water wetting contact angle of the pure epoxy sample is 84.96 ± 9.03°. The introduction of 30 wt.% of wheat straw powder filler transforms the surface into hydrophobic one (average value of water wetting contact angle is 96.69 ± 5.71°). The developed composites can be applied in furniture production including tabletops or panels for floors. Future research will focus on expanding the types of plant-based fillers for polymer composites. Full article
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11 pages, 2110 KiB  
Article
Effect of a Tetraethoxysilane Hydrolysis Reaction Catalyst on the Precipitation of Hydrolysis Products in the Pores of a Polyimide Track Membrane
by Natalia Igorevna Cherkashina, Vyacheslav Ivanovich Pavlenko, Semen Nikolayevich Domarev and Nikolay Valeriyevich Kashibadze
ChemEngineering 2023, 7(2), 32; https://doi.org/10.3390/chemengineering7020032 - 10 Apr 2023
Viewed by 1782
Abstract
This paper presents the results of obtaining a composite film based on polyimide track membranes filled with a silica filler, although the issue of the deposition of this filler in the pores of the given membranes remained unexplored. The filler was obtained by [...] Read more.
This paper presents the results of obtaining a composite film based on polyimide track membranes filled with a silica filler, although the issue of the deposition of this filler in the pores of the given membranes remained unexplored. The filler was obtained by hydrolysis of tetraethoxysilane using an alkaline and acid catalyst. This paper presents the results of the effect of the tetraethoxysilane hydrolysis reaction catalyst on the precipitation of hydrolysis products in the pores of the polyimide track membrane. The factors influencing the formation of silicon oxide nanofibers within the matrix template (polyimide track membrane) are determined. It was found that the use of an acid catalyst provides the highest rates of filling, while when using an alkaline catalyst, the filling is practically not observed, and only single pores are filled. The properties of the composite film obtained were investigated. SEM images of the surface and chip of the composite while using alkaline and acid catalyst are presented. The spatial structure of composite films based on track membranes was investigated by FTIR spectroscopy. The hydrolysis of tetraethoxysilane in an acid medium significantly decreases the optical density index of the membranes and simultaneously increases their light transmission index. The greatest changes are observed in the range of 500–1000 nm, and there are no detectable changes in the range of 340–500 nm. When using an alkaline catalyst, there is not the same significant decrease in the relative optical density index D. Full article
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39 pages, 9794 KiB  
Article
Effective Adsorptive Removal of Coomassie Violet Dye from Aqueous Solutions Using Green Synthesized Zinc Hydroxide Nanoparticles Prepared from Calotropis gigantea Leaf Extract
by Vairavel Parimelazhagan, Kannan Natarajan, Srinath Shanbhag, Sumanth Madivada and Harish S. Kumar
ChemEngineering 2023, 7(2), 31; https://doi.org/10.3390/chemengineering7020031 - 6 Apr 2023
Cited by 8 | Viewed by 2732
Abstract
The removal of color from dye wastewater is crucial, since dyes are extremely toxic and can cause cancer in a variety of life forms. Studies must be done to use cost-effective adsorbents for the removal of color from dye effluents to protect the [...] Read more.
The removal of color from dye wastewater is crucial, since dyes are extremely toxic and can cause cancer in a variety of life forms. Studies must be done to use cost-effective adsorbents for the removal of color from dye effluents to protect the environment. To our knowledge, virtually no research has been done to describe the possibility of using Calotropis gigantea leaf extract zinc hydroxide nanoparticles (CG-Zn(OH)2NPs) as an adsorbent for the decolorization of Coomassie violet (CV) from the aqueous emulsion, either in batch mode or continuously. In the present batch investigation, CV dye is removed from the synthetic aqueous phase using CG-Zn(OH)2NPs as an adsorbent. The synthesized nanoparticles were characterized using various instrumental techniques such as Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS) and Brunauer–Emmett–Teller (BET) surface area and pore volume, a particle size analyser, and zero-point charge. The decolorization efficacy of CV dye from an aqueous phase by the adsorbent was examined in batch mode by varying process parameters. The consequences of various experimental variables were optimized using response surface methodology (RSM) to achieve the maximum decolorization efficiency (90.74%) and equilibrium dye uptake, qe (35.12 mg g−1). The optimum pH, dye concentration, CG-Zn(OH)2NPs adsorbent dosage, and particle size were found to be 1.8, 225 mg L−1, 5 g L−1, and 78 μm, respectively for CV dye adsorption capacity at equilibrium. The adsorbent zero-point charge was found to be at pH 8.5. The Langmuir isotherm model provided a good representation of the equilibrium data in aqueous solutions, with a maximum monolayer adsorption capability (qmax) of 40.25 mg g−1 at 299 K. The dye adsorption rate follows a pseudo-second-order kinetic model at various dye concentrations, which indicated that the reaction is more chemisorption than physisorption. The negative values of ΔG and positive values of ΔH at different temperatures indicate that the adsorption process is spontaneous and endothermic, respectively. Reusability tests revealed that the prepared nanoparticles may be used for up to three runs, indicating that the novel CG-Zn(OH)2NPs seems to be a very promising adsorbent for the removal of Coomassie violet dye from wastewater. Full article
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