How are WEEE doing? A global review of the management of electrical and electronic wastes

Kinetic investigation on the catalytic pyrolysis of plastic fractions of waste electrical and electronic equipment (WEEE): A mathematical deconvolution approach

Waste electrical and electronic equipment (WEEE) has become a critical environmental problem. Catalytic pyrolysis is an ideal technique to treat and convert the plastic fraction of WEEE into chemicals and fuels. Unfortunately, research using real WEEE remains relatively limited. Furthermore, the complexity of WEEE complicates the analysis of its pyrolytic kinetics. This study applied the Fraser-Suzuki mathematical deconvolution method to obtain the pseudo reactions of the thermal degradation of two types of WEEE, using four different catalysts (Al2O3, HBeta, HZSM-5, and TiO2) or without a catalyst. The main contributor(s) to each pseudo reaction were identified by comparing them with the pyrolysis results of the pure plastics in WEEE. The nth order model was then applied to estimate the kinetic parameters of the obtained pseudo reactions. In the low-grade electronics pyrolysis, the pseudo-1 reaction using TiO2 as a catalyst achieved the lowest activation energy of 92.10 kJ/mol, while the pseudo-2 reaction using HZSM-5 resulted in the lowest activation energy of 101.35 kJ/mol among the four catalytic cases. For medium-grade electronics, pseudo-3 and pseudo-4 were the main reactions for thermal degradation, with HZSM-5 and TiO2 yielding the lowest pyrolytic activation energies of 75.24 and 226.39 kJ/mol, respectively. This effort will play a crucial role in comprehending the pyrolysis kinetic mechanism of WEEE and propelling this technology toward a brighter future.

Enhanced removal of tetrabromobisphenolA (TBBPA) from e-waste by Fe-S nanoparticles and Fe-S/CuS nanocomposite with response surface methodology (RSM)

TetrabromobisphenolA is a well-known member of the brominated flame retardant group and is widely used as a highly effective fire-retardant additive in electronic and electrical equipment. TBBPA is commonly found in various environmental sources and can be harmful to human health. This study presents a simple approach to preparing a magnetic nanocomposite, offering a straightforward method that results in consistent quality and low resource consumption. The nanocomposite has a high surface-to-volume ratio for the removal of tetrabromobisphenolA. Various characterization techniques, including XRD, FTIR, EDX, FESEM, VSM, TEM, and BET analyses were used to characterize the Fe-S nanoparticles and Fe-S/CuS. The results showed that Fe-S/CuS nanocomposite successfully removed over 97% of the initial TBBPA (15 mg L-1) under optimized conditions determined by RSM, such as a contact time of 15 min, pH of 7, Fe-S/CuS nanocomposite dosage of 0.69 g L-1, and salt concentration of 0.10%. The RSM analysis provided a second-order polynomial model with a confidence level of 93% (F = 29.58; p < 0.0001) to predict the TBBPA removal efficiency at various concentrations. In the adsorption kinetic studies, the second-order kinetic model provided the best fit for the experimental data. Additionally, Fe-S/CuS nanocomposite shows great potential for practical applications and environmental remediation efforts, making it a valuable asset for real-sample use in environmental settings.

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.

Opportunity and challenges in recovering and functionalizing anode graphite from spent lithium-ion batteries: A review

Recent concerns have emerged regarding the improper disposal of spent lithium-ion batteries (LIBs), which has garnered widespread societal attention. Graphite materials accounted for 12-21 wt % of LIBs' mass, typically contain heavy metals, binders, and residual electrolytes. Regenerating spent graphite not only alleviated the shortage of plumbago, but also contributed to the supports environmental protection as well as national carbon peak and neutrality ("dual carbon" goals). Despite significant advancements in recycling spent LIBs had been made, a comprehensive overview of the processes for pretreatment, regeneration, and functionalization of spent graphite from retired LIBs, along with the associated technical standards and industry regulations enabling their smooth implementation still needed to be mentioned. Hence, we conducted the following research work. Firstly, the pre-treatment process of spent graphite, including discharging, crushing, and screening was summed up. Next,. Subsequently, graphite recovery methods, such as acid leaching, pyrometallurgy, and combined methods were summarized. Moreover, the modification and doping approach was used to enhance the electrochemical properties of graphite. Afterwards, we reviewed the functionalization of anode graphite from an economically and environmentally friendly view. Meanwhile, the technical standards and industry regulations of spent LIBs in domestic and oversea industries were described. Finally, we provided an overview of the technical challenges and development bottlenecks in graphite recycling, along with future prospects Overall, this study outlined the opportunities and challenges in recovering and functionalizing of anode materials via a efficient and sustainable processes.

Assessing Neurobehavioral Alterations Among E-waste Recycling Workers in Hong Kong

Background

E-waste workers in Hong Kong are handling an unprecedented amount of e-waste, which contains various neurotoxic chemicals. However, no study has been conducted to evaluate the neurological health status of e-waste workers in Hong Kong. This study aimed to evaluate the prevalence of neurobehavioral alterations and to identify the vulnerable groups among Hong Kong e-waste workers.

Methods

We recruited 109 Hong Kong e-waste workers from June 2021 to September 2022. Participants completed standard questionnaires and wore a GENEActiv accelerometer for seven days. Pittsburgh Sleep Quality Index and Questionnaire 16/18 (Q16/18) were used to assess subjective neurobehavioral alterations. The GENEActiv data generated objective sleep and circadian rhythm variables. Workers were grouped based on job designation and entity type according to the presumed hazardous level. Unconditional logistic regression models measured the associations of occupational characteristics with neurobehavioral alterations after adjusting for confounders.

Results

While dismantlers/repairers and the workers in entities not funded by the government were more likely to suffer from neurotoxic symptoms in Q18 (adjusted odds ratio: 3.18 [1.18-9.39] and 2.77 [1.10-7.46], respectively), the workers from self-sustained recycling facilities also have poor performances in circadian rhythm. Results also showed that the dismantlers/repairers working in entities not funded by the government had the highest risk of neurotoxic symptoms compared to the lowest-risk group (i.e., workers in government-funded companies with other job designations).

Conclusion

This timely and valuable study emphasizes the importance of improving the working conditions for high-risk e-waste workers, especially the dismantlers or repairers working in facilities not funded by the government.

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).

Towards a REASSURED reality: A less-is-more electronic design strategy for self-powered glucose test

Sensing strategies adopting minimal electronic systems help in realizing REASSURED diagnostic tests. However, the challenge in developing such strategies escalates with demand in power and electronics during pursuit of reliable and accurate sensing. Herein, we present an electronic design strategy using a smart strip, operating with power generated from 3.5 μL of serum sample, to reveal glucose concentration through a response preserved in a capacitor. Further, by integrating an NFC tag alongside the strip, we devised a self-powered glucose measuring card, mobile-glucocard (or mGlucocard) for retrieving this stored digital response using smartphone, enabling 'connected mobile-health diagnostics'. The response from our device relates linearly to glucose concentration offering a sensitivity of 11.3 mV/mM and good correlation (R = 0.974) with colorimetric reference method. Interestingly, the design strategy uses only four components - two resistors, diode, and capacitor - of simple architecture likely transferable to printed technologies to deliver advanced self-powered sustainable devices.

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.

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.

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.

A decision-making technique under interval-valued Fermatean fuzzy Hamacher interactive aggregation operators

The evolution of a novel technique to handle multi-attribute decision-making (MADM) problems under interval-valued Fermatean fuzzy numbers is the main motivation of this paper. We aim to introduce several initiative aggregation operators (AOs), including Hamacher interactive weighted averaging, Hamacher interactive ordered weighted averaging, Hamacher interactive hybrid weighted averaging operations, etc., to acquire our desired outcomes. Then, the distinguished characteristics of these AOs are investigated. Furthermore, the suggested AOs are carried out to build a technique to MADM issues using interval-valued Fermatean fuzzy information. A case study of mine emergency plan selection is then narrated to elaborate the practicality and effectiveness of the developed method. The influence of parametric values on decision-making outcomes is investigated considering the distinct values of parameter. After discussing the developed work and seeing its applications, we come across with the conclusion that the dominant privilege of adaptation of the above-mentioned AOs is situated in the fact that these operators allow a progressively complete approach on the matters to decision-makers. Hence, the method recommended in this study offers progressively wide, enhanced accuracy and actual outcomes when compared with the prevailing associated strategies. Therefore, this technique plays a vital role in actual-life MADM problems.

Bio-Graphene Sensors for Monitoring Moisture Levels in Wood and Ambient Environment

Wood is an inherently hygroscopic material which tends to absorb moisture from its surrounding. Moisture in wood is a determining factor for the quality of wood being employed in construction, since it causes weakening, deformation, rotting, and ultimately leading to failure of the structures resulting in costs to the economy, the environment, and to the safety of residents. Therefore, monitoring moisture in wood during the construction phase and after construction is vital for the future of smart and sustainable buildings. Employing bio-based materials for the construction of electronics is one way to mitigate the environmental impact of such electronics. Herein, a bio-graphene sensor for monitoring the moisture inside and around wooden surfaces is fabricated using laser-induced graphitization of a lignin-based ink precursor. The bio-graphene sensors are used to measure humidity in the range of 10% up to 90% at 25 °C. Using laser induced graphitization, conductor resistivity of 18.6 Ω sq^-1 is obtained for spruce wood and 57.1 Ω sq^-1 for pine wood. The sensitivity of sensors fabricated on spruce and pine wood is 2.6 and 0.74 MΩ per % RH. Surface morphology and degree of graphitization are investigated using scanning electron microscopy, Raman spectroscopy, and thermogravimetric analysis methods.

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.

Waste of electrical and electronic equipment management from the perspective of a circular economy: A Review

In addition to the difficulties involved in the management of conventional solid waste, the management of waste of electrical and electronic equipment (WEEE) is significantly more complex due to its unusual chemical composition and fast generation. Both developed and developing countries have been looking for solutions to deal with the problems caused by the growing flow of WEEE, especially regarding sustainable solutions based on reducing resource exploitation by the recovery of materials from this type of waste. In this context, this work presents a quali-quantitative and comprehensive literature review of the publications on the management of WEEE, from the perspective of a circular economy. The results showed that the first publications on the topic appear in 2006, with a significant increase from 2015, the year when the Circular Economy Action Plan was instituted in the European Community. The most prominent authors have been giving emphasis to researches on recycling, reuse and technologies for the recovery of materials/energy from WEEE. Nevertheless, few studies have been found focusing on the prevention/reduction in WEEE generation, priority actions of the WEEE management hierarchy. The works analysed show that the current management of WEEE, despite considering the circularity of materials, prioritizes the development of technological solutions of the end-of-pipe type, greatly represented by the recovery of materials, instead of preventing the generation, which may be detrimental to long-term sustainability. The work ends with the presentation of a SWOT-TOWS (strengths, weaknesses, opportunities and threats) analysis conducted to define the main strategies for the improvement of WEEE management from a circular economy perspective.

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.

Environmental impact of e-waste management in Indian microscale informal sectors

Inappropriate e-waste processing in the informal sector is a serious issue in developing countries. Field investigations in microscale informal recycling sites have been performed to study the impact of hazardous metal(loid)s (released from e-waste dismantling) on the environment (water and soil). Eight hazardous metal(loid)s (Pb, Cd, Cu, Zn, As, Hg, Ni, and Cr) were primarily found in the monitored water and soil samples (Sangrampur, West Bengal) because of widespread informal e-waste handling and primitive processing. Elevated concentrations of Cd, Pb, As, Cu, and Cr were observed in pond water samples (0.04, 1.62, 0.03, 1.40, 1.74 mg/L respectively). These ponds, which are regularly used for e-waste handling/dismantling, are usually flooded during the monsoon season mixing with further larger water resources - posing a serious threat to public health. Enriched levels of Pb, Cd, Cu, and Zn were detected in collected soil samples, both top surface soil (Pb up to 2042.27 ± 206.80, Cd up to 25.90 ± 9.53, Cu up to 6967.30 ± 711.70, and Zn up to 657.10 ± 67.05 mg/Kg) and deeper subsurface soil (Pb, 419.70 ± 44.70; Cd, 18.34 ± 3.81; Cu, 3928.60 ± 356.40; and Zn, 134.40 ± 33.40 mg/Kg), compared to the levels of As, Hg, Ni, and Cr. Seasonal variation of soil metal(loid) content indicated that higher levels of most of the metal(loids) were detected in the pre-monsoon (Nov-May) season, possibly due to the monsoonal dilution effect, except for Pb and Cd. The results highlighted that the composition and the handling of e-waste were important factors affecting the metal(loid) concentrations. E-waste policy and legislation have great influence on the handling and disposal procedures. An improved e-waste management practice has been proposed to encourage eco-friendly and safe e-waste disposal. It is recommended that regulatory agencies and manufacturers should create a road map to convince the informal sector to develop a systematic approach towards a more standardized formal e-waste management practices at the microscale field level.

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.

Multi-attribute decision-making for electronic waste recycling using interval-valued Fermatean fuzzy Hamacher aggregation operators

The utilization of electrical and electronics equipments in waste recycling has become a paramount for various countries. The waste electrical and electronics equipment (WEEE) recyclers own a crucial position in the environmental growth of a country as they help to minimize the carbon emissions during the recycling of WEEE in the most eco-friendly way. Therefore, the selection and assessment of an appropriate WEEE recycling partner has become a most important part of DM (decision-making) applications. The collusion of numerous quantitative and qualitative factors makes the recycling partner selection problem, a multifaced and significant decision for the managerial experts. The main objective of this work is to propose MADM (multi-attribute decision-making) techniques to evaluate the WEEE recycling partners under interval-valued Fermatean fuzzy (IVFF) information. In this regard, certain Hamacher AOs (aggregation operators) are proposed to develop the required DM method. These AOs include Hamacher weighted averaging, ordered weighted averaging, weighted geometric, ordered weighted geometric, generalized Einstein weighted averaging, generalized Einstein ordered weighted averaging, generalized Einstein weighted geometric, etc. Then, these averaging operators are utilized to come up with a MADM techniques under IVFF environment. Furthermore, the constructed technique is applied to a case study in China to incorporate with the e-waste recycling partner selection problem. Moreover, a brief comparison of the proposed with is presented with various existing techniques to manifest the productivity and coherence of the proposed model. Finally, the accuracy and consistency of results shows that the proposed technique is fully compatible and applicable to handle any MADM problem.

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.

Characteristics of microplastics and the role for complex pollution in e-waste recycling base of Shanghai, China

Plastics used in electric and electronic products cover a wide range, and contain many additives, such as brominated flame retardant and so on. These compounds and microplastics may be released into environment when the electric and electronic products are obsoleted and recycled. This study explores the characteristics of microplastics and the complex pollutions in a formal e-waste recycling base in Shanghai, China. The maximum abundance of microplastics is observed in dust samples of the recycling base and the average abundance is 44277 ± 69032p/50 g. 103 kinds of polymers are identified, including 4 kinds of packaging plastics, 32 kinds of engineering plastics, 18 kinds of rubber, and 49 kinds of other polymers. It is found that microplastics show weak adsorption effect for heavy metals. However, microplastics are important carrier of ∑₈PBDEs released during the whole recycling processes, and BDE-209 account for more than 50 % of PBDEs in microplastics. It is estimated that the microplastics load inside the e-waste recycling base was 4.01 tons based on the measured statistics. This study will provide theoretical basis for further understanding the potential pollution of microplastics and upgrading the corresponding control measures.

The benefits of circular economy strategies in urban water facilities

Circular economy has become a very popular item in the last decades in many fields. Particularly, in the water and wastewater sector, since a lot of pressure has been put on water resources. Although the main target of the application of circular economy in this sector has been waste management, the current research intends to extend its application to other aspects. In this sense, it is highlighted the role that asset management could play in wastewater treatments plants extending the useful life of the equipment and the facilities, and how it could contribute to the circular economy, measuring the impact in economic and environmental terms. Making use of the Analytical Hierarchy Process (AHP) it can be observed that maintenance tasks are one of the most important factors to avoid equipment deterioration. This research offers valuable results that will be useful to assess the condition of the equipment helping the decision-makers to optimize the maintenance tasks and plan replacement strategies that will lead to accomplishing the principles of circular economy, increasing the service life span of the equipment, and reducing the repairing costs, and minimizing the environmental impact associated to the replacement of the equipment.

What drives WEEE recycling? A comparative study concerning legislation, collection and recycling

Waste electrical and electronic equipment (WEEE) has been rising worldwide, and its improper management incurs in economic losses and environmental damage. To provide a better understanding of the forces that drive the management of WEEE, economic and political roles are discussed by comparing the WEEE recycling system of Brazil and Australia. Additional insights about the recycling systems were gathered from interviews with recyclers of both countries (in-loco visits and online/phone surveys). Previous studies show that both countries act as first stage recyclers, dismantling WEEE to ship their valuable components for international recyclers (such as printed circuit boards) while keeping less valuable material (such as polymeric and ferrous pieces). Australia has defined the responsibilities of most agents involved in the WEEE management and recycling setup, while Brazil inadvertently has left the system to be defined through free market regulation. As Brazil recently signed a reverse logistic agreement, there is an important opportunity to channel WEEE into formal routes and implement improvements in the entire recycling system (some suggestions are provided). Australian recyclers were found more organised in their disassembly lines, and some characteristics of the Australian model can be adapted for the Brazilian benefit. In conclusion, economic factors will drive first stage recycling (where labour wages are a small fraction of the total costs) and international downstream recycling, while a political framework is necessary to establish a comprehensive collection system, first stage recycling (where wages are representative) and domestic downstream recycling, given these are generally non-profitable activities in the short term.

Engineering Self-Powered Electrochemical Sensors Using Analyzed Liquid Sample as the Sole Energy Source

Many healthcare and environmental monitoring devices use electrochemical techniques to detect and quantify analytes. With sensors progressively becoming smaller-particularly in point-of-care (POC) devices and wearable platforms-it creates the opportunity to operate them using less energy than their predecessors. In fact, they may require so little power that can be extracted from the analyzed fluids themselves, for example, blood or sweat in case of physiological sensors and sources like river water in the case of environmental monitoring. Self-powered electrochemical sensors (SPES) can generate a response by utilizing the available chemical species in the analyzed liquid sample. Though SPESs generate relatively low power, capable devices can be engineered by combining suitable reactions, miniaturized cell designs, and effective sensing approaches for deciphering analyte information. This review details various such sensing and engineering approaches adopted in different categories of SPES systems that solely use the power available in liquid sample for their operation. Specifically, the categories discussed in this review cover enzyme-based systems, battery-based systems, and ion-selective electrode-based systems. The review details the benefits and drawbacks with these approaches, as well as prospects of and challenges to accomplishing them.

A Forest-Based Triboelectric Energy Harvester

Triboelectric nanogenerators (TENGs) are a new class of energy harvesting devices that have the potential to become a dominating technology for producing renewable energy. The versatility of their designs allows TENGs to harvest mechanical energy from sources like wind and water. Currently used renewable energy technologies have a restricted number of materials from which they can be constructed, such as metals, plastics, semiconductors, and rare-earth metals. These materials are all non-renewable in themselves as they require mining/drilling and are difficult to recycle at end of life. TENGs on the other hand can be built from a large repertoire of materials, including materials from bio-based sources. Here, a TENG constructed fully from wood-derived materials like lignin, cellulose, paper, and cardboard, thus making it 100% green, recyclable, and even biodegradable, is demonstrated. The device can produce a maximum voltage, current, and power of 232 V, 17 mA m-2, and 1.6 W m-2, respectively, which is enough to power electronic systems and charge 6.5 µF capacitors. Finally, the device is used in a smart package application as a self-powered impact sensor. The work shows the feasibility of producing renewable energy technologies that are sustainable both with respect to their energy sources and their material composition.

Influence of Ga Content on the Microstructure and Mechanical Properties of Cadmium-Free Filler Metal

The influence of Ga content on the melting temperature, wettability, microstructure, and mechanical properties of low-silver 12AgCuZnSn-2In-0.15Pr cadmium-free filler metal was investigated systematically by means of differential thermal analysis, X-ray diffractometer, scanning electron microscopy, energy-dispersive spectrometer, etc. The results showed that the addition of the Ga element reduced the solidus and liquidus temperatures of the novel low-silver filler metals, and effectively increased the spreading area of the filler metal on the copper and 304 stainless steel substrates. Furthermore, an appropriate amount of Ga element significantly optimized the interface morphology and improved the mechanical properties of the brazed joints. When the Ga content was 1wt.%, the shear strength of the brazed joints reached a peak value of 448 MPa, and the corresponding fracture morphology showed typical ductile characteristics with obvious dimples.

Characteristics of unorganized emissions of microplastics from road fugitive dust in urban mining bases

Nowadays, plastic pollution attracts attention, while data on microplastic (MP) emissions to atmosphere from urban mining bases are rarely quantified. In this paper, the emission characteristics of MPs in road fugitive dust from two urban mining bases were studied, the emission factors of MPs from road fugitive dust source were updated, and emission inventories were established. It is estimated that the waste glass recycling base and the e-waste dismantling plant emit 1265.53 g and 40.5 g of MPs into atmosphere respectively each year, with the highest percentage of tire micro-rubber. The roads with the most emissions are located in the middle of warehouses and workshops. Emission factors for MPs mainly depend on average vehicle weight, and heavy vehicles cause more MP emissions. Uncertainty analysis of the inventory indicated that the random error of MP emissions on a single road in waste glass recycling base was -79.1%-187.1%, while in e-waste dismantling plant was -62.7%-102.05%, which is mainly related to the silt loading. This study completes the quantitative data on the unorganized emissions of MPs from road fugitive dust in these two typical urban mining bases, and provides guidance for air pollution prevention and control.

Mathematical modeling of metal recovery from E-waste using a dark-fermentation-leaching process

In this work, an original mathematical model for metals leaching from electronic waste in a dark fermentation process is proposed. The kinetic model consists of a system of non-linear ordinary differential equations, accounting for the main biological, chemical, and physical processes occurring in the fermentation of soluble biodegradable substrates and in the dissolution process of metals. Ad-hoc experimental activities were carried out for model calibration purposes, and all experimental data were derived from specific lab-scale tests. The calibration was achieved by varying kinetic and stoichiometric parameters to match the simulation results to experimental data. Cumulative hydrogen production, glucose, organic acids, and leached metal concentrations were obtained from analytical procedures and used for the calibration. The results confirmed the high accuracy of the model in describing biohydrogen production, organic acids accumulation, and metals leaching during the biological degradation process. Thus, the mathematical model represents a useful and reliable tool for the design of strategies for valuable metals recovery from waste or mineral materials. Moreover, further numerical simulations were carried out to analyze the interactions between the fermentation and the leaching processes and to maximize the efficiency of metals recovery due to the fermentation by-products.

A comparative study of national variations of the European WEEE directive: manufacturer's view

We are facing the challenge of rapid growth in waste from electrical products (e-waste). In Europe, handling e-waste is regulated by the European Waste Electrical and Electronic Equipment (WEEE) directive, which is based on the extended producer responsibility (EPR) model as a regulatory tool forcing manufacturers and importers to take responsibility for their products throughout their lifecycles. However, the directive allows for great variations in implementations in each country, causing e-manufacturers and e-waste handling operators to face challenges in their transition to more sustainable operations. To identify the challenges involved, this study investigates the effect of the WEEE directive from a manufacturer's perspective. A case study of an e-manufacturer operating subsidiaries in several European countries and the associated producer responsibility organizations (PROs) is presented. The case study includes interviews from 17 stakeholders in 12 organizations in eight European countries. Key findings are as follows. First, the WEEE data reported are not harmonized. Second, the calculations of the environmental fee differ across countries. Third, following up on different national WEEE obligations sometimes leads to over-reporting to avoid negative effects on environmental corporate social responsibility, brand reputation, and profitability. Fourth, outsourcing end-of-life (EoL) treatment responsibility to PROs is seen as positive by the manufacturer but results in a decoupling of the EPR and the operational EoL treatment, which may reduce efforts to transfer to a higher circularity level of its EEE products. Fifth, WEEE is considered a way for e-manufacturers to handle waste not to adopt a circular focus. This paper contributes to both practitioners and researchers within reverse logistics and sustainability by adding knowledge from real-life context of how EPR is implemented in WEEE.

Waste electrical and electronic equipments as urban mines in Burkina Faso: Characterization and release of metal particles

Like other developing countries, Burkina Faso is one of the preferential destinations for second-hand electrical and electronic equipments (EEE). At the end of their life, these EEEs are classified as waste electrical and electronic equipment (WEEE) including Printed Circuit Boards (PCB). A particle size reduction is realized for the release of metals by shredding and grinding to obtain particles smaller 1.5 mm. A granulometric sorting was realized and nine granulometric portions were obtained. Particles were characterized by optical microscopy and Scanning Electron Microscopy coupled with Energy Dispersive X-ray Spectroscopy (EDS). The experiments confirmed that the fractions contained polymers, glass fibers and metals under the form of single metals or alloys. The release of metal was efficient for particles with a size smaller than 0.71 mm. Three digestion procedures were experimented on four components to assess the impact on metals leaching. Microwave-assisted digestion method was the best procedure, compared to the analysis methods ISO 11466: 1995, and method 3050B, adapted. The characterization by Inductively coupled plasma atomic emission spectroscopy (ICP-AES) of these PCBs exhibited important amounts of precious metals (Ag, Au, Pd) and other metals in greater quantities (Cu, Pb, Ni, Co, etc.), leading to their qualification as "Urban Mines" calling for their recovery. The characterization of metals in each granulometric portion is realized. Precious and others metals were distributed in all granulometric size portions. So granulometric size reduction was not efficient for metal separation and recovery from PCBs and alternative methods should be investigated for selective precious metal recovery.

Analysis of national policies for Circular Economy transitions: Modelling and simulating the Brazilian industrial agreement for electrical and electronic equipment

Public policies, incentives, and infrastructure are top-down instruments that can align stakeholders' roles and expectations for Circular Economy (CE) transitions, but it is crucial to analyse the possible effects of such instruments before implementation. This research investigates the Brazilian Industrial Agreement for Electrical and Electronic Equipment (BIAEEE) that governs the responsibilities and targets for nationwide collection and treatment of Waste from Electrical and Electronic Equipment (WEEE). A system dynamics simulation model is adapted for the use of smartphones in Brazil, and interventions focused on the collection of end-of-life products are examined against the BIAEEE targets. Twelve policy scenarios investigate three aspects of EEE collection: coverage increase, distribution of collection points and rewards. All scenarios show improvement in the EEE collection, but only one meets the BIAEEE targets. This research demonstrates how modelling and simulation can inform strategic decision-making in public policies for CE transitions.

Pollution characteristics and risk assessment of air multi-pollutants from typical e-waste dismantling activities

This study investigated the characteristics of air multi-pollutants emitted during typical electronic waste (e-waste) dismantling processes and assessed their risks to the environment and human health. Concentrations of total volatile organic compounds (TVOCs), polybrominated diphenyl ethers (PBDEs), and polycyclic aromatic hydrocarbons (PAHs) in a typical e-waste dismantling workshop were 137 μg/m³, 135 ng/m³ and 42 ng/m³, respectively, which were lower than those without emission control measures. The partial removal of pollutants due to the emission control measures also decreased the ozone formation potential and non-cancer risk of volatile organic compounds (VOCs). In the workshop, the lifetime cancer risk (LCR) of VOCs (8.1 × 10^-5) was close to the recommended values. Conversely, the LCR of PAHs (3.6 × 10^-5) and the total exposure index of PBDEs (19 ng/d) were remarkably lower than the recommended values of 10^-3 and that without emission control measures, respectively. Meanwhile, the concentrations of TVOCs, polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs), PBDEs, and PAHs in the outlet were approximately 10-30 times higher than those in the workshop. In addition, the LCR of TVOCs within a 5-km radius area remained higher than the accepted value (10^-6), and the inhalation exposure risk of PCDD/Fs within a 20-km radius area was five times higher than the recommended value. Therefore, the emissions from e-waste recycling processes should be considered as an important source of air pollution, and more efficient control measures should be taken in the future.

Collecting Small-Waste Electrical and Electronic Equipment in Poland—How Can Containers Help in Disposal of E-Waste by Individuals?

The effectiveness of e-waste collection depends on organizational and social factors. Individuals should have easy access to collection points and be aware of proper methods of e-waste disposal. This article investigates the availability, usability, and occurring irregularities of the container collection of small-waste electrical and electronic equipment. The study explores the attitude and behavior of individuals when disposing of small-waste equipment in the South of Poland. The results show that ninety-five percent of supermarkets’ managers responsible for waste management find a growing interest in the disposal of small e-waste by individuals. An increasing number of collection containers encourages residents to dispose of small-waste appliances. More than eighty-three percent of respondents are aware of proper methods of e-waste disposal. Additional information campaigns addressed to residents are required to prevent mixing electrical and electronic waste with other waste and to encourage the disposal of small e-waste. The intention to dispose of small e-waste was declared by only thirty-two percent of respondents. Containers with discarded easy breakable items, such as lamps, should be removed more frequently. The collection containers’ noticeability is evaluated by individuals as of average difficulty. The containers in supermarkets have simple designs and labels indicating the category of waste for disposal. The containers installed in residential areas have attractive designs and advertising slogans. The individuals expect the containers should be available in more locations that are easily accessible from households. The results of this study should be helpful for local authorities, waste collection companies, and waste electrical and electronic organizations, to support design, location selection, and information campaigns for small e-waste container collections.

Pro-environmental behavior and smartphone uses of on-campus engineering students in Xi'an, China

BACKGROUND

The usage status, waste electrical and electronic equipment (WEEE) related to the smartphones of on-campus engineering students should be studied. Furthermore, the correlations between their smartphone profiles with energy consumption and environmental knowledge should be understood make measures improve their environmental behaviors.

METHODS

Pro-environmental behavior and smartphone uses of the on-campus engineering undergraduates in Xi'an, China, were investigated with a self-designed questionnaire anonymously. The energy-saving activities they participated in and their e-waste treatment patterns were analyzed.

RESULTS

Most of the respondents had a smartphone with large screen and high battery capacity, which also had long standby/usage time and frequent charging. Average daily power consumption of one smartphone was estimated to be 6.475 Wh. The surveyed undergraduate students changed their smartphones frequently, which produced large quantities of WEEE annually.

CONCLUSION

Most on-campus students treated their waste smartphones in the proper ways. However, some of them were short of environmental knowledge about their smartphones. Some measures were suggested to improve their environmental concerns. The findings will help the on-campus engineering undergraduates in China to use their smartphones rationally and to deal with their waste smartphones appropriately.

The Political Economy of Australia's Waste Crisis: From Neoliberalism to the Circular Economy Agenda

The international trade of waste has come under public spotlight in recent years with China, the world's main waste sink for several decades, effectively banning its waste imports in 2018 and subsequently starting a waste crisis in Australia. This article compares the perspectives of orthodox economics, circular economy and political economy on waste economics and policy in Australia. Taking an approach combining both qualitative and quantitative analysis, this article finds that the political economy of Australia's waste crisis can be understood in terms of two phases: (1) an expansionary phase in Australia's waste industry from the 1990s onwards, driven by export-oriented growth and neoliberal policy which ultimately led to a waste crisis in 2018, and (2) an emerging recovery stage for the industry led by circular economy policy and more domestically oriented development. These findings contribute to ongoing discourse on the circular economy agenda, demonstrating that in the case of Australia's waste crisis, circular economy is more of a pragmatic strategy to stimulate economic recovery rather than some radical change towards environmental sustainability.

Characterization of top 100 researches on e-waste based on bibliometric analysis

With rapid development of energy, information, and communication technology, e-waste problem has become one of the global issues to be settled urgently. The main features on publication years, journals, countries and institutions, authors, keywords, and content types of the 100 most-cited articles on e-waste had been unfolded in this research. The direction and way forward were illustrated, the trends to date were demonstrated, and the terrain and pathways were evaluated on the research of e-waste. Bibliometric analysis method was applied to analyze various attributes on the 100 most-cited articles which were retrieved from WoSCC on May 25, 2021, by utilizing the software tools Microsoft Excel 2016 and VOS viewer 1.6.9. The publication year and citation number of the 100 articles ranged between 2003 and 2017 and from 83 to 925, respectively. Environmental Science & Technology (n=17) published the maximum articles. Waste Management, Journal of Hazardous Materials, and Environmental Science & Technology were the core journals on e-waste. One hundred twenty-three institutions and 25 countries were involved in publishing the 100 articles. Three hundred seventy authors contributed to the 100 articles in total. A total of 267 keywords occurred in the 100 articles. The keywords "e-waste" and "recycling" held the highest occurrences. The study content of the 100 articles could be classified into four types including the characteristic-and-property type, the environment-and-health type, the management-and-economic type, and the technique-and-processing type. Overall completeness and applicability of the evidence found in this study were verified sufficiently; the potential biases in the review process were also considered. The innovations of the research from the past bibliometric analysis work on e-waste were stated, and the implication for practice and research of this study were explained as well. 2007, 2008, and 2009 were a peak of the researches on e-waste, while the recent years were experiencing a valley. China and its institutions were most influential in this field on e-waste. India was becoming more and more influential on e-waste research in the world. Nigeria was the research center in Africa, and Brazil was the research center in Latin America. Wong Minghung was the most important expert on e-waste. The impact on environment and human being's health was the hot topic of researches on e-waste; the characteristic and property of e-waste were studied not enough. The researches of technique and processing would be the direction and way forward in the study field on e-waste. The characteristic and property on e-waste would need more attention to be researched. The researchers could develop new pathways based on and beyond the four types of content evaluated in this research.

Strategies of cadmium and copper uptake and translocation in different plant species growing near an E-waste dismantling site at Wenling, China

This study aimed to explore the interactions between cadmium (Cd) and copper (Cu) during uptake and translocation in plants growing in soil polluted with heavy metals derived from electronic waste (E-waste). We collected the roots, stems, leaves, and root-surrounding soils of ten dominant plant species growing in farmland near an E-waste dismantling site, and analyzed their Cd and Cu concentrations. Among the ten plant species, Echinochloa crus-galli (L.) P. Beauv., Cucurbita moschata (Duch. ex Lam.) Duch. ex Poiret, Phragmites australis (Cav.) Trin. ex Steud., and Benincasa hispida (Thunb.) Cogn. accumulated Cd (2.40-4.56 mg kg^-1) and Cu (19.60-35.21 mg kg^-1) in the roots. In Polygonum hydropiper L. and Sesbania cannabina (Retz.) Poir., the Cd (0.50-0.81 mg kg^-1) and Cu (11.04-15.55 mg kg^-1) concentrations were similar among the three organs. Glycine max (L.) Merr. accumulated more Cu in the roots (16.42 mg kg^-1) than in the stems (5.61 mg kg^-1) and leaves (7.75 mg kg^-1), and accumulated Cd at similar levels in the three organs (0.65-0.99 mg kg^-1). Sesamum indicum L., Bidens pilosa L., and Solidago decurrens Lour. accumulated Cd at similar levels among the three organs (0.16-3.34 mg kg^-1) and accumulated less Cu in the stems (6.89-8.28 mg kg^-1) than in the roots (12.61-21.63 mg kg^-1) and leaves (12.93-22.38 mg kg^-1). S. indicum had a stronger capacity to accumulate and translocate Cd and Cu according to transfer coefficient and translocation factor. The concentrations of Cd and Cu in soils were significantly positively correlated with those in the roots (p<0.01) but not those in the stems and leaves. We detected significantly positive correlations between Cd and Cu concentrations in the roots and leaves (p<0.01) but not in the stems. These results suggest that there is a synergetic strategy of Cd and Cu transport from soils to the roots and from the roots to the leaves, while the stems may not be the key organ controlling Cd and Cu transport in plants. These findings have important implications for the phytoremediation of soils contaminated with Cd and Cu, the mechanisms of plant Cd and Cu transport, and the food safety of agricultural products.

Proposed Methodology for End-of-Life Option using Multi Criteria Decision Analysis: A Study for General Paper Product

Over the years, the world population has been growing exponentially. This population growth affects the number of waste products due to the increased production, which leads to greater environmental impact and other problems. There are different numbers of product end-of-life (EOL) options to handle waste based on product characteristics. This research is designed to develop a methodology to determine the best EOL option for a paper product using the analytical hierarchy process (AHP). AHP is one of the multi-criteria decision analysis (MCDA) methods employed to select the best option by considering the user’s preferences and output of competing EOL options related to different product criteria. A graphical user interface (GUI) called AHP-based software was developed using Microsoft Excel through the programming function of Visual Basic for Applications as a user facilitating tool when conducting the analysis. The case study technique is applied to five different types of paper products to assess the capability of the proposed AHP-based software. Results from the AHP-based software reveal that recycling is the most suitable EOL technique for most paper products compared to other techniques. However, polluted products with ink or food waste and coating may not be suitable for this method. The research assists the users to identify the most sustainable ways to handle paper product waste based on the product condition.

An assessment of e-waste generation and environmental management of selected countries in Africa, Europe and North America: A systematic review

Waste generated from electrical and electronic equipment collectively known as e-waste has remained a persistent environmental problem. Globally, approximately 53.6 million tons of e-waste was generated in 2019. Of this amount generated, less than 13% was recycled and the rest ended up in landfills or incinerators creating enormous environmental and health concerns due to the presence of hazardous materials. While there are several previous-studies on e-waste, research findings of the United Nations global e-waste report 2020 shows that many countries are not sufficiently managing e-waste generated and greater effort is urgently required to ensure smarter and more sustainable e-waste management. On this premise, this study critically reviews previous research on e-waste generation and management practices of selected-countries - Canada, France, United States, United Kingdom, Nigeria and South Africa; provides an overview of progress made and identifies areas for improvement. These countries are selected because they are some of the largest-producers of e-waste worldwide. To achieve the objectives of this study, previous-studies from 2005 to 2020 are collected from databases. The study focuses on aspects such as e-waste generation, e-waste recycling, e-waste disposal methods and behaviour, environmental management of e-waste, e-waste problems and challenges and e-waste legislation of these countries. This study further categorised previous-studies of selected-countries in relation to type and scope of research, e-waste categories evaluated and study locations. Based on the findings/outcomes of the analysis on the current-situation of the selected-countries in the literature, this study proposes generic best-practice approaches to e-waste generation and environmental management taking into account country-specific issues and identifies future research areas.

WEEE treatment and system management in Italy and Serbia: A comparison

Waste electrical and electronic equipment (WEEE) represent one of the growing waste streams in Europe, whose content of hazardous substances and valuable materials focus on how it is handled. However, there are differences between countries regarding e-waste management system in Europe. This paper analyses and presents data regarding the e-waste management system in Italy, one of the founding countries of the EU and Serbia - EU candidate country. Within this work, the following aspects were considered: legislative framework and EU directive goals in terms of e-waste, institutional setup, collection system, and existing recycling and treatment technologies. In addition, material flow analysis is used to model mass balance within WEEE treatment plants in both countries. Finally, through assessment and comparison of current systems in both countries, problems and shortages of Serbia's e-waste management system are addressed.

A Systematic Review of E-Waste Generation and Environmental Management of Asia Pacific Countries

Due to the rapid increase in the use of electrical and electronic equipment (EEE) worldwide, e-waste has become a critical environmental issue for many governments around the world. Several studies have pointed out that failure to adopt appropriate recycling practices for e-waste may cause environmental disasters and health concerns to humans due to the presence of hazardous materials. This warrants the need for a review of the existing processes of e-waste management. In view of the growing e-waste generation in the Asia Pacific region and the importance of e-waste management, this study critically reviews previous research on e-waste generation and management practices of major e-waste producing nations (Australia, China, India, Indonesia, and Malaysia) in the Asia Pacific region, provides an overview of progress made and identifies areas for improvement. To fulfil the aims of this research, previous studies from 2005 to 2020 are collected from various databases. Accordingly, this study focuses on e-waste generation and environmental management of these countries. This study found that e-waste management practices of the selected countries need to be enhanced and recommends several best practices for effectively managing e-waste.

Electronic waste generation, recycling and resource recovery: Technological perspectives and trends

The growing population and increased disposal of end-of-life (EoL) electrical and electronic products have caused serious concerns to the environment and human health. Electronic waste (e-waste) is a growing problem because the quantity and the rate at which it is generated has increased exponentially in the last 5 years. The rapid changes or upgradation in technologies, IT requirements for working or learning from home during COVID-19, manufacturers releasing new electronic gadgets and devices that serves the consumers comfort and a declension in services has contributed to an increase in the e-waste or waste of electrical and electronic equipment (WEEE) generation rates. The current status of e-waste generation, handling procedures and regulatory directives in USA, EU, China, India, Vietnam and Gulf Cooperation Council (GCC) countries are presented in this review. The recent developments in e-waste recycling methods/recovery of base and precious metals, the advantages and limitations of hydrometallurgy, pyrometallurgy, biohydrometallurgy and pyrolysis are discussed. Considering the impediments in the present technologies, the extraction of valuable resources, i.e. precious metals, from e-waste using suitable biocatalysts shows promising applications. This review also stresses on the research needs to assess the economic effects of involving different unit operations/process industries for resource recovery, reuse and recycling.

E-Waste in Africa: A Serious Threat to the Health of Children

Waste electronic and electrical equipment (e-waste) consists of used and discarded electrical and electronic items ranging from refrigerators to cell phones and printed circuit boards. It is frequently moved from developed countries to developing countries where it is dismantled for valuable metals in informal settings, resulting in significant human exposure to toxic substances. E-waste is a major concern in Africa, with large sites in Ghana and Nigeria where imported e-waste is dismantled under unsafe conditions. However, as in many developing countries, used electronic and electrical devices are imported in large quantities because they are in great demand and are less expensive than new ones. Many of these used products are irreparable and are discarded with other solid waste to local landfills. These items are then often scavenged for the purpose of extracting valuable metals by heating and burning, incubating in acids and other methods. These activities pose significant health risks to workers and residents in communities near recycling sites. E-waste burning and dismantling activities are frequently undertaken at e-waste sites, often in or near homes. As a result, children and people living in the surrounding areas are exposed, even if they are not directly involved in the recycling. While toxic substances are dangerous to individuals at any age, children are more vulnerable as they are going through important developmental processes, and some adverse health impacts may have long-term impacts. We review the e-waste situation in Africa with a focus on threats to children's health.

Effect of In and Pr on the Microstructure and Properties of Low-Silver Filler Metal

The novel low-silver 12AgCuZnSn filler metals containing In and Pr were used for flame brazing of copper and 304 stainless steel in this study. The effects of In and Pr content on the melting temperature, wettability, mechanical properties and microstructure of 12AgCuZnSn filler metal were analyzed. The results indicate that the solidus and liquidus temperatures of filler metals decrease with the addition of In. Trace amounts of Pr have little impact on the melting temperature of the low-silver filler metals. In addition, the spreading area of filler metals on copper and 304 stainless steel is improved. The highest shear strength of brazed joint is 427 MPa when the content of In and Pr are 2 wt.% and 0.15 wt.%, respectively. Moreover, it is observed that the trace amount of Pr significantly refines the microstructure of brazed joint matrix. A bright Pr3Cu4Sn4 phase is found in filler metal and brazing seam when the contents of In and Pr are 5 wt.% and 0.5 wt.%, respectively.

Recovery of copper and aluminium from coaxial cable wastes using comparative mechanical processes analysis

This work aims to perform a comparative study of two mechanical processes for the recycling of metals from coaxial cables (aluminium and copper-clad steel): Process I - comminution, sieving and electrostatic separation; and Process II - comminution, magnetic separation and electrostatic separation. Characterization techniques were performed on the cables to discover their composition. The parameters evaluated of electrostatic separation were: roll speed (n), electrostatic electrode distance (D2), voltage applied to the electrodes (U) and splitter angle (γ). The best conditions for electrostatic separation were: Process I - n = 30 rpm, D2 = 8 cm, U = 30 kV and γ = 0°; Process II - n = 10 rpm, D2 = 10 cm, U = 25 kV and γ = 2.5°. Process I presented aluminium with purity of 99.51% and recovery efficiency of 94.53%, as well as copper-clad steel with purity of 96.79% and recovery efficiency of 99.68%. Process II presented aluminium with purity of 96.51% and recovery of 70.12%, as well as copper-clad steel with purity of 99.53% and recovery of 99.46%. A simplified economic assessment was performed on both process, and Process I has demonstrated to be the most profitable for coaxial cable recycling. The results showed that Process I is promising for the recovery of metals from cables due to its simplicity and lower cost, being capable of wide application to other processes that contain a mixture of conductive and non-conductive particles.

Selective Gold and Palladium Adsorption from Standard Aqueous Solutions

The intensive exploitation of resources on a global level has led to a progressive depletion of mineral reserves, which were proved to be insufficient to meet the high demand for high-technological devices. On the other hand, the continuous production of Waste from Electrical and Electronic Equipment (WEEE) is causing serious environmental problems, due to the complex composition of WEEE, which makes the recycling and reuse particularly challenging. The average metal content of WEEE is estimated to be around 30% and varies depending on the manufacturing period and brand of production. It contains base metals and precious metals, such as gold and palladium. The remaining 70% of WEEEs is composed of plastics, resins, and glassy materials. The recovery of metals from WEEEs is characterized by two main processes well represented by the literature: Pyrometallurgy and hydrometallurgy. Both of them require the pre-treatment of WEEEs, such as dismantling and magnetic separation of plastics. In this work, the selective adsorption of precious metals has been attempted, using copper, gold, and palladium aqueous solutions and mixtures of them. A screening on different adsorbent materials such as granular activated carbons and polymers, either as pellets or foams, has been performed. Among these, PolyEther Block Amide (PEBA) was elected as the most performing adsorbent in terms of gold selectivity over copper. Spent PEBA has been then characterized using scanning electron microscope, coupled with energy dispersive spectroscopy, demonstrating the predominant presence of gold in most analyzed sites, either in the pellet or foam form.