Integrating the valence theory and the norm activation theory to understand consumers’ e-waste recycling intention

Electrical and electronic waste(e-waste)is a growing challenge,matching the widespread boom in the use of information and communication technology.Opposite to an alarming increasing amount of e-waste,a low rate of consumer engagement in ensuring the proper disposal of such materials intensifies the pressure on the exist‐ing e-waste crisis.To deal with this thorny problem,it is of great interest to grasp consumers’disposal and re‐cycling behavioral intentions.Therefore,this study attempts to understand complementary perspectives around consumers’e-waste recycling intention based on the integration of the valence theory and the norm activation theory.Four data mining models using classification and prediction-based algorithms,namely Chi squared automatic interaction detector(CHAID),Neural network,Discriminant analysis,and Quick,unbiased,efficient statistical tree(QUEST),were employed to analyze a set of the 398 data collected in Vietnam.The re‐sults revealed that the social support value is by far the most critical predictor,followed by the utilitarian value,task difficulty,and monetary risk.It is also noteworthy that the awareness of consequences,education background,the ascription of responsibility,and age were also ranked as critical affecting factors.The lowest influential predictors found in this study were income and gender.In addition,a comparison was made in terms of the classification performance of the four utilized data mining techniques.Based on several evalua‐tion measurements(confusion matrix,accuracy,precision,recall,specificity,F-measure,ROC curve,and AUC),the aggregated results suggested that CHAID and Neural network performed the best.The findings of this research are expected to assist policymakers and future researchers in updating all information surround‐ing consumer behavioral intention-related topics focusing on e-waste.Furthermore,the adoption of data min‐ing algorithms for prediction is another insight of this study,which may shed the light on data mining applica‐tions in such environmental studies in the future.

Thoughts on e-waste recycling

This paper summarizes the situation of e-waste recycling in China, points out several key problems, identify the causes and draw lessons and experiences abroad about e-waste management, propose systematic suggestions from the production side, the recovery side, consumers side, government departments and thelegislation.

Comparative Study on the E-waste Recycling Systems in Japan and China

This study aims to identify processes, current situations and issues of recycling systems for four home appliances, namely, air conditioners, television receivers, refrigerators, and washing machines, among e-wastes in China and Japan for understanding and comparison of their characteristics. In accordance with results of a literature search, review of information disclosed online, and questionnaire survey conducted, the findings of this study are summarized in the following two points： （1） The results show that in Japan most of the home appliances mentioned above have been collected through home appliance recycling tickets, resulting in an issue of ＂requiring some effort＂ in treatment and recycling stages, and most plants have contracted out their e-waste recycling; （2） It is found out that advantages of the recycling system in Japan include easiness to monitor concrete data and thorough environmental friendliness ensured while its disadvantages include illegal dumping and export. It becomes apparent that advantages of the recycling system in China include a high reuse rate, low treatment cost, and fewer illegal dumping while its disadvantages include less safe reused products, environmental pollution caused by e-waste treatment, illegal import and difficulty in obtaining data.

Developing an Extended Theory of Planned Behavior Model for Small E-Waste Recycling:An Analysis of Consumer Behavior Determinants

WEEE(Waste Electrical and Electronic Equipment),also called e-waste,has become the world’s fastest-growing waste stream but only has a 17.4%recycling rate according to the Global E-waste Monitor 2020.The collection rate for sWEEE(Small WEEE),e.g.,used mobile phones,is even lower than 10%due to stockpiling at home and improper disposal via the general waste or private informal channels.The purpose of this paper was to(a)review how the TPB(Theory of Planned Behavior)was applied in the literature related to consumer behavioral intention for WEEE recycling and determine the most significant TPB predictors by comparing their standardized influence coefficients across various studies,and(b)identify additional behavior determinants specific to sWEEE recycling and thus develop a new TPB-sWEEE theoretical framework by integrating the TPB model with these new determinants in order to improve the predictability of consumers’sWEEE recycling behavioral intention.This paper reviewed over 30 peer-reviewed studies from Scopus and high impact factor journals and led to the following three key findings:(a)More variables of recycling behavioral intention determinants such as the size of WEEE need to be considered;(b)Eight sWEEE-specific behavioral determinants have been identified and included in the newly developed TPB-sWEEE model,including consumers’Sentimental Attachment,Data Security Concern,Economic Incentives,and How-to Knowledge;(c)For some sWEEE-specific determinants,their extent of influence differs across various regions and countries.This paper contributes to the sWEEE-specific consumer recycling behavior theoretical framework to fill the existing gap in the literature and provides recommendations through the new model for research-based behavioral intervention strategies and policy designs globally.

Contamination and Remediation of Heavy Metals in Soils near E-waste Recycling Area

In order to assess heavy metals pollution in agricultural soil after renovation in typical e-waste recycling areas, 212 soil samples were col- lected and the mass fractions of 7 kinds of heavy metals （Cd, Cr, Cu, Hg, Ni, Pb and Zn） were analyzed. The results indicated that heavy metals pollution in agricultural soil was commonly existed in the study areas, and the soil was slightly contaminated by Pb but was moderately or critically polluted by Cd and Cu. However, the carcinogenic risk and non-carcinogenic risk status by heavy metals pollution were beyond acceptable levels, and soil remediation was quite necessary. After some investigations of bioremediation, we found that saponin as washing agent could highly strenqthen the behavior of heavy metals desorption from soil ,which had a good prospect of engineering practice.

Colloid-facilitated release of polybrominated diphenyl ethers at an e-waste recycling site: evidence from undisturbed soil core leaching experiments

Polybrominated diphenyl ethers (PBDEs), a class of persistent organic pollutants, have been frequently detected in soil at e-waste recycling sites. However, the key factors controlling the transport of PBDEs from surface soil to the vadose zone and groundwater are unclear. Here, colloid-enhanced leaching of PBDEs from undisturbed soil cores collected at an e-waste recycling site in Tianjin, China, is reported. Spatially heterogeneous release of colloids and PBDEs was observed in all the tested soil cores under chemical and hydrodynamic perturbations, indicating the presence of preferential flow paths. Colloid concentration in the effluent significantly increased as ionic strength decreased (from 10 to 0.01 mmol/L), probably due to the stronger electrostatic repulsion between colloidal particles and the soil matrix at lower ionic strength. In contrast, colloid mobilization was not significantly affected by the changes in pH of the influent (from 4.0 to 10.0) and flow rate (from a Darcy velocity of 1.5 to 6.0 cm/h). The concentrations of 2,2′,3,3′,4,4′,5,5′,6,6′-decabromodiphenyl ether (BDE-209), the predominant PBDE congener at the site, detected in the leachate (ranging from 1.09 to 3.43 ng/L) were much lower than previously reported results from packed column leaching tests, and were positively correlated with colloid concentrations. This indicates that remobilization of colloids at e-waste recycling sites can promote the leaching and downward migration of PBDEs from surface soil. The findings highlight the potential risk of surface soil PBDE contamination to groundwater quality and call for further understanding of colloid-facilitated transport for predicting the fate of PBDEs at e-waste recycling sites.

Legacies and health risks of heavy metals,polybrominated diphenyl ethers,and polychlorinated dibenzo-dioxins/furans at e-waste recycling sites in South China

Informal electronic-waste(e-waste)recycling sites pose substantial health risks to surrounding environments and populations,yet they are not properly regulated.In this study,the soil levels of copper,lead,cadmium,eight polybrominated diphenyl ethers(PBDEs),and 18 polychlorinated dibenzo-dioxins/furans(PCDD/Fs)were measured at two e-waste recycling sites in South China between 2014 and 2019.Both sites have been abandoned for natural restoration.Our results indicate that the mean Cd and PCDD/F levels at Site A in 2019 were higher than those recommended by current safety guidelines.Meanwhile,the highest exposure among children was 1.36×10^(−2)mg/(kg·d)for Cu,followed by 5.05×10^(−3)mg/(kg·d)for Pb,9.71 ng/(kg·d)for PBDEs,and 6.82 ng TEQ/(kg·d)for PCDD/Fs.Children were at elevated risk for health problem posed by Pb and Cu exposure at both sites(hazard quotient>1)and by PCDD/Fs at Site A.Further risk assessment was conducted on the target organs and endpoints of heavy metals and PCDD/Fs.The hazard index(HI)for the target organ mixed-risk of heavy metals was high(HI=1.27),as was that of PCDD/Fs(HI=1.66),which can disrupt endocrine function and pose a risk of reproductive toxicity in children.Owing to incomplete cleaning,contaminants persist in soils over long periods and may harm nearby environments and communities.Our study demonstrates that heavy metal,PBDE,and PCDD/F contamination have not yet been remediated,and intervention is needed to reduce pollution and associated risks in areas affected by e-waste.

Airborne PCDD/Fs in two e-waste recycling regions after stricter environmental regulations

Since the 2010 s, the authorities of Guangdong province and local governments have enhanced law enforcement and environmental regulations to abolish open burning, acid washing, and other uncontrolled e-waste recycling activities. In this study, ambient air and indoor dust near different kinds of e-waste recycling processes were collected in Guiyu and Qingyuan to investigate the pollution status of particles and polychlorinated dibenzo-pdioxins and furans（PCDD/Fs） after stricter environmental regulations. PM_（2.5） and PCDD/Fs both showed significantly reduced levels in the two regions compared with the documented data. The congener distribution and principal component analysis results also confirmed the significant differences between the current PCDD/Fs pollution characterizations and the historical ones. The estimated total intake doses via air inhalation and dust ingestion of children in the recycling region of Guiyu ranged from 10 to 32 pg TEQ/（kg·day）, which far exceeded the tolerable daily intake（TDI） limit（1–4 pg TEQ/（kg·day）. Although the measurements showed a significant reduction of the release of PCDD/Fs, the pollution status was still considered severe in Guiyu town after stricter regulations were implemented.

Progress,challenges,and prospects of spent lithium-ion batteries recycling:A review

The recycling and reutilization of spent lithium-ion batteries(LIBs)have become an important measure to alleviate problems like resource scarcity and environmental pollution.Although some progress has been made,battery recycling technology still faces challenges in terms of efficiency,effectiveness and environmental sustainability.This review aims to systematically review and analyze the current status of spent LIB recycling,and conduct a detailed comparison and evaluation of different recycling processes.In addition,this review introduces emerging recycling techniques,including deep eutectic solvents,molten salt roasting,and direct regeneration,with the intent of enhancing recycling efficiency and diminishing environmental repercussions.Furthermore,to increase the added value of recycled materials,this review proposes the concept of upgrading recycled materials into high value-added functional materials,such as catalysts,adsorbents,and graphene.Through life cycle assessment,the paper also explores the economic and environmental impacts of current battery recycling and highlights the importance that future recycling technologies should achieve a balance between recycling efficiency,economics and environmental benefits.Finally,this review outlines the opportunities and challenges of recycling key materials for next-generation batteries,and proposes relevant policy recommendations to promote the green and sustainable development of batteries,circular economy,and ecological civilization.

Direct recycling of Li-ion batteries from cell to pack level:Challenges and prospects on technology,scalability,sustainability,and economics

Direct recycling is a novel approach to overcoming the drawbacks of conventional lithium-ion battery(LIB)recycling processes and has gained considerable attention from the academic and industrial sectors in recent years.The primary objective of directly recycling LIBs is to efficiently recover and restore the active electrode materials and other components in the solid phase while retaining electrochemical performance.This technology's advantages over traditional pyrometallurgy and hydrometallurgy are costeffectiveness,energy efficiency,and sustainability,and it preserves the material structure and morphology and can shorten the overall recycling path.This review extensively discusses the advancements in the direct recycling of LIBs,including battery sorting,pretreatment processes,separation of cathode and anode materials,and regeneration and quality enhancement of electrode materials.It encompasses various approaches to successfully regenerate high-value electrode materials and streamlining the recovery process without compromising their electrochemical properties.Furthermore,we highlight key challenges in direct recycling when scaled from lab to industries in four perspectives:(1)battery design,(2)disassembling,(3)electrode delamination,and(4)commercialization and sustainability.Based on these challenges and changing market trends,a few strategies are discussed to aid direct recycling efforts,such as binders,electrolyte selection,and alternative battery designs;and recent transitions and technological advancements in the battery industry are presented.

Increasing Threat of Scarcity Prompts Rise in Water Recycling

In January 2018,construction wrapped on Salesforce Tower(Fig.1),a 61-story office building that now dominates the skyline of San Francisco,CA,USA.In addition to being the tallest building in the city,Salesforce Tower is the largest structure in the world with an onsite water recycling system.Built by the Australian com-pany Aquacell(Milton,NSW,Australia),the system cleans 113 m^(3)of sewage,sink,shower,and other wastewater each day for use in irrigation and flushing toilets,saving an estimated 35000 m?of water anmually[1].The building is just one of dozens in San Fran-cisco outitted with their own water recycling systems,thanks to a city mandate enacted in 2015[1].

Erratum to: Pyrometallurgical recycling of end -of-life lithium-ion batteries

Erratum to:International Journal of Minerals,Metallurgy and Materials Volume 31,Number 7,July 2024,Page 1554 https://doi.org/10.1007/s12613-024-2907-7 In this article,affiliation 1 has been erroneously given as Department of Materials Science and Engineering,Seoul 03722,Korea.

Pyrometallurgical recycling of end-of-life lithium-ion batteries

The global importance of lithium-ion batteries(LIBs)has been increasingly underscored with the advancement of high-performance energy storage technologies.However,the end-of-life of these batteries poses significant challenges from environmental,economic,and resource management perspectives.This review paper focuses on the pyrometallurgy-based recycling process of lithium-ion batteries,exploring the fundamental understanding of this process and the importance of its optimization.Centering on the high energy consumption and emission gas issues of the pyrometallurgical recycling process,we systematically analyzed the capital-intensive nature of this process and the resulting technological characteristics.Furthermore,we conducted an in-depth discussion on the future research directions to overcome the existing technological barriers and limitations.This review will provide valuable insights for researchers and industry stakeholders in the battery recycling field.

An efficient and mild recycling of waste melamine formaldehyde foams by alkaline hydrolysis

Melamine formaldehyde foam(MFF)generates many poisonous chemicals through the traditional recycling methods for organic resin wastes.Herein,a high MFF degradation ratio of ca.97 wt.%was achieved under the mild conditions(160℃)in a NaOH–H2O system with ammelide and ammeline as the main degradation products.The alkaline solvent had an obvious corrosion effect for MFF,as indicated by scanning electron microscopy(SEM).The reaction process and products distribution were studied by Fourier-transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS),and ^(13)C nuclear magnetic resonance(NMR).Besides,the MFF degradation products that have the similar chemical structures and bonding performances to those of melamine can be directly used as the raw material for synthesis of melamine urea-formaldehyde resins(MUFs).Moreover,the degradation system demonstrated here showed the high degradation efficiency after reusing for 7 times.The degradation process generated few harmful pollutants and no pre-or post-treatments were required,which proves its feasibility in the safe removal or recovery of waste MFF.

Multi-Component Resource Recycling from Waste Light-Emitting Diode Under Hydrothermal Condition:Plastic Package Degradation,Speciation of Nano-TiO_(2),and Environmental Impact Assessment

Light emitting diodes(LEDs)have accounted for most of the lighting market as the technology matures and costs continue to reduce.As a new type of e-waste,LED is a double-edged sword,as it contains not only precious and rare metals but also organic packaging materials.In previous studies,LED recycling focused on recovering precious and strategic metals while ignoring harmful substances such as organic packaging materials.Unlike crushing and other traditional methods,hydrothermal treatment can provide an environment-friendly process for decomposing packaging materials.This work developed a closed reaction vessel,where the degradation rate of plastic polyphthalamide(PPA)was close to 100%,with nano-TiO_(2)encapsulated in plastic PPA being efficiently recovered,while metals contained in LED were also recycled efficiently.Besides,the role of water in plastic PPA degradation that has been overlooked in current studies was explored and speculated in detail in this work.Environmental impact assessment revealed that the proposed recycling route for waste LED could significantly reduce the overall environmental impact compared to the currently published processes.Especially the developed method could reduce more than half the impact of global warming.Furthermore,this research provides a theoretical basis and a promising method for recycling other plastic-packaged e-waste devices,such as integrated circuits.

Simultaneous purification of minor components in natural products using twin-column recycling chromatography with a step solvent gradient

The isolation of minor components from complex natural product matrices presents a significant challenge in the field of purification science due to their low concentrations and the presence of structurally similar compounds.This study introduces an optimized twin-column recycling chromatography method for the efficient and simultaneous purification of these elusive constituents.By introducing water at a small flowing rate between the twin columns,a step solvent gradient is created,by which the leading edge of concentration band would migrate at a slower rate than the trailing edge as it flowing from the upstream to downstream column.Hence,the band broadening is counterbalanced,resulting in an enrichment effect for those minor components in separation process.Herein,two target substances,which showed similar peak position in high performance liquid chromatography(HPLC)and did not exceed 1.8%in crude paclitaxel were selected as target compounds for separation.By using the twin-column recycling chromatography with a step solvent gradient,a successful purification was achieved in getting the two with the purity almost 100%.We suggest this method is suitable for the separation of most components in natural produces,which shows higher precision and recovery rate compared with the common lab-operated separation ways for natural products(thin-layer chromatography and prep-HPLC).

Development of sustainable and efficient recycling technology for spent Li-ion batteries: Traditional and transformation go hand in hand

Clean and efficient recycling of spent lithium-ion batteries(LIBs)has become an urgent need to promote sustainable and rapid development of human society.Therefore,we provide a critical and comprehensive overview of the various technologies for recycling spent LIBs,starting with lithium-ion power batteries.Recent research on raw material collection,metallurgical recovery,separation and purification is highlighted,particularly in terms of all aspects of economic efficiency,energy consumption,technology transformation and policy management.Mechanisms and pathways for transformative full-component recovery of spent LIBs are explored,revealing a clean and efficient closed-loop recovery mechanism.Optimization methods are proposed for future recycling technologies,with a focus on how future research directions can be industrialized.Ultimately,based on life-cycle assessment,the challenges of future recycling are revealed from the LIBs supply chain and stability of the supply chain of the new energy battery industry to provide an outlook on clean and efficient short process recycling technologies.This work is designed to support the sustainable development of the new energy power industry,to help meet the needs of global decarbonization strategies and to respond to the major needs of industrialized recycling.

Comparison of isotope-based linear and Bayesian mixing models in determining moisture recycling ratio

Stable water isotopes are natural tracers quantifying the contribution of moisture recycling to local precipitation,i.e.,the moisture recycling ratio,but various isotope-based models usually lead to different results,which affects the accuracy of local moisture recycling.In this study,a total of 18 stations from four typical areas in China were selected to compare the performance of isotope-based linear and Bayesian mixing models and to determine local moisture recycling ratio.Among the three vapor sources including advection,transpiration,and surface evaporation,the advection vapor usually played a dominant role,and the contribution of surface evaporation was less than that of transpiration.When the abnormal values were ignored,the arithmetic averages of differences between isotope-based linear and the Bayesian mixing models were 0.9%for transpiration,0.2%for surface evaporation,and–1.1%for advection,respectively,and the medians were 0.5%,0.2%,and–0.8%,respectively.The importance of transpiration was slightly less for most cases when the Bayesian mixing model was applied,and the contribution of advection was relatively larger.The Bayesian mixing model was found to perform better in determining an efficient solution since linear model sometimes resulted in negative contribution ratios.Sensitivity test with two isotope scenarios indicated that the Bayesian model had a relatively low sensitivity to the changes in isotope input,and it was important to accurately estimate the isotopes in precipitation vapor.Generally,the Bayesian mixing model should be recommended instead of a linear model.The findings are useful for understanding the performance of isotope-based linear and Bayesian mixing models under various climate backgrounds.

Reduction Discoloration of Reactive Dyed Cotton Waste and Chemical Recycling via Ionic Liquid

The textile industry generates large volumes of waste throughout its production process.Most of this waste is colored,therefore,discoloration is an important step toward recycling and reusing this waste.This study focused on the chemical reductive discoloration of textile waste composed of cotton dyed with reactive dye.The experimental design demonstrated the significant influence of the concentration of reducing agent and time of reaction on the degree of whiteness of the cotton fibers.The concentration of the alkaline agent was not significant in the process.The optimization of the reaction conditions lead to Berger degree of 50.5±3.5.The discolored cotton was chemically recycled through dissolution in ionic liquid 1-ethyl-3-methylimidazolium chloride and regeneration in film form in water.The microstructure of the regenerated cellulose films was evaluated by Scanning Electron Microscopy(SEM)indicating complete dissolution and uniform regeneration.The discoloration process reduced the polymerization degree and crystallinity index of the cotton fibers but retained the cellulose I structure.The dissolution and cellulose regeneration process results in transparent films with an amorphous structure.The thermal behavior,evaluated by thermogravimetric analysis,indicated that residues and regenerated film presented a main decomposition step.The maximum decomposition rate temperature of the regenerated films was approximately 40℃lower than the cotton fibers,which correlates well with the reduction in polymerization degree and amorphous structure.In general,the study demonstrated that textile cotton waste dyed with reactive dyes can be chemically discolored to form transparent and amorphous films,contributing to the development of sustainable strategies for the textile industry.

Analysis of the Characteristics of Materials Obtained by Recycling Scrap Metal in Guinea

The aim of this study was to determine the quality of rebar produced from recycled scrap metal collected throughout the country,and imported rebar sold in the Republic of Guinea.To do this,the samples were subjected to various mechanical tests involving traction,bending and microscopic analysis.In the Lambanyi and Casse Sonfonia samples,all the tensile strength values for diameters 12,14 and 16 were above 550 MPa.Conversely,the iron samples from Baillobaye and the 10 mm diameters of the samples from Casse Sonfonio and Lambanyi have less appreciable values.The limits of elasticity were determined.The various values found vary more or less from the conventional yield strength of the NF A35-016 reference supplied by CBITEC,which is 500 MPa.Microscopic analysis gives us an insight into the internal structure of the iron samples used.This study may provide the company and the vendors with an alternative for their improvements.