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Rielly A, Dahms-Verster S, Greenfield R. Biomarker responses in Danio rerio following an acute exposure (96 h) to e-waste leachate. ECOTOXICOLOGY (LONDON, ENGLAND) 2024:10.1007/s10646-024-02784-6. [PMID: 38995499 DOI: 10.1007/s10646-024-02784-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/05/2024] [Indexed: 07/13/2024]
Abstract
Electronic waste (e-waste) has been identified as an emerging pollutant and is the fastest growing waste stream at the present time. Significant technological development and modernization within the last decade has led to the rapid accumulation of outdated, broken and unwanted electrical and electronic equipment (EEE). Electronic products mainly consist of a range of metal containing components that, when disposed of improperly, could result in metal constituents leached into the environment and posing a health risk to humans and animals alike. Metal exposure can induce oxidative stress in organisms, which could lead to synergistic, antagonistic and additive effects. The metals found highest in abundance in the simulated e-waste leachate, were nickel (Ni), barium (Ba), zinc (Zn), lithium (Li), iron (Fe), aluminium (Al) and copper (Cu). An acute exposure study was conducted over a 96 h period to determine the potential toxicity of e-waste on the test organism Danio rerio. Biomarker analysis results to assess the biochemical and physiological effects induced by e-waste leachate, showed a statistically significant effect induced on acetylcholinesterase activity, superoxide dismutase, catalase activity, reduced glutathione content, glutathione s-transferase, malondialdehyde and glucose energy available. The Integrated Biomarker Response (IBRv2) analysis revealed a greater biomarker response induced as the exposure concentration of e-waste leachate increased.
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Affiliation(s)
- A Rielly
- Department of Zoology, University of Johannesburg, Auckland Park, Johannesburg, South Africa
| | - S Dahms-Verster
- School of Geography, Archaeology and Environmental Studies, Wits University, Johannesburg, South Africa
| | - R Greenfield
- Department of Zoology, University of Johannesburg, Auckland Park, Johannesburg, South Africa.
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2
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Mishra S, Hunter TN, Pant KK, Harbottle D. Green Deep Eutectic Solvents (DESs) for Sustainable Metal Recovery from Thermally Treated PCBs: A Greener Alternative to Conventional Methods. CHEMSUSCHEM 2024:e202301418. [PMID: 38189582 DOI: 10.1002/cssc.202301418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 12/26/2023] [Accepted: 01/05/2024] [Indexed: 01/09/2024]
Abstract
Waste PCBs the core of e-waste is rich in copper, tin, zinc, iron, and nickel. Leaching base metals from PCB used to be done in toxic, corrosive acidic/alkali mediums. In this work, an environmentally friendly method for leaching metals from thermally treated PCBs (TPCBs) of mobile phones was proposed using choline chloride based deep eutectic solvents (DES). DES selectivity and solubility of metals from metal oxides were the main screening criteria. FA-ChCl had the maximum solubility of Cu, Fe, and Ni, while Urea-ChCl had high Zn selectivity and solubility. Oxalic acid has high selectivity for Sn. FA-ChCl extracted Cu and Fe best at 16 h, 100 °C, and 1/30 g/mL. Urea-ChCl extracted Zn (90.4±2.9 %) from TPCBs at 100 °C, 21 h, 1/20 g/mL, and 400 rpm. Oxalic acid (1 M) removed 92.3±2.1 % Sn from TPCBs in 1 h at 80 °C and 1/20 g/mL. The shrinking core model-based kinetic investigation of FA-ChCl for Cu extraction showed a diffusion-controlled process. The proposed method is greener than mineral acids utilized for metal extraction.
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Affiliation(s)
- Snigdha Mishra
- Green and Sustainable Engineering Lab, Department of Chemical Engineering, IIT Delhi, Hauz Khaz, Delhi, 110016, India
- School of Chemical and Process Engineering, University of Leeds, Leeds, LS29JT, United Kingdom
| | - T N Hunter
- School of Chemical and Process Engineering, University of Leeds, Leeds, LS29JT, United Kingdom
| | - K K Pant
- Green and Sustainable Engineering Lab, Department of Chemical Engineering, IIT Delhi, Hauz Khaz, Delhi, 110016, India
- Department of Chemical Engineering, IIT Roorkee, Roorkee, 247667, India
| | - David Harbottle
- School of Chemical and Process Engineering, University of Leeds, Leeds, LS29JT, United Kingdom
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Cenci MP, Eidelwein EM, Veit HM. Composition and recycling of smartphones: A mini-review on gaps and opportunities. WASTE MANAGEMENT & RESEARCH : THE JOURNAL OF THE INTERNATIONAL SOLID WASTES AND PUBLIC CLEANSING ASSOCIATION, ISWA 2023; 41:1512-1528. [PMID: 37052313 DOI: 10.1177/0734242x231164324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
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.
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Affiliation(s)
- Marcelo Pilotto Cenci
- LACOR, Department of Materials Engineering, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
| | - Estela Moschetta Eidelwein
- LACOR, Department of Materials Engineering, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
| | - Hugo Marcelo Veit
- LACOR, Department of Materials Engineering, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
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Botelho Meireles de Souza G, Bisinotto Pereira M, Clementino Mourão L, Gonçalves Alonso C, Jegatheesan V, Cardozo-Filho L. Valorization of e-waste via supercritical water technology: An approach for obsolete mobile phones. CHEMOSPHERE 2023; 337:139343. [PMID: 37379987 DOI: 10.1016/j.chemosphere.2023.139343] [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: 04/05/2023] [Revised: 06/21/2023] [Accepted: 06/24/2023] [Indexed: 06/30/2023]
Abstract
The improper handling of electronic waste has not only severe environmental impacts but also results in the loss of high economic potential. To address this issue, the use of supercritical water (ScW) technology for the eco-friendly processing of waste printed circuit boards (WPCBs) obtained from obsolete mobile phones has been explored in this study. The WPCBs were characterized via MP-AES, WDXRF, TG/DTA, CHNS elemental analysis, SEM and XRD. A L9 Taguchi orthogonal array design was employed to evaluate the impact of four independent variables on the organic degradation rate (ODR) of the system. After optimization, an ODR of 98.4% was achieved at a temperature of 600 °C, a reaction time of 50 min, a flowrate of 7 mL min-1, and the absence of an oxidizing agent. The removal of the organic content from the WPCBs resulted in an increase in the metal concentration, with up to 92.6% of the metal content being efficiently recovered. During the ScW process, the decomposition by-products were continuously removed from the reactor system through the liquid or gaseous outputs. The liquid fraction, which was composed of phenol derivatives, was treated using the same experimental apparatus, achieving a total organic carbon reduction of 99.2% at 600 °C using H2O2 as the oxidizing agent. The gaseous fraction was found to contain hydrogen, methane, CO2, and CO as the major components. Finally, the addition of co-solvents, namely ethanol and glycerol, enhanced the production of combustible gases during the ScW processing of WPCBs.
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Affiliation(s)
- Guilherme Botelho Meireles de Souza
- Programa de Pós-Graduação Em Engenharia Química, Universidade Estadual de Maringá (UEM), Avenida Colombo, 5790 - Zona 7, Maringá, PR, 87020-900, Brazil; Programa de Pós-Graduação Em Engenharia Química, Universidade Federal de Goiás (UFG), Avenida Esperança, S/n - Chácaras de Recreio Samambaia, Goiânia, GO, 74690-900, Brazil; School of Engineering and Water: Effective Technologies and Tools (WETT) Research Centre, RMIT University, Melbourne, VIC, 3000, Australia.
| | - Mariana Bisinotto Pereira
- Programa de Pós-Graduação Em Engenharia Química, Universidade Estadual de Maringá (UEM), Avenida Colombo, 5790 - Zona 7, Maringá, PR, 87020-900, Brazil.
| | - Lucas Clementino Mourão
- Programa de Pós-Graduação Em Engenharia Química, Universidade Federal de Goiás (UFG), Avenida Esperança, S/n - Chácaras de Recreio Samambaia, Goiânia, GO, 74690-900, Brazil.
| | - Christian Gonçalves Alonso
- Programa de Pós-Graduação Em Engenharia Química, Universidade Federal de Goiás (UFG), Avenida Esperança, S/n - Chácaras de Recreio Samambaia, Goiânia, GO, 74690-900, Brazil.
| | - Veeriah Jegatheesan
- School of Engineering and Water: Effective Technologies and Tools (WETT) Research Centre, RMIT University, Melbourne, VIC, 3000, Australia.
| | - Lucio Cardozo-Filho
- Programa de Pós-Graduação Em Engenharia Química, Universidade Estadual de Maringá (UEM), Avenida Colombo, 5790 - Zona 7, Maringá, PR, 87020-900, Brazil; School of Engineering and Water: Effective Technologies and Tools (WETT) Research Centre, RMIT University, Melbourne, VIC, 3000, Australia; Escola de Engenharia, Universidade Estadual de São Paulo (UNESP), Avenida Professora Isette Corrêa Fontão, 505 - Jardim Das Flores, São João da Boa Vista, SP, 13876-750, Brazil.
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5
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Seif R, Salem FZ, Allam NK. E-waste recycled materials as efficient catalysts for renewable energy technologies and better environmental sustainability. ENVIRONMENT, DEVELOPMENT AND SUSTAINABILITY 2023:1-36. [PMID: 36691418 PMCID: PMC9848041 DOI: 10.1007/s10668-023-02925-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 01/07/2023] [Indexed: 06/17/2023]
Abstract
Waste from electrical and electronic equipment exponentially increased due to the innovation and the ever-increasing demand for electronic products in our life. The quantities of electronic waste (e-waste) produced are expected to reach 44.4 million metric tons over the next five years. Consequently, the global market for electronics recycling is expected to reach $65.8 billion by 2026. However, electronic waste management in developing countries is not appropriately handled, as only 17.4% has been collected and recycled. The inadequate electronic waste treatment causes significant environmental and health issues and a systematic depletion of natural resources in secondary material recycling and extracting valuable materials. Electronic waste contains numerous valuable materials that can be recovered and reused to create renewable energy technologies to overcome the shortage of raw materials and the adverse effects of using non-renewable energy resources. Several approaches were devoted to mitigate the impact of climate change. The cooperate social responsibilities supported integrating informal collection and recycling agencies into a well-structured management program. Moreover, the emission reductions resulting from recycling and proper management systems significantly impact climate change solutions. This emission reduction will create a channel in carbon market mechanisms by trading the CO2 emission reductions. This review provides an up-to-date overview and discussion of the different categories of electronic waste, the recycling methods, and the use of high recycled value-added (HAV) materials from various e-waste components in green renewable energy technologies.
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Affiliation(s)
- Rania Seif
- Energy Materials Laboratory, School of Sciences and Engineering, The American University in Cairo, New Cairo, 11835 Egypt
| | - Fatma Zakaria Salem
- Energy Materials Laboratory, School of Sciences and Engineering, The American University in Cairo, New Cairo, 11835 Egypt
| | - Nageh K. Allam
- Energy Materials Laboratory, School of Sciences and Engineering, The American University in Cairo, New Cairo, 11835 Egypt
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6
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Zhang ZY, Wu L, He K, Zhang FS. A sequential leaching procedure for efficient recovery of gold and silver from waste mobile phone printed circuit boards. WASTE MANAGEMENT (NEW YORK, N.Y.) 2022; 153:13-19. [PMID: 36029533 DOI: 10.1016/j.wasman.2022.08.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 07/24/2022] [Accepted: 08/14/2022] [Indexed: 06/15/2023]
Abstract
The present study reports a sequential, non-acid process for effective recovery of copper and precious metals from mobile phone printed circuit boards. In this process, gold and silver were first enriched during the synthesis process of cuprous chloride and then leached by thiosulfate method. Results indicated that the distribution of gold and silver in the liquid and solid phases during the synthesis of cuprous chloride process was affected by the [Cu]/[Cu2+] ratio. Enrichment of gold and silver in the residue after the cuprous chloride synthesis could be achieved by the adjusting the [Cu]/[Cu2+] ratio. The silver and gold leaching rates of the residue after cuprous chloride synthesis (93.8 % silver and 99 % gold) were much higher than those of the raw PCB sample (27.0 % silver and 14.2 % gold) under the same conditions. This process has the advantages of high leaching efficiency, high leaching rate and avoiding the use of HNO3 or aqua regia commonly used for copper, gold and silver recovery. Thus, this study offers a promising and environmentally friendly method for recovering valuable metals from e-waste.
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Affiliation(s)
- Zhi-Yuan Zhang
- Department of Solid Waste Treatment and Recycling, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lixiang Wu
- Department of Solid Waste Treatment and Recycling, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kai He
- Department of Solid Waste Treatment and Recycling, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fu-Shen Zhang
- Department of Solid Waste Treatment and Recycling, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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7
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Zhao J, Liu Z, He C, Yang Y, Li J, Fujita T, Wang G, Shen F. Improved leaching of Cu, Sn, Pb, Zn, and Al from waste printed circuit boards by electro-generated Cl 2 in HCl solution. WASTE MANAGEMENT (NEW YORK, N.Y.) 2022; 153:386-396. [PMID: 36198214 DOI: 10.1016/j.wasman.2022.09.022] [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: 05/13/2022] [Revised: 08/28/2022] [Accepted: 09/22/2022] [Indexed: 06/16/2023]
Abstract
This paper investigated the improved leaching of Cu, Sn, Pb, Zn, and Al from waste printed circuit boards (WPCBs) by electro-generated Cl2 in HCl solution through multiple leaching cells in series, double intake pipes, and bubble stone for leaching. The leaching agents in the leaching cell include Cl2(aq), HCl, HClO, and Cl3-. The leaching rate and leaching speed of Zn, Sn, Al, and Pb exceeded that of Cu. Leaching time and HCl concentration have a strong impact on the dissolution of Cu, whereas the effect of the electrolytic current and the leaching temperature is comparably weak. The series of leaching cells improved the effective utilization of Cl2 and increased the treatment capacity of the WPCBs. Bubble stones significantly enhanced the efficiency and rate of leaching. Reduction of the size of the Cl2 gas bubbles improved the leaching kinetics. The leaching rate of Cu reached 87.22%, whereas the leaching rate of Zn, Sn, Al, and Pb exceeded 90% after 100 min. Our experimental data provide a reference for electrolytic leaching recovery of metals from WPCBs, and our method improves the metal leaching and electrolytic efficiency in practice.
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Affiliation(s)
- Jian Zhao
- School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China
| | - Zunzhang Liu
- School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China
| | - Chunlin He
- School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China; Guangxi Key Laboratory of Processing for Non-ferrous Metal and Featured Materials, Nanning 530004, China.
| | - Yingnan Yang
- School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China
| | - Jie Li
- School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China
| | - Toyohisa Fujita
- School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China; Guangxi Key Laboratory of Processing for Non-ferrous Metal and Featured Materials, Nanning 530004, China.
| | - Guiwang Wang
- School of Resources, Environment and Materials, Guangxi University, Nanning 530004, China; Guangxi Key Laboratory of Processing for Non-ferrous Metal and Featured Materials, Nanning 530004, China
| | - Fang Shen
- College of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China
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8
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Kumari R, Samadder SR. A critical review of the pre-processing and metals recovery methods from e-wastes. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 320:115887. [PMID: 35933880 DOI: 10.1016/j.jenvman.2022.115887] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 07/24/2022] [Accepted: 07/25/2022] [Indexed: 06/15/2023]
Abstract
E-wastes being potential sources of numerous valuable metals are promoted to undergo recycling and recovery under the umbrella of urban mining and circular economy. Thus, the present study provides a critical review of the technological details of different metal recycling processes, pre-treatment methods, and the advancements made in these techniques. Critical evaluation of different metal recovery techniques has also been presented based on the available life cycle assessment (LCA), techno-economic, and industrial-scale studies. The study revealed that the integrated metal recovery techniques serve better in terms of recovery efficiency and environmental performance than any single recovery technique. Also, scaling up of biometallurgical, electrochemical, and super critical fluid extraction methods needs to be promoted due to their better environmental performances.
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Affiliation(s)
- Rima Kumari
- Department of Environmental Science & Engineering, Indian Institute of Technology (Indian School of Mines), Dhanbad, 826004, India.
| | - Sukha Ranjan Samadder
- Department of Environmental Science & Engineering, Indian Institute of Technology (Indian School of Mines), Dhanbad, 826004, India.
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9
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Wang G, Yuan M, Xu H. The impact of subsidy and preferential tax policies on mobile phone recycling: A system dynamics model analysis. WASTE MANAGEMENT (NEW YORK, N.Y.) 2022; 152:6-16. [PMID: 35964401 DOI: 10.1016/j.wasman.2022.08.004] [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: 12/17/2020] [Revised: 03/24/2022] [Accepted: 08/02/2022] [Indexed: 06/15/2023]
Abstract
This paper analyzes the impact of possible subsidy and preferential tax policies on mobile phone (MP) recycling industries in China using system dynamics methodology, aiming to offer a reference for the construction of a reasonable policy system for MP recycling. First, different subsidy and preferential tax policies were introduced to establish a system dynamics model. Then the impact of policies proposed on MP recycling industries was analyzed using the model. The results showed that: (1) newly discarded MPs could be completely recycled annually if recyclers could achieve a RMB10 recycling subsidy for each MP formally recycled; (2) an initial subsidy policy can effectively increase the number of remanufacturers, but is harmful to remanufacturing capacity; (3) stage R&D subsidy policy outperforms equalization R&D subsidy policy. Additionally, more subsidies allocated to remanufactures means more profit when R&D subsidy is limited; (4) more tax benefits provide more output and profit. Remanufacturers are more sensitive to tax benefits than recovery enterprises in the short run. Finally, several suggestions related to the construction of MP recycling policy systems were put forward based on evaluation results.
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Affiliation(s)
- Guangzheng Wang
- College of Environmental Science and Engineering, Nankai University, Tianjin 300350, PR China.
| | - Mengnan Yuan
- College of Environmental Science and Engineering, Nankai University, Tianjin 300350, PR China.
| | - He Xu
- College of Environmental Science and Engineering, Nankai University, Tianjin 300350, PR China; Institute of Ecological Civilization, Nankai University, Tianjin 300350, PR China.
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10
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Oladeji AV, Courtney JM, Fernandez-Villamarin M, Rees NV. Electrochemical Metal Recycling: Recovery of Palladium from Solution and In Situ Fabrication of Palladium-Carbon Catalysts via Impact Electrochemistry. J Am Chem Soc 2022; 144:18562-18574. [PMID: 36179328 PMCID: PMC9562286 DOI: 10.1021/jacs.2c08239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
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Recycling of critical materials, regeneration of waste,
and responsible
catalyst manufacture have been repeatedly documented as essential
for a sustainable future with respect to the environment and energy
production. Electrochemical methods have become increasingly recognized
as capable of achieving these goals, and “impact” electrochemistry,
with the advantages associated with dynamic nanoelectrodes, has recently
emerged as a prime candidate for the recovery of metals from solution.
In this report, the nanoimpact technique is used to generate carbon-supported
palladium catalysts from low-concentration palladium(II) chloride
solutions (i.e., a waste stream mimic) as a proof of concept. Subsequently,
the catalytic properties of this material in both synthesis (Suzuki
coupling reaction) and electrocatalysis (hydrogen evolution) are demonstrated.
Transient reductive impact signals are shown and analyzed at potentials
negative of +0.4 V (vs SCE) corresponding to the onset of palladium
deposition in traditional voltammetry. Direct evidence of Pd modification
was obtained through characterization by environmental scanning electron
microscopy/energy-dispersive X-ray spectroscopy, inductively coupled
plasma mass spectrometry, X-ray photoelectron spectroscopy, transmission
electron microscopy, and thermogravimetric analysis of impacted particles.
This showed the formation of deposits of Pd0 partially covering the
50 nm carbon black particles with approximately 14% Pd (wt %) under
the conditions used. This material was then used to demonstrate the
conversion of iodobenzene into its biphenyl product (confirmed through
nuclear magnetic resonance) and the successful production of hydrogen
as an electrocatalyst under acidic conditions (under cyclic voltammetry).
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Affiliation(s)
- Abiola V Oladeji
- School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, U. K
| | - James M Courtney
- School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, U. K
| | | | - Neil V Rees
- School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, U. K
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11
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Copper recovery through biohydrometallurgy route: chemical and physical characterization of magnetic (m), non-magnetic (nm) and mix samples from obsolete smartphones. Bioprocess Biosyst Eng 2022:10.1007/s00449-022-02775-z. [PMID: 36097089 DOI: 10.1007/s00449-022-02775-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Accepted: 08/10/2022] [Indexed: 11/02/2022]
Abstract
The more modern electronics are, the smaller and complex printed circuit boards are. Thus, these materials are continually changed (physicochemically), increasing the copper concentrations in smartphones. In this sense, it is challenging to set standardized recycling processes to improve metal recovery. In addition, biohydrometallurgy is a clean and cheap process to obtain critical metals from low-grade sources and waste electronic equipment. Therefore, the aim of this work was to characterize, physicochemically, 21 PCBs from smartphones manufactured from 2010 to 2015, and then to recover the copper by Acidithiobacillus ferrooxidans (biohydrometallurgy). The PCBs were comminuted and separated into Magnetic (M), Nonmagnetic (NM) and without magnetic separation (MIX) samples. It was identified 217.8; 560.3 and 401.3 mg Cu/g of PCBs for M, NM and MIX samples, respectively. Regarding biohydrometallurgy, the culture media iron-supplemented (NM + Fe and MIX + Fe) increased the copper content by 2.6 and 7.2%, respectively, and the magnetic separation step was insignificant.
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12
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Advancements in the field of electronic waste Recycling: Critical assessment of chemical route for generation of energy and valuable products coupled with metal recovery. Sep Purif Technol 2022. [DOI: 10.1016/j.seppur.2022.120773] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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Chakraborty SC, Zaman MWU, Hoque M, Qamruzzaman M, Zaman JU, Hossain D, Pramanik BK, Nguyen LN, Nghiem LD, Mofijur M, Mondal MIH, Sithi JA, Shahriar SMS, Johir MAH, Ahmed MB. Metals extraction processes from electronic waste: constraints and opportunities. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:32651-32669. [PMID: 35220520 DOI: 10.1007/s11356-022-19322-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 02/16/2022] [Indexed: 06/14/2023]
Abstract
The skyrocketing demand and progressive technology have increased our dependency on electrical and electronic devices. However, the life span of these devices has been shortened because of rapid scientific expansions. Hence, massive volumes of electronic waste (e-waste) is generating day by day. Nevertheless, the ongoing management of e-waste has emerged as a major threat to sustainable economic development worldwide. In general, e-waste contains several toxic substances such as metals, plastics, and refractory oxides. Metals, particularly lead, mercury, nickel, cadmium, and copper along with some valuable metals such as rare earth metals, platinum group elements, alkaline and radioactive metal are very common; which can be extracted before disposing of the e-waste for reuse. In addition, many of these metals are hazardous. Therefore, e-waste management is an essential issue. In this study, we critically have reviewed the existing extraction processes and compared among different processes such as physical, biological, supercritical fluid technologies, pyro and hydrometallurgical, and hybrid methods used for metals extraction from e-waste. The review indicates that although each method has particular merits but hybrid methods are eco-friendlier with extraction efficiency > 90%. This study also provides insight into the technical challenges to the practical realization of metals extraction from e-waste sources.
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Affiliation(s)
- Shovra Chandra Chakraborty
- Department of Applied Chemistry and Chemical Engineering, University of Rajshahi, Rajshahi, 6205, Bangladesh
| | - Md Wahad Uz Zaman
- Department of Applied Chemistry and Chemical Engineering, University of Rajshahi, Rajshahi, 6205, Bangladesh
| | - Mozammel Hoque
- Department of Applied Chemistry and Chemical Engineering, University of Rajshahi, Rajshahi, 6205, Bangladesh
| | - Md Qamruzzaman
- Department of Applied Chemistry and Chemical Engineering, University of Rajshahi, Rajshahi, 6205, Bangladesh
| | - Jahid Uz Zaman
- Department of Applied Chemistry and Chemical Engineering, University of Rajshahi, Rajshahi, 6205, Bangladesh
| | - Delowar Hossain
- Department of Applied Chemistry and Chemical Engineering, University of Rajshahi, Rajshahi, 6205, Bangladesh
| | | | - Luong Ngoc Nguyen
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, 15, Broadway, Sydney, NSW, 2007, Australia
| | - Long Duc Nghiem
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, 15, Broadway, Sydney, NSW, 2007, Australia
| | - Md Mofijur
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, 15, Broadway, Sydney, NSW, 2007, Australia
- Mechanical Engineering Department, Prince Mohammad Bin Fahd University, Al Khobar, 31952, Saudi Arabia
| | - Md Ibrahim H Mondal
- Department of Applied Chemistry and Chemical Engineering, University of Rajshahi, Rajshahi, 6205, Bangladesh
| | - Jeni Aprazita Sithi
- Department of Applied Chemistry and Chemical Engineering, University of Rajshahi, Rajshahi, 6205, Bangladesh
| | - Sha Md Shahan Shahriar
- Department of Applied Chemistry and Chemical Engineering, University of Rajshahi, Rajshahi, 6205, Bangladesh
| | - Md Abu Hasan Johir
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, 15, Broadway, Sydney, NSW, 2007, Australia.
| | - Mohammad Boshir Ahmed
- Department of Applied Chemistry and Chemical Engineering, University of Rajshahi, Rajshahi, 6205, Bangladesh.
- Centre for Technology in Water and Wastewater, School of Civil and Environmental Engineering, University of Technology Sydney, 15, Broadway, Sydney, NSW, 2007, Australia.
- School of Material Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, 61005, Republic of Korea.
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14
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Chen J, Meng T, Leng E, E J. Review on metal dissolution characteristics and harmful metals recovery from electronic wastes by supercritical water. JOURNAL OF HAZARDOUS MATERIALS 2022; 424:127693. [PMID: 34799178 DOI: 10.1016/j.jhazmat.2021.127693] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 10/21/2021] [Accepted: 10/31/2021] [Indexed: 06/13/2023]
Abstract
Supercritical water (SCW) technology can be applied as an efficient and environment-friendly method to recover toxic or complex chemical wastes. Separation and chemical reactions under supercritical conditions may be realized by changing the temperature, pressure, and other operating parameters to adjust the physical and chemical properties of water. However, salt deposition and corrosion are often encountered during the treatment of inorganic substances, which will hinder the commercial applications of SCW technology. The solubility of salt in high pressure/temperature water forms the theoretical basis for studying the recovery of metal salts in supercritical water and understanding salt deposition. Therefore, this work systematically and objectively reviews different research methods used to analyze salt solubility in high pressure/temperature water, including the experimental method, prediction theoretical modeling, and computer simulation method; the research status and existing data of this parameter are also analyzed. The purpose of this review is to provide ideas and references for follow-up research by providing a comprehensive overview of salt solubility research methods and the current situation. Suggestions for more efficient metal recovery through technology integration are also provided.
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Affiliation(s)
- Jingwei Chen
- College of Mechanical and Vehicle Engineering, Hunan University, Changsha 410082, China; Institute of New Energy and Energy-Saving & Emission-Reduction Technology, Hunan University, Changsha 410082, China.
| | - Tian Meng
- College of Mechanical and Vehicle Engineering, Hunan University, Changsha 410082, China
| | - Erwei Leng
- College of Mechanical and Vehicle Engineering, Hunan University, Changsha 410082, China
| | - Jiaqiang E
- College of Mechanical and Vehicle Engineering, Hunan University, Changsha 410082, China; Institute of New Energy and Energy-Saving & Emission-Reduction Technology, Hunan University, Changsha 410082, China
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15
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Song Z, Xiu FR, Qi Y. Degradation and partial oxidation of waste plastic express packaging bags in supercritical water: Resources transformation and pollutants removal. JOURNAL OF HAZARDOUS MATERIALS 2022; 423:127018. [PMID: 34461531 DOI: 10.1016/j.jhazmat.2021.127018] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 08/18/2021] [Accepted: 08/21/2021] [Indexed: 06/13/2023]
Abstract
Millions of waste plastic express packaging bags (PEPBs) were generated with the rapid development of the express delivery industry due to the boom of electronic commerce. Waste PEPBs contain polyethylene (PE) material and large number of pollutants such as plasticizers and flame retardants. In this study, two effective and environmental-friendly methods were proposed to produce valuable products and remove pollutants from waste PEPBs by supercritical water degradation (SCWD) and supercritical water partial oxidation (SCWPO) treatments. Both SCWD and SCWPO treatments could effectively obtain valuable products (wax, liquid oil, CaCO3) and remove bisphenol A (BPA) and di-(2-ethylhexyl) phthalate (DEHP) from waste PEPBs. No obvious difference about the conversion could be found between SCWD and SCWPO treatments. 425 °C, 60 min, solid-to-liquid ratio of 1:20 g/mL, and V(H2O2):V(H2O) ratio of 1:3 mL/mL were the optimal conditions for the conversion of waste PEPBs by SCWD and SCWPO treatments. The maximum conversion could reach 98.13%. The produced wax and liquid oil were easily separated from each other. The produced wax mainly included long-chain olefins or long-chain alkanes, and a small amount of alcohols, ethers and aldehydes. SCWD treatment was favorable for obtaining long-chain alkenes, while SCWPO treatment was favorable for obtaining long-chain alkanes. The main chemical compounds contained in the produced liquid oil were decomposed from DEHP and BPA. DEHP was decomposed to produce 2-ethyl-1-hexanol and acetophenone. BPA was decomposed to produce 4-tert-butylphenol and other alkylated derivatives of benzene and phenol. In comparison with SCWD treatment, DEHP and BPA could be decomposed more thoroughly by SCWPO treatment.
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Affiliation(s)
- Zhiqi Song
- College of Geology and Environment, Xi'an University of Science and Technology, Xi'an 710054, China
| | - Fu-Rong Xiu
- College of Geology and Environment, Xi'an University of Science and Technology, Xi'an 710054, China; Shaanxi Provincial Key Laboratory of Geological Support for Coal Green Exploitation, Xi'an 710054, China.
| | - Yingying Qi
- College of Geology and Environment, Xi'an University of Science and Technology, Xi'an 710054, China; Shaanxi Provincial Key Laboratory of Geological Support for Coal Green Exploitation, Xi'an 710054, China
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16
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Neto IFF, Soares HMVM. Simple and near-zero-waste processing for recycling gold at a high purity level from waste printed circuit boards. WASTE MANAGEMENT (NEW YORK, N.Y.) 2021; 135:90-97. [PMID: 34478952 DOI: 10.1016/j.wasman.2021.08.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 08/14/2021] [Accepted: 08/17/2021] [Indexed: 06/13/2023]
Abstract
This work proposes an efficient and simple hydrometallurgical process based on a chlorination step followed by an ion-exchange step for recycling gold (Au) from a waste printed circuit boards (WPCBs) enriched in Au resulting from a first leaching step under mild oxidizing conditions for extracting Cu and other base metals. Under optimized [3.5 mol/L HCl and 0.46 mol/L NaClO, with a liquid/solid (L/S) ratio of 40, at 40 °C for 3 h with agitation] leaching conditions, 95% Au was extracted from the residue originating a multi-metal solution containing 1.0% Au. Subsequently, Au (initial concentration: 38 µmol/L) present in the multimetal-leached solution was purified in continuous mode using two strong anionic exchange resins: DOW™ XZ-91419.00 and Purogold™ A194. Both resins were suitable in purifying Au from the multimetal-leaching solution, with at least 70% of Au recovered relative to the initial residue. When the DOW™ XZ-91419.00 resin was used, a solution containing 1.7 mmol/L Au with a purity grade of 94% was obtained, with Pb and Sn being the major contaminants (3.3 and 2.4%, respectively). For Purogold™ A194 resin, a solution containing 0.73 mmol/L Au with a purity grade of 92% was achieved; Ag, Pb and Pd were the major contaminants (1.4, 3.6 and 1.8%, respectively). In conclusion, this work demonstrates a novel hydrometallurgical strategy for recycling Au with a high grade from WPCBs, minimizing the number of leaching and purification steps and the amount of waste created.
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Affiliation(s)
- Isabel F F Neto
- REQUIMTE/LAQV, Departamento de Engenharia Química, Faculdade de Engenharia, Universidade do Porto, rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| | - Helena M V M Soares
- REQUIMTE/LAQV, Departamento de Engenharia Química, Faculdade de Engenharia, Universidade do Porto, rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
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17
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Jadhao PR, Pandey A, Pant KK, Nigam KDP. Efficient recovery of Cu and Ni from WPCB via alkali leaching approach. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 296:113154. [PMID: 34216905 DOI: 10.1016/j.jenvman.2021.113154] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 05/22/2021] [Accepted: 06/22/2021] [Indexed: 06/13/2023]
Abstract
The large generation of electronic waste (e-waste) is posing a serious threat to society. It is important to develop sustainable technology for the effective management of e-waste and the recovery of valuable metals from it. The present study employed hydrometallurgical approach for Cu and Ni extraction from waste printed circuit boards (WPCB) of mobile phones. This study demonstrates the application of ammonia-ammonium sulfate leaching for the maximum recovery of Cu and Ni. Investigations revealed that the most favourable reaction parameters for efficient metal extraction are - ammonia concentration - 90 g/L, ammonium sulfate concentration - 180 g/L, H2O2 concentration - 0.4 M, time - 4 h, liquid to solid ratio - 20 mL/g, temperature - 80 °C and agitation speed - 700 rpm. Under these conditions, 100% Cu and 90% Ni were extracted. Furthermore, the kinetic study was performed using the shrinking core model which revealed that the internal diffusion is the rate-controlling step for Cu and Ni extraction. The activation energies for Cu and Ni extraction were found out to be 4.5 and 5.7 kJ/mol, respectively. Finally, Cu was recovered with 98.38% purity using electrowinning at a constant DC voltage of 2.0 V at Al cathode. The present study provides a solution for concurrent extraction of Cu and Ni from the raw WPCB of mobile phones and selective recovery of Cu from metal leached solution. The process has the potential to recover the resources from WPCB while minimising the pollution caused by mismanagement of WPCB.
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Affiliation(s)
- Prashant Ram Jadhao
- Chemical Engineering Department, Indian Institute of Technology Delhi, New Delhi, 110016, India
| | - Ashish Pandey
- Chemical Engineering Department, Indian Institute of Technology Delhi, New Delhi, 110016, India
| | - K K Pant
- Chemical Engineering Department, Indian Institute of Technology Delhi, New Delhi, 110016, India.
| | - K D P Nigam
- Chemical Engineering Department, Indian Institute of Technology Delhi, New Delhi, 110016, India
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18
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Li J, Xu T, Liu J, Wen J, Gong S. Bioleaching metals from waste electrical and electronic equipment (WEEE) by Aspergillus niger: a review. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:44622-44637. [PMID: 34215982 DOI: 10.1007/s11356-021-15074-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 06/18/2021] [Indexed: 06/13/2023]
Abstract
In the twenty-first century, the increasing demand for electrical and electronic equipment (EEE) has caused its quick update and the shortening of its service life span. As a consequence, a large number of waste electrical and electronic equipment (WEEE) needs to be processed and recycled. As an environmentally friendly method, biometallurgy has received extensive attention in the disposal of WEEE in recent years. Aspergillus niger is an acid-producing fungus with a potential applicability to improve metals' recycling efficiency. This review article describes the latest statistical status of WEEE and presents the latest progress of various metallurgical methods involved in WEEE recycling for metal recovery. Moreover, based on the summary and comparison towards studies have been reported for bioleaching metals from WEEE by A. niger, the bioleaching mechanisms and the bioleaching methods are explained, as well as the effects of process parameters on the performance of the bioleaching process are also discussed. Some insights and perspectives are provided for A. niger to be applied to industrial processing scale.
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Affiliation(s)
- Jingying Li
- College of Environment and Safety Engineering, Qingdao University of Science & Technology, Qingdao, 266042, China.
| | - Tong Xu
- College of Environment and Safety Engineering, Qingdao University of Science & Technology, Qingdao, 266042, China
| | - Jinyuan Liu
- College of Environment and Safety Engineering, Qingdao University of Science & Technology, Qingdao, 266042, China
| | - Jiangxian Wen
- College of Environment and Safety Engineering, Qingdao University of Science & Technology, Qingdao, 266042, China
| | - Shuli Gong
- College of Environment and Safety Engineering, Qingdao University of Science & Technology, Qingdao, 266042, China
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19
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Abstract
The need to drive towards sustainable metal resource recovery from end-of-cycle products cannot be overstated. This review attempts to investigate progress in the development of recycling strategies for the recovery of strategic metals, such as precious metals and base metals, from catalytic converters, e-waste, and batteries. Several methods for the recovery of metal resources have been explored for these waste streams, such as pyrometallurgy, hydrometallurgy, and biohydrometallurgy. The results are discussed, and the efficiency of the processes and the chemistry involved are detailed. The conversion of metal waste to high-value nanomaterials is also presented. Process flow diagrams are also presented, where possible, to represent simplified process steps. Despite concerns about environmental effects from processing the metal waste streams, the gains for driving towards a circular economy of these waste streams are enormous. Therefore, the development of greener processes is recommended. In addition, countries need to manage their metal waste streams appropriately and ensure that this becomes part of the formal economic activity and, therefore, becomes regulated.
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20
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Chung J, Seo B, Lee J, Kim JY. Comparative analysis of I 2-KI and HNO 3 leaching in a life cycle perspective: Towards sustainable recycling of end-of-life c-Si PV panel. JOURNAL OF HAZARDOUS MATERIALS 2021; 404:123989. [PMID: 33053466 DOI: 10.1016/j.jhazmat.2020.123989] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 08/12/2020] [Accepted: 09/12/2020] [Indexed: 06/11/2023]
Abstract
An iodine-iodide system was investigated as an alternative lixiviant for HNO3 for leaching precious metals from the end-of-life c-Si photovoltaic (PV) cell. A series of batch experiments were conducted for the optimization of leaching kinetics and thermodynamic equilibrium followed by a life cycle assessment (LCA) using data from the experiments. The results showed that more than 95% of Ag and Al leached out within the first 5 min. The optimum conditions for equilibrium leaching were as follows: solid to liquid ratio of 1:10 for Ag (1:9 ml for Al), and I2 concentration of 0.35 M for Ag (0.3 M for Al), with I- concentration of 0.7 M. In addition, selective leaching of Ag could also be accomplished by adjusting the reaction pH to 9.6%, and 93% of reproducibility was achieved via the rejuvenation of the exhausted leaching solution, which can benefit the subsequent recovery process. The leaching efficiency of iodine-iodide system was nearly comparable to that of HNO3, and the environmental impacts of the two cycle of continuous process with rejuvenation of the iodine leaching solution can be effectively reduced especially in the acidification & eutrophication, respiratory effect, and mineral extraction categories with subsequent exclusion of the additional neutralization process.
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Affiliation(s)
- Jaeshik Chung
- Water Cycle Research Center, Korea Institute of Science and Technology, Seoul 136-791, Republic of Korea.
| | - Bora Seo
- Department of Civil and Environmental Engineering, Seoul National University, Seoul 151-744, Republic of Korea
| | - Jooyoung Lee
- Water Cycle Research Center, Korea Institute of Science and Technology, Seoul 136-791, Republic of Korea
| | - Jae Young Kim
- Department of Civil and Environmental Engineering, Seoul National University, Seoul 151-744, Republic of Korea
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21
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Zhu L, Zhang M, He J, Liu C, Yao Y, Xu J, Liu B, Yin S, Xu X. Recovery of metal fractions from waste printed circuit boards via the vibrated gas-solid fluidized bed. ADV POWDER TECHNOL 2021. [DOI: 10.1016/j.apt.2020.12.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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22
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Golzary A, Abdoli MA. Recycling of copper from waste printed circuit boards by modified supercritical carbon dioxide combined with supercritical water pre-treatment. J CO2 UTIL 2020. [DOI: 10.1016/j.jcou.2020.101265] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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23
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Ambaye TG, Vaccari M, Castro FD, Prasad S, Rtimi S. Emerging technologies for the recovery of rare earth elements (REEs) from the end-of-life electronic wastes: a review on progress, challenges, and perspectives. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:36052-36074. [PMID: 32617815 DOI: 10.1007/s11356-020-09630-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Accepted: 06/05/2020] [Indexed: 06/11/2023]
Abstract
The demand for rare earth elements (REEs) has significantly increased due to their indispensable uses in integrated circuits of modern technology. However, due to the extensive use of high-tech applications in our daily life and the depletion of their primary ores, REE's recovery from secondary sources is today needed. REEs have now attracted attention to policymakers and scientists to develop novel recovery technologies for materials' supply sustainability. This paper summarizes the recent progress for the recovery of REEs using various emerging technologies such as bioleaching, biosorption, cryo-milling, electrochemical processes and nanomaterials, siderophores, hydrometallurgy, pyrometallurgy, and supercritical CO2. The challenges facing this recovery are discussed comprehensively and some possible improvements are presented. This work also highlights the economic and engineering aspects of the recovery of REE from waste electrical and electronic equipment (WEEE). Finally, this review suggests that greener and low chemical consuming technologies, such as siderophores and electrochemical processes, are promising for the recovery of REEs present in small quantities. These technologies present also a potential for large-scale application.
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Affiliation(s)
- Teklit Gebregiorgis Ambaye
- Department of Civil, Environmental, Architectural Engineering and Mathematics, University of Brescia, Via Branze 43, 25123, Brescia, Italy.
- Department of chemistry, Mekelle University, Mekelle, Ethiopia.
| | - Mentore Vaccari
- Department of Civil, Environmental, Architectural Engineering and Mathematics, University of Brescia, Via Branze 43, 25123, Brescia, Italy
| | - Francine Duarte Castro
- Department of Civil, Environmental, Architectural Engineering and Mathematics, University of Brescia, Via Branze 43, 25123, Brescia, Italy
| | - Shiv Prasad
- Centre for Environment Science & Climate Resilient Agriculture (CESCRA), Indian Agricultural Research Institute, New Delhi, 110012, India
| | - Sami Rtimi
- Ecole Polytechnique Fédérale de Lausanne, CH-1015, Lausanne, Switzerland.
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24
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Thakur P, Kumar S. Metallurgical processes unveil the unexplored "sleeping mines" e- waste: a review. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:32359-32370. [PMID: 32533494 DOI: 10.1007/s11356-020-09405-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 05/21/2020] [Indexed: 06/11/2023]
Abstract
The aim of this review paper is to critically analyze the existing studies on waste electric and electronic equipment (WEEE), which is one of the most increasing solid waste streams. This complex solid waste stream has pushed many scientific communities to develop novel technologies with minimum ecological disturbance. Noteworthy amount of valuable metals makes e-waste to a core of "urban mining"; therefore, it warrants special attention. Present study is focused on all the basic conceptual knowledge of WEEE ranging from compositional analysis, global statistics of e-waste generation, and metallurgical processes applied for metals extraction from e-waste. This review critically analyses the existing studies to emphasize on the heterogeneity nature of e-waste, which has not been focused much in any of the existing review articles. Comprehensive analysis of conventional approaches such as pyrometallurgy and hydrometallurgy reveals that high costs and secondary pollution possibilities limit the industrial feasibilities of these processes. Therefore biohydrometallurgy, a green technology, has been attracting researchers to focus on this novel technique to implement it for metal extraction from WEEE.
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Affiliation(s)
- Pooja Thakur
- Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Waknaghat, Solan, Himachal Pradesh, 173234, India
| | - Sudhir Kumar
- Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Waknaghat, Solan, Himachal Pradesh, 173234, India.
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25
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Chen G, Xu Y, Xie M, Huang M, Lin Y, Tan W. Membrane distillation of a silver leaching solution: Role of the coexisting aluminum ions on silica scaling. J Memb Sci 2020. [DOI: 10.1016/j.memsci.2020.118021] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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26
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Liu Y, Zhang L, Song Q, Xu Z. Recovery of palladium and silver from waste multilayer ceramic capacitors by eutectic capture process of copper and mechanism analysis. JOURNAL OF HAZARDOUS MATERIALS 2020; 388:122008. [PMID: 31951988 DOI: 10.1016/j.jhazmat.2019.122008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Revised: 10/15/2019] [Accepted: 12/30/2019] [Indexed: 06/10/2023]
Abstract
Recycling waste multilayer ceramic capacitors (MLCCs) is significant for environmental protection and resource recovery, which contain rich precious metals including palladium and silver. The existing recycling methods have many shortcomings such as environmental pollution, low recovery efficiency and low purity of precious metals. In view of the special structure of MLCCs and low content of precious metals per unit mass, a novel approach of enrichment for recovering palladium and silver from waste MLCCs by eutectic capture process of copper was proposed, in which process precious metals were separated and enriched for subsequent recovery. The recovery rates of palladium and silver reached 100 % and 87.53 %, respectively under the optimal condition. And the enrichment multiples of palladium and silver were 13.16 and 7.37. The Cu-Pd-Ag alloy was formed in the capture process, of which palladium and copper formed Cu-Pd solid solution, while silver was a separate phase through the analysis of SEM-EDS, XPS and XRD. Besides, the molten residue can be reused to prepare glass-ceramics. Finally, the mechanism was analyzed through thermodynamics, which was divided into two processes: migration of precious metals and alloy formation. This study provides a highly efficient and environmentally friendly method for recycling precious metals from waste MLCCs.
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Affiliation(s)
- Ya Liu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, People's Republic of China
| | - Lingen Zhang
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, People's Republic of China
| | - Qingming Song
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, People's Republic of China
| | - Zhenming Xu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, People's Republic of China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, People's Republic of China.
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27
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Rao MD, Singh KK, Morrison CA, Love JB. Challenges and opportunities in the recovery of gold from electronic waste. RSC Adv 2020; 10:4300-4309. [PMID: 35495234 PMCID: PMC9049023 DOI: 10.1039/c9ra07607g] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 01/15/2020] [Indexed: 01/16/2023] Open
Abstract
Rapid global technological development has led to the rising production of electronic waste that presents both challenges and opportunities in its recycling. In this review, we highlight the value of metal resources in the printed circuit boards (PCBs) commonly found in end-of-life electronics, the differences between primary (ore) mining applications and secondary ('urban') mining, and the variety of metallurgical separations, in particular those that have the potential to selectively and sustainably recover gold from waste PCBs.
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Affiliation(s)
- Mudila Dhanunjaya Rao
- Department of Metallurgical Engineering, Indian Institute of Technology (Banaras Hindu University) Varanasi-221005 India
| | - Kamalesh K Singh
- Department of Metallurgical Engineering, Indian Institute of Technology (Banaras Hindu University) Varanasi-221005 India
| | - Carole A Morrison
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, The King's Buildings David Brewster Road Edinburgh EH9 3FJ UK
| | - Jason B Love
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, The King's Buildings David Brewster Road Edinburgh EH9 3FJ UK
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28
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Zhang CC, Zhang FS. Enhanced dehalogenation and coupled recovery of complex electronic display housing plastics by sub/supercritical CO 2. JOURNAL OF HAZARDOUS MATERIALS 2020; 382:121140. [PMID: 31518770 DOI: 10.1016/j.jhazmat.2019.121140] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 08/30/2019] [Accepted: 09/02/2019] [Indexed: 06/10/2023]
Abstract
Electronic display housing plastics contain a high amount of halogenated compounds such as brominated flame retardants (BFRs) and polyvinyl chloride (PVC). Compared with moderate critical conditions of conventional eco-friendly sub/supercritical carbon dioxide (Sc-CO2), a novel and sustainable procedure by using improved Sc-CO2 was developed for disposal of this type of plastic. The main merit of the process was that complex halogen-containing plastics were safely disposed and halogen-free products were recycled without using catalysts or additives. It was discovered that additive BFRs were initially extracted by Sc-CO2 technique and then it decomposed accompanied with PVC rapidly to form HBr and HCl, which could be separated by traditional bromine stripping techniques from seawater. Based on response surface methodology (RSM), the maximum debromination and dechlorination efficiencies were achieved at 99.51% and 99.12% respectively. After the treatment, halogen-free products such as solid carbon materials and organic chemical feedstocks were obtained. Mechanism study elucidated that free radicals reaction involving chain initiation, growth and termination induced the polymer decomposition to form these products. This study provides an applicable and green approach for disposal and recovery of halogen-containing plastics.
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Affiliation(s)
- Cong-Cong Zhang
- Department of Solid Waste Treatment and Recycling, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing, 100085, China.
| | - Fu-Shen Zhang
- Department of Solid Waste Treatment and Recycling, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
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Fontana D, Pietrantonio M, Pucciarmati S, Rao C, Forte F. A comprehensive characterization of End-of-Life mobile phones for secondary material resources identification. WASTE MANAGEMENT (NEW YORK, N.Y.) 2019; 99:22-30. [PMID: 31470263 DOI: 10.1016/j.wasman.2019.08.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 08/01/2019] [Accepted: 08/09/2019] [Indexed: 06/10/2023]
Abstract
In this paper a full recognition of the different materials and valuable metals constituting mobile phones was performed. To this aim, a sample of 20 end-of-life devices has been dismantled and quantitative and qualitative chemical composition of the individual components was determined. From dismantling operations, it was found that plastics, metals, electronic components, batteries and displays account for 33%, 11%, 23%, 24% and 9% respectively, as a weighted average. Plastic parts of each item were analyzed by spectroscopy and then classified according to the plastic polymer type; it was found that polymeric components of mobile phones were made of five polymers: acrylonitrile-butadienestyrene, polycarbonate, polyurethane, polymethylmethacrylate and silicone. Electronic parts were leached by a twofold aqua regia treatment and the metal composition was determined: 15 elements were identified with concentration >0.2%. On the basis of these results, some considerations about the recycling context of end-of-life mobile phones were performed.
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Affiliation(s)
- Danilo Fontana
- ENEA, Italian National Agency for New Technologies, Energy, Sustainable Economic Development, Via Anguillarese 301, 00123 Rome, Italy.
| | - Massimiliana Pietrantonio
- ENEA, Italian National Agency for New Technologies, Energy, Sustainable Economic Development, Via Anguillarese 301, 00123 Rome, Italy
| | - Stefano Pucciarmati
- ENEA, Italian National Agency for New Technologies, Energy, Sustainable Economic Development, Via Anguillarese 301, 00123 Rome, Italy
| | - Concetta Rao
- ENEA, Italian National Agency for New Technologies, Energy, Sustainable Economic Development, Via Anguillarese 301, 00123 Rome, Italy
| | - Federica Forte
- ENEA, Italian National Agency for New Technologies, Energy, Sustainable Economic Development, Via Anguillarese 301, 00123 Rome, Italy
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30
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Niu B, Xu Z. From E-Waste to Nb-Pb Co-Doped and Pd-Loaded TiO 2 /BaTiO 3 Heterostructure: Highly Efficient Photocatalytic Performance. CHEMSUSCHEM 2019; 12:2819-2828. [PMID: 30806026 DOI: 10.1002/cssc.201900071] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 02/10/2019] [Indexed: 06/09/2023]
Abstract
A new and sustainable process was reported for the in situ synthesis of Nb-Pb co-doped and Pd-loaded TiO2 /BaTiO3 nanometer heterostructures from waste multilayer ceramic capacitors through a simple chlorination-leaching route. The particle size of the Nb-Pb co-doped heterostructure and the Pd loading were 20-50 nm and less than 5 nm, respectively. The bandgaps of the prepared samples were in the range 2.81-2.92 eV. The optimal simulated-sunlight photocatalytic H2 production rate and Rhodamine B degradation rate of the prepared heterostructure could reach 576.8 μmol g-1 h-1 and 0.29911 min-1 , respectively, which were approximately 11.3 and 19.1 times higher than those of commercial TiO2 , and 5.96 and 8.91 times higher than those of bare TiO2 /BaTiO3 . The recycled heterostructure exhibited excellent photostability and reusability. Such superior photocatalytic performance of the sample was attributed to the formation of the heterostructure, the Nb-Pb co-doping, and the Pd loading, which enhanced the visible light absorption and charge separation efficiency. Furthermore, DFT calculations were applied to explore the enhanced mechanism. This study demonstrates a sustainable process for the conversion of e-waste to a high-value-added and highefficiency photocatalyst, which has the advantages of waste utilization, low-cost preparation, and environmental protection.
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Affiliation(s)
- Bo Niu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, P.R. China
| | - Zhenming Xu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, P.R. China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, P.R. China
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31
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Sahan M, Kucuker MA, Demirel B, Kuchta K, Hursthouse A. Determination of Metal Content of Waste Mobile Phones and Estimation of Their Recovery Potential in Turkey. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:ijerph16050887. [PMID: 30862075 PMCID: PMC6427248 DOI: 10.3390/ijerph16050887] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 02/23/2019] [Accepted: 02/27/2019] [Indexed: 01/07/2023]
Abstract
Waste mobile phones constitute one of the fastest growing Waste Electrical and Electronic Equipment (WEEE) types all over the world due to technological innovations and shortening of their life span. They contain a complex mix of various materials, such as basic metals, precious metals and rare earth elements and represent an important secondary raw metal source. The main objectives of this study were to characterize the metal concentration of waste mobile phones by optimizing the inductively coupled plasma optical emission spectrometer (ICP-OES) operation parameters and estimate the metal recovery potential of waste mobile phones in Turkey. Therefore, selected mobile phone samples collected from a recycling center in Turkey were analyzed to determine their metal concentrations. Then, the theoretical recovery potentials of precious and rare earth metals from waste mobile phones were estimated for Turkey. The analytical methods optimized in this study can help further research activities to obtain comprehensive data for determination of the critical metals (precious metals and rare earth elements) in WEEE samples so that proper recycling and recovery strategies can be selected and implemented.
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Affiliation(s)
- Merve Sahan
- Institute of Environmental Sciences, Bogazici University, Bebek, Istanbul 3432, Turkey.
| | - Mehmet Ali Kucuker
- Institute of Environmental Technology and Energy Economics, Waste Resources Management, TUHH-Hamburg University of Technology, Harburger Schloßstr. 36, 21079 Hamburg, Germany.
- Department of Environmental Engineering, Engineering Faculty, Terzioğlu Campus, Çanakkale Onsekiz Mart University, 17020 Çanakkale, Turkey.
| | - Burak Demirel
- Institute of Environmental Sciences, Bogazici University, Bebek, Istanbul 3432, Turkey.
| | - Kerstin Kuchta
- Institute of Environmental Technology and Energy Economics, Waste Resources Management, TUHH-Hamburg University of Technology, Harburger Schloßstr. 36, 21079 Hamburg, Germany.
| | - Andrew Hursthouse
- Computing Engineering & Physical Sciences, University of the West of Scotland, Paisley PA1 2BE, UK.
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32
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Xiu FR, Li Y, Qi Y, Yu X, He J, Lu Y, Gao X, Deng Y, Song Z. A novel treatment of waste printed circuit boards by low-temperature near-critical aqueous ammonia: Debromination and preparation of nitrogen-containing fine chemicals. WASTE MANAGEMENT (NEW YORK, N.Y.) 2019; 84:355-363. [PMID: 30691910 DOI: 10.1016/j.wasman.2018.12.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 11/30/2018] [Accepted: 12/07/2018] [Indexed: 06/09/2023]
Abstract
In waste printed circuit boards (PCBs), brominated epoxy resin (BER) and copper are the two types of material that attracts the most attention due to their environmental risk and resource value. In this study, a novel and high-efficiency process for debromination and resource recovery of waste PCBs by low-temperature near-critical aqueous ammonia (NCAA) was successfully developed. A batch reactor was used in experiments with the temperatures ranging from 200 to 350 °C and the reaction times from 30 to 90 min. The ammonia water in near critical conditions can act not only as a medium but also as a reactant. Approximately 100% of the Br in waste PCBs could be removed and trapped by the NCAA at 300 °C. Copper foil could be easily separated and recovered from waste PCBs after the NCAA process. No brominated organic compounds could be detected in the oil phase products after the NCAA treatment of waste PCBs even at low temperature of 200 °C. Two new products (pyrazine and pyridine compounds) with high value-added were obtained for the first time by the treatment of waste PCBs. This study provides a novel and efficient strategy for the debromination, the recovery of copper, and the preparation of high value-added nitrogen-containing fine chemicals from waste PCBs. The low-temperature NCAA processing of waste PCBs could effectively reduce the energy consumption in comparison with traditional thermal decomposition processes, and promote the sustainable waste management strategy for waste electrical and electronic equipment (WEEE).
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Affiliation(s)
- Fu-Rong Xiu
- College of Geology and Environment, Xi'an University of Science and Technology, Xi' an 710054, People's Republic of China.
| | - Yifan Li
- College of Geology and Environment, Xi'an University of Science and Technology, Xi' an 710054, People's Republic of China
| | - Yingying Qi
- College of Geology and Environment, Xi'an University of Science and Technology, Xi' an 710054, People's Republic of China
| | - Xuan Yu
- College of Geology and Environment, Xi'an University of Science and Technology, Xi' an 710054, People's Republic of China
| | - Jiahuan He
- College of Geology and Environment, Xi'an University of Science and Technology, Xi' an 710054, People's Republic of China
| | - Yongwei Lu
- College of Geology and Environment, Xi'an University of Science and Technology, Xi' an 710054, People's Republic of China
| | - Xiang Gao
- College of Geology and Environment, Xi'an University of Science and Technology, Xi' an 710054, People's Republic of China
| | - Yuehua Deng
- College of Geology and Environment, Xi'an University of Science and Technology, Xi' an 710054, People's Republic of China
| | - Zhiqi Song
- College of Geology and Environment, Xi'an University of Science and Technology, Xi' an 710054, People's Republic of China
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Affiliation(s)
- C J Liang
- College of Materials Science and Engineering, Hanshan Normal University, Chaozhou China
| | - J Y Li
- College of Environment and Safety Engineering, Qingdao University of Science & Technology, Qingdao, China
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Li J, Ge Z, Liang C, An N. Present status of recycling waste mobile phones in China: a review. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2017; 24:16578-16591. [PMID: 28555392 DOI: 10.1007/s11356-017-9089-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2016] [Accepted: 04/24/2017] [Indexed: 06/07/2023]
Abstract
A large number of waste mobile phones have already been generated and are being generated. Various countries around the world have all been positively exploring the way of recycling and reuse when facing such a large amount of waste mobile phones. In some countries, processing waste mobile phones has been forming a complete industrial chain, which can not only recycle waste mobile phones to reduce their negative influence on the environment but also turn waste into treasure to acquire economic benefits dramatically. However, the situation of recycling waste mobile phones in China is not going well. Waste mobile phones are not formally covered by existing regulations and policies for the waste electric and electronic equipment in China. In order to explore an appropriate system to recover waste mobile phones, the mobile phone production and the amount of waste mobile phones are introduced in this paper, and status of waste mobile phones recycling is described; then, the disposal technology of electronic waste that would be most likely to be used for processing of electronic waste in industrial applications in the near future is reviewed. Finally, rationalization proposals are put forward based on the current recovery status of waste mobile phones for the purpose of promoting the development of recycling waste mobile phones in developing countries with a special emphasis on China.
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Affiliation(s)
- Jingying Li
- College of Environment and Safety Engineering, Qingdao University of Science & Technology, Qingdao, 266042, Shandong, People's Republic of China.
| | - Zhongying Ge
- College of Environment and Safety Engineering, Qingdao University of Science & Technology, Qingdao, 266042, Shandong, People's Republic of China
| | | | - Ni An
- College of Environment and Safety Engineering, Qingdao University of Science & Technology, Qingdao, 266042, Shandong, People's Republic of China
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35
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Ning C, Lin CSK, Hui DCW, McKay G. Waste Printed Circuit Board (PCB) Recycling Techniques. Top Curr Chem (Cham) 2017; 375:43. [PMID: 28353257 DOI: 10.1007/s41061-017-0118-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2016] [Accepted: 01/31/2017] [Indexed: 10/19/2022]
Abstract
With the development of technologies and the change of consumer attitudes, the amount of waste electrical and electronic equipment (WEEE) is increasing annually. As the core part of WEEE, the waste printed circuit board (WPCB) is a dangerous waste but at the same time a rich resource for various kinds of materials. In this work, various WPCB treatment methods as well as WPCB recycling techniques divided into direct treatment (landfill and incineration), primitive recycling technology (pyrometallurgy, hydrometallurgy, biometallurgy and primitive full recovery of NMF-non metallic fraction), and advanced recycling technology (mechanical separation, direct use and modification of NMF) are reviewed and analyzed based on their advantages and disadvantages. Also, the evaluation criteria are discussed including economic, environmental, and gate-to-market ability. This review indicates the future research direction of WPCB recycling should focus on a combination of several techniques or in series recycling to maximize the benefits of process.
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Affiliation(s)
- Chao Ning
- Chemical and Biomolecular Engineering Department, The Hong Kong University of Science and Technology, Hong Kong SAR, Hong Kong
| | - Carol Sze Ki Lin
- School of Energy and Environment, The City University of Hong Kong, Tat Chee Avenue, Hong Kong SAR, Hong Kong
| | - David Chi Wai Hui
- Chemical and Biomolecular Engineering Department, The Hong Kong University of Science and Technology, Hong Kong SAR, Hong Kong
| | - Gordon McKay
- Chemical and Biomolecular Engineering Department, The Hong Kong University of Science and Technology, Hong Kong SAR, Hong Kong. .,College of Science and Engineering, Hamad bin Khalifa University, Education City, Qatar Foundation, Doha, Qatar.
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Liu K, Zhang Z, Zhang FS. Direct extraction of palladium and silver from waste printed circuit boards powder by supercritical fluids oxidation-extraction process. JOURNAL OF HAZARDOUS MATERIALS 2016; 318:216-223. [PMID: 27427888 DOI: 10.1016/j.jhazmat.2016.07.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2016] [Revised: 06/28/2016] [Accepted: 07/03/2016] [Indexed: 06/06/2023]
Abstract
The current study was carried out to develop an environmental benign process for direct recovery of palladium (Pd) and silver (Ag) from waste printed circuit boards (PCBs) powder. The process ingeniously combined supercritical water oxidation (SCWO) and supercritical carbon dioxide (Sc-CO2) extraction techniques. SCWO treatment could effectively enrich Pd and Ag by degrading non-metallic component, and a precious metal concentrate (PMC) could be obtained, in which the enrichment factors of Pd and Ag reached 5.3 and 4.8, respectively. In the second stage, more than 93.7% Pd and 96.4% Ag could be extracted from PMC by Sc-CO2 modified with acetone and KI-I2 under optimum conditions. Mechanism study indicated that Pd and Ag extraction by Sc-CO2 was a complicated physiochemical process, involving oxidation, complexation, anion exchange, mass transfer and migration approaches. Accordingly, this study established a benign and effective process for selective recovery of dispersal precious metals from waste materials.
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Affiliation(s)
- Kang Liu
- Department of Solid Waste Treatment and Recycling, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhiyuan Zhang
- Department of Solid Waste Treatment and Recycling, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fu-Shen Zhang
- Department of Solid Waste Treatment and Recycling, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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37
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Liu K, Zhang Z, Zhang FS. Advanced degradation of brominated epoxy resin and simultaneous transformation of glass fiber from waste printed circuit boards by improved supercritical water oxidation processes. WASTE MANAGEMENT (NEW YORK, N.Y.) 2016; 56:423-430. [PMID: 27287009 DOI: 10.1016/j.wasman.2016.05.022] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 05/11/2016] [Accepted: 05/21/2016] [Indexed: 06/06/2023]
Abstract
This work investigated various supercritical water oxidation (SCWO) systems, i.e. SCWO1 (only water), SCWO2 (water+H2O2) and SCWO3 (water+H2O2/NaOH), for waste printed circuit boards (PCBs) detoxification and recycling. Response surface methodology (RSM) was applied to optimize the operating conditions of the optimal SCWO3 systems. The optimal reaction conditions for debromination were found to be the NaOH of 0.21g, the H2O2 volume of 9.04mL, the time of 39.7min, maximum debromination efficiency of 95.14%. Variance analysis indicated that the factors influencing debromination efficiency was in the sequence of NaOH>H2O2>time. Mechanism studies indicated that the dissociated ions from NaOH in supercritical water promoted the debromination of brominated epoxy resins (BERs) through an elimination reaction and nucleophilic substitution. HO2, produced by H2O2 could induce the oxidation of phenol ring to open (intermediates of BERs), which were thoroughly degraded to form hydrocarbons, CO2, H2O and NaBr. In addition, the alkali-silica reaction between OH(-) and SiO2 induced the phase transformation of glass fibers, which were simultaneously converted into anorthite and albite. Waste PCBs in H2O2/NaOH improved SCWO system were fully degraded into useful products and simultaneously transformed into functional materials. These findings are helpful for efficient recycling of waste PCBs.
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Affiliation(s)
- Kang Liu
- Department of Solid Waste Treatment and Recycling, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhiyuan Zhang
- Department of Solid Waste Treatment and Recycling, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fu-Shen Zhang
- Department of Solid Waste Treatment and Recycling, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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38
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Xiu FR, Weng H, Qi Y, Yu G, Zhang Z, Zhang FS. A novel reutilization method for waste printed circuit boards as flame retardant and smoke suppressant for poly (vinyl chloride). JOURNAL OF HAZARDOUS MATERIALS 2016; 315:102-109. [PMID: 27179704 DOI: 10.1016/j.jhazmat.2016.04.076] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2016] [Revised: 04/18/2016] [Accepted: 04/30/2016] [Indexed: 06/05/2023]
Abstract
In this study, a novel reutilization method for waste printed circuit boards (PCBs) as flame retardant and smoke suppressant for poly (vinyl chloride) (PVC) was successfully testified. A supercritical water oxidation (SCWO) process was applied to treat waste PCBs before they could be used as flame retardants of PVC. The results indicated that SCWO conditions had a significant effect on the flame retarding and smoke suppressing properties of waste PCBs for PVC. Cu2O, CuO, and SnO2 were the main active ingredients in waste PCBs-derived flame retardants. A conversion of Cu elements (Cu(0)→Cu(+)→Cu(2+)) during SCWO process with the increase of reaction temperature was found to be the key influence factor for the flame retarding properties of SCWO-treated PCBs. The experiment results also showed that there was a synergistic effect of flame retardancy between Cu(+) and Cu(2+). After the optimized SCWO treatment, SCWO-treated PCBs significantly improved the flame retardancy and smoke suppression of PVC. Limiting oxygen index (LOI) and char yield (CY) increased with increasing SCWO-treated PCBs content in PVC, while smoke density rating (SDR) and maximum smoke density (MSD) decreased markedly. The mechanical properties of PVC samples were influenced in different degree by adding different content SCWO-treated PCBs.
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Affiliation(s)
- Fu-Rong Xiu
- College of Ecological Environment and Urban Construction, Fujian University of Technology, Fuzhou 350108, People's Republic of China.
| | - Huiwei Weng
- College of Ecological Environment and Urban Construction, Fujian University of Technology, Fuzhou 350108, People's Republic of China
| | - Yingying Qi
- College of Ecological Environment and Urban Construction, Fujian University of Technology, Fuzhou 350108, People's Republic of China
| | - Gending Yu
- College of Ecological Environment and Urban Construction, Fujian University of Technology, Fuzhou 350108, People's Republic of China
| | - Zhigang Zhang
- College of Ecological Environment and Urban Construction, Fujian University of Technology, Fuzhou 350108, People's Republic of China
| | - Fu-Shen Zhang
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, People's Republic of China
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Zhang J, Liu S, Chen J, Zu J, Wang Y. Preparation of anion exchange resin by recycling of waste printed circuit boards. RSC Adv 2015. [DOI: 10.1039/c5ra18142a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The treatment of the non-metal components of waste printed circuit boards (WPCBs) is very difficult because they are inflexible and insoluble, and thus a new method to convert them into anion exchange resin was studied.
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Affiliation(s)
- Jianqiu Zhang
- School of Environmental and Chemical Engineering
- Shanghai University
- Shanghai 200444
- China
| | - Songhang Liu
- School of Environmental and Chemical Engineering
- Shanghai University
- Shanghai 200444
- China
| | - Jinyang Chen
- School of Environmental and Chemical Engineering
- Shanghai University
- Shanghai 200444
- China
| | - Jianhua Zu
- School of Nuclear Science and Engineering
- Shanghai Jiao Tong University
- Shanghai
- 200240 China
| | - Yangjun Wang
- School of Environmental and Chemical Engineering
- Shanghai University
- Shanghai 200444
- China
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