Cost-benefit analysis of metal recovery from e-waste: Implications for international policy

An investigation on the operational resilience of the Canadian electronic product stewardship program and the recycling business characteristics

Electronic waste recycling companies have proliferated in many countries due to valuable materials present in end-of-life electronic and electrical equipment. This article examined the business characteristics and management performance of Electronic Products Recycling Association (EPRA), a Canadian nationwide electronic product stewardship organization. The organization's annual performance reports, from 2012 to 2020, for nine Canadian provinces in which it currently operates were aggregated and analyzed. Temporal analysis using regression and Mann-Kendall tests were employed, and five characteristics of EPRA's business were analyzed, including e-waste products collected, number of drop-off locations, efforts to build public awareness, operating expenses, and growth of e-waste stewardship. Results show a decline in the amount of e-waste collected across the provinces, except in New Brunswick, which started its program in 2017. The Mann-Kendall test revealed declining temporal trends in most provinces. Although the collection/drop off sites and stewardship organizations increased astronomically over the study period in Canada, the amounts of e-waste collected decreased. We found that public awareness generally did not increase the amount of e-waste collected, and these campaigns only appeared to be effective in jurisdictions with good accessibility of e-waste recycling. Processing cost accounted for the majority of the e-waste management budget in Canada, and different factors affected the financial success of the stewards differently.

Sustainable technologies for the recycling and upcycling of precious metals from e-waste

E-waste is the fastest growing solid waste in the world. Each year, over 50 million tonnes of e-waste are produced, with its rate increasing by 3-5 % annually. Currently, only 17 % of e-waste is properly recycled, leaving the majority managed unsustainably, thereby causing detrimental environmental and economic effects. Cleaner e-waste management technologies are essential to address this urgent and rapidly expanding issue. Precious metals within e-waste significantly contribute to recycling revenues. In this paper, we review state-of-the-art technologies for sustainable recycling and upcycling of these metals from e-waste, including cleaner extractive metallurgy, solution purification technologies, and direct synthesis of green nanomaterials. We also discuss the potential impacts and constraints of these technologies and provide recommendations for improving and implementing both existing and prospective technologies.

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.

Process intensification for sustainable extraction of metals from e-waste: challenges and opportunities

The electrical and electronic waste is expected to increase up to 74.7 million metric tons by 2030 due to the unparalleled replacement rate of electronic devices, depleting the conventional sources of valuable metals such as rare earth elements, platinum group metals, Co, Sb, Mo, Li, Ni, Cu, Ag, Sn, Au, and Cr. Most of the current techniques for recycling, recovering, and disposing of e-waste are inappropriate and therefore contaminate the land, air, and water due to the release of hazardous compounds into the environment. Hydrometallurgy and pyrometallurgy are two such conventional methods used extensively for metal recovery from waste electrical and electronic equipment (WEEE). However, environmental repercussions and higher energy requirements are the key drawbacks that prevent their widespread application. Thus, to ensure the environment and elemental sustainability, novel processes and technologies must be developed for e-waste management with enhanced recovery and reuse of the valued elements. Therefore, the goal of the current work is to examine the batch and continuous processes of metal extraction from e-waste. In addition to the conventional devices, microfluidic devices have been also analyzed for microflow metal extraction. In microfluidic devices, it has been observed that the large specific surface area and short diffusion distance of microfluidic devices are advantageous for the efficient extraction of metals. Additionally, cutting-edge technologies have been proposed to enhance the recovery, reusability, and recycling of e-waste. The current study may support decision-making by researchers in deciding the direction of future research and moving toward sustainable development.

Electrochemical treatment of wastewaters containing metal-organic complexes: A one-step approach for efficient metal complex decomposition and selective metal recovery

Metal-organic complexes, especially those of ethylenediaminetetraacetic acid (EDTA) with metals such as copper (Cu) and nickel (Ni) (denoted here as Cu-EDTA and Ni-EDTA), are common contaminants in wastewaters from chemical and plating industries. In this study, a multi-electrode (ME) system using a two-chamber reactor and two pairs of electrodes is proposed for simultaneous electrochemical oxidation of a wastewater containing both Cu-EDTA and Ni-EDTA complexes as well as separation and selective recovery of Cu and Ni onto two different cathodes via electrodeposition. Our results demonstrate that the ME system successfully achieved 90% EDTA removal, 99% solid Cu recovery at the Cu recovery cathode and 56% Ni recovery (33.3% on the Ni recovery cathode and 22.6% in the solution) after a four-hour operation. The system further achieved 85.5% Ni recovery after consecutive five cycles of operation for 20 h. While Cu removal was mainly driven by the direct reduction of EDTA-complexed Cu(II) at the cathode, oxidation of EDTA within the Ni-EDTA complex at the anode was a prerequisite for Ni removal. The oxidation of metal-bound EDTA and free EDTA was driven by •OH and direct electron transfer on the PbO2 anode surface and graphite anode, respectively. We further show that ME system performs well for all pH conditions, treatment of real wastewaters as well as wastewaters containing other metals ions (Cr and Zn) along with Cu/Ni. The separation efficiency of Cu and Ni is dependent on applied electrode potential as well as nature and concentration of binding ligand present with comparatively lower separation efficiency achieved in the presence of weaker binding capacity and/or at lower ligand concentration and lower applied electrode potential. As such, some optimization of electrode potential is required depending on the nature/concentration of ligands in the wastewaters. Overall, this study provides new insights into the design and operation of EAOP technology for effective organic abatement and metal recovery from wastewaters containing mixtures of various metal-organic complexes.

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.

Composition and recycling of smartphones: A mini-review on gaps and opportunities

After more than a decade since smartphones became consolidated in the market, many recycling solutions have been proposed to deal with them. To continue developing useful solutions and enable adjustment of routes, this mini-review aims to analyse the current research scenario, presenting relevant gaps, trends and opportunities. From a structured searching and screening procedure, a vast source of data was arranged and is available to extract useful information (43 studies on composition and 93 studies on recycling). The study provides discussions about the history of smartphone development, constituent materials and recycling methods for different components, comparisons between feature phones and smartphones and others. Among some conclusions, the authors highlight the lack of studies on pre-extractive methods, green chemistry, recovery of critical and precious metals, determination of priority materials for recovery and solutions for entire devices. In the end, a list containing six research gaps for composition studies and seven research gaps for recycling studies is provided and may be seen as opportunities for future research.

Investigating recycling decisions of internet recyclers: A step towards zero waste economy

Online recycling has been recognized as an efficient method for waste recycling. This paper focuses on the information asymmetry between an internet recycler and consumers in the online transaction of used products. This paper is to find an optimal strategy for the internet recycler when the consumers would make an adverse selection in submitting the classification results (the used products would be classified into two kinds according to the quality: High quality and Low quality) of used products in online orders to avoid the loss because of internet recycler's moral hazard, which might bring the extra cost for internet recycler. Therefore, this study used game theory to establish a Stackelberg game model for analyzing an internet recycler and consumers' decision-making in the online transaction of used products. Based on the analysis of consumers' behaviors in an online transaction, internet recycler's strategies are divided into two kinds: A, high moral hazard strategy, and B, low moral hazard strategy. It is found that the strategy of low moral hazard is optimal for the internet recycler compared to the strategy of high moral hazard. Further, though strategy B is optimal, the internet recyclers is suggested to increase their moral hazard probability when the H used products are increasing (High-quality ones). Besides, for strategy B, the correction cost for wrong H orders and correction benefit from correction of wrong L orders would decrease the optimal moral hazard probability, and the impact of the correction benefit from correction of wrong L orders on the decision of moral hazard probability is more obvious.

University students' awareness of e-waste and its disposal practices in Pakistan: a construction of the conceptual framework

Pakistan is among the few countries generating and receiving enormous e-waste, which posits a threat to its future generations. A systematic literature review also suggests exploring e-waste awareness in Asia to understand awareness and behavior. Therefore, the present study explored university students' awareness of e-waste and the factors hindering the disposal of laptops, personal computers, and cellphones and suggested a conceptual framework. The study used the qualitative research approach and non-probability sampling. We collected data through four focus group discussions (FGDs) with students at a Pakistani university. After data saturation, we developed themes from FGDs and found computer sciences and engineering students with better awareness than others. The factors hindering e-waste disposal were lower monetary benefits for disposal, breach of sensitive information, nostalgic association with devices, and non-availability of disposal facilities. Other variables like lower resale value and high family sharing increased the storage of e-devices and reduced e-waste disposal. The research is among a few initial attempts to explore e-waste awareness and factors hindering disposal behavior in e-waste-receiving countries (e.g., Pakistan) and provides evidence from students who are the primary users. Our findings are crucial for policymakers to take corrective actions, introduce monetary benefits, and secure disposal to reduce e-waste.

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.

A cleaner approach for high-efficiency regeneration of base and precious metals from waste printed circuit boards through stepwise oxido-acidic and thiocyanate leaching

This work evaluated a green route for developing an eco-friendly flowsheet to regenerate base and precious metals from waste printed circuits boards (WPCBs). Copper (as nanoparticles with an average diameter of 50 nm) and other base metals were extracted via oxidative acid leaching with high efficiency. Thiocyanate was employed for the first time as a green and economical reagent for the extraction of gold from pretreated WPCB. The effect of various parameters, including reagent dosage and temperature, was evaluated on the gold leaching rate, and 100% gold dissolution was achieved at the optimal condition. It was found that ferric iron concentration as the gold leaching oxidant has a notable effect on gold extraction. Also, at temperatures above room temperature, the recovery rate increases in a short period and then decreases continuously. The activation energy of the optimum gold thiocyanate leaching was found to be 42.84 kJ/mol, indicating chemical reaction to be the rate-controlling step. Gold extraction from the thiocyanate medium was carried out by employing activated carbon, where 100% gold adsorption was achieved in 2 h. Toxicity assessment of final residue revealed that it could be categorized as an environmentally safe waste with negligible risk.

Sustainability performance evaluation of the E-waste closed-loop supply chain with the SCOR model

From a sustainability perspective, the performance of a company's supply chain will be satisfactory when it has reached in all aspects a desirable eco-environmentally friendly level. Assessing the sustainability performance in the closed-loop e-waste supply chain becomes vital because its activities are primarily targeted towards sustainability goals related to the process of production, supply, recycling, and disposal of electrical components. This study evaluates the performance of e-waste supply chain sustainability and identifies its performance indicators as a framework for evaluating supply chain performance using the Best-Worst Method (BWM), which is a multi-criteria decision-making (MCDM) approach. For this, the supply chain operations reference (SCOR) model is considered the basic performance evaluation reference. Moreover, through reviewing the literature, the complementary indicators of this model, especially in terms of sustainability, are added to the performance evaluation indices using the Nominal Group Technique (NGT). After specifying and forming a performance evaluation hierarchy, the BWM method is used to determine the criteria score. The results of implementing the framework on some well-known supply chains in New Zealand indicate that the attributes of "Costs," "Quality," and "GreenScor" are crucial for achieving high performance, while in this developed country, there is less concern about social issues.

Analysis of the influence of mobile phones' material composition on the economic profitability of their manual dismantling

This work presents a systematic characterisation of 100 waste mobile phones (73 feature phones and 23 smartphones) produced between 1989 and 2016. All items were inventoried and the evolvement of the relative abundances of their macro-components (mechanic and electro-mechanic parts, electronics and others) and materials was investigated. The average lifetime was 15.1 years for feature phones and 6.4 years for smartphones. The main component was plastic, on average 46%-wt. in feature phones and 37%-wt. in smartphones; over the years electronics' and plastic's amounts decreased (respectively 80% and 70%), while metal components' amount increased (12%). A cost-benefit analysis explored the profitability of the management of waste mobile phones through manual dismantling followed by the sale of the separated components and materials. The average cost of manual dismantling was estimated as 6.93 € per item according to EU average labour costs and 1.50 € per item based on minimum EU labour costs. According to the performed economic analysis, the actual market prices for the potentially recoverable materials and components of waste mobile phones were not able (particularly mixed plastics) to counterbalance the costs of manual dismantling according to the European standard labour costs.

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.