The amount of electronic waste (e-waste) globally has doubled in just five years, from approximately 20 million tons to 40 million tons of e-waste generated per year. In 2016, the global amount of e-waste reached an all-time high of 44.7 million tons. E-waste is an invaluable unconventional resource due to its high metal content, as nearly 40% of e-waste is comprised of metals. Unfortunately, the rapid growth of e-waste is alarming due to severe environmental impacts and challenges associated with complex resource recovery that has led to the use of toxic chemicals. Furthermore, there is a very unfortunate ethical issue related to the flow of e-wastes from developed countries to developing countries. At this time, e-waste is often open pit burned and toxic chemicals are used without adequate regulations to recover metals such as copper. The recovered metals are eventually exported back to the developed countries. Thus, the current global circular economy of e-waste is not sustainable in terms of environmental impact as well as creation of ethical dilemmas. Although traditional metallurgical processes can be extended to e-waste treatment technologies, that is not enough. The complexity of e-waste requires the development of a new generation of metallurgical processes that can separate and extract metals from unconventional components such as polymers and a wide range of metals. This review focuses on the science and engineering of both conventional and innovative separation and recovery technologies for e-wastes with special attention being given to the overall sustainability. Physical separation processes, including disassembly, density separation, and magnetic separation, as well as thermal treatment of the polymeric component, such as pyrolysis, are discussed for the separation of metals and non-metals from e-wastes. The subsequent metal recovery processes through pyrometallurgy, hydrometallurgy, and biometallurgy are also discussed in depth. Finally, insights on future research towards sustainable treatment and recovery of e-waste are presented including the use of supercritical CO 2 .
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Electronic Waste, an Environmental Problem Exported to Developing Countries: The GOOD, the BAD and the UGLY
Electronic waste (e-waste) is a rapidly developing environmental problem particularly for the most developed countries. There are technological solutions for processing it, but these are costly, and the cheaper option for most developed countries has been to export most of the waste to less developed countries. There are various laws and policies for regulating the processing of e-waste at different governance scales such as the international Basel Convention, the regional Bamoko Convention, and various national laws. However, many of the regulations are not fully implemented and there is substantial financial pressure to maintain the jobs created for processing e-waste. Mexico, Brazil, Ghana Nigeria, India, and China have been selected for a more detailed study of the transboundary movements of e-waste. This includes a systematic review of existing literature, the application of the Driver, Pressure, State, Impact, Response (DPSIR) framework for analysing complex problems associated with social ecological systems, and the application of the Life Cycle Assessment (LCA) for evaluating the environmental impact of electronic devices from their manufacture through to their final disposal. Japan, Italy, Switzerland, and Norway have been selected for the LCA to show how e-waste is diverted to developing countries, as there is not sufficient data available for the assessment from the selected developing countries. GOOD, BAD and UGLY outcomes have been identified from this study: the GOOD is the creation of jobs and the use of e-waste as a source of raw materials; the BAD is the exacerbation of the already poor environmental conditions in developing countries; the UGLY is the negative impact on the health of workers processing e-waste due to a wide range of toxic components in this waste. There are a number of management options that are available to reduce the impact of the BAD and the UGLY, such as adopting the concept of a circular economy, urban mining, reducing loopholes and improving existing policies and regulations, as well as reducing the disparity in income between the top and bottom of the management hierarchy for e-waste disposal. The overarching message is a request for developed countries to help developing countries in the fight against e-waste, rather than exporting their environmental problems to these poorer regions.
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- Award ID(s):
- 1840868
- NSF-PAR ID:
- 10280247
- Date Published:
- Journal Name:
- Sustainability
- Volume:
- 13
- Issue:
- 9
- ISSN:
- 2071-1050
- Page Range / eLocation ID:
- 5302
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3390/su13095302
