Global E-waste management: Can WEEE make a difference? A review of e-waste trends, legislation, contemporary issues and future challenges

Physicochemical reactions in e-waste recycling

Electronic waste (e-waste) recycling is becoming a global concern owing to its immense quantity, hazardous character and the potential loss of valuable metals. The many processes involved in e-waste recycling stem from a mixture of physicochemical reactions, and understanding the principles of these reactions can lead to more efficient recycling methods. In this Review, we discuss the principles behind photochemistry, thermochemistry, mechanochemistry, electrochemistry and sonochemistry for metal recovery, polymer decomposition and pollutant elimination from e-waste. We also discuss how these processes induce or improve reaction rates, selectivity and controllability of e-waste recycling based on thermodynamics and kinetics, free radicals, chemical bond energy, electrical potential regulation and more. Lastly, key factors, limitations and suggestions for improvements of these physicochemical reactions for e-waste recycling are highlighted, wherein we also indicate possible research directions for the future.

Augmentation in bioleaching potential of indigenous Bacillus sp. ISO1 for metals recovery from waste computer-printed circuit boards

The bio-cyanidation process of various cyanogenic microorganisms is found to be a sustainable and effective method for metals recovery from primary and secondary sources. This process has surpassed the limitations of the chemical cyanide treatment process; thus, prioritized as a promising approach for e-waste "urban mining" strategies. The main focus of the study was to enhance the bioleaching capacity of indigenous Bacillus sp. ISO1 and to implement optimized parameters in large-scale bioleaching operations. The assessment of various amino acids unveiled that like other cyanogenic microorganisms Bacillus sp. ISO1 also preferred glycine as a prime precursor for cyanide synthesis, as maximum metal solubilization was achieved with glycine amino acid. Other amino acids influenced the bacterial growth but not significantly affected the biocyanidation process. The evaluation and optimization of methionine as a lixiviant stimulator demonstrated that the addition of 1 mg/L methionine effectively enhance the production of glycine-utilizing cyanide lixiviant, that led to a significant solubilization of Cu (86%), Au (75%), and Ag (63%) metals. Furthermore, the kinetics of metal solubilization and operating conditions were explored at increased volume (i.e., 3 L working volume) of bioleaching medium to assess the industrial scale potential of this potent bacterial strain with optimized parameters such as temperature, pH, pulp density, and inoculum size. The significant recovery of Cu (˃ 60%) and other metals at this substantial volume suggested the implementation of a bioleaching process with this potent bacterial strain at industrial scale operations.

An alternative classification approach for waste electronic and electrical equipment (WEEE) recovery in low-income countries: case study in Burkina Faso

Waste electrical and electronic equipment (WEEE) is defined as "urban mines" due to the various recoverable minerals they contain. However, current WEEE classification methods are mostly limited to their physical characteristics, focusing on collection, transport, and treatment purposes rather than on valorization. In the present study, our aim is to propose an alternative classification approach adapted for low-income countries for WEEE recovery that highlights their content of precious and valuable metals. A typology of WEEE was created based on WEEE generated in Ouagadougou (Burkina Faso). Principal component analysis (PCA) and the moving center technique (K-means) were used for the classification method. Ultimately, we have found that to improve the recovery of WEEE, they can be classified into three main groups: (i) a group of WEEE-containing batteries, (ii) a group of WEEE-containing valuable and precious metals, and finally, (iii) a group of WEEE made up of cathode ray tube televisions (CRT-TV) waste. The WEEE belonging to the second group are the ones that could generate higher economical values. This alternative classification approach will help investors and operators to better orient their valorization activities towards WEEE types that present the best precious metals recovery potential, maximizing their profits. On the other hand, decision-makers will find this classification useful for reorganizing the WEEE value chain.

HBM4EU E-waste study: Assessing persistent organic pollutants in blood, silicone wristbands, and settled dust among E-waste recycling workers in Europe

E-waste recycling is an increasingly important activity that contributes to reducing the burden of end-of-life electronic and electrical apparatus and allows for the EU's transition to a circular economy. This study investigated the exposure levels of selected persistent organic pollutants (POPs) in workers from e-waste recycling facilities across Europe. The concentrations of seven polychlorinated biphenyls (PCBs) and eight polybrominated diphenyl ethers (PBDEs) congeners were measured by GC-MS. Workers were categorized into five groups based on the type of e-waste handled and two control groups. Generalized linear models were used to assess the determinants of exposure levels among workers. POPs levels were also assessed in dust and silicone wristbands (SWB) and compared with serum. Four PCB congeners (CB 118, 138, 153, and 180) were frequently detected in serum regardless of worker's category. With the exception of CB 118, all tested PCBs were significantly higher in workers compared to the control group. Controls working in the same company as occupationally exposed (Within control group), also displayed higher levels of serum CB 180 than non-industrial controls with no known exposures to these chemicals (Outwith controls) (p < 0.05). BDE 209 was the most prevalent POP in settled dust (16 μg/g) and SWB (220 ng/WB). Spearman correlation revealed moderate to strong positive correlations between SWB and dust. Increased age and the number of years smoked cigarettes were key determinants for workers exposure. Estimated daily intake through dust ingestion revealed that ΣPCB was higher for both the 50th (0.03 ng/kg bw/day) and 95th (0.09 ng/kg bw/day) percentile exposure scenarios compared to values reported for the general population. This study is one of the first to address the occupational exposure to PCBs and PBDEs in Europe among e-waste workers through biomonitoring combined with analysis of settled dust and SWB. Our findings suggest that e-waste workers may face elevated PCB exposure and that appropriate exposure assessments are needed to establish effective mitigation strategies.

Occurrence and ecotoxicological impacts of polybrominated diphenyl ethers (PBDEs) in electronic waste (e-waste) in Africa: Options for sustainable and eco-friendly management strategies

Polybrominated diphenyl ethers (PBDEs) are persistent contaminants used as flame retardants in electronic products. PBDEs are contaminants of concern due to leaching and recalcitrance conferred by the stable and hydrophobic bromide residues. The near absence of legislatures and conscious initiatives to tackle the challenges of PBDEs in Africa has allowed for the indiscriminate use and consequent environmental degradation. Presently, the incidence, ecotoxicity, and remediation of PBDEs in Africa are poorly elucidated. Here, we present a position on the level of contamination, ecotoxicity, and management strategies for PBDEs with regard to Africa. Our review shows that Africa is inundated with PBDEs from the proliferation of e-waste due to factors like the increasing growth in the IT sector worsened by the procurement of second-hand gadgets. An evaluation of the fate of PBDEs in the African environment reveals that the environment is adequately contaminated, although reported in only a few countries like Nigeria and Ghana. Ultrasound-assisted extraction, microwave-assisted extraction, and Soxhlet extraction coupled with specific chromatographic techniques are used in the detection and quantification of PBDEs. Enormous exposure pathways in humans were highlighted with health implications. In terms of the removal of PBDEs, we found a gap in efforts in this direction, as not much success has been reported in Africa. However, we outline eco-friendly methods used elsewhere, including microbial degradation, zerovalent iron, supercritical fluid, and reduce, reuse, recycle, and recovery methods. The need for Africa to make and implement legislatures against PBDEs holds the key to reduced effect on the continent.

Electricity out of electronic trash: Triboelectric nanogenerators from discarded smartphone displays for biomechanical energy harvesting

In the context of escalating electronic waste (e-waste) generated by the rapid evolution of electronic devices, particularly smartphones/mobiles, the imperative for effective e-waste management to mitigate adverse environmental and health consequences has become increasingly apparent. Herein, novel mobile phone-based triboelectric nanogenerators (M-TENGs) are fabricated from discarded smartphone displays of eight different brands (B1-B8) for harvesting electrical energy. Analytical characterization techniques such as SEM and EDS are employed for morphological investigation. The tribopositivity and tribonegativity of the smartphone display layers are confirmed using the FTIR technique and test materials. The percentage tensile strength of the selected triboactive layers is measured to assess the mechanical durability. The electrical measurements are performed for all eight M-TENG devices, notably the device constructed from B8 smartphone display layers outperforms other brands by generating about three and five times higher voltage and current than the M-TENG device composed of B1 layers. Further, the optimized device is subjected to frequency, force, and stability tests, and also the impact of fluctuating humidity on the device performance is analyzed. Moreover, the M-TENG demonstrates its versatility by efficiently charging commercial electrolytic capacitors, powering LEDs, and effectively harvesting biomechanical energy. Thus, the present study represents a significant step towards mitigating the challenges posed by electronic smartphone waste disposal while simultaneously offering a viable pathway to harvest electricity and power a variety of applications.

Airborne antibiotic and metal resistance genes - A neglected potential risk at e-waste recycling facilities

Heavy metal-rich environments can promote the selection of metal-resistance genes (MRGs) in bacteria, often leading to the simultaneous selection of antibiotic-resistance genes (ARGs) through a process known as co-selection. To comprehensively evaluate the biological pollutants at electronic-waste (e-waste) recycling facilities, air, soil, and river samples were collected at four distinct Swiss e-waste recycling facilities and analyzed for ARGs, MRGs, mobile genetic elements (MGEs), endotoxins, and bacterial species, with correlations drawn to heavy metal occurrence. To our knowledge, the present work marks the first attempt to quantify these bio-pollutants in the air of e-waste recycling facilities, that might pose a significant health risk to workers. Although ARG and MRG's profiles varied among the different sample types, intl1 consistently exhibited high relative abundance rates, identifying it as the predominant MGE across all sample types and facilities. These findings underscore its pivol role in driving diverse bacterial adaptations to extreme heavy metal exposure by selection and dissemination of ARGs and MRGs. All air samples exhibited consistent profiles of ARGs and MRGs, with blaTEM emerging as the predominant ARG, alongside pbrT and nccA as the most prevalent MRGs. However, one facility, engaged in batteries recycling and characterized by exceptionally high concentrations of heavy metals, showcased a more diverse resistance gene profile, suggesting that bacteria in this environment required more complex resistance mechanisms to cope with extreme metal exposure. Furthermore, this study unveiled a strong association between gram-negative bacteria and ARGs and less with MRGs. Overall, this research emphasizes the critical importance of studying biological pollutants in the air of e-waste recycling facilities to inform robust safety measures and mitigate the risk of resistance gene dissemination among workers. These findings establish a solid foundation for further investigations into the complex interplay among heavy metal exposure, bacterial adaptation, and resistance patterns in such distinctive ecosystems.

Target setting and performance analysis: Promoting e-waste collection in China under the collection target responsibility models

The increasing volume of electronic waste (e-waste) poses significant challenges for efficient collection in China. Despite many measures were taken over the past two decades, the e-waste collection rate was still not high. To this end, the Chinese government issued a new policy, the collection target responsibility (CTR) policy. Under the CTR policy, however, it is essential for participants to know how to share the responsibility of collection and how much reasonable targets are set to ensure the efficiency of the collection models. Therefore, the purpose of this paper is to explore the determination of optimal collection targets and the corresponding performance from the perspective of responsibility sharing to support the successful implementation of the CTR. Firstly, the study focuses on participants including the government, manufacturers, and recyclers, and develops three CTR models, independent collection model, government cost-sharing model, and enterprise collaboration model. Secondly, collection target equations for each model are established by employing dynamic differential game analysis, and corresponding collection performances are derived. Thirdly, through practical case simulations, the evolution of collection performance is dynamically analyzed to determine reasonable collection targets for the three models, as 23.8%, 32.3%, and 34.4%, respectively. The findings highlight the effectiveness of CTR in improving e-waste collection targets and performance, with the highest levels attained when the collection responsibilities are shared by government cost-sharing and enterprise collaboration. This study provides theoretical support for setting reasonable collection targets under CTR, and assists decision-makers in developing targeted CTR implementation measures.

Selective recovery of gold and silver from electronic wastes through a sequential process of Qalkari and room-temperature hydrometallurgy

This work was focused on the selective recovery of gold and silver from electronic wastes using a sequential process of pyrometallurgy (Qalkari) and room-temperature hydrometallurgy. In the first step, electronic wastes underwent Qalkari recycling, yielding tablets containing precious elements (Qalkari furnace product) and melting slag (Qalkari furnace waste). In the subsequent hydrometallurgy phase, the nitric acid concentration and the input solid amount were optimized for the effective room-temperature recovery of gold. Due to the successful separation of precision elements and disturbing substances in Qalkari, the gold recovery efficiency of 99.99% was obtained at the acid concentration of 50% (v/v) and the solid input of 15% (w/v). Afterwards, HCl, NH4Cl, and NaCl were used for silver recovery from the Qalkari-processed gold-recovered leaching solution, leading to the efficiency of 99.99%. But NH4Cl was recognized as the most effective precipitant as it promises the most enhanced potential for the possible subsequent recovery of palladium. In conclusion, this study draws the effectiveness of Qalkari in recycling electronic wastes, with a significant impact on the efficiency of succeeding room-temperature hydrometallurgical processes for gold and silver recovery within a reasonable leaching time.

Driving sustainable circular economy in electronics: A comprehensive review on environmental life cycle assessment of e-waste recycling

E-waste, encompassing discarded materials from outdated electronic equipment, often ends up intermixed with municipal solid waste, leading to improper disposal through burial and incineration. This improper handling releases hazardous substances into water, soil, and air, posing significant risks to ecosystems and human health, ultimately entering the food chain and water supply. Formal e-waste recycling, guided by circular economy models and zero-discharge principles, offers potential solutions to this critical challenge. However, implementing a circular economy for e-waste management due to chemical and energy consumption may cause environmental impacts. Consequently, advanced sustainability assessment tools, such as Life Cycle Assessment (LCA), have been applied to investigate e-waste management strategies. While LCA is a standardized methodology, researchers have employed various routes for environmental assessment of different e-waste management methods. However, to the authors' knowledge, there lacks a comprehensive study focusing on LCA studies to discern the opportunities and limitations of this method in formal e-waste management strategies. Hence, this review aims to survey the existing literature on the LCA of e-waste management under a circular economy, shedding light on the current state of research, identifying research gaps, and proposing future research directions. It first explains various methods of managing e-waste in the circular economy. This review then evaluates and scrutinizes the LCA approach in implementing the circular bioeconomy for e-waste management. Finally, it proposes frameworks and procedures to enhance the applicability of the LCA method to future e-waste management research. The literature on the LCA of e-waste management reveals a wide variation in implementing LCA in formal e-waste management, resulting in diverse results and findings in this field. This paper underscores that LCA can pinpoint the environmental hotspots for various pathways of formal e-waste recycling, particularly focusing on metals. It can help address these concerns and achieve greater sustainability in e-waste recycling, especially in pyrometallurgical and hydrometallurgical pathways. The recovery of high-value metals is more environmentally justified compared to other metals. However, biometallurgical pathways remain limited in terms of environmental studies. Despite the potential for recycling e-waste into plastic or glass, there is a dearth of robust background in LCA studies within this sector. This review concludes that LCA can offer valuable insights for decision-making and policy processes on e-waste management, promoting environmentally sound e-waste recycling practices. However, the accuracy of LCA results in e-waste recycling, owing to data requirements, subjectivity, impact category weighting, and other factors, remains debatable, emphasizing the need for more uncertainty analysis in this field.

Solid waste management in the context of the waste hierarchy and circular economy frameworks: An international critical review

Growing populations and consumption drive the challenges of solid waste management (SWM); globalization of transport, food production, and trade, including waste trading, distributes risks worldwide. Using waste hierarchy (WH; reduce, reuse, and recycle) and circular economy (CE) concepts, we updated a conceptual waste framework used by international organizations to evaluate SWM practices. We identified the key steps and the important factors, as well as stakeholders, which are essential features for effective SWM. Within this updated conceptual framework, we qualitatively evaluated global SWM strategies and practices, identifying opportunities, barriers, and best practices. We find that, although a few exceptional countries exhibit zero-waste compliance, most fare poorly, as exhibited by the high waste generation, incineration, and disposal (open dumping, landfilling) volumes. In the Global North, SWM strategies and practices rely heavily on technologies, economic tools, regulatory frameworks, education, and social engagement to raise stakeholder awareness and enhance inclusion and participation; in the Global South, however, many governments take sole legal responsibility for SWM, seeking to eliminate waste as a public "nuisance." Separation and recycling in the Global South are implemented mainly by "informal" economies in which subsistence needs drive recyclable material retrieval. Imported, regionally inappropriate tools, economic constraints, weak policies and governance, waste trading, noninclusive stakeholder participation, data limitations, and limited public awareness continue to pose major waste and environmental management challenges across nations. In the context of the framework, we conclude that best practices from around the world can be used to guide decision-making, globally. Despite variations in drivers and needs across regions, nations in both the Global North and South need to improve WH and CE compliance, and enhance stakeholder partnership, awareness, and participation throughout the SWM process. Partnerships between the Global North and South could better manage traded wastes, reduce adverse impacts, and enhance global environmental sustainability and equity, supporting UN Sustainable Development Goals. Integr Environ Assess Manag 2024;20:9-35. © 2023 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Learning from the past to plan for the future: An historical review of the evolution of waste and resource management 1970-2020 and reflections on priorities 2020-2030 - The perspective of an involved witness

Improving waste and resource management (WaRM) around the world can halve the weight of plastics entering the oceans, significantly mitigate global heating and contribute directly to 12 of 17 sustainable development goals (SDGs). Achieving such results demands understanding and learning from historical evolution of WaRM. The baseline is 1970, prior to environmental legislation. Early steps in the Global North focused on the 'technical fix' within strictly enforced legal frameworks, first bringing hazardous wastes and municipal solid wastes (MSW) under control, then gradually ramping up environmental standards. Using modern technologies to the Global South often failed due to institutional and financial constraints. From 1990, focus switched to integrating technical and governance aspects: local institutional coherence, financial sustainability, provider inclusivity, user inclusivity, national legislative and policy framework. The Global North rediscovered recycling, using policy measures to promote segregation at source; this relied on new markets in emerging economies, which had largely disappeared by 2020. The Global South is making progress on bringing wastes under control, but around 2.7 billion people lack access to waste collection, while ~40% of collected MSW is open dumped or burned - a continuing global waste emergency. So, much remains to be done to move further towards a circular economy. Three policy priorities are critical for all countries: access to sustainable financing, rethinking sustainable recycling and worldwide extended producer responsibility with teeth. Extending services to unserved communities (SDG11.6.1) requires a people-centred approach, working with communities to provide both quality services and decent livelihoods for collection and recycling workers.

Critical factors for implementing collection target responsibility in e-waste collection in China: A DEMATEL-ISM analysis

The Collection Target Responsibility (CTR) is the direction for the proper management of e-waste reuse and recycling. Despite its potential, the CTR policy is still in its infancy in China and faces significant challenges to its effective implementation. There are a few studies that have systematically identified and analyzed the factors that influence the application of CTR to e-waste collection systems in China. This study proposes a comprehensive process that considers collection targets and behaviors to develop the critical factors (CFs) involved in e-waste collection under CTR by participants including government, manufacturers and recyclers. The Decision-making Trial and Evaluation Laboratory and Interpretative Structural Modeling (DEMATEL-ISM) method was applied to analyze these CFs. The findings show that the development of policy and regulation is the root factor influencing the implementation of CTR in China, both in terms of collection targets and behaviors. Incentives and regulation of government, collection channels, and benefits of manufacturers and recyclers are important CFs that participants consider when adopting CTR and should be prioritized. This study not only contributes to the literature on e-waste collection under CTR, but also provides valuable insights for decision-makers to improve the performance of e-waste collection practices.

Enabling the recycling of metals from the shredder light fraction derived from waste of electrical and electronic equipment via continuous pyrolysis process

The surge in Waste Electrical and Electronic Equipment (WEEE) generation, reaching 53.6 million metric tons (Mt) in 2019, demands efficient recycling solutions. This study focuses on the Shredder Light Fraction (SLF), a material stream derived from the mechanical pre-processing of WEEE, which is considered "municipal waste". SLF constitutes 4.2% of the output material and is rich in metals like copper, tin, lead, zinc, silver, and gold. Pyrolysis treatment was applied to SLF, enabling recyclability. Both batch and continuous setups were employed for materials flow analysis and technical evaluation of the resource potential. The research evaluates the impact of pyrolysis technology on solid fraction metal content and pyrolysis gas/oil energy potential. Scaling up the process addressed material heterogeneity and increased the reliability of the obtained results. An innovative pyrometallurgical extraction approach was suggested, to recover valuable metals in SLF which otherwise could be lost via energy recovery methods. The resulting solid product after pyrolysis showed enriched concentrations of copper, zinc, lead, and precious metals with concentrations acceptable for industrial use. Additionally, it displayed reduced mass and diminished hazardous constituents. The non-condensable gas, rich in hydrogen, carbon monoxide, and methane, exhibited potential as an alternative energy source or reducing agent in the metallurgical sector. This research advances metal recycling from SLF, offering valuable insights for environmental impact mitigation as waste was transformed into a valuable by-product for potential use in the copper industry.

Incorporating self-employed maintainers into WEEE formal recycling system: A system dynamic approach

The establishment and operation of a formal recycling system for waste electrical and electronic equipment is an important measure to reduce environmental hazards and improve the recycling of resources, but how to incorporate self-employed maintainers into the system has formed an important research gap. Based on the perspective of extended producer responsibility, we argue that self-employed maintainers are required to assume the corresponding environmental responsibility for the environmental externality caused by informal maintenance activities. Using qualitative structural analysis techniques of system dynamics approach with quantitative simulation analysis techniques, we construct an incentive model for self-employed maintainers' participation in formal recycling system, based on which we propose four incentive strategies. A simulation analysis is further conducted by using the case of waste mobile phones recycling in Qingdao to verify the effectiveness of our incentive model and strategies.

Challenges to implement and operationalize the WEEE reverse logistics system at the micro level

Waste electrical and electronic equipment (WEEE) possesses unique characteristics such as its growing production and the potential for resource extraction due to its composition. The implementation and operationalization of a reverse logistics system (RLS) for WEEE is a challenge, particularly concerning the micro level. The implementation of such systems often prioritizes urban centers and their higher population densities, generally overlooking the micro level. The latter refers to ward- or village-level divisions, which can be regarded as the smallest administrative divisions of both urban and rural areas. Furthermore, it encompasses any area facing logistical challenges regarding RLS operationalization due to factors such as geographical isolation, budgetary constraints, imbalances, social isolation, environmental aspects, and even geopolitical conflicts. This study is aimed at addressing this literature gap by discussing the challenges to implement and operationalize a WEEE RLS at the micro level. A systematic literature review was employed as our methodology. We found 13 challenges for developed and developing countries without distinction between macro and micro levels. An additional approach highlighted the significance of monitoring and controlling WEEE RLS. The challenge The population and LRS entities' lack or insufficient training and awareness received the most citations in the conducted search. These challenges were organized by operational phase and discussed from the perspective of the micro level to comprehend multifactorial local challenges involving all stakeholders in the reverse logistics of WEEE in emerging nations. This can assist local administrators and constitutes the primary contribution of this study.

Informal E-Waste Flows in Montréal: Implications for Extended Producer Responsibility and Circularity

Environmental agencies around the world have adopted policies to manage e-waste and reduce the negative environmental impacts associated with its collection, sorting, dismantling, and recycling. In many OECD countries, where adequate policies and processing technologies exist, those who manage extended producer responsibility programs claim performance challenges due to competition from various actors collecting and managing e-waste "under the radar". While the material and economic losses attributed to such informal activities have been estimated by previous research, a detailed understanding of who is involved in these activities, why and how they operate, and with what social and environmental impacts, is often lacking. Our research offers an in-depth investigation into Montréal's informal e-waste flows. Whereas e-waste research and advocacy posit a dichotomy between "formal" and "informal" e-waste flows, our research reveals a more nuanced situation, with no water-tight separation between these flows. Formal and informal flows are often blurred, and change over time; and many actors are involved in both formal and informal activities. We reveal mechanisms whereby actors inadvertently contribute to informal activities because of inadequate incentives, limited program scope, reuse, parts harvesting, and documentation issues. This nuanced understanding helps identify policy loopholes, program shortcomings, and strategies for more sustainable e-waste flows, taking account of more ambitious circularity objectives and a just transition.

Carbon Trading in China Reduces the Dependence of Household Waste Electrical and Electronic Equipment Recycling on Government Subsidies

China's enterprises of waste electrical and electronic equipment (WEEE) recycling suffer from low profitability that is highly dependent on government subsidies. This low economic gain impedes the sustainable growth of China's WEEE-recycling sector and also adds to the government's financial burden. Prior life-cycle studies have approved the carbon reduction potentials or net carbon credit of recycling WEEE. However, policymakers fail to know whether the revenue from selling carbon credits can offset the government's financial subsidy. We performed life-cycle and cost-benefit analyses for a case recycling enterprise that processes six categories of household appliances. The results show that the reduction potentials of greenhouse gases range from 930-3450 kgCO2e by recycling per ton of household appliances and materials substitution. The recycling enterprise would gain extra revenue ranging from 32 to 160 RMB per ton of appliance if the carbon credits were sold at China's current carbon price, i.e., 45-60 RMB tCO2e-1. Recycling waste refrigerators exhibits the highest carbon revenue, offsetting 6-17% of the government's financial subsidy. Microcomputers, by contrast, indicate the lowest carbon revenue, equivalent to 1-3% of its highest government subsidy. For each household appliance category, when the carbon price reaches 270-600 RMB tCO2e-1, selling carbon credits can fully offset the government's financial subsidy. Constrained by the processing capacity of the case enterprise, optimizations for appliance-recycling composition contribute a 15-25% profit growth to the current economic gains. Interpreting the specific profit depends on the predefined scenarios of carbon price and the substitution rate of the regenerated materials for the virginal ones. Our findings show that raising the profitability of WEEE recycling enterprises through the carbon trading policy contributes to the sustainable growth of China's WEEE-recycling sector while alleviating the government's financial burden.

Exploring factors of e-waste recycling intention: The case of generation Y

The seriousness of the e-waste crisis stems from the fact that consumers do not participate much in ensuring the proper disposal of electronic materials. In this context, millennials are the largest segment of consumers of electronic products who are not yet motivated to get sustainably rid of them. However, to inspire consumers to recycle e-waste, it is necessary to investigate consumers' behavioral intentions towards e-waste thoroughly. This study integrates the theory of planned behavior, social influence theory, and personality traits to examine how consumers gauge their choice to recycle e-waste. Data were collected from randomly surveying 300 Lithuanians through a structured questionnaire. Using the PLS-SEM approach, results show that attitude, subjective norms, and perceived behavioral control significantly influence consumers' e-waste recycling intention. Regarding personality traits, only openness to experience significantly affects consumers' e-waste recycling intention. In contrast, other traits such as agreeableness, conscientiousness, extraversion, and neuroticism have a non-significant influence on consumers' e-waste recycling intention. In addition, normative and informational social influence affects consumers' e-waste recycling intention. The current study advances our understanding of e-waste recycling behavior by examining how TPB, personality factors, and social influence theory influence intentions. It provides valuable insights for policymakers and marketers on understanding and encouraging the e-waste behavior of Lithuanian Y-generation consumers.

An efficient approach for enhancement of gold and silver bioleaching from spent telecommunication printed circuit boards using cyanogenic bacteria: Prevention of biofilm formation

Environmentally friendly bioleaching of gold and silver from electronic waste using cyanogenic bacteria has emerged as a promising approach. In the process of cyanide bioleaching, cyanide ions produced by cyanogenic bacteria form complexes (such as AuCN and AgCN) with metals in the waste structure and lead to their dissolution. The recovery rate of these valuable elements during bioleaching is influenced by extracellular polymeric substances (EPS). For the first time, this study presents an investigation into the role of EPS from Pseudomonas atacamensis in the bioleaching of gold and silver from spent telecommunication printed circuit boards (STPCBs). The experimental results demonstrate that, after 6 days of bioleaching, gold and silver recoveries reached 22% and 36.2%, respectively. Complementary analyses employing FE-SEM and attachment tests shed light on the interactions between EPS, bacterial attachment to particle surfaces, and biofilm development stages during gold and silver bioleaching. Notably, the most significant bacterial attachment occurred on the fourth day of bioleaching. Zeta potential tests conducted on bacteria and EPS provided insights into the potential absorption of soluble cations such as Au+ and Ag+ by EPS. Furthermore, 250 mg/L polyvinylpyrrolidone (PVP) effectively removed EPS from the particle surfaces, improving gold and silver recovery rates, reaching 26% and 43.2%, respectively. These findings highlight the importance of understanding the role of EPS in bioleaching processes and offer insights into enhancing gold and silver recovery from electronic waste.

Sustainable Engineering Design in Education: A Pilot Study of Teaching Right-to-Repair Principles through Project-Based Learning

Over 60 million tons of E-waste is expected to be generated in 2023, with associated significant impacts on health and the environment. To reduce the number of products sent to landfills, "Right to Repair" (RtR) movements are gaining momentum in many countries, including the UK, USA, and EU member states. While Universities are seen as important stakeholders to drive forward sustainable design practices, there is currently little work looking at training undergraduate design engineers in the principles of designing household products in support of RtR. In particular, the project-based learning (PBL) pedagogy shows promise in engaging and training students with the skills and knowledge required to successfully design products for RtR. In this paper, a pilot-study of teaching engineers is presented to design products compatible with RtR principles, alongside many technical skills, in a first-year PBL course. The key outputs of this paper are the design of the module, which can be used to help inform first-year engineering education, the high engagement of students, with 100% of respondents agreeing that they intend to try to implement sustainable design practices in future, and some of the innovative features that students implement in their projects.

Soil heavy metal pollution from waste electrical and electronic equipment of repair and junk shops in southern Thailand and their ecological risk

The waste electrical and electronic equipment (WEEE) stream in Thailand shifted from exporting WEEE to recycling them in domestic enterprises after China's import restrictions on e-waste in 2018. This study aims to investigate the pollution status, pollution sources, and ecological risk of heavy metals from manual WEEE dismantling facilities (12 repair shops and 8 junk shops) in the Nakhon Si Thammarat province of southern Thailand by examining the concentrations of As, Cd, Ni, and Pb in the topsoil (0-15 cm) during the wet and dry seasons. The results revealed that the mean concentrations of all heavy metals were higher during the dry season than in the wet season. The concentrations of analyzed soil heavy metals decreased as the intensity of e-waste dismantling activities increased, with recycling sites > repair sites > control sites (no e-waste recycling activities). Only 10% of WEEE processing workshops (junk shops) had soil Pb and As concentrations that exceeded Thailand's residential soil quality standards. However, ecological indexing models based on the geo-accumulation index found that 75% of electric repair shops were contaminated with the analyzed heavy metals, particularly Pb. Moreover, the Nemerow integrated pollution index indicated that 16.7% of electric repair shops were on the pollution warning line. Our findings suggest that policymakers should promote ecological risk assessment as a method for mitigating the negative environmental impact of electronic repair businesses, which are widely dispersed in residential areas and tend to dominate the WEEE stream because of the circular economy concept of "right to repair", and highlight the decline of junk shops and e-waste dismantling villages for waste export resulting from China's ban.

Valorization of e-waste via supercritical water technology: An approach for obsolete mobile phones

The improper handling of electronic waste has not only severe environmental impacts but also results in the loss of high economic potential. To address this issue, the use of supercritical water (ScW) technology for the eco-friendly processing of waste printed circuit boards (WPCBs) obtained from obsolete mobile phones has been explored in this study. The WPCBs were characterized via MP-AES, WDXRF, TG/DTA, CHNS elemental analysis, SEM and XRD. A L9 Taguchi orthogonal array design was employed to evaluate the impact of four independent variables on the organic degradation rate (ODR) of the system. After optimization, an ODR of 98.4% was achieved at a temperature of 600 °C, a reaction time of 50 min, a flowrate of 7 mL min-1, and the absence of an oxidizing agent. The removal of the organic content from the WPCBs resulted in an increase in the metal concentration, with up to 92.6% of the metal content being efficiently recovered. During the ScW process, the decomposition by-products were continuously removed from the reactor system through the liquid or gaseous outputs. The liquid fraction, which was composed of phenol derivatives, was treated using the same experimental apparatus, achieving a total organic carbon reduction of 99.2% at 600 °C using H2O2 as the oxidizing agent. The gaseous fraction was found to contain hydrogen, methane, CO2, and CO as the major components. Finally, the addition of co-solvents, namely ethanol and glycerol, enhanced the production of combustible gases during the ScW processing of WPCBs.

A review of various strategies in e-waste management in line with circular economics

Waste management of electrical and electronic equipment has become a key challenge for electronics manufacturers due to globalization and the rapid expansion of information technology. As the volume of e-waste grows, legal departments lack the infrastructure, technology, and ability to collect and manage it environmentally soundly. Government laws, economic reasons, and social issues are important considerations in e-waste management. The circular economy concept is built on reusing and recycling goods and resources. A novel idea called the circular economy might prevent the negative consequences brought on by the exploitation and processing of natural resources while also having good effects such as lowering the demand for raw materials, cutting down on the use of fundamental resources, and creating jobs. To demonstrate the significance of policy implementation, the necessity for technology, and the need for societal awareness to build a sustainable and circular economy, the study intends to showcase international best practices in e-waste management. This study uses circular economy participatory implementation methods to provide a variety of possible approaches to assist decision-makers in e-waste management. The purpose of this article is to review the most accepted methods for e-waste management to emphasize the importance of implementing policies, technology requirements, and social awareness in creating a circular economy. To conclude, this paper highlights the necessity of a common legal framework, reform of the informal sector, the responsibility of different stakeholders, and entrepreneurial perspectives.

Decarbonization in waste recycling industry using digitalization to promote net-zero emissions and its implications on sustainability

Digitalization and sustainability have been considered as critical elements in tackling a growing problem of solid waste in the framework of circular economy (CE). Although digitalization can enhance time-efficiency and/or cost-efficiency, their end-results do not always lead to sustainability. So far, the literatures still lack of a holistic view in understanding the development trends and key roles of digitalization in waste recycling industry to benefit stakeholders and to protect the environment. To bridge this knowledge gap, this work systematically investigates how leveraging digitalization in waste recycling industry could address these research questions: (1) What are the key problems of solid waste recycling? (2) How the trends of digitalization in waste management could benefit a CE? (3) How digitalization could strengthen waste recycling industry in a post-pandemic era? While digitalization boosts material flows in a CE, it is evident that utilizing digital solutions to strengthen waste recycling business could reinforce a resource-efficient, low-carbon, and a CE. In the Industry 4.0 era, digitalization can add 15% (about USD 15.7 trillion) to global economy by 2030. As digitalization grows, making the waste sector shift to a CE could save between 30% and 35% of municipalities' waste management budget. With digitalization, a cost reduction of 3.6% and a revenue increase of 4.1% are projected annually. This would contribute to USD 493 billion in an increasing revenue yearly in the next decade. As digitalization enables tasks to be completed shortly with less manpower, this could save USD 421 billion annually for the next decade. With respect to environmental impacts, digitalization in the waste sector could reduce global CO₂ emissions by 15% by 2030 through technological solutions. Overall, this work suggests that digitalization in the waste sector contributes net-zero emission to a digital economy, while transitioning to a sustainable world as its social impacts.

Exploring bioleaching potential of indigenous Bacillus sporothermodurans ISO1 for metals recovery from PCBs through sequential leaching process

The low efficiency and selectivity limitations of biohydrometallurgy technique compel the researchers to explore novel microbial strains acclimated to metal existence site with higher toxicity tolerance and bioleaching capability in order to improve the role of bioleaching process for e-waste management. The current study aimed to explore bioleaching potential of indigenous Bacillus sporothermodurans ISO1; isolated from metal habituated site. The statistical approach was utilized to optimize a variety of culture variables including temperature, pH, glycine concentration and pulp density that impact bio-cyanide production and leaching efficiency. The highest dissolution of Cu and Ag, 78% and 37% respectively, was obtained at 40 °C, pH 8, glycine concentration 5 g L^-1, and pulp density 10 g L^-1 through One Factor at a Time (OFAT), which was further increased up to 95% Cu and 44% Ag recovery through the interactive effect of key factors in the Response Surface Methodology (RSM) approach. Furthermore, Chemo-biohydrometallurgy approach was utilized to overwhelm the specificity limitation; as higher concentration of Cu in computer printed circuit boards (CPCBs) causes interference to recover other metals. The sequential leaching through ferric chloride (FeCl₃), recovered Cu prior to bio-cyanidation by B. sporothermodurans ISO1 and resulted in the improved leaching of Ag (57%), Au (67%), Pt (60%), etc. The current work reports on B. sporothermodurans ISO1, a new Bacillus strain that exhibits highest toxicity tolerance (EC50 = 425 g L^-1) than earlier reported stains and has higher leaching potential that can be implemented to large-scale biometallurgical process for e-waste treatment to achieve the agenda of sustainable development goal (SDG) under the strategies of urban mining.

Human health risk associated with metal exposure at Agbogbloshie e-waste site and the surrounding neighbourhood in Accra, Ghana

Agbogbloshie in Accra, Ghana, was a center for informal e-waste recycling until it was closed recently. This study investigated the potential health risks of toxic metals (including As, Cd, Cu, Ni, Pb, Sb, and Zn) found in the surface soils based on their concentrations and in vitro bioaccessibility. Mean concentrations at the burning sites were As: 218; Cd: 65; Cr: 182; Cu: 15,841; Ni: 145; Pb: 6,106; Sb: 552; and Zn: 16,065 mg/kg while the dismantling sites had mean concentrations of As: 23; Cd: 38; Cr: 342; Cu: 3239; Ni: 96; Pb: 681; Sb: 104; and Zn: 1658 mg/kg. The findings confirmed the enrichment of potentially toxic metals at the dismantling and burning sites, exceeding international environmental soil quality guidelines. Based on the total metal concentrations, bioaccessibility, and calculated risk indices, the risks associated with incidental ingestion of soil-borne metal contaminants at the dismantling and burning sites were very high. Despite evidence of higher metal concentrations in the communities near the burning and dismantling sites, the human health risk associated with soil ingestion was significantly lower in the surrounding neighborhood.

Informal E-waste recycling practices and environmental pollution in Africa: What is the way forward?

Globally, e-waste is the fastest growing and most valuable waste-stream. While countries worldwide are increasingly acknowledging the e-waste problem and introducing policies and regulations that deal with e-waste, large quantities of e-waste still go undocumented. Much of these global e-wastes are accumulating in open-dumpsites and landfills in African-countries where they are recycled informally resulting in significant environmental and public-health concerns. Although, there is a plethora of studies on e-waste management and disposal, only a few-studies have focused on African-countries who are major recipients of e-waste. Moreover, despite the attempts to mitigate the problem of e-waste in African-countries, e-waste has remained a major-concern and there are currently very limited workable solutions. This study examines informal e-waste recycling, environmental pollution and the extent of environmental and health impacts in major countries of concern including Ghana, Nigeria, Egypt, Kenya and South Africa. The global e-waste Waste Atlas Report, 2020 identified these countries as major recipients of e-waste. To achieve the aims of this research, previous studies from 2005 to 2022 are collected from various databases and analyzed. Accordingly, this study focuses on environmental pollution and public-health impacts resulting from e-waste dumping and informal recycling practices, illegal transboundary shipment of e-waste to the selected countries, and the interventions of governments and international organizations in reducing the impact of e-waste pollution and informal recycling practices in Africa. Based on the outcomes of this study, practical approaches on the way-forward are recommended. The findings of this study contribute to a growing-body of research on informal e-waste recycling practices in Africa to document that individuals working within e-waste sites and residents in nearby communities are exposed to a number of toxic-substances, some at potentially concerning levels.

Towards a sustainable and green approach of electrical and electronic waste management in Rwanda: a critical review

Electric and electronic equipment (EEE) consumption has grown to worrisome proportions in developing countries (DC_S), resulting in massive amounts of electrical and electronic waste (e-waste) being produced. A diagnosis of e-waste proliferation is required for its sustainable management plan in Rwanda. This review is based on open-access papers with e-waste as a keyword, the present situation of EEE, and e-waste in Rwanda. The need for various information communication and technology (ICT) tools, such as end-user devices, cooling-system devices, network equipment, and telecommunication devices, is strongly encouraged by Rwandan national plans, which deem ICT as a vital enabler of knowledge-based economy and development. In 2014, EEE was 33,449 tonnes (t), which is expected to be 267,741 t in 2050, with a yearly increase rate of 5.95%. In this regard, out-of-date EEE is being dumped as e-waste in large quantities and at an increasing rate across Rwanda. E-waste is often disposed of in uncontrolled landfills together with other types of household waste. To address this rising threat, as well as to preserve the environment and human health, proper e-waste management involving e-waste sorting/separation from other waste streams, repairs, reuse, recycling, remanufacturing, and disposal has been proposed.

Valorisation of spent tire rubber as carbon adsorbents for Pb(II) and W(VI) in the framework of a Circular Economy

Spent tire rubber-derived chars and their corresponding H3PO4 and CO2-activated chars were used as adsorbents in the recovery of Pb(II) ion and (W(VI)) oxyanion from synthetic solutions. The developed chars (both raw and activated) were thoroughly characterized to have insight about their textural and surface chemistry properties. H3PO4-activated chars presented lower surface areas than the raw chars and an acidic surface chemistry which affected the performance of these samples as they showed the lowest removals of the metallic ions. On the other hand, CO2-activated chars presented increased surface areas and increased mineral content compared to the raw chars, having presented higher uptake capacities for both Pb(II) (103-116 mg/g) and W(VI) (27-31 mg/g) ions. Cation exchange with Ca, Mg and Zn ions was appointed as a mechanism for Pb removal, as well as surface precipitation in the form of hydrocerussite (Pb3(CO3)2(OH)2). W(VI) adsorption might have been ruled by strong electrostatic attractions between the negatively charged tungstate species and the highly positively charged carbons' surface.The results shown in this work allow concluding that the valorisation of spent tire rubber through pyrolysis and the subsequent activation of the obtained chars is an alternative and a feasible option to generate adsorbent materials with a high uptake capacity of critical metallic elements.

One Digital Health Intervention for Monitoring Human and Animal Welfare in Smart Cities: Viewpoint and Use Case

Smart cities and digital public health are closely related. Managing digital transformation in urbanization and living spaces is challenging. It is critical to prioritize the emotional and physical health and well-being of humans and their animals in the dynamic and ever-changing environment they share. Human-animal bonds are continuous as they live together or share urban spaces and have a mutual impact on each other's health as well as the surrounding environment. In addition, sensors embedded in the Internet of Things are everywhere in smart cities. They monitor events and provide appropriate responses. In this regard, accident and emergency informatics (A&EI) offers tools to identify and manage overtime hazards and disruptive events. Such manifold focuses fit with One Digital Health (ODH), which aims to transform health ecosystems with digital technology by proposing a comprehensive framework to manage data and support health-oriented policies. We showed and discussed how, by developing the concept of ODH intervention, the ODH framework can support the comprehensive monitoring and analysis of daily life events of humans and animals in technologically integrated environments such as smart homes and smart cities. We developed an ODH intervention use case in which A&EI mechanisms run in the background. The ODH framework structures the related data collection and analysis to enhance the understanding of human, animal, and environment interactions and associated outcomes. The use case looks at the daily journey of Tracy, a healthy woman aged 27 years, and her dog Mego. Using medical Internet of Things, their activities are continuously monitored and analyzed to prevent or manage any kind of health-related abnormality. We reported and commented on an ODH intervention as an example of a real-life ODH implementation. We gave the reader examples of a "how-to" analysis of Tracy and Mego's daily life activities as part of a timely implementation of the ODH framework. For each activity, relationships to the ODH dimensions were scored, and relevant technical fields were evaluated in light of the Findable, Accessible, Interoperable, and Reusable principles. This "how-to" can be used as a template for further analyses. An ODH intervention is based on Findable, Accessible, Interoperable, and Reusable data and real-time processing for global health monitoring, emergency management, and research. The data should be collected and analyzed continuously in a spatial-temporal domain to detect changes in behavior, trends, and emergencies. The information periodically gathered should serve human, animal, and environmental health interventions by providing professionals and caregivers with inputs and "how-to's" to improve health, welfare, and risk prevention at the individual and population levels. Thus, ODH complementarily combined with A&EI is meant to enhance policies and systems and modernize emergency management.

Large Virtual Transboundary Hazardous Waste Flows: The Case of China

The Basel Convention and prior studies mainly focused on the physical transboundary movements of hazardous waste (transporting waste from one region to another for cheaper disposal). Here, we take China, the world's largest waste producer, as an example and reveal the virtual hazardous waste flows in trade (outsourcing waste by importing waste-intensive products) by developing a multiregional input-output model. Our model characterizes the impact of international trade between China and 140 economies and China's interprovincial trade on hazardous waste generated by 161,599 Chinese enterprises. We find that, in 2015, virtual hazardous waste flows in China's trade reached 26.6 million tons (67% of the national total), of which 31% were generated during the production of goods that were ultimately consumed abroad. Trade-related production is much dirtier than locally consumed production, generating 26% more hazardous waste per unit of GDP. Under the impact of virtual flows, 40% of the waste-intensive production and relevant disposal duty is unequally concentrated in three Chinese provinces (including two least-developed ones, Qinghai and Xinjiang). Our findings imply the importance of expanding the scope of transboundary waste regulations and provide a quantitative basis for introducing consumer responsibilities. This may help relieve waste management burdens in less-developed "waste havens".

Investigating Metal-Tributyl Phosphate Complexes during Supercritical Fluid Extraction of the NdFeB Magnet Using Density Functional Theory and X-ray Absorption Spectroscopy

Supercritical fluid extraction (SCFE) is gaining significant interest as a green technology for the recycling of end-of-life waste electrical and electronic equipment (WEEE). Neodymium iron boron (NdFeB) magnets, which contain large quantities of critical rare-earth elements such as neodymium, praseodymium, and dysprosium, are widely used in wind turbines and electric/hybrid vehicles. Hence, they are considered a promising secondary resource for these elements when they reach their end-of-life. Previously, the SCFE process was developed for recycling WEEE, including NdFeB; however, the process mechanism remains unexplored. Here, density functional theory, followed by extended X-ray absorption fine structure and X-ray absorption near-edge structure analyses, are utilized to determine the structural coordination and interatomic interactions of complexes formed during the SCFE of the NdFeB magnet. The results indicate that Fe(II), Fe(III), and Nd(III) form Fe(NO₃)₂(TBP)₂, Fe(NO₃)₃(TBP)₂, and Nd(NO₃)₃(TBP)₃ complexes, respectively. This theory-guided investigation elucidates the complexation chemistry and mechanism during the SCFE process by rigorously determining the structural models.

Recovery of copper and silver from industrial e-waste leached solutions using sustainable liquid membrane technology: a review

Waste electrical and electronic equipment or e-waste has recently emerged as a significant global concern. This waste contains various valuable metals, and via recycling, it could become a sustainable resource of metals (viz. copper, silver, gold, and others) while reducing reliance on virgin mining. Copper and silver with their superior electrical and thermal conductivity have been reviewed due to their high demand. Recovering these metals will be beneficial to attain the current needs. Liquid membrane technology has appeared as a viable option for treating e-waste from various industries as a simultaneous extraction and stripping process. It also includes extensive research on biotechnology, chemical and pharmaceutical, environmental engineering, pulp and paper, textile, food processing, and wastewater treatment. The success of this process depends more on the selection of organic and stripping phases. In this review, the use of liquid membrane technology in treating/recovering copper and silver from industrial e-waste leached solutions was highlighted. It also assembles critical information on the organic phase (carrier and diluent) and stripping phase in liquid membrane formulation for selective copper and silver. In addition, the utilization of green diluent, ionic liquids, and synergist carrier was also included since it gained prominence attention latterly. The future prospects and challenges of this technology were also discussed to ensure the industrialization of technology. Herein, a potential process flowchart for the valorization of e-waste is also proposed.

Integration of electronic waste management: a review of current global generation, health impact, and technologies for value recovery and its pertinent management technique

The fast evolution of waste electrical and electronic equipment (WEEE) has developed into a prime environmental perturb in recent days. Today, electrical and electronic products merely become a needed part of people life's and professional lives. The whole process of e-waste contains an organized collection system, appropriate dismantling, and its treatment of recycling. The unparalleled hastening of e-waste and unceremonious discarding lead to an adverse impact on a country's development. Currently, challenges in e-waste have a lack of practical aid, poor structure, and insufficient economic support. Several legislations have been imposed which aim to enhance the handling of e-waste. Operative management of e-waste is now essential for the protective atmosphere and human beings as well. This article provides the systemic flow of the e-waste definition, global information, and generation of e-waste and composition of e-waste which were discussed. The study categorized the hazardous effect of e-waste on human beings, and the content analysis of e-waste in recent LCA applications was highlighted. Further different metal extraction and recovery techniques from e-waste have been reviewed. A few sets of current practices and some recommendations on a global scale level were provided. Finally, based on analysis, some approaches to e-waste was accomplished, and equitable environmental management was taken into account to identify the future outlook areas.

Concepts of circular economy for sustainable management of electronic wastes: challenges and management options

The electronic and electrical industrial sector is exponentially growing throughout the globe, and sometimes, these wastes are being disposed of and discarded with a faster rate in comparison to the past era due to technology advancements. As the application of electronic devices is increasing due to the digitalization of the world (IT sector, medical, domestic, etc.), a heap of discarded e-waste is also being generated. Per-capita e-waste generation is very high in developed countries as compared to developing countries. Expansion of the global population and advancement of technologies are mainly responsible to increase the e-waste volume in our surroundings. E-waste is responsible for environmental threats as it may contain dangerous and toxic substances like metals which may have harmful effects on the biodiversity and environment. Furthermore, the life span and types of e-waste determine their harmful effects on nature, and unscientific practices of their disposal may elevate the level of threats as observed in most developing countries like India, Nigeria, Pakistan, and China. In the present review paper, many possible approaches have been discussed for effective e-waste management, such as recycling, recovery of precious metals, adopting the concepts of circular economy, formulating relevant policies, and use of advance computational techniques. On the other hand, it may also provide potential secondary resources valuable/critical materials whose primary sources are at significant supply risk. Furthermore, the use of machine learning approaches can also be useful in the monitoring and treatment/processing of e-wastes. HIGHLIGHTS: In 2019, ~ 53.6 million tons of e-wastes generated worldwide. Discarded e-wastes may be hazardous in nature due to presence of heavy metal compositions. Precious metals like gold, silver, and copper can also be procured from e-wastes. Advance tools like artificial intelligence/machine learning can be useful in the management of e-wastes.

Biodegradable electrohydraulic actuators for sustainable soft robots

Combating environmental pollution demands a focus on sustainability, in particular from rapidly advancing technologies that are poised to be ubiquitous in modern societies. Among these, soft robotics promises to replace conventional rigid machines for applications requiring adaptability and dexterity. For key components of soft robots, such as soft actuators, it is thus important to explore sustainable options like bioderived and biodegradable materials. We introduce systematically determined compatible materials systems for the creation of fully biodegradable, high-performance electrohydraulic soft actuators, based on various biodegradable polymer films, ester-based liquid dielectric, and NaCl-infused gelatin hydrogel. We demonstrate that these biodegradable actuators reliably operate up to high electric fields of 200 V/μm, show performance comparable to nonbiodegradable counterparts, and survive more than 100,000 actuation cycles. Furthermore, we build a robotic gripper based on biodegradable soft actuators that is readily compatible with commercial robot arms, encouraging wider use of biodegradable materials systems in soft robotics.

Product Lifecycle Information Flow in E-waste Handling: a Means to Increase Circularity?

Electronic waste (e-waste) is a growing waste stream. In Europe, e-waste is regulated by the Waste Electrical and Electronic Equipment (WEEE) Directive. Each manufacturer or importer is responsible for the end-of-life (EoL) treatment of the equipment it handles, although this task is usually outsourced to producer responsibility organizations (PROs) that collect and treat the e-waste. The WEEE regime has been criticized for focusing on waste handling according to the traditional linear economy, while, in a circular economy, the goal is to eliminate waste. Information sharing helps improve circularity, and digital technology is seen as enabling information transparency and visibility in the supply chain. However, there is need for empirical studies demonstrating the use of information in supply chains to improve circularity. We conducted a case study of a manufacturer, including its subsidiaries and PROs in eight European countries, in which we investigated the product lifecycle information flow related to e-waste. Our findings indicate that product lifecycle information is available, but that it is provided for purposes other than e-waste handling. Actors are willing to share this information, but it is not regarded as useful for EoL treatment since the actors involved in EoL handling believe that using this information could lead to delays and poorer performance in e-waste handling. Our findings contradict the optimistic view of digital technology as improving circularity in circular supply chain management. The findings further give reason to question the implementation of digital technology to improve the product lifecycle information flow as long as the involved actors do not request this information.

The Triple-S framework: ensuring scalable, sustainable, and serviceable practices in educational technology

Educational institutions are increasingly investing into digital delivery, acquiring new devices, and employing novel software and services. The rising costs associated with maintenance, in combination with increasing redundancy of older technologies, presents multiple challenges. While lesson content itself may not have changed, the educational landscape constantly evolves, where tertiary institutions are incorporating new modes of content delivery, hybrid-style learning, and interactive technologies. Investments into digital expansions must be taken with caution, particularly prior to the procurement of technology, with a need for the proposed interventions' scalability, sustainability, and serviceability to be considered. This article presents the Triple-S framework for educators, administrators, and educational institutions, and outlines examples of its application within curricula. The paper synthesises research evidence to provide the foundation underlying the key principles of the Triple-S framework, presenting a useful model to use when evaluating digital interventions. Utilising the framework for decisions regarding the acquisition of educational technology, devices, software, applications, and online resources can assist in the assurance of viable and  appropriate investments.

Extended producer responsibility's effect on producers' electronic waste management practices in Japan and Canada: drivers, barriers, and potential of the urban mine

Electronic waste is the fastest-growing domestic waste stream globally, continuously outstripping projections. With increasing ubiquity of complex computing, many non-renewables are contained in end-of-life electronics, creating a vast urban mine, potentially hazardous, depending on treatment. The aim of this study is to compare how Extended Producer Responsibility (EPR) policy is applied in two case countries, Japan and Canada, the practical implications of EPR policy design on producer operations, and how EPR affects electronic waste management improvements in each case. These cases share international obligations for electronic waste management but employ contrasting EPR policies. These policies are widespread in both cases, yet are not presided over by larger, regional obligations. Therefore, country-level interviews with electronic waste management stakeholders focusing on how EPR regulation affects producer practice were conducted. The physical application of EPR, as seen in Japan, drives design changes by producers intending to simplify downstream treatment, while financial responsibility in Canada, creates greater concern with cost-savings for producers, complicating end-of-life processing. EPR implementation, along with specific geographical factors, also create contrasting resource recovery results between countries. Regulation primarily drives EPR implementation in both countries, which is consistent with the literature. This study presents new drivers and barriers, namely pre-emptive legislation, and no incentive to improve, classifying the Japanese and Canadian systems as suffering from externalities on an insular system, and lack of harmonization, respectively. This research addresses a gap in comparative studies across regions of physical and financial EPR effects on producer practice.

A review on recovery processes of metals from E-waste: A green perspective

E-waste management has become a global concern because of the enormous rise in the rate of end-of-life electrical and electronic equipment's (EEEs). Disposal of waste EEE directly into the environment leads to adverse effects on the environment as well as on human health. For the management of E-waste, numerous studies have been carried out for extracting metals (base, precious, and rare earth) following pyrometallurgy, hydrometallurgy, and biometallurgy. Irrespective of the advantages of these processes, certain limitations still exist with each of these options in terms of their adoption as treatment techniques. Several journal publications regarding the different processes have been made which aids in future research in the field of E-waste management. This review provides a comprehensive summary of the various metal recovery processes (pyrometallurgy, hydrometallurgy, and biometallurgy) from E-waste, along with their advantages and limitations. A bibliometric study based on the published articles using different keywords in Scopus has been provided for a complete idea about E-waste with green technology perspective like bioleaching, biosorption, etc. The present study also focussed on the circular economic approach towards sustainable E-waste management along with its socio-economic aspects and the economic growth of the country. The present study would provide valuable knowledge in understanding E-waste and its different treatment processes to the students, researchers, industrialists, and policymakers of the country.

Autogeddon or autoheaven: Environmental and social effects of the automotive industry from launch to present

The automotive industry is one of the most significant and increasing sources of pollution worldwide. Previous studies examining its impacts focus on the post-1950 era as data available before this period is scarce. This study carefully reconstructs six datasets from the early 20th century to 2019 for the UK: annual number of motor cars, road lengths, road fatalities, NOx and CO emissions, and fuel consumption. Interpolation was prudently used to fill gaps in the data sets. Results highlight changing health, social and environmental effects throughout the growth of the automotive sector. Ratios of fatalities to cars indicate social ingraining of the car and rapid response to legislation. Significant emissions resulted from the early industry. Successful remediation of emissions occurred in the late 20th century. All variables studied were interrelated, but expansion of road networks particularly contributed to a range of both positive and (unintended) negative consequences. World War 2 appears to have been a landmark for the automotive industry, producing capacity for mass production, personal mobility and research and therefore a struggle between impacts and social policies. We have demonstrated that technological developments and regulatory interventions relating to the motor industry, alongside events that have catalysed societal change, have been crucial in terms of subsequently providing benefits to society whilst also acting to mitigate (but not prevent) the adverse and frequently devastating impacts of motor vehicles on human health and the environment. A periodic, regular, overarching, independent review (~ every 5 years) of the collective positive and negative impacts of the motor vehicle industry and appropriate interventions are essential to maintain and improve social benefits and public and environmental health, as well as supporting delivery of the United Nations' Sustainable Development Goals by 2030 and beyond.

Smart technologies for collection and classification of electronic waste

Purpose

The main aim of this study is to understand the role of smart technologies and show the rankings of various smart technologies in collection and classification of electronic waste (e-waste).

Design/methodology/approach

This study presents a framework integrating the concepts of collection and classification mechanisms and smart technologies. The criteria set includes three main, which are economic, social and environmental criteria, including a total of 15 subcriteria. Smart technologies identified in this study were robotics, multiagent systems, autonomous tools, smart vehicles, data-driven technologies, Internet of things (IOT), cloud computing and big data analytics. The weights of all criteria were found using fuzzy analytic network process (ANP), and the scores of smart technologies which were useful for collection and classification of e-waste were calculated using fuzzy VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR).

Findings

The most important criterion was found as collection cost, followed by pollution prevention and control, storage/holding cost and greenhouse gas emissions in collection and classification of e-waste. Autonomous tools were found as the best smart technology for collection and classification of e-waste, followed by robotics and smart vehicles.

Originality/value

The originality of the study is to propose a framework, which integrates the collection and classification of e-waste and smart technologies.

Evolutionary game analysis of WEEE recycling tripartite stakeholders under variable subsidies and processing fees

The standardization of formal recycling and rational subsidy plays an important role in waste electrical and electronic equipment recycling. In order to explore the tripartite decision and evolution path of waste electrical and electronic equipment recycling in different time periods, a tripartite evolutionary game model consisting of recyclers, manufacturers, and government are presented. Moreover, the evolution stability strategies and conditions in each period are calculated by replicating the dynamic equation and Jacobian matrix. Numerical simulations on tripartite evolution stability strategies corresponding to different stages of industry development are used to verify the rationality of the model. The results indicate that there is existed an indirect effect between tripartite decisions, and the indirect effect can expand the slack of tripartite decisions' thresholds of waste electrical and electronic equipment recycling. The variable subsidy in waste electrical and electronic equipment recycling proposed in this paper is useful to incentive recyclers to choose a formal recycling strategy, and manufacturers also choose production with recycled materials as subsidy varies. Besides, the appropriate waste electrical and electronic equipment processing fee is a conducive indirect effect for the tripartite decision to the optimal evolutionary stability strategy in waste electrical and electronic equipment recycling and can promote manufacturers to produce with the recycled materials. The research can assist in benefit coordination and behavior adjustment of waste electrical and electronic equipment recycling members and provide a theoretical basis for the government to formulate appropriate recycling subsidies to promote the formal recycling of electronic waste recycling.

Electronic waste control and management in Ghana: A critical assessment of the law, perceptions and practices

The aim of the study was to assess the impact of Ghana's hazardous and e-waste control and management Act 917 of 2016 on current e-waste management practices and the level of awareness among key stakeholders (general public, repairers, wholesalers/retailers, recyclers and importers of electronic items) in the Greater Accra Region of Ghana. Both quantitative and qualitative data were collected and examined in this study. Results showed a low level (12%) of awareness among stakeholders on the e-waste legislation. Almost 13% of respondents had been educated on e-waste management. Community engagement and the mass media were the main sources of information on e-waste. Significant associations between background information of respondents and awareness level on 'Ghana's Act 917' were observed. Relative to general e-waste issues, only education and stakeholder showed significant associations with e-waste legislation and management. The main e-waste disposal methods adopted by respondents were disposal at dumpsites (22.7%), repair and reuse (21.1%) and reselling (20.1%). Almost 10% of respondents made changes to their e-waste disposal practices over the past 5 years. These changes were mainly due to the economic benefits derived from reselling e-waste (37.6%) and the perceived adverse impacts of e-waste on the environment (23.9%). Overall, there is the need to intensify awareness on 'Ghana's Act 917', especially issues regarding sustainable e-waste management practices.

On the implementation of the circular economy route for E-waste management: A critical review and an analysis for the case of the state of Kuwait

Electronic waste (e-waste) has become one of the major causes of environmental concerns due to its large volume, high generation rate and toxic environmental burdens. Recent estimates put e-waste generation at about 54 million tonnes per annum with figures reaching approximately 75 million tonnes per annum by 2030. In this manuscript, the state-of-the-art technologies and techniques for segregation, recovery and recycling of e-waste with a special focus on the valorisation aspects of e-plastics and e-metals which are critically reviewed. A history and insight into environmental aspects and regulation/legislations are presented including those that could be adopted in the near future for e-waste management. The prospects of implementing such technologies in the State of Kuwait for the recovery of materials and energy from e-waste where infrastructure is lacking still for waste management are presented through Material Flow Analysis. The information showed that Kuwait has a major problem in waste accumulation. It is estimated that e-waste in Kuwait (with no accumulation or backlog) is generated at a rate of 67,000 tpa, and the imports of broadcasting electronics generate some 19,428 tonnes. After reviewing economic factors of potential recovered plastics, iron and glass from broadcasting devices in Kuwait as e-waste, a total revenue of $399,729 per annum is estimated from their valorisation. This revenue will open the prospect of ventures for other e-waste and fuel recovery options as well as environmental benefits and the move to a circular economy.

Analysis of the Adsorption-Release Isotherms of Pentaethylenehexamine-Modified Sorbents for Rare Earth Elements (Y, Nd, La)

Waste from electrical and electronic equipment (WEEE) is constantly increasing in quantity and becoming more and more heterogeneous as technology is rapidly advancing. The negative impacts it has on human and environment safety, and its richness in valuable rare earth elements (REEs), are accelerating the necessity of innovative methods for recycling and recovery processes. The aim of this work is to comprehend the adsorption and release mechanisms of two different solid sorbents, activated carbon (AC) and its pentaethylenehexamine (PEHA)-modified derivative (MAC), which were deemed adequate for the treatment of REEs deriving from WEEE. Experimental data from adsorption and release tests, performed on synthetic mono-ionic solutions of yttrium, neodymium, and lanthanum, were modelled via linear regression to understand the better prediction between the Langmuir and the Freundlich isotherms for each REE-sorbent couple. The parameters extrapolated from the mathematical modelling were useful to gain an a priori knowledge of the REEs-sorbents interactions. Intraparticle diffusion was the main adsorption mechanism for AC. PEHA contributed to adsorption by means of coordination on amino groups. Release was based on protons fostering both a cation exchange mechanism and protonation. The investigated materials confirmed their potential suitability to be employed in real processes on WEEE at the industrial level.

Improved leaching of Cu, Sn, Pb, Zn, and Al from waste printed circuit boards by electro-generated Cl2 in HCl solution

This paper investigated the improved leaching of Cu, Sn, Pb, Zn, and Al from waste printed circuit boards (WPCBs) by electro-generated Cl₂ in HCl solution through multiple leaching cells in series, double intake pipes, and bubble stone for leaching. The leaching agents in the leaching cell include Cl₂(aq), HCl, HClO, and Cl₃^-. The leaching rate and leaching speed of Zn, Sn, Al, and Pb exceeded that of Cu. Leaching time and HCl concentration have a strong impact on the dissolution of Cu, whereas the effect of the electrolytic current and the leaching temperature is comparably weak. The series of leaching cells improved the effective utilization of Cl₂ and increased the treatment capacity of the WPCBs. Bubble stones significantly enhanced the efficiency and rate of leaching. Reduction of the size of the Cl₂ gas bubbles improved the leaching kinetics. The leaching rate of Cu reached 87.22%, whereas the leaching rate of Zn, Sn, Al, and Pb exceeded 90% after 100 min. Our experimental data provide a reference for electrolytic leaching recovery of metals from WPCBs, and our method improves the metal leaching and electrolytic efficiency in practice.

Application of persulfate-based oxidation processes to address diverse sustainability challenges: A critical review

Over the past years, persulfate (PS) is widely applied due to their high versatility and efficacy in decontamination and sterilization. While treatment of organic chemicals, remediation of soil and groundwater, sludge treatment, disinfection on pathogen microorganisms have been covered by most published reviews, there are no comprehensive and specific reviews on its application to address diverse sustainability challenges, including solid waste treatment, resources recovery and regeneration of ecomaterials. PS applications mainly rely on direct oxidation by PS itself or the reactive sulfate radical (SO₄^•-) or hydroxyl radical (^•OH) from the activation of peroxodisulfate (PDS, S₂O₈^2-) or peroxymonosulfate (PMS, HSO₅^-) in SO₄^•--based advanced oxidation processes (SO₄^•--AOPs). From a broader perspective of environmental cleanup and sustainability, this review summarizes the various applications of PS except pollutant decontamination and elaborates the possible reaction mechanisms. Additionally, the differences between PS treatment and conventional technologies are highlighted. Challenges, research needs and future prospect are thus discussed to promote the development of the applications of PS-based oxidation processes in niche environmental fields. In all, this review is a call to pay more attention to the possibilities of PS application in practical resource reutilization and environmental protection except widely reported pollutant degradation.