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Development and Modification of New or Recycled Materials and Technological Processes toward Sustainable Development

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Green Materials".

Deadline for manuscript submissions: closed (20 January 2024) | Viewed by 18607

Special Issue Editors

Institute of Recycling Technologies, Faculty of Materials, Metallurgy and Recycling, Technical University of Košice, Letná 9, 042 00 Kosice, Slovakia
Interests: technological and material innovations; elemental composition of materials; recycling technologies; utilization of recycled materials; measurement techniques for physical parameters; circular economy; sustainable development
Special Issues, Collections and Topics in MDPI journals
Institute of Geotechnics, Slovak Academy of Sciences, Watsonova 45, 040 01 Košice, Slovakia
Interests: research and development of electroceramic materials; applications of progressive methods in the field of electron microscopy and microanalytical methods
Special Issues, Collections and Topics in MDPI journals
Institute of Materials and Quality Engineering, Faculty of Materials, Metallurgy and Recycling, Technical University of Košice, Letná 9, 042 00 Kosice, Slovakia
Interests: safety of advanced materials for Li-ion batteries; safety of nanotechnologies in different environment; safety of advanced materials in hydrogen technologies; application of artificial neural networks in material science

Special Issue Information

Dear Colleagues,

Currently, the relationship between sustainable development and circular economy is being intensively discussed. Even if the relationships between these concepts are not explicitly expressed, their common goal is undoubtedly a sustainable society. The basis of this understanding is that natural resources provide inputs for the production and consumption of materials and products, and at the same time, after the end of their useful life, they serve as a stock of materials in the form of waste. This results in clear dependence on the circular economy, sustainable development, and the quality of the environment.

A very important area in this issue is advanced material research as well as technological development, the basis of which is the development and production of sustainable products and processes. The development, modification, and recycling of materials are an integral part of circular economy and sustainability strategies. The importance is also evident in the increasing adoption of these terms in scientific-academic, industrial, and economic fields.

The aim of this Special Issue is to publish original research articles in areas related to the development and modification of new as well as recycled materials and their application possibilities. At the same time, studies focused on innovative technological methods for the processing and recovery of industrially important metals and their alloys, non-metallic materials and composites are also welcome. Additionally, innovative procedures for testing, increasing efficiency, and optimizing processes, aim to recover materials to improve the sustainability of earth's resources. Research in the field of any kind of materials will result in the improvement of the mechanical, chemical, electrical, magnetic, acoustic, and thermal properties of the materials, as well as the understanding of the interrelationship between the composition, structure, and properties of a material. Contributions that use the methods of multicriteria analysis or LCA assessment for comparing products and processes with a focus on environmental, technological, and economic aspects and impacts will also be greatly appreciated.

The scope is designed for scientific and engineering fields such as materials, metallurgy, chemical, mechanical, electrotechnical, environmental, biomedical, aerospace, industrial, earth resources, and others. Fields of operation are not limited and may include, e.g., physical metallurgy, progressive materials, nanomaterials, progressive technologies, structure, chemical composition and properties of materials, hydrometallurgy, pyrometallurgy, biohydrometallurgy, electrometallurgy, primary and secondary materials, recycling technologies, modeling and simulation, SEM, XRF, XRD analyses, LCA assessment, eco-design, mechanics of materials, ceramics, metals and metal alloys, non-metals, composites, electromobility, batteries and accumulators, electronics, hydrogen technologies, applications of materials in various areas and the like.

Dr. Pavol Liptai
Prof. Dr. Jaroslav Briančin
Guest Editors

Dr. Maroš Halama
Guest Editor Assistant

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 special issue 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. Materials 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 2600 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

  • sustainable development
  • advanced materials
  • material innovations
  • circular economy
  • technological innovations

Related Special Issue

Published Papers (15 papers)

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Research

Jump to: Review

14 pages, 4180 KiB  
Article
Comparative Evaluation of Titanium Feedstock Powder Derived from Recycled Battlefield Scrap vs. Virgin Powder for Cold Spray Processing
by Kiran G. Judd, Kyle Tsaknopoulos, Bryer C. Sousa, Marc Pepi and Danielle L. Cote
Materials 2024, 17(5), 1122; https://doi.org/10.3390/ma17051122 - 29 Feb 2024
Viewed by 583
Abstract
Gas-atomization is extensively used to produce metallic feedstock powders for additive manufacturing processes, including gas dynamic cold spray processing. This work explores the potential utility of on-demand recycled titanium scrap feedstock powder as a viable substitute for virgin powder sources. Three recycled titanium [...] Read more.
Gas-atomization is extensively used to produce metallic feedstock powders for additive manufacturing processes, including gas dynamic cold spray processing. This work explores the potential utility of on-demand recycled titanium scrap feedstock powder as a viable substitute for virgin powder sources. Three recycled titanium powders were atomized from different battlefield scrap sources using a mobile foundry developed by MolyWorks Materials Corporation. Recycled titanium alloy powders were compared against virgin Ti-6Al-4V powder to verify there were no significant variations between the recycled and virgin materials. Powder characterization methods included chemical analysis, particle size distribution analysis, scanning electron microscopy (SEM), Karl Fischer (KF) titration moisture content analysis, X-ray diffraction (XRD) phase analysis, microparticle compression testing (MCT), and nanoindentation. Results indicate that recycled titanium powder provides a viable alternative to virgin titanium alloy powders without compromising mechanical capabilities, microstructural features, or ASTM-specified composition and impurity standards. The results of this work will be used to aid future research efforts that will focus on optimizing cold spray parameters to maximize coating density, mechanical strength, and hardness of recycled titanium feedstock powders. “Cold spray” presents opportunities to enhance the sustainability of titanium component production through the utilization of recycled feedstock powder, mitigating issues of long lead times and high waste associated with the use of conventional virgin feedstock. Full article
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24 pages, 3541 KiB  
Article
Evolutionary Optimizing Process Parameters in the Induction Hardening of Rack Bar by Response Surface Methodology and Desirability Function Approach under Industrial Conditions
by Grzegorz Dziatkiewicz, Krzysztof Kuska and Rafał Popiel
Materials 2023, 16(17), 5791; https://doi.org/10.3390/ma16175791 - 24 Aug 2023
Viewed by 768
Abstract
Conditions of industrial production introduce additional complexities while attempting to solve optimization problems of material technology processes. The complexity of the physics of such processes and the uncertainties arising from the natural variability of material parameters and the occurrence of disturbances make modeling [...] Read more.
Conditions of industrial production introduce additional complexities while attempting to solve optimization problems of material technology processes. The complexity of the physics of such processes and the uncertainties arising from the natural variability of material parameters and the occurrence of disturbances make modeling based on first principles and modern computational methods difficult and even impossible. In particular, this applies to designing material processes considering their quality criteria. This paper shows the optimization of the rack bar induction hardening operation using the response surface methodology approach and the desirability function. The industrial conditions impose additional constraints on time, cost and implementation of experimental plans, so constructing empirical models is more complicated than in laboratory conditions. The empirical models of nine system responses were identified and used to construct a desirability function using expert knowledge to describe the quality requirements of the hardening operation. An analysis of the hypersurface of the desirability function is presented, and the impossibility of using classical gradient algorithms during optimization is empirically established. An evolutionary strategy in the form of a floating-point encoded genetic algorithm was used, which exhibits a non-zero probability of obtaining a global extremum and is a gradient-free method. Confirmation experiments show the improvement of the process quality using introduced measures. Full article
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20 pages, 5922 KiB  
Article
Removal of Impurities from EAFD Ammonium Carbonate Leachate and Upgrading the Purity of Prepared ZnO
by Zita Takacova, Jana Piroskova, Andrea Miskufova, Tomas Vindt, Maria Hezelova and Dusan Orac
Materials 2023, 16(14), 5004; https://doi.org/10.3390/ma16145004 - 14 Jul 2023
Cited by 2 | Viewed by 583
Abstract
The paper describes cementation as a suitable method applied in the refining of EAFD leachates in order to obtain required purity of ZnO for specific industrial application. For study of cementation conditions, the leachate from alkaline leaching with (NH4)2CO [...] Read more.
The paper describes cementation as a suitable method applied in the refining of EAFD leachates in order to obtain required purity of ZnO for specific industrial application. For study of cementation conditions, the leachate from alkaline leaching with (NH4)2CO3 was used. The leachates contained a high amount of zinc (8000–12,000 µg/mL) and a low content of impurities such as iron, lead, copper, chromium and manganese in the range of 1–21 µg/mL. Cementation conditions were predicted by thermodynamic study, theoretically confirming the viability of the proposed experiments at the considered pH = 8–9. Cementation experiments were carried out using powdered zinc and aluminium (5 g/L) as cementation agents in the first phase separately. To increase the cementation efficiency, their combination was used (2.5:2.5 g/L or 5:5 g/L) at temperatures of 20, 40, 60 and 80 °C for 30 min. The optimum cementation conditions were established as: Zn:Al = 5:5 g/L, 60 °C. Under the given conditions, 100% of Fe, Cu, Pb and Mn were removed from the leachate. The ZnO with the maximum purity of 96.67% was obtained by crystallization of cemented leachate at 105 °C, followed by calcination at 900 °C for 4 h. ZnO with such a purity is suitable for use in the electrical or rubber industries. Full article
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12 pages, 5131 KiB  
Article
The Synergistic Lubrication Effects of h-BN and g-C3N4 Nanoparticles as Oil-Based Additives for Steel/Steel Contact
by Wen Zhong, Jiazhi Dong, Siqiang Chen and Zhe Tong
Materials 2023, 16(14), 4979; https://doi.org/10.3390/ma16144979 - 13 Jul 2023
Viewed by 836
Abstract
The synergistic effect of different types of solid particles in liquid lubricants is of great interest. In this work, g-C3N4 nanosheets were initially prepared using a calcination method and then as-prepared, and h-BN were used as lubricating additives to the [...] Read more.
The synergistic effect of different types of solid particles in liquid lubricants is of great interest. In this work, g-C3N4 nanosheets were initially prepared using a calcination method and then as-prepared, and h-BN were used as lubricating additives to the white oil. A comparison between the mixed additives and the single g-C3N4 or h-BN additives revealed that the base oil with the addition of g-C3N4 and h-BN showed the best lubricating properties. The results show a 12.3% reduction in friction coefficient, resulting in a 68.6% reduction in wear rate compared to the white oil when filled with 0.5 wt% g-C3N4 and h-BN (1:1 by weight). Moreover, the addition of g-C3N4 and h-BN improves the high-temperature lubrication properties of the white oil. However, the friction coefficient and wear rate increase with increasing oil temperature. The large contact area between g-C3N4 and its sliding counterpart and the strong adhesive force between h-BN and its sliding counterpart improve the film formation efficiency, leading to enhanced tribological properties under oil lubrication conditions. Full article
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12 pages, 4459 KiB  
Article
The Influence of Manganese Addition on the Properties of Biodegradable Zinc-Manganese-Calcium Alloys
by Wanda Mamrilla, Zuzana Molčanová, Beáta Ballóková, Miroslav Džupon, Róbert Džunda, Dávid Csík, Štefan Michalik, Maksym Lisnichuk and Karel Saksl
Materials 2023, 16(13), 4655; https://doi.org/10.3390/ma16134655 - 28 Jun 2023
Viewed by 785
Abstract
This study focuses on the preparation and characterization of zinc-based alloys containing magnesium, calcium, and manganese. The alloys were prepared by the melting of pure elements, casting them into graphite molds, and thermo-mechanically treating them via hot extrusion. The phase compositions of the [...] Read more.
This study focuses on the preparation and characterization of zinc-based alloys containing magnesium, calcium, and manganese. The alloys were prepared by the melting of pure elements, casting them into graphite molds, and thermo-mechanically treating them via hot extrusion. The phase compositions of the samples were analyzed using X-ray diffraction technique and SEM/EDX analysis. The analysis confirmed that in addition to the Zn matrix, the materials are reinforced by the CaZn13, MgZn2, and Mn-based precipitates. The mechanical properties of the alloys were ascertained by tensile, compressive, and bending tests, measurement of the samples microhardness and elastic modulus. The results indicate that an increase in Mn content leads to an increase in the maximum stress experienced under both tension and compression. However, the plastic deformation of the alloys decreases with increasing Mn content. This study provides valuable insights into the microstructural changes and mechanical behavior of zinc-based alloys containing magnesium, calcium, and manganese, which can be used to design alloys for specific biomedical applications. Full article
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14 pages, 3458 KiB  
Article
A Comprehensive View of the Optimization of Chromium (VI) Processing through the Application of Electrocoagulation Using a Pair of Steel Electrodes
by Ľubomír Pikna, Mária Heželová, Dagmar Remeteiová, Silvia Ružičková, Róbert Findorák and Jaroslav Briančin
Materials 2023, 16(8), 3027; https://doi.org/10.3390/ma16083027 - 11 Apr 2023
Viewed by 866
Abstract
In the presented article, an electrocoagulation method using a steel cathode and a steel anode was used to obtain chromium from laboratory-prepared model solutions with known compositions. The study aimed to analyze the effect of solution conductivity, pH, and 100% efficiency of chromium [...] Read more.
In the presented article, an electrocoagulation method using a steel cathode and a steel anode was used to obtain chromium from laboratory-prepared model solutions with known compositions. The study aimed to analyze the effect of solution conductivity, pH, and 100% efficiency of chromium removal from the solution, as well as the highest possible Cr/Fe ratio in the final solid product throughout the process of electrocoagulation. Different concentrations of chromium (VI) (100, 1000, and 2500 mg/L) and different pH values (4.5, 6, and 8) were investigated. Various solution conductivities were provided by the addition of 1000, 2000, and 3000 mg/L of NaCl to the studied solutions. Chromium removal efficiency equal to 100% was achieved for all studied model solutions for different experiment times, depending on the selected current intensity. The final solid product contained up to 15% chromium in the form of mixed FeCr hydroxides obtained under optimal experimental conditions: pH = 6, I = 0.1 A, and c (NaCl) = 3000 mg/L. The experiment indicated the advisability of using a pulsed change of electrode polarity, which led to a reduction in the time of the electrocoagulation process. The results may help in the rapid adjustment of the conditions for further electrocoagulation experiments, and they can be used as the optimization experimental matrix. Full article
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18 pages, 2897 KiB  
Article
Development of High Temperature Water Sorbents Based on Zeolites, Dolomite, Lanthanum Oxide and Coke
by Esther Acha, Ion Agirre and V. Laura Barrio
Materials 2023, 16(7), 2933; https://doi.org/10.3390/ma16072933 - 06 Apr 2023
Cited by 2 | Viewed by 1087
Abstract
Methanation is gaining attention as it produces green methane from CO2 and H2, through Power-to-Gas technology. This process could be improved by in situ water sorption. The main difficulty for this process intensification is to find effective water sorbents at [...] Read more.
Methanation is gaining attention as it produces green methane from CO2 and H2, through Power-to-Gas technology. This process could be improved by in situ water sorption. The main difficulty for this process intensification is to find effective water sorbents at useful reaction temperatures (275–400 °C). The present work comprises the study of the water sorption capacity of different materials at 25–400 °C. The sorption capacity of the most studied solid sorbents (zeolites 3A & 4A) was compared to other materials such as dolomite, La2O3 and cokes. In trying to improve their stability and sorption capacity at high temperatures, all these materials were modified with alkaline-earth metals (Ba, Ca & Mg). Lanthana-Ba and dolomite sorbents were the most promising materials, reaching water sorption values of 120 and 102 mgH2O/gsorbent, respectively, even at 300 °C, i.e., values 10-times higher than the achieved ones with zeolites 3A or 4A under the same operating conditions. At these high temperatures, around 300 °C, the water sorption process was concluded to be closer to chemisorption than to physisorption. Full article
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12 pages, 3632 KiB  
Article
One-Step Electrochemical Synthesis and Surface Reconstruction of NiCoP as an Electrocatalyst for Bifunctional Water Splitting
by Minhao Sheng, Yawei Yang, Xiaoqing Bin and Wenxiu Que
Materials 2023, 16(4), 1529; https://doi.org/10.3390/ma16041529 - 11 Feb 2023
Cited by 5 | Viewed by 1870
Abstract
We adopted a simple one-step electrochemical deposition to acquire an efficient nickel cobalt phosphorus (NiCoP) catalyst, which avoided the high temperature phosphatization engineering involved in the traditional synthesis method. The effects of electrolyte composition and deposition time on electrocatalytic performance were studied systematically. [...] Read more.
We adopted a simple one-step electrochemical deposition to acquire an efficient nickel cobalt phosphorus (NiCoP) catalyst, which avoided the high temperature phosphatization engineering involved in the traditional synthesis method. The effects of electrolyte composition and deposition time on electrocatalytic performance were studied systematically. The as-prepared NiCoP achieved the lowest overpotential (η10 = 111 mV in the acidic condition and η10 = 120 mV in the alkaline condition) for the hydrogen evolution reaction (HER). Under 1 M KOH conditions, optimal oxygen evolution reaction (OER) activity (η10 = 276 mV) was also observed. Furthermore, the bifunctional NiCoP catalyst enabled a high-efficiency overall water-splitting by applying an external potential of 1.69 V. The surface valence and structural evolution of NiCoP samples with slowly decaying stability under alkaline conditions are revealed by XPS. The NiCoP is reconstructed into the Ni(Co)(OH)2 (for HER) and Ni(Co)OOH (for OER) on the surface with P element loss, acting as real “active sites”. Full article
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16 pages, 4126 KiB  
Article
Determining the Mechanical Properties of Solid Plates Obtained from the Recycling of Cable Waste
by Maciej Wędrychowicz, Władysław Papacz, Janusz Walkowiak, Adam Bydałek, Andrzej Piotrowicz, Tomasz Skrzekut, Jagoda Kurowiak, Piotr Noga and Mirosław Kostrzewa
Materials 2022, 15(24), 9019; https://doi.org/10.3390/ma15249019 - 16 Dec 2022
Viewed by 1120
Abstract
In this article, the possibility of obtaining a solid plate from waste cable sheaths, by mechanical recycling, i.e., grinding, plasticising and pressing, is discussed—waste cable sheaths being pure PVC with a slight admixture of silicone. Press moulding was carried out under the following [...] Read more.
In this article, the possibility of obtaining a solid plate from waste cable sheaths, by mechanical recycling, i.e., grinding, plasticising and pressing, is discussed—waste cable sheaths being pure PVC with a slight admixture of silicone. Press moulding was carried out under the following conditions: temperature 135 °C, heating duration 1 h and applied pressure 10 MPa. The yield point of the obtained solid plate obtained was 15.0 + −0.6 MPa, flexural strength 0.94 MPa, yield point 0.47 MPa and Charpy’s impact strength 5.1 kJ/m2. The resulting solid plate does not differ significantly from the input material, in terms of mechanical strength, so, from the point of view of strength, that is, from a technical point of view, such promising processing of waste cables can be carried out successfully in industrial practice. Full article
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15 pages, 5873 KiB  
Article
Theoretical and Practical Evaluation of the Feasibility of Zinc Evaporation from the Bottom Zinc Dross as a Valuable Secondary Material
by Pauerová Katarína, Trpčevská Jarmila, Briančin Jaroslav and Plešingerová Beatrice
Materials 2022, 15(24), 8843; https://doi.org/10.3390/ma15248843 - 11 Dec 2022
Cited by 1 | Viewed by 1132
Abstract
This study presents a theoretical and practical evaluation of zinc evaporation from bottom zinc dross (hard zinc) as a secondary zinc source (zinc content approximately 94–97%), which originates in the batch hot-dip galvanizing process. The thermodynamics of the zinc evaporation process were studied [...] Read more.
This study presents a theoretical and practical evaluation of zinc evaporation from bottom zinc dross (hard zinc) as a secondary zinc source (zinc content approximately 94–97%), which originates in the batch hot-dip galvanizing process. The thermodynamics of the zinc evaporation process were studied under the normal pressure (100 kPa) in the inert atmosphere, using argon with flow rate 90 mL/min. Samples were subjected to the evaporation process for 5, 10 and 20 min under the temperature of 700 °C and 800 °C, respectively. For the theoretical thermodynamic study, HSC Chemistry 6.1 software was used and final products, as well as residuals after the evaporation process, were analyzed by SEM (Scanning Electron Microscopy) and EDX (Energy Dispersive X-ray). Calculated and experimental argon consumption in the process of zinc evaporation has been compared. A high purity zinc with efficiency over 99% was reached. Due to a dynamic regime, argon consumption at the temperature of 700 °C and 800 °C were 7 times and 3 times, respectively, less than calculated. Full article
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Review

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20 pages, 6208 KiB  
Review
Recent Progress of Layered Double Hydroxide-Based Materials in Wastewater Treatment
by Yanli Fu, Xiaoqian Fu, Wen Song, Yanfei Li, Xuguang Li and Liangguo Yan
Materials 2023, 16(16), 5723; https://doi.org/10.3390/ma16165723 - 21 Aug 2023
Cited by 4 | Viewed by 1384
Abstract
Layered double hydroxides (LDHs) can be used as catalysts and adsorbents due to their high stability, safety, and reusability. The preparation of modified LDHs mainly includes coprecipitation, hydrothermal, ion exchange, calcination recovery, and sol–gel methods. LDH-based materials have high anion exchange capacity, good [...] Read more.
Layered double hydroxides (LDHs) can be used as catalysts and adsorbents due to their high stability, safety, and reusability. The preparation of modified LDHs mainly includes coprecipitation, hydrothermal, ion exchange, calcination recovery, and sol–gel methods. LDH-based materials have high anion exchange capacity, good thermal stability, and a large specific surface area, which can effectively adsorb and remove heavy metal ions, inorganic anions, organic pollutants, and oil pollutants from wastewater. Additionally, they are heterogeneous catalysts and have excellent catalytic effect in the Fenton system, persulfate-based advanced oxidation processes, and electrocatalytic system. This review ends with a discussion of the challenges and future trends of the application of LDHs in wastewater treatment. Full article
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31 pages, 5768 KiB  
Review
Current Trends in Spent Portable Lithium Battery Recycling
by Zita Takacova, Dusan Orac, Jakub Klimko and Andrea Miskufova
Materials 2023, 16(12), 4264; https://doi.org/10.3390/ma16124264 - 08 Jun 2023
Cited by 4 | Viewed by 1875
Abstract
This paper provides an overview of the current state of the field in spent portable lithium battery recycling at both the research and industrial scales. The possibilities of spent portable lithium battery processing involving pre-treatment (manual dismantling, discharging, thermal and mechanical-physical pre-treatment), pyrometallurgical [...] Read more.
This paper provides an overview of the current state of the field in spent portable lithium battery recycling at both the research and industrial scales. The possibilities of spent portable lithium battery processing involving pre-treatment (manual dismantling, discharging, thermal and mechanical-physical pre-treatment), pyrometallurgical processes (smelting, roasting), hydrometallurgical processes (leaching followed by recovery of metals from the leachates) and a combination of the above are described. The main metal-bearing component of interest is the active mass or cathode active material that is released and concentrated by mechanical-physical pre-treatment procedures. The metals of interest contained in the active mass include cobalt, lithium, manganese and nickel. In addition to these metals, aluminum, iron and other non-metallic materials, especially carbon, can also be obtained from the spent portable lithium batteries. The work describes a detailed analysis of the current state of research on spent lithium battery recycling. The paper presents the conditions, procedures, advantages and disadvantages of the techniques being developed. Moreover, a summary of existing industrial plants that are focused on spent lithium battery recycling is included in this paper. Full article
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15 pages, 4093 KiB  
Review
Zeolite-Encaged Luminescent Silver Nanoclusters
by Ling Pan, Song Ye, Xinling Xv, Peixuan Lin, Ruihao Huang and Deping Wang
Materials 2023, 16(10), 3736; https://doi.org/10.3390/ma16103736 - 15 May 2023
Cited by 3 | Viewed by 1158
Abstract
Silver nanoclusters (Ag NCs) are nanoscale aggregates that possess molecular-like discrete energy levels, resulting in electronic configuration-dependent tunable luminescence spanning the entire visible range. Benefiting from the efficient ion exchange capacity, nanometer dimensional cages, and high thermal and chemical stabilities, zeolites have been [...] Read more.
Silver nanoclusters (Ag NCs) are nanoscale aggregates that possess molecular-like discrete energy levels, resulting in electronic configuration-dependent tunable luminescence spanning the entire visible range. Benefiting from the efficient ion exchange capacity, nanometer dimensional cages, and high thermal and chemical stabilities, zeolites have been employed as desirable inorganic matrices to disperse and stabilize Ag NCs. This paper reviewed the recent research progresses on the luminescence properties, spectral manipulation, as well as the theoretical modelling of electronic structure and optical transition of Ag NCs confined inside various zeolites with different topology structures. Furthermore, potential applications of the zeolite-encaged luminescent Ag NCs in lighting, gas monitoring and sensing were presented. This review concludes with a brief comment on the possible future directions in the study of zeolite-encaged luminescent Ag NCs. Full article
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17 pages, 8459 KiB  
Review
Sustainable Lifecycle of Perforated Metal Materials
by Viktors Mironovs, Jekaterina Kuzmina, Dmitrijs Serdjuks, Yulia Usherenko and Mihails Lisicins
Materials 2023, 16(8), 3012; https://doi.org/10.3390/ma16083012 - 11 Apr 2023
Cited by 1 | Viewed by 1757
Abstract
In an era of rapidly growing consumer demand and the subsequent development of production, light materials and structures with a wide range of applications are becoming increasingly important in the field of construction and mechanical engineering, including aerospace engineering. At the same time, [...] Read more.
In an era of rapidly growing consumer demand and the subsequent development of production, light materials and structures with a wide range of applications are becoming increasingly important in the field of construction and mechanical engineering, including aerospace engineering. At the same time, one of the trends is the use of perforated metal materials (PMMs). They are used as finishing, decorative and structural building materials. The main feature of PMMs is the presence of through holes of a given shape and size, which makes it possible to have low specific gravity; however, their tensile strength and rigidity can vary widely depending on the source material. In addition, PMMs have several properties that cannot be achieved with solid materials; for example, they can provide considerable noise reduction and partial light absorption, significantly reducing the weight of structures. They are also used for damping dynamic forces, filtering liquids and gases and shielding electromagnetic fields. For the perforation of strips and sheets, cold stamping methods are usually used, carried out on stamping presses, particularly using wide-tape production lines. Other methods of manufacturing PMMs are rapidly developing, for example, using liquid and laser cutting. An urgent but relatively new and little-studied problem is the recycling and further efficient use of PMMs, primarily such materials as stainless and high-strength steels, titanium, and aluminum alloys. The life cycle of PMMs can be prolonged because they can be repurposed for various applications such as constructing new buildings, designing elements, and producing additional products, making them more environmentally friendly. This work aimed to overview sustainable ways of PMM recycling, use or reuse, proposing different ecological methods and applications considering the types and properties of PMM technological waste. Moreover, the review is accompanied by graphical illustrations of real examples. PMM waste recycling methods that can prolong their lifecycle include construction technologies, powder metallurgy, permeable structures, etc. Several new technologies have been proposed and described for the sustainable application of products and structures based on perforated steel strips and profiles obtained from waste products during stamping. With more developers aiming for sustainability and buildings achieving higher levels of environmental performance, PMM provides significant environmental and aesthetic advantages. Full article
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19 pages, 31279 KiB  
Review
Morphological, Mechanical and Thermal Properties of Rubber Foams: A Review Based on Recent Investigations
by Ehsan Rostami-Tapeh-Esmaeil and Denis Rodrigue
Materials 2023, 16(5), 1934; https://doi.org/10.3390/ma16051934 - 26 Feb 2023
Cited by 3 | Viewed by 1819
Abstract
During recent decades, rubber foams have found their way into several areas of the modern world because these materials have interesting properties such as high flexibility, elasticity, deformability (especially at low temperature), resistance to abrasion and energy absorption (damping properties). Therefore, they are [...] Read more.
During recent decades, rubber foams have found their way into several areas of the modern world because these materials have interesting properties such as high flexibility, elasticity, deformability (especially at low temperature), resistance to abrasion and energy absorption (damping properties). Therefore, they are widely used in automobiles, aeronautics, packaging, medicine, construction, etc. In general, the mechanical, physical and thermal properties are related to the foam’s structural features, including porosity, cell size, cell shape and cell density. To control these morphological properties, several parameters related to the formulation and processing conditions are important, including foaming agents, matrix, nanofillers, temperature and pressure. In this review, the morphological, physical and mechanical properties of rubber foams are discussed and compared based on recent studies to present a basic overview of these materials depending on their final application. Openings for future developments are also presented. Full article
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