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He Y, Kiehbadroudinezhad M, Hosseinzadeh-Bandbafha H, Gupta VK, Peng W, Lam SS, Tabatabaei M, Aghbashlo M. Driving sustainable circular economy in electronics: A comprehensive review on environmental life cycle assessment of e-waste recycling. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 342:123081. [PMID: 38072018 DOI: 10.1016/j.envpol.2023.123081] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Revised: 11/27/2023] [Accepted: 11/30/2023] [Indexed: 12/17/2023]
Abstract
E-waste, encompassing discarded materials from outdated electronic equipment, often ends up intermixed with municipal solid waste, leading to improper disposal through burial and incineration.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.
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Affiliation(s)
- Yifeng He
- Henan Province International Collaboration Lab of Forest Resources Utilization, School of Forestry, Henan Agricultural University, Zhengzhou, 450002, China
| | | | | | - Vijai Kumar Gupta
- Centre for Safe and Improved Food, SRUC, Kings Buildings, West Mains Road, Edinburgh, EH9 3JG, United Kingdom; Biorefining and Advanced Materials Research Centre, SRUC, Barony Campus, Parkgate, Dumfries DG1 3NE, United Kingdom
| | - Wanxi Peng
- Henan Province Engineering Research Center for Biomass Value-Added Products, School of Forestry, Henan Agricultural University, Zhengzhou, 450002, China
| | - Su Shiung Lam
- Higher Institution Centre of Excellence (HICoE), Institute of Tropical Aquaculture and Fisheries (AKUATROP), Universiti Malaysia Terengganu, 21030, Kuala Nerus, Terengganu, Malaysia; Department of Chemical Engineering and Materials Science, Yuan Ze University, Taoyuan, Taiwan
| | - Meisam Tabatabaei
- Higher Institution Centre of Excellence (HICoE), Institute of Tropical Aquaculture and Fisheries (AKUATROP), Universiti Malaysia Terengganu, 21030, Kuala Nerus, Terengganu, Malaysia; Department of Biomaterials, Saveetha Dental College, Saveetha Institute of Medical and Technical Sciences, Chennai, 600 077, India.
| | - Mortaza Aghbashlo
- Henan Province Engineering Research Center for Biomass Value-Added Products, School of Forestry, Henan Agricultural University, Zhengzhou, 450002, China; Department of Mechanical Engineering of Agricultural Machinery, Faculty of Agricultural Engineering and Technology, College of Agriculture and Natural Resources, University of Tehran, Karaj, Iran.
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Javed A, Singh J. Process intensification for sustainable extraction of metals from e-waste: challenges and opportunities. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:9886-9919. [PMID: 36995505 DOI: 10.1007/s11356-023-26433-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 03/09/2023] [Indexed: 06/19/2023]
Abstract
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.
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Affiliation(s)
- Aaliya Javed
- Department of Chemical Engineering, Sardar Vallabhbhai National Institute of Technology, Surat, Gujarat, 395007, India
| | - Jogender Singh
- Department of Chemical Engineering, Sardar Vallabhbhai National Institute of Technology, Surat, Gujarat, 395007, India.
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Preetam A, Dwivedi U, N Naik S, Pant KK, Kumar V. A feasible approach for the treatment of waste computer casing plastic using subcritical to supercritical acetone: Statistical modelling and optimization. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 345:118549. [PMID: 37421717 DOI: 10.1016/j.jenvman.2023.118549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 06/08/2023] [Accepted: 06/28/2023] [Indexed: 07/10/2023]
Abstract
Electronic waste (e-waste) usage has increased tremendously with the rapid evolution of technologies. The accumulated e-waste has now emerged as one of the crucial concerns regarding environmental pollution and human health. Recycling e-waste is commonly focused on metal recovery; nevertheless, a significant fraction of plastics (20-30%) are in e-waste. There is an indispensable need to focus on e-waste plastic recycling in an effective way, which has been mostly overlooked to date. An environmentally safe and efficient study is conducted using subcritical to supercritical acetone (SCA) to degrade the real waste computer casing plastics (WCCP) in the central composite design (CCD) of response surface methodology (RSM) to achieve the maximum oil yield of the product. The experiment parameters were varied in the temperature span of 150-300 °C, residence time between 30 and 120 min, solid/liquid ratio between 0.02 and 0.05 (g/ml), and NaOH amount from 0 to 0.5 g. Adding NaOH into the acetone helps to achieve efficient degradation and debromination efficiency. The study emphasized the attributes of oils and solid products recovered from the SCA-treated WCCP. The characterization of feed and formed products is performed with different characterization techniques such as TGA, CHNS, ICP-MS, FTIR, GC-MS, Bomb calorimeter, XRF, and FESEM. The highest oil yield achieved is 87.89% from the SCA process at 300 °C, in 120min, 0.05 S/L ratio, and 0.5 g of NaOH. GC-MS results disclose that the liquid product (oil) comprises single- and duplicate-ringed aromatic and oxygen-containing compounds. Isophorone is the significant component of the liquid product obtained. Furthermore, SCA's possible polymer degradation mechanistic route, bromine distribution, economic feasibility, and environmental aspect were also explored. This present work represents an environmentally friendly and promising approach for recycling the plastic fraction of e-waste and recovering valuable chemicals from WCCP.
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Affiliation(s)
- Amrita Preetam
- Supercritical Fluid Extraction Laboratory, Centre for Rural Development and Technology, IIT Delhi, 110016, India; Catalytic Reaction Engineering Laboratory, Chemical Engineering Department, Indian, IIT Delhi, 110016, India
| | - Uma Dwivedi
- Supercritical Fluid Extraction Laboratory, Centre for Rural Development and Technology, IIT Delhi, 110016, India; Catalytic Reaction Engineering Laboratory, Chemical Engineering Department, Indian, IIT Delhi, 110016, India
| | - S N Naik
- Supercritical Fluid Extraction Laboratory, Centre for Rural Development and Technology, IIT Delhi, 110016, India
| | - K K Pant
- Catalytic Reaction Engineering Laboratory, Chemical Engineering Department, Indian, IIT Delhi, 110016, India.
| | - Vivek Kumar
- Supercritical Fluid Extraction Laboratory, Centre for Rural Development and Technology, IIT Delhi, 110016, India
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Mir S, Dhawan N. Investigation of pyrolysis for the recovery of metallic values from ball grid arrays. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:90180-90194. [PMID: 36692715 DOI: 10.1007/s11356-023-25494-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 01/18/2023] [Indexed: 06/17/2023]
Abstract
The massive generation of electronic waste has led to a significant interest in sustainable metal recovery and recycling. Ball grid arrays, mounted on printed circuit boards, are identified as a potentially valuable source of metals (Cu, Ni, Au, Ag, Pb, and Sn). In this study, pyrolysis is found as a promising treatment for the degradation of the epoxy resin of ball grid arrays. As a consequence, the liberation of metallic values and glass fibers is attained. The thermal analysis revealed that the major degradation occurs in the temperature range of 300-650 °C, with overall activation energy estimated as ~ 243 kJ/mol. The concentration of CO gas reaches a maximum value at a comparatively lower residence time with an increase in pyrolysis temperature. The metal enrichment was significantly influenced by the variation in pyrolysis temperatures with an optimal condition chosen as 600 °C. The metallic fractions (Cu, Ni, Ag, and Au) were separated from the glass fibers by water-based density separation and enriched in the sink product by three-fold. The recovery of Cu, Ni, Ag, and Au is achieved at 97%, 88%, 95%, and 96%, respectively. The metal fraction can be either used as a feedstock for the Cu smelting process or can be subjected to selective hydrometallurgical treatment. The glass fiber fraction comprises of Si, Al, and Ca oxides with potential application in laminate fabrication. High-quality gaseous products can be reutilized as fuel for other metallurgical processes. It can be concluded that 100 g of BGA yielded Cu ~ 23.7 g, Ni ~ 0.57 g, Ag ~ 23.4 mg, and Au ~ 73 mg after pyrolysis and density separation, which is equivalent to 1.35 kg, of primary Cu ore, 0.042 kg Ni ore, 4.68 kg Ag ore, and 14.6 kg Au ore.
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Affiliation(s)
- Shaila Mir
- Materials Recycling Laboratory, Indian Institute of Technology, Roorkee, Uttarakhand, 247667, India
| | - Nikhil Dhawan
- Materials Recycling Laboratory, Indian Institute of Technology, Roorkee, Uttarakhand, 247667, India.
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Jadhao PR, Mishra S, Singh A, Pant KK, Nigam KDP. A sustainable route for the recovery of metals from waste printed circuit boards using methanesulfonic acid. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 335:117581. [PMID: 36867901 DOI: 10.1016/j.jenvman.2023.117581] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 02/13/2023] [Accepted: 02/23/2023] [Indexed: 06/18/2023]
Abstract
The rapid increase in electronic waste (e-waste) generation and its unsustainable management pose a threat to the environment and human well-being. However, various valuable metals are present in e-waste, which makes it a potential secondary source to recover metals. Therefore, in the present study, efforts were made to recover valuable metals (Cu, Zn, and Ni) from waste printed circuit boards (WPCB) of computers using methanesulfonic acid (MSA). MSA is contemplated as a biodegradable green solvent and has a high solubility for various metals. The effect of various process parameters (MSA concentration, H2O2 concentration, stirring speed, liquid to solid ratio, time, and temperature) was investigated on metal extraction to optimize the process. At the optimized process conditions, 100% extraction of Cu and Zn was achieved, while Ni extraction was around 90%. The kinetic study for metal extraction was performed using a shrinking core model and findings showed that MSA-aided metal extraction is a diffusion-controlled process. Activation energies were found to be 9.35, 10.89, and 18.86 kJ/mol for Cu, Zn, and Ni extraction, respectively. Furthermore, the individual recovery of Cu and Zn was achieved using the combination of cementation and electrowinning, which resulted in 99.9% purity of Cu and Zn. The current study proposes a sustainable solution for the selective recovery of Cu and Zn from WPCB.
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Affiliation(s)
- Prashant Ram Jadhao
- Department of Chemical Engineering, Indian Institute of Technology Delhi, New Delhi, 110016, India.
| | - Snigdha Mishra
- Department of Chemical Engineering, Indian Institute of Technology Delhi, New Delhi, 110016, India
| | - Aditya Singh
- Department of Chemical Engineering, Indian Institute of Technology Delhi, New Delhi, 110016, India
| | - K K Pant
- Department of Chemical Engineering, Indian Institute of Technology Delhi, New Delhi, 110016, India.
| | - K D P Nigam
- Department of Chemical Engineering, Indian Institute of Technology Delhi, New Delhi, 110016, India
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Preetam A, Jadhao PR, Naik S, Pant K, Kumar V. Supercritical fluid technology - an eco-friendly approach for resource recovery from e-waste and plastic waste: A review. Sep Purif Technol 2023. [DOI: 10.1016/j.seppur.2022.122314] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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A critical review on extraction of valuable metals from solid waste. Sep Purif Technol 2022. [DOI: 10.1016/j.seppur.2022.122043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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