Green Recycling Research Articles

The Influence of Major Ergonomic Factors on the Demand for Underwear in the Highly Educated Male Group

At present, it is unclear how ergonomic factors of underwear affect men’s work, lifestyle, physiology and psychology, and whether the demand factors of some special groups will affect the development of underwear. This study analyzed the underwear preferences of male groups working in Chinese and European universities from the perspective of ergonomics. The survey results confirm that ergonomic factors significantly affect men’s preference for underwear, including subjective style preference and objective comfort. These problems come from style structure, materials, functional design and size standards. In general, this typical male group needs underwear with good support in standing posture and good comfort in sitting state. This study also provides important information and evidence for the analysis and prediction of group characteristics and demand-oriented product development. Designing underwear products according to consumer needs and avoiding waste of resources from inefficient development has a positive impact on the green development and recycling of textiles.

Catalytic process toward green recycling of polyvinyl chloride: A study on thermodynamic, kinetic and pyrolysis characteristics

Municipal solid wastes (MSW) include a considerable amount of polyvinyl chloride (PVC). How to quickly and harmlessly dispose of the PVC-containing MSW and convert them into a valuable resource is an urgent issue at present. The application of catalysts has yet been proven to be effective in mitigating organic pollutant production. In the present study, a thermogravimetric analyzer (TGA) and pyrolysis-gas chromatography-mass spectrometer (Py-GC/MS) were utilized to investigate the thermodynamic properties, kinetic parameters and pyrolysis characteristics of PVC with different zeolites including HZSM-5 with the Si/Al of 80 and 280, ferrierite, HY and MCM-41 zeolite. It turned out that the introduction of different catalysts with different pore structures and acid site concentrations made different catalytic effects on the cracking mechanism of PVC. Among the five zeolites, MCM-41 decreased temperature at the 50 % conversion to 296 °C, increased weight loss mate at a maximum of 25 %/min and generated fewer PAHs (whose changing amplitude decreased by 94 % in ex-situ catalytic mode in comparison to non-catalytic mode), indicative of its higher catalytic activity in PVC polymer degradation. Under the consideration of maximizing catalytic cracking activity and minimizing secondary pollutants production, non-catalytic dechlorination at approximately 300 °C followed by catalytic degradation in ex-situ mode over mesoporous MCM-41 at higher temperatures was the best recommendation.

Investigating the Effects of Recycled Micropowder and Aggregate on the Properties of Cement Stabilization of Crushed Aggregate (CSCA)

The recycled powder produced in the process of crushing concrete and brick waste (C&BW) into recycled aggregate will cause environmental pollution. To realize the green full recycling of concrete and brick waste, the cement stabilization of crushed aggregate (CSCA) containing recycled brick-concrete composite micropowder (RBCP) and recycled brick-concrete composite aggregate (RBCA) is proposed. In this paper, RBCP, recycled brick-concrete composite fine aggregate (RBCFA), and recycled brick-concrete composite coarse aggregate (RBCCA) were the recycled materials from C&BW. The orthogonal test table was used to analyze the effects of the three recycled materials on the compaction characteristics, mechanical properties, and shrinkage behavior of CSCA at different dosages. The effects of RBCP, RBCCA, and RBCFA on the properties of CSCA are studied by variance analysis methods. On this basis, the micromorphology and the interface transition zone (ITZ) were studied for CSCA and the cement stabilization of crushed aggregate with RBCP, RBCFA, and RBCCA through scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS), and the mechanism was revealed. The results indicate that the addition of RBCP and RBCA can increase the optimal water content while decreasing the optimal dry density of CSCA, and the influence of RBCCA on the optimal water content is greater than that of RBCFA. Three optimal composite replacement systems for CSCA, including 20% RBCP/20%RBCFA/40%RBCCA, are proposed and have the best mechanical and antishrinkage performance through the range analysis. Furthermore, the variance analysis test results show that RBCCA and RBCFA have the most significant effect on the compressive strength and shrinkage strain properties, while RBCP has the most significant effect on the bending tensile strength. It is found that RBCP played a filling effect and pozzolanic activity in the strength formation of CSCA. The SEM/EDS test shows that the CSCA with recycled materials produced the Ca/Si ratio in the interfacial zone between the cement paste and aggregate lower than the CSCA without recycled materials, the largest decline 52.83%. The research results of this paper can provide the potential application of RBCP and RBCA.

Innovative Closed-Loop Recyclable Bio-Based Composites from Epoxidized Waste Flour and Recycled Carbon Fibers.

Epoxy-based composites are designed for long-lasting applications, though their wide use is in contrast with their poor recyclability, which poses serious end-of-life issues. In order to reduce their environmental impact, precursors derived from fossil fuel based raw materials should be replaced with eco-friendly sources. This can be attained by using naturally derived epoxy matrices, or by finding a suitable solution for recycling at the end of life. In this paper, both strategies were analyzed, by replacing traditional monomers with epoxidized waste flour (EWF), an innovative bio-precursor derived from the organic waste stream, and a cleavable hardener, which allowed the recyclability of the matrix. The recyclable matrix was reinforced with recycled carbon fibers, derived from pyrolysis. DSC measurements were carried out in order to optimize the curing steps of the matrix, then flexural tests were performed in order to evaluate the mechanical response of the composite. A green recycling procedure was then investigated, which involved the use of non-toxic solvents and mild working conditions, and allowed recovery of the matrix while still preserving the properties of the carbon fibers. The components obtained after recycling were analyzed by FTIR analysis, which revealed the presence of the epoxy ring on the recycled waste flour. Hence, recycled waste flour was again used as a precursor and mixed with the cleavable hardener, thus, obtaining a closed-loop recycling.

Green and Energy-Saving Recycling of LiCoO2 by Synergetic Pyrolysis with Polyvinyl Chloride Plastics

Green and Energy-Saving Recycling of LiCoO₂ by Synergetic Pyrolysis with Polyvinyl Chloride Plastics

Carbon nanodots as light-activated peroxidase nanozyme for eco-friendly leaching of copper from scrap

The copper is the second largest strategic raw material. Since there is a huge gap between copper production and consumption, a green and eco-sustainable recycling technology is necessary that is able to process the copper from secondary sources of waste and scraps. Here we demonstrate the photo-oxidising properties of pyrrolic nitrogen-dominated carbon nanodots as eco-friendly and powerful oxidase-mimicking nanozyme for leaching of copper from metal scrap under irradiation with either ultraviolet or natural sun light (average intensity of 59 000 lux). The ultra-small nanoparticles with diameter < 5 nm were prepared by 600 W microwave-assisted pyrolysis, which might be considered as energy efficient synthetic method. The developed strategy enables to dissolve Cu metal at neutral pH range (between 5.1 – 8.3) and it might break the pH limitation for recycling of copper in the conventional chemical methods, where toxic and corrosive substances are used. The obtained yield was about 5 %, which is still not satisfactory for practical application in recycle technology. Nevertheless, according to our knowledge there is not any other reported photosensitizer nanozyme, which is capable to induce oxidation and dissolving of copper under natural light irradiation of neutral leaching solution.

Preparation of high-purity lead carbonate and lead oxide from spent lead paste

Compared with pyrometallurgical recycling, hydrometallurgical recycling of spent lead paste has obvious advantages such as energy saving and emission reduction, however, hydrometallurgical recycling of spent lead paste is also characterized by high levels of impurities (e.g.,Fe, Ba and Cu) in the recovered products. In this study, a green process for the conversion of spent lead paste into high-purity lead carbonate is presented. The process consists of four steps: sulfation, desulfurization leaching, distillation and carbonization to obtain high-purity lead carbonate. The details are as follows: (1) Spent lead paste (mainly composed of lead sulfate, lead dioxide, lead oxide and lead monomers) was converted into sulfated lead paste using sulfuric acid, hydrogen peroxide and sodium chloride. (2) The sulfated lead paste was reacted with ammonium acetate to leach the lead while desulfurizing; the leaching rate was reached 99.94% under the conditions of 30 wt% ammonium acetate concentration, 40 °C reaction temperature and 7.5 min reaction time. (3) Glycerol was added to the mother liquor and distilled to obtain a glycerol solution containing lead acetate. (4) Using ammonium carbonate (aq) as a carbonizing agent, reacting for 20 min under the condition that the molar ratio of CO32−/Pb is 1.10 can make more than 99.9% of lead precipitate to obtain high-purity lead carbonate products. (5) The lead carbonate product decomposed into orthorhombic α-PbO at 350 °C. (6) Recovered lead oxide product has better electrochemical performance than commercial lead oxide. This process prepares high-purity lead carbonate and lead oxide products with reduced energy consumption and recycles the spent lead paste. This study provides a feasible technology for green recycling of spent lead paste.

Environmental Effects of Bio-Waste Recycling on Industrial Circular Economy and Eco-Sustainability

Few prior studies have examined the social and environmental consequences of waste generation and recycling, resulting in a policy gap in the sustainability agenda. The research filled a knowledge vacuum in the literature by investigating the environmental repercussions of different waste generation and recycling processes in the Chinese economy. The study analyzed waste production and recycling statistics over the last 46 years, from 1975 to 2020, and their impact on the nation’s emissions per capita. This study used four primary approaches to determine the links between the examined variables, beginning with the unit root test, which identifies the stationary process of the variables’ underlying processes. Second, the autoregressive distributed lag (ARDL) model was used to produce the variables’ short- and long-run estimates. Third, estimations of Granger causality examined the causal relationships between the variables. Finally, innovation accounting matrices (IAM)were utilized to predict the relationships between variables during the following decade. The unit root estimates imply the mix order of variable integration; hence, it is appropriate to employ ARDL modeling for parameter estimations. The ARDL estimations demonstrate that combustible renewables and waste decrease a nation’s carbon emissions by boosting industrial waste recycling. Despite recycling systems, carbon emissions have escalated to uncontrolled levels owing to the massive production of municipal solid garbage. Sustainable waste management and recycling are vital to reducing carbon emissions. Granger’s estimations of causation imply that combustible renewables and waste and carbon emissions cause industrial and municipal solid waste recycling. Additionally, population growth is responsible for greenhouse gas emissions, biowaste recycling, and industrial waste recycling. Furthermore, this shows the two-way connections between combustible renewables and waste and carbon emissions, implying the need to develop green waste recycling strategies in a nation. The IAM method identified future relationships between variables, which aids policymakers in implementing sustainable waste management practices for a nation. This study concludes that the environmental consequences of waste generation and recycling impede the nation’s circular economy agenda, which can be sustained by knowledge spillovers, chemical reduction in manufacturing, and allocating a certain amount of US dollars to ecological resource conservation.

Corrosion behavior of silica-alumina refractories for scrap brass smelter linings

Silica-alumina refractories are extensively served as smelter linings for scrap brass due to their good thermal insulation and cost advantage, yet the sudden failure of refractory caused great disturbance to industrial production, such as furnace stoppage. Thus, the corrosion behavior of the silica-alumina refractory exposed to scrap brass slag was researched. Based on the element occurrence states of slag and refractory, the possible reactions between them were first determined to analyze the thermodynamic feasibility. Then, the effects of temperature and time on corrosion behavior were investigated by static laboratory tests. At the slag-refractory interface, the products of continuous reaction were presented. Three parts of the corrosion process were ascertained: (1) The solid oxides (ZnO, CuO, Cu2O, PbO, etc.) reacted with the compounds of the refractory; (2) The injected liquid composition (NaF, Cu, Pb, Zn, etc.) further reacted with the refractory; (3) The gas phase (fluorine vapor and zinc vapor) invaded and reacted with the interior refractory. Furthermore, it is concluded from the static laboratory tests that the consumption rate of refractory increased by 8.5412 * 10−4 g/day per 100 °C rise, and an intact brick was entirely corroded in 41.40 days. In the industrial process, continuous chemical corrosion and discontinuous physical damage led to the refractory failure. Lastly, the suggestions for prolonging the service life of refractory were proposed. This study will provide guidance for industrial application of silica-alumina refractory in scrap brass production, which has important implications for the green recycling of scrap brass.

Synthesis of Nucleoshell γ-AlOOH as an ultra-high-capacity adsorbent for organic pollutants removal

To solve the problem of effective and low cost of dye removal treatment methods. In this paper, a simple and efficient ionic liquid method for Nucleoshell γ-AlOOH (NA) synthesis is proposed. Hollow γ-AlOOH (HA) prepared by the template method and commercial aluminum hydroxide was also discussed. NA formed a core-shell layered structure with small particle size and large specific surface area, for which the surface space of the adsorbent is fully utilized. The maximum adsorption capacities of Congo red and Methylene blue were 3881.46 mg/g and 1514.66 mg/g, compared to 2544.26 mg/g and 920.52 mg/g for HA. The adsorption process of NA shows a good correlation with pseudo-second-order and the Langmuir model. The adsorption reaction is an exothermic spontaneous reaction. Subsequent treatment can be accomplished by roasting to achieve green recycling. It is shown that NA, as an effective adsorbent, has great potential in the field of wastewater treatment.

Environmental-friendly low-cost direct regeneration of cathode material from spent LiFePO4

The green and low-cost recycling of spent LiFePO4 (LFP) cathode materials has become an urgent problem to be solved. In this work, a completely green and easy scale-up recycling process is developed to recycle the cathode powders from spent LFP batteries. The optimal regeneration conditions are obtained by adjusting temperature, Li+ concentration and reductant dosage. Meanwhile, the mechanism of regeneration is investigated by microscopic characterization and electrochemical performance testing. The regenerated LFP shows a good discharge specific capacity of 148 mAh/g at 0.05 C, which exhibits around 96% the capacity of raw LFP. Additionally, the costs of the consumption only account for 19.8% the price of raw LFP, which indicates that this method has good prospect of economic returns. This regeneration method is low in cost, simple in process, mild in conditions and easy to scale up, providing technical supports for the sustainable development of lithium-ion battery industry.

Green recycling of aramid fiber waste as the friction modifier of POM by solid state shear milling technology

AbstractAramid fiber is widely used in aerospace, machinery, construction, and other fields for its high strength, high elastic modulus, lightweight, and superior comprehensive performance. However, because aramid fiber is difficult to be melted and reprocessed, efficient and environmentally friendly recycling of aramid fiber waste (AFW) is an urgent and challenging issue. In this work, we reported a facile way to recycle AFW for the preparation of friction‐resistant polyoxymethylene (POM)/AFW composites. The ultrafine AFW powder with 64.69 μm in size was fabricated by solid state shear milling (S3M) technology, which broke the amide bond due to the strong compression and shearing during milling. With the increase of milling cycles, the roughness and active groups on the surface of AFW were increased, which was contributed to improving the compatibility between AFW and POM matrix. The morphology observation indicated a good dispersion of AFW in POM. The mechanical property test results showed that the flexural strength increased from 52.69 MPa to 80.12 MPa with 20 wt.% AFW. As a friction modifier, the addition of AFW could improve the tribological properties of POM/AFW composites, and the coefficient of friction (COF) and wear rate of composites with 20 wt.% AFW could decrease by 53.02% and 69.52%, respectively. The S3M technology presented in this work is an efficient and industrialized strategy for AFW recycling to prepare value‐added products, which has great potential in the engineering application field.

Deep Eutectic Solvents (DESs) for Green Recycling of Wasted Lithium-Ion Batteries (LIBs): Progress on Pushing the Overall Efficiency

Deep Eutectic Solvents (DESs) for Green Recycling of Wasted Lithium-Ion Batteries (LIBs): Progress on Pushing the Overall Efficiency

Medical Products and Environmentally Friendly Purchase Intention: What Is the Role of Green Consumers Behavior, Environment Concern, and Recycle Behavior?

Medical Products and Environmentally Friendly Purchase Intention: What Is the Role of Green Consumers Behavior, Environment Concern, and Recycle Behavior?

Hydrometallurgical stepwise separation of alumina and recovery of aluminum fluoride from waste anode cover material of aluminum electrolysis

Anode cover material holds marked importance owing to its effect of maintaining the thermal balance of aluminum reduction cells, and is categorized as solid waste because of its continuous accumulation. However, cover materials contain large amounts of alumina and fluoride; thus, can be considered for strategic resource recovery. This research has developed a process for separating alumina and recovering aluminum fluoride from anode cover materials by aluminum salt solution leaching. In the present work, the effects of different factors on the leaching behaviors of sodium and fluoride during aluminum salt solution leaching were investigated. The results showed that 98.1 % sodium and 95.1 % fluoride were extracted when the Al3+ concentration was 2.5 mol/L, the liquid to solid ratio was 20 mL/g, and the stirring speed was 300 rpm at 90 °C for 2 h. Aluminum and fluoride were then precipitated as aluminum hydroxyfluoride hydrate (AHF) from the leachate. The aluminum fluoride (AlF3) product with high purity was obtained by calcining AHF precipitation, and the average particle size was 66.1 μm. This work demonstrates significant application potential on green recycling of anode cover materials and realize a high-value utilization of aluminum and fluoride resources. This plays a crucial role in the life cycle assessment (LCA) of the anode cover material.

Electrons-Driven Recycling Processes As Alternative for Green Lithium-Ion Battery Recycling

Electrons sourced from low carbon energy sources can be used as a green reagent to enable hydrometallurgical recycling of lithium-ion batteries (LIB), significantly reducing the chemical consumption and carbon footprint of the recycling process. In this talk we will describe electrochemical driven alternatives for metals extraction and separation developed within the critical materials institute (CMI) for the recycling of end-of-life LIBs. The discussion will focus on how these technologies can be incorporated in the battery recycling flowsheet, and the impact of the electrochemical processes in the economic and carbon footprint of battery recycling

(Invited) Electrochemical Pathways Towards Recycling Spent Lithium-Ion Batteries

The ever-increasing grid-scale energy storage farms and electric vehicles call for more secondary lithium-ion batteries (LIBs). However, the battery resource is limited. Thus, the retired LIB is a potential secondary resource for remaking LIBs. Thus, it is urgent to develop efficient and green methods to recycle spent LIBs. Based on the long-time establishments in high-temperature molten salt and electrochemistry, the author developed electrochemical ways to repurpose spent LIBs, including molten salt electrolysis, cathodic assisted electrolysis, and paired electrolysis approaches. Unlike traditional way using chemicals to break down the chemical bonds, the electrochemical methods use electrons to enable the separation. As such, the electrochemical ways are green if renewable electricity is integrated. Hence, we hope to employ electrochemical technologies and classical thermodynamic principles to develop green recycling methods, aiming to provide fundamental insights into the sustainable battery development and renewable energy utilization.

Toward green and efficient recycling of Au(III), Pd(II) and Pt(IV) from acidic medium using UCST-type ionic liquid

The development of efficient ionic liquids (ILs) for disposable separation and recovery of various precious metals was of great importance, but still faced difficult challenges. A phase change temperature-controlled system composed of IL and HCl solution was developed for the extraction and separation of Au(III), Pd(II) and Pt(IV) from secondary resources. UCST (upper critical solution temperature)-type IL ([1,4,7-TMTA][Tf2N]) possessed outstanding selectivity of precious metals and the property of temperature-controlled phase transition. The ability of ILs to form solvated hydrogen bonds was confirmed by quantum-chemical calculation to be correlated with their corresponding UCST. Different experimental parameters were optimized to explore the extraction behavior of IL. It is noteworthy that homogeneous liquid-liquid extraction system (HLLE) constructed by UCST-type IL could significantly enhance the extraction kinetic of Au(III), Pd(II) and Pt(IV) by decreasing phase interface resistance. For Au(III), Pd(II) and Pt(IV), when the system temperatures were higher than 40 °C, 49 °C and 65 °C, the maximum values were 98.5%, 98.3% and 93.2% at the highest efficiency. In addition, the extraction mechanism of anion exchange was revealed by UV–vis, IR, NMR and LC-MS spectrometry. At last, Au(III), Pd(II) and Pt(IV) could be selectively separated from multi-metal solutions where impurity ions coexist by K2C2O4, NH3·H2O and CS(NH2)2/HCl, respectively. After 5 cycles, the extraction performance of [1,4,7-TMTA][Tf2N] maintained. In summary, this paper overcame the obstacle of slow kinetics of solvent extraction technology, and pointed out a way for polymetallic co-extraction and separation in HLLE system.

Internal Motivations, External Contexts, and Sustainable Consumption Behavior in China—Based on the TPB-ABC Integration Model

Population expansion and the depletion of the planet’s natural resources make it necessary to look at human consumption behavior in sustainable development. The purpose of this study is to investigate the influence factors, the influence paths, and the decision-making mechanisms of Chinese consumers’ sustainable consumption behavior through the TPB–ABC integration theory. Based on survey data from 534 consumers in Dongying, China, this study used the partial least squares structural equation model (PLS-SEM) to analyze the main factors that influence the three sections of sustainable consumption behaviors, which are green purchase behavior, green transportation behavior, and recycling and resource conservation behavior. Decision-making mechanisms are discussed concerning impact pathways. The results prove that three internal motivations and two external contexts are intimately linked to customers’ behavioral decisions, with external contexts indirectly shaping individual attitudes. Furthermore, the factors that influence various types of sustainable consumption practices differ. Specifically, green purchase behavior and green transportation behavior are mainly influenced by attitude variables, and negative contexts mainly influence recycling and resource conservation behavior. Finally, the study suggested corresponding policy recommendations to promote sustainable consumption.

Co-Utilization of Sewage Sludge and Rice Husk in Ceramsite Preparation with Selective Adsorption Capacity to Pb.

Realizing the green recycling of sludge is an important link to effectively solve the problem of sludge disposal. In this paper, sewage sludge (SS) and rice husk (RH) were utilized as raw materials in preparing novel ceramsite (SRC) for the treatment of lead-containing wastewater, and its adsorption mechanism was explored. The results showed that the optimal preparation conditions were 40% RH + 60% SS mixture, a sintering temperature of 1190 °C, and a sintering time of 20 min. The basic properties of SRC met Chinese artificial ceramsite filter material standards for water treatment (CJ/T 299-2008). Under optimum adsorption conditions (pH = 6, 1 g/L SRC dosage, 20 mg/L Pb(NO)3 concentration, 18 h), the removal rate of Pb2+ reached 94.7%, and the equilibrium adsorption capacity was 18.94 mg/g. The adsorption process was more consistent with the pseudo-second-order kinetic model and the Langmuir isotherm model, indicating that the adsorption process was dominated by chemisorption. Thermodynamic parameters (ΔH0 > 0, ΔG0 < 0, ΔS0 > 0) indicated that the adsorption reaction was spontaneous and endothermic. The possible adsorption mechanisms are as follows: (1) SRC is rich in layered mesoporous structure, which provides sufficient reaction sites for Pb adsorption; (2) the sintered lawsonite and muscovite can strongly attract Pb and then form a new phase (Pb10[Si2O7]3(OH)2); (3) Pb2+ can bond with the Si–O- bond in aluminosilicates, and the introduction of Pb elevates the degree of polymerization of aluminosilicates in turn, indicating that the adsorption process is stable.