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Xi Z, Gao R, Chen Z, Du H, Xu Z. In situ high-valued transformation of nonmetals in waste printed circuit boards into supercapacitor electrodes with excellent performance. RSC Adv 2024; 14:1386-1396. [PMID: 38174251 PMCID: PMC10763618 DOI: 10.1039/d3ra08125g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 12/15/2023] [Indexed: 01/05/2024] Open
Abstract
Nonmetals in waste printed circuit boards after metal separation containing brominated resin and fiberglass are considered hazardous and low-recoveryvalue e-waste. However, if these nonmetals are not treated or are improperly treated, they can cause serious environmental pollution. Therefore, there is an urgent and significant need to develop an efficient recycling process for these nonmetals. Based on the concept of high-valued recycling of waste, this study in situ utilized such nonmetals to prepare a porous supercapacitor electrode through a facile carbonization, activation, and carbon thermal reduction process. The results indicated that the activation was a key role in constructing a porous structure. The optimal parameters for activation were a temperature of 800 °C, mass ratio of KOH to pyrolytic residues of 2, and an activation time of 1 h. The electrode materials exhibited a surface area of 589 m2 g-1 and hierarchical porous structures. In addition, the supercapacitors exhibited a capacitance of 77.14 mF cm-2 (62.5 mF cm-2) at 0.5 mA cm-2 (100 mV s-1). Moreover, the supercapacitors had excellent temperature resistance and adaptability. The capacitance retention was 89.36% and 90% at -50 °C and 100 °C after 10 000 cycles, respectively. This study provides a high-valued recycling strategy to utilize the nonmetals in e-waste as energy materials.
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Affiliation(s)
- Zhen Xi
- College of Chemistry and Chemical Engineering, Institute for Sustainable Energy and Resources, Qingdao University Qingdao, 308 Ningxia Road Qingdao 266071 P.R. China +86 15806391156 +86 18953271778
| | - Ruitong Gao
- College of Chemistry and Chemical Engineering, Institute for Sustainable Energy and Resources, Qingdao University Qingdao, 308 Ningxia Road Qingdao 266071 P.R. China +86 15806391156 +86 18953271778
| | - Zhaojun Chen
- College of Chemistry and Chemical Engineering, Institute for Sustainable Energy and Resources, Qingdao University Qingdao, 308 Ningxia Road Qingdao 266071 P.R. China +86 15806391156 +86 18953271778
| | - Hui Du
- College of Chemistry and Chemical Engineering, Institute for Sustainable Energy and Resources, Qingdao University Qingdao, 308 Ningxia Road Qingdao 266071 P.R. China +86 15806391156 +86 18953271778
| | - Zhenming Xu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University 800 Dongchuan Road Shanghai 200240 P.R. China
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2
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Gómez Duran JA, Arroyo ZG, Gómez Castro FI, Owen PQ, Sánchez Cadena LE, Ayala Gómez MV. Evaluation of the effect of physical and chemical factors in the recovery of Cu, Pb and Fe from waste PCB through acid leaching. Heliyon 2023; 9:e21348. [PMID: 38027605 PMCID: PMC10651467 DOI: 10.1016/j.heliyon.2023.e21348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 10/07/2023] [Accepted: 10/19/2023] [Indexed: 12/01/2023] Open
Abstract
Electronic waste recycling is a strategy that contributes to implement a circular economy model which include reuse, component and raw material recovery and minimum final deposition. Given the importance of reincorporating the components of electronic devices into the productive chain and a correct recovery for some hazardous metals such as lead contained in such residues. This study is focused on the effect of maximum available content (MAC) of metal, sulfuric acid initial concentration, agitation velocity, and oxidising agent on the recovery of copper, lead and iron from electronic waste through acid leaching. A solid-state characterization before and after treatment and electrochemical analysis was carried out to analyse MCA effects and surface chemistry. It was found that sub-millimetric particles show a better available extraction percentage in case of copper and iron, being opposite for lead. Presence of hydrogen peroxide enhance the extraction efficiency, however, this cause iron and lead precipitation, therefore it is inefficient for metals recovery as well as for reagent consumption. The presence of calcium salts reacts producing gypsum, which reduces the extraction yield of copper at particle size below 250 μm.
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Affiliation(s)
- Jaime A. Gómez Duran
- Departamento de Ingeniería Química, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Noria Alta S/N, Guanajuato, Gto., 36050, Mexico
| | - Zeferino Gamiño Arroyo
- Departamento de Ingeniería Química, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Noria Alta S/N, Guanajuato, Gto., 36050, Mexico
| | - Fernando Israel Gómez Castro
- Departamento de Ingeniería Química, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Noria Alta S/N, Guanajuato, Gto., 36050, Mexico
| | - Patricia Quintana Owen
- Departamento de Física Aplicada, CINVESTAV-IPN, A.P. 73, Cordemex, 97310, Mérida, Yucatán, Mexico
| | - Lorena Eugenia Sánchez Cadena
- Departamento de Ingeniería Civil, Campus Guanajuato, Universidad de Guanajuato, Calle Juárez 77, Col. Centro, Guanajuato, Gto, C.P, 36000 , Mexico
| | - Mónica V. Ayala Gómez
- Departamento de Química, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Noria Alta S/N, Guanajuato, Gto, 36050, Mexico
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3
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Lecomte F, Porras Guiterrez AG, Huvé M, Moissette A, Sicoli G, Rollet AL, Daviero-Minaud S. Degradation mechanisms of organic compounds in molten hydroxide salts: a radical reaction yielding H 2 and graphite. RSC Adv 2023; 13:19955-19964. [PMID: 37409032 PMCID: PMC10318416 DOI: 10.1039/d3ra02537c] [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] [Received: 04/17/2023] [Accepted: 06/07/2023] [Indexed: 07/07/2023] Open
Abstract
Molten salts are used in various waste treatments, such as recycling, recovery or making inert. Here, we present a study of the degradation mechanisms of organic compounds in molten hydroxide salts. Molten salt oxidation (MSO) using carbonates, hydroxides and chlorides is known for the treatment of hazardous waste, organic material or metal recovery. This process is described as an oxidation reaction due to the consumption of O2 and formation of H2O and CO2. We have treated various organic products, carboxylic acids, polyethylene and neoprene with molten hydroxides at 400 °C. However, the reaction products obtained in these salts, especially carbon graphite and H2 without CO2 emission, challenges the previous mechanisms described for the MSO process. Combining several analyses of the solid residues and the gas produced during the reaction of organic compounds in molten hydroxides (NaOH-KOH), we demonstrate that these mechanisms are radical-based instead of oxidative. We also show that the obtained end products are highly recoverable graphite and H2, which opens a new way of recycling plastic residues.
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Affiliation(s)
- Florent Lecomte
- Unité de Catalyse et Chimie du Solide (UCCS), Université de Lille 59655 Villeneuve d'Ascq France
- Laboratoire Physico-Chimie des Electrolytes et Nanosystèmes Interfaciaux (PHENIX), CNRS, Sorbonne Université 75005 Paris France
| | - Ana Gabriela Porras Guiterrez
- Laboratoire Physico-Chimie des Electrolytes et Nanosystèmes Interfaciaux (PHENIX), CNRS, Sorbonne Université 75005 Paris France
| | - Marielle Huvé
- Unité de Catalyse et Chimie du Solide (UCCS), Université de Lille 59655 Villeneuve d'Ascq France
| | - Alain Moissette
- Laboratoire de Spectrochimie pour l'Interactions, la Réactivité et l'Environnement (LASIRE), Université de Lille 59655 Villeneuve-d'Ascq France
| | - Giuseppe Sicoli
- Laboratoire de Spectrochimie pour l'Interactions, la Réactivité et l'Environnement (LASIRE), Université de Lille 59655 Villeneuve-d'Ascq France
| | - Anne-Laure Rollet
- Laboratoire Physico-Chimie des Electrolytes et Nanosystèmes Interfaciaux (PHENIX), CNRS, Sorbonne Université 75005 Paris France
| | - Sylvie Daviero-Minaud
- Unité de Catalyse et Chimie du Solide (UCCS), Université de Lille 59655 Villeneuve d'Ascq France
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Zhang Z, Xue Y, Yan YD, Li GQ, Xu WD, Ma FQ, Liu X, Zhang QG. The effect of air on oxidation decomposition of uranium-containing cationic exchange resins in Li 2CO 3-Na 2CO 3-K 2CO 3 molten-salt system. RSC Adv 2023; 13:18347-18362. [PMID: 37342806 PMCID: PMC10277827 DOI: 10.1039/d3ra02723f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 06/09/2023] [Indexed: 06/23/2023] Open
Abstract
With the development of nuclear energy, spent cationic exchange resins after purification of radioactive wastewater must be treated. Molten-salt oxidation (MSO) can minimize the disposal content of resins and capture SO2. In this work, the decomposition of uranium-containing resins in carbonate molten salt in N2 and air atmospheres was investigated. Compared to N2 atmosphere, the content of SO2 released from the decomposition of resins was relatively low at 386-454 °C in an air atmosphere. The SEM morphology indicated that the presence of air facilitated the decomposition of the resin cross-linked structure. The decomposition efficiency of resins in an air atmosphere was 82.6% at 800 °C. The XRD analysis revealed that uranium compounds had the reaction paths of UO3 → UO2.92 → U3O8 and UO3 → K2U2O7 → K2UO4 in the carbonate melt, and sulfur elements in resins were fixed in the form of K3Na(SO4)2. The XPS result illustrated that peroxide and superoxide ions accelerated the conversion of sulfone sulfur to thiophene sulfur and further oxidized to CO2 and SO2. Besides, the ion bond formed by uranyl ions on the sulfonic acid group was decomposed at high temperature. Finally, the decomposition of uranium-containing resins in the carbonate melt in an air atmosphere was explained. This study provided more theoretical guidance and technical support for the industrial treatment of uranium-containing resins.
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Affiliation(s)
- Zhi Zhang
- Harbin Engineering University Harbin 150001 Heilongjiang P. R. China
- China Institute for Radiation Protection Taiyuan 030006 Shanxi P. R. China
| | - Yun Xue
- Harbin Engineering University Harbin 150001 Heilongjiang P. R. China
| | - Yong-De Yan
- Harbin Engineering University Harbin 150001 Heilongjiang P. R. China
| | - Guo-Qiang Li
- China Institute for Radiation Protection Taiyuan 030006 Shanxi P. R. China
| | - Wen-Da Xu
- Yantai Standard Metrology Inspection & Test Center, National Steam Flowrate Measurement Station Yantai 264000 Shandong P. R. China
| | - Fu-Qiu Ma
- Harbin Engineering University Harbin 150001 Heilongjiang P. R. China
| | - Xin Liu
- Harbin Engineering University Harbin 150001 Heilongjiang P. R. China
| | - Qing-Guo Zhang
- Harbin Engineering University Harbin 150001 Heilongjiang P. R. China
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5
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Zhang Z, Xue Y, Wang YL, Xu WD, Yan YD, Zheng YH, Ma FQ, Li GQ. Effect of copper ions on transformation of organic sulfur in cationic exchange resins in Li 2CO 3-Na 2CO 3-K 2CO 3 molten-salt system. CHEMOSPHERE 2023; 331:138837. [PMID: 37146777 DOI: 10.1016/j.chemosphere.2023.138837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 04/17/2023] [Accepted: 04/30/2023] [Indexed: 05/07/2023]
Abstract
Cationic exchange resins (CERs) were applied for purification and clarifying process of radioactive wastewater in nuclear industry, which was a kind of sulfur-containing organic material. Molten-salt oxidation (MSO) method can be applied for the treatment of spent CERs and the absorption of acid gas (such as SO2). The experiments about the molten salt destruction of the original resin and Cu ions doped resin were conducted. The transformation of organic sulfur in Cu ions doped resin was investigated. Compared with the original resin, the content of tail gas (such as CH4, C2H4, H2S and SO2) released from the decomposition of Cu ions doped resin was relatively high at 323-657 °C. Sulfur elements in the form of sulfates and copper sulfides were fixed in spent salt through XRD analysis. The XPS result revealed that the portion of functional sulfonic acid groups (-SO3H) in Cu ions doped resin was converted into sulfonyl bridges (-SO2-) at 325 °C. With the enhancement of temperature, sulfonyl bridges (-SO2-) were further decomposed to sulfoxides sulfur (-SO-) and organic sulfide sulfur. The destruction of thiophenic sulfur to H2S and CH4 was prompted by copper ions in copper sulfide. Sulfoxide were oxidized to the sulfone sulfur in molten salt. Sulfones sulfur consumed by reduction of Cu ions at 720 °C was more than it produced by oxidation of sulfoxide through XPS analysis, and the relative proportion of sulfone sulfur was 16.51%.
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Affiliation(s)
- Zhi Zhang
- Harbin Engineering University, Harbin, 150001, Heilongjiang, China; China Institute for Radiation Protection, Taiyuan, 030006, Shanxi, China
| | - Yun Xue
- Harbin Engineering University, Harbin, 150001, Heilongjiang, China.
| | - Yue-Lin Wang
- Harbin Engineering University, Harbin, 150001, Heilongjiang, China
| | - Wen-Da Xu
- Yantai Standard Metrology Inspection & Test Center, National Steam Flowrate Measurement Station, Yantai, 264006, Shandong, China
| | - Yong-De Yan
- Harbin Engineering University, Harbin, 150001, Heilongjiang, China.
| | - Yang-Hai Zheng
- Harbin Engineering University, Harbin, 150001, Heilongjiang, China
| | - Fu-Qiu Ma
- Harbin Engineering University, Harbin, 150001, Heilongjiang, China.
| | - Guo-Qiang Li
- China Institute for Radiation Protection, Taiyuan, 030006, Shanxi, China
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6
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Liu J, Zhan L, Xu Z. Debromination with Bromine Recovery from Pyrolysis of Waste Printed Circuit Boards Offers Economic and Environmental Benefits. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:3496-3504. [PMID: 36794988 DOI: 10.1021/acs.est.2c06448] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Bromine is an important resource that is widely used in medical, automotive, and electronic industries. Waste electronic products containing brominated flame retardants can cause serious secondary pollution, which is why catalytic cracking, adsorption, fixation, separation, and purification have gained significant attention. However, the bromine resources have not been effectively reutilized. The application of advanced pyrolysis technology could help solve this problem via converting bromine pollution into bromine resources. Coupled debromination and bromide reutilization during pyrolysis is an important field of research in the future. This prospective paper presents new insights in terms of the reorganization of different elements and adjustment of bromine phase transition. Furthermore, we proposed some research directions for efficient and environmentally friendly debromination and reutilization of bromine: 1) precise synergistic pyrolysis should be further explored for efficient debromination, such as using persistent free radicals in biomass, polymer hydrogen supply, and metal catalysis, 2) rematching of Br elements and nonmetal elements (C/H/O) will be a promising direction for synthesizing functionalized adsorption materials, 3) oriented control of the bromide migration path should be further studied to obtain different forms of bromine resources, and 4) advanced pyrolysis equipment should be well developed.
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Affiliation(s)
- Jiangshan Liu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Lu Zhan
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zhenming Xu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
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7
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One dimensional wormhole corrosion in metals. Nat Commun 2023; 14:988. [PMID: 36813779 PMCID: PMC9946947 DOI: 10.1038/s41467-023-36588-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 02/06/2023] [Indexed: 02/24/2023] Open
Abstract
Corrosion is a ubiquitous failure mode of materials. Often, the progression of localized corrosion is accompanied by the evolution of porosity in materials previously reported to be either three-dimensional or two-dimensional. However, using new tools and analysis techniques, we have realized that a more localized form of corrosion, which we call 1D wormhole corrosion, has previously been miscategorized in some situations. Using electron tomography, we show multiple examples of this 1D and percolating morphology. To understand the origin of this mechanism in a Ni-Cr alloy corroded by molten salt, we combined energy-filtered four-dimensional scanning transmission electron microscopy and ab initio density functional theory calculations to develop a vacancy mapping method with nanometer-resolution, identifying a remarkably high vacancy concentration in the diffusion-induced grain boundary migration zone, up to 100 times the equilibrium value at the melting point. Deciphering the origins of 1D corrosion is an important step towards designing structural materials with enhanced corrosion resistance.
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8
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Xue Y, Wang YL, Zheng YH, Yang YS, Xu WD, Yan YD, Zhao R, Zhang QG, Liu X, Ma FQ, Zhang ML. Effects of oxygen content on gaseous and solid products during molten salt oxidation of cation exchange resins. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:16729-16740. [PMID: 36525196 DOI: 10.1007/s11356-022-24762-3] [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: 10/04/2022] [Accepted: 12/10/2022] [Indexed: 06/17/2023]
Abstract
Molten salt oxidation (MSO) is an advanced method for waste resins treatment; nevertheless, the research about gas product variations of resins under different stoichiometric air feed coefficient (α) is rare. The optimal working condition of hazardous waste disposal is obtained through thermodynamic equilibrium calculation, and the method to improve the treatment efficiency is found to guide the optimization of the actual experiment. In this paper, Fact Sage was used to calculate the oxidation products of cation exchange resins (CERs) at different temperatures and α, focusing on the similarities and differences through the contents of CO, CH4, CO2, and SO2 during the oxidation of CERs, the MSO of CERs, and the theoretical calculation. The results indicated that the gas products of the calculation and reality of the oxidation process of CERs are quite different, while the CO contents of CERs during MSO are close to the calculated values. The main reason for this consequence is that in the oxidation process of CERs, the S in the sulfonic acid group will form thermally stable C-S with the styrene-divinylbenzene skeleton. Moreover, the introduction of carbonate can promote the destruction of C-S and absorb SO2 as sulfate, weakening the influence of C-S on the oxidation products of CERs. The gas chromatograph results indicated that the SO2 content is reduced from 0.66% in the process of CERs oxidation to 0.28% in MSO of CERs. When 1.25 times stoichiometric air feed coefficient is fed, the sulfate content in the carbonate is the highest at 900 °C, which is 23.4%.
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Affiliation(s)
- Yun Xue
- Yantai Research Institute & Graduate School, Harbin Engineering University, Yantai, 264006, Shandong, China
| | - Yue-Lin Wang
- Yantai Research Institute & Graduate School, Harbin Engineering University, Yantai, 264006, Shandong, China
| | - Yang-Hai Zheng
- Yantai Research Institute & Graduate School, Harbin Engineering University, Yantai, 264006, Shandong, China
| | - Yu-Sheng Yang
- Inner Mongolia University of Science & Technology, Baotou, 014017, Inner Mongolia, China
| | - Wen-Da Xu
- Yantai Standard Metrology Inspection & Test Center, National Steam Flowrate Measurement Station, Yantai, 264006, Shandong, China
| | - Yong-De Yan
- Yantai Research Institute & Graduate School, Harbin Engineering University, Yantai, 264006, Shandong, China.
| | - Ran Zhao
- Inner Mongolia University of Science & Technology, Baotou, 014017, Inner Mongolia, China
| | - Qing-Guo Zhang
- Yantai Research Institute & Graduate School, Harbin Engineering University, Yantai, 264006, Shandong, China
| | - Xin Liu
- Yantai Research Institute & Graduate School, Harbin Engineering University, Yantai, 264006, Shandong, China
| | - Fu-Qiu Ma
- Yantai Research Institute & Graduate School, Harbin Engineering University, Yantai, 264006, Shandong, China
| | - Mi-Lin Zhang
- Yantai Research Institute & Graduate School, Harbin Engineering University, Yantai, 264006, Shandong, China
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9
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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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10
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Dai S, Liu L, He H, Yang B, Wu D, Zhao Y, Niu D. Highly-efficient molten NaOH-KOH for organochlorine destruction: Performance and mechanism. ENVIRONMENTAL RESEARCH 2023; 217:114815. [PMID: 36400224 DOI: 10.1016/j.envres.2022.114815] [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: 09/05/2022] [Revised: 10/29/2022] [Accepted: 11/12/2022] [Indexed: 06/16/2023]
Abstract
Molten salt has been increasingly acknowledged to be useful in the destruction of chlorine-containing organic wastes (COWs), e.g., organochlorine. However, the operational temperatures are usually high, and local structure and thermodynamic property of the molten salt remain largely unclear. In this study, novel molten NaOH-KOH is developed for organochlorine destruction, and its eutectic point can be lowered to 453 K with 1:1 mol ratio of NaOH to KOH. Further experiment shows that this molten NaOH-KOH is highly-efficient towards the destructions of both trichlorobenzene and dichlorophenol, acquiring the final dechlorination efficiencies as 88.2% and 94.1%, respectively. The organochlorine destruction and chloride salt enrichment are verified by fourier-transform infrared spectrometer. Molten NaOH-KOH not only eliminates the C-Cl and CC bonds, but also traps generated CO2, other acidic gases, and possibly particulate matters as a result of the high surface area and high viscosity. This makes it possibly advantageous over incineration for organic waste destruction for carbon neutrality. To sufficiently reveal the inherent mechanism for the temperature dependent performance, molecular dynamics simulation is further adopted. Results show that the radial distance between ions increases with temperature, causing larger molar volume and lower resistance to shear deformation. Moreover, thermal expansion coefficient, specific heat capacity, and ion self-diffusion coefficient of the molten NaOH-KOH are found to increase linearly with temperature. All these microscopic alterations contribute to the organochlorine destruction. This study benefits to develop highly-efficient molten system for COWs treatment via a low-carbon approach.
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Affiliation(s)
- Shijin Dai
- Baoan District City Appearance and Environment Comprehensive Management Service Center, Shenzhen, 518101, China; College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China
| | - Libing Liu
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Hongping He
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, 518060, China.
| | - Bo Yang
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Deli Wu
- College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
| | - Youcai Zhao
- College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
| | - Dongjie Niu
- College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China
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11
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Chen Z, Liu Y, Wang D, Wu N, Wang K, Zhang Y. Preparation, chemical structure and α-glucosidase inhibitory activity of sulfated polysaccharide from Grifola frondosa. J Funct Foods 2022. [DOI: 10.1016/j.jff.2022.105289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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12
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Faraji F, Golmohammadzadeh R, Pickles CA. Potential and current practices of recycling waste printed circuit boards: A review of the recent progress in pyrometallurgy. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 316:115242. [PMID: 35588669 DOI: 10.1016/j.jenvman.2022.115242] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 04/22/2022] [Accepted: 05/04/2022] [Indexed: 06/15/2023]
Abstract
Over the last few decades, a substantial amount of e-waste including waste printed circuit boards (WPCBs) has been produced and is accumulating worldwide. More recently, the rate of production has increased significantly, and this trend has raised some serious concerns regarding the need to develop viable recycling methods. The presence of other materials in the WPCBs, such as ceramics and polymers, and the multi-metal nature of WPCBs all contribute to the increased complexity of any recycling process. Among the viable techniques, pyrometallurgy, with the inherent ability to process the waste independent of its composition, is a promising candidate for both rapid and large-scale treatment. In the present study, firstly, the principles of the pyrometallurgical methods for WPCB recycling are discussed. Secondly, the different unit operations of thermochemical pretreatment including incineration, pyrolysis, and molten salt processing are reviewed. Thirdly, the smelting processes for the recovery of metals from WPCBs, as well as the issues surrounding slag formation and subsequent treatment are explained. Fourthly, alternative methods for the recovery of polymers and ceramics, in addition to metal recycling, are elucidated. Fifthly, emission control techniques and the potential for energy recovery are evaluated.
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Affiliation(s)
- Fariborz Faraji
- The Robert M. Buchan Department of Mining, Queen's University, Kingston, ON, K7L 3N6, Canada.
| | - Rabeeh Golmohammadzadeh
- Department of Chemical Engineering, Monash University, Clayton, Victoria, 3800, Australia; Institute for Frontier Materials, Deakin University, Geelong, Victoria 3200, Australia
| | - Christopher A Pickles
- The Robert M. Buchan Department of Mining, Queen's University, Kingston, ON, K7L 3N6, Canada.
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Galek V, Černá A, Pražák P, Horníček J, Mastný L, Hadrava J. The decomposition of halogenated hydrocarbons by MSO. MONATSHEFTE FUR CHEMIE 2022. [DOI: 10.1007/s00706-022-02939-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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14
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Pyrolysis Characteristics and Non-Isothermal Kinetics of Integrated Circuits. MATERIALS 2022; 15:ma15134460. [PMID: 35806585 PMCID: PMC9267151 DOI: 10.3390/ma15134460] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 05/29/2022] [Accepted: 05/30/2022] [Indexed: 02/04/2023]
Abstract
Due to the complexity of components and high hazard of emissions, thermochemical conversions of plastics among waste-integrated circuits (ICs) are more favorable compared with the common treatment options of electronic waste (E-waste), such as chemical treatment and burning. In this study, the waste random-access memory, as the representative IC, was used to investigate the thermal degradation behaviors of this type of E-waste, including a quantitative analysis of pyrolysis characteristics and non-isothermal kinetics. The results show that the pyrolysis of the ICs can be divided into three different decomposition stages. The pyrolysis temperature and gas atmosphere play an important role in the pyrolysis reaction, and the heating rate greatly affects the rate of the pyrolysis reaction. The non-isothermal kinetic parameters and reaction mechanisms of ICs are determined using the Friedman method, Coats and Redfern (CR) method, and Kissinger method. The results show that the actual average activation energy of the pyrolysis reaction of ICs should be between 170 and 200 kJ·mol−1. The optimally fitting model for the ICs pyrolysis is the three-step parallel model consisting of the random nucleation model (Am) and reaction order model (Cn).
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15
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Xia R, Overa S, Jiao F. Emerging Electrochemical Processes to Decarbonize the Chemical Industry. JACS AU 2022; 2:1054-1070. [PMID: 35647596 PMCID: PMC9131369 DOI: 10.1021/jacsau.2c00138] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 04/19/2022] [Accepted: 04/21/2022] [Indexed: 05/20/2023]
Abstract
Electrification is a potential approach to decarbonizing the chemical industry. Electrochemical processes, when they are powered by renewable electricity, have lower carbon footprints in comparison to conventional thermochemical routes. In this Perspective, we discuss the potential electrochemical routes for chemical production and provide our views on how electrochemical processes can be matured in academic research laboratories for future industrial applications. We first analyze the CO2 emission in the manufacturing industry and conduct a survey of state of the art electrosynthesis methods in the three most emission-intensive areas: petrochemical production, nitrogen compound production, and metal smelting. Then, we identify the technical bottlenecks in electrifying chemical productions from both chemistry and engineering perspectives and propose potential strategies to tackle these issues. Finally, we provide our views on how electrochemical manufacturing can reduce carbon emissions in the chemical industry with the hope to inspire more research efforts in electrifying chemical manufacturing.
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Affiliation(s)
- Rong Xia
- Center
for Catalytic Science and Technology, Department of Chemical and Biomolecular
Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Sean Overa
- Center
for Catalytic Science and Technology, Department of Chemical and Biomolecular
Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Feng Jiao
- Center
for Catalytic Science and Technology, Department of Chemical and Biomolecular
Engineering, University of Delaware, Newark, Delaware 19716, United States
- Email for F.J.:
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16
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Ma C, Kumagai S, Saito Y, Kameda T, Yoshioka T. An integrated utilization strategy of printed circuit boards and waste tire by fast co-pyrolysis: Value-added products recovery and heteroatoms transformation. JOURNAL OF HAZARDOUS MATERIALS 2022; 430:128420. [PMID: 35149505 DOI: 10.1016/j.jhazmat.2022.128420] [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: 12/21/2021] [Revised: 01/31/2022] [Accepted: 02/02/2022] [Indexed: 06/14/2023]
Abstract
Fast co-pyrolysis has been suggested as a promising technique to solve the environmental issues and simultaneously recover value-added products from polymer wastes. However, to date, no studies have focused on fast co-pyrolysis of printed circuit boards (PCB) and waste tire (WT). Therefore, we comprehensively investigated the fast co-pyrolysis of PCB and WT using pyrolysis-gas chromatography/mass spectrometry. The results show that an increase in temperature during fast pyrolysis improved the interactions between the PCB and WT pyrolyzates, increasing the formation of aliphatic and aromatic compounds. The formation of p-cymene was greatly induced by the isomerization and dehydrogenation reactions of D-limonene. Co-pyrolysis reduced the formation of brominated phenols and benzothiazole from PCB and WT pyrolysis, respectively, whereas promoted the interactions between Br- and S/N-containing radicals, concentrating them into heavy compounds. Increasing the temperature enhanced the release of heteroatom compounds. The findings suggest that debromination of PCB achieved via dehydrogenation of WT pyrolysis provoked secondary reactions of olefins and interactions of heteroatom radicals. The major products were accurately predicted by different fitting models using response surface methodology, indicating the synergistic interactions during co-pyrolysis. The results were beneficial for optimizing the experimental parameters to obtain the maximum yield of desired products.
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Affiliation(s)
- Chuan Ma
- Graduate School of Environmental Studies, Tohoku University, 6-6-07 Aoba, Aramaki-aza, Aoba-ku, Sendai, Miyagi 980-8579, Japan.
| | - Shogo Kumagai
- Graduate School of Environmental Studies, Tohoku University, 6-6-07 Aoba, Aramaki-aza, Aoba-ku, Sendai, Miyagi 980-8579, Japan; Division for the Establishment of Frontier Sciences of Organization for Advanced Studies, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
| | - Yuko Saito
- Graduate School of Environmental Studies, Tohoku University, 6-6-07 Aoba, Aramaki-aza, Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Tomohito Kameda
- Graduate School of Environmental Studies, Tohoku University, 6-6-07 Aoba, Aramaki-aza, Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Toshiaki Yoshioka
- Graduate School of Environmental Studies, Tohoku University, 6-6-07 Aoba, Aramaki-aza, Aoba-ku, Sendai, Miyagi 980-8579, Japan
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17
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Salinas-Rodríguez E, Hernández-Ávila J, Cerecedo-Sáenz E, Arenas-Flores A, Veloz-Rodríguez MA, Toro N, Gutiérrez-Amador MDP, Acevedo-Sandoval OA. Leaching of Copper Contained in Waste Printed Circuit Boards, Using the Thiosulfate-Oxygen System: A Kinetic Approach. MATERIALS 2022; 15:ma15072354. [PMID: 35407686 PMCID: PMC8999890 DOI: 10.3390/ma15072354] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 03/11/2022] [Accepted: 03/16/2022] [Indexed: 11/16/2022]
Abstract
The present work is related to the treatment of crushed waste of printed circuit boards (WPCBs) from electrical and electronic devices (WEEE), carrying out the recovery of copper in solution. In the first stage, the studied material was characterized by AAS, SEM-EDS, and XRD. The results revealed significantly high amounts of copper (744.42 mg/g), compared with the rest of the metals present in the sample, mainly iron and zinc. In the second stage of the work, alkali dynamic leaching experiments were carried out in the S2O3−2− O2 medium, evaluating important kinetic variables in order to verify the controlling step of the system and adjust the data to a kinetic model. According to the results obtained from the various experimental tests executed, it was found that in the studied system of S2O3−2− O2, the leaching of copper was preferably adjusted to the model of spherical particles with a shrinking core finding a mixed chemical−diffusive control, with values of Ea = 25.78 kJ/mol and n = 0.22 (for the leaching reagent), indicating that the reaction was controlled by the oxygen transport to the solid−liquid interface and also by the chemical reaction in the surface of particles, obtaining up to 99.82% copper in solution.
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Affiliation(s)
- Eleazar Salinas-Rodríguez
- Academic Area of Earth Science and Materials, Institute of Basis Sciences and Engineering, Autonomous University of the State of Hidalgo, Highway Pachuca-Tulancingo km. 4.5, Mineral de la Reforma 42184, Hidalgo, Mexico; (J.H.-Á.); (E.C.-S.); (A.A.-F.); (M.A.V.-R.)
- Correspondence: (E.S.-R.); (O.A.A.-S.); Tel.: +52-771-207-4171 (E.S.-R.); +52-771-151-7643 (O.A.A.-S.)
| | - Juan Hernández-Ávila
- Academic Area of Earth Science and Materials, Institute of Basis Sciences and Engineering, Autonomous University of the State of Hidalgo, Highway Pachuca-Tulancingo km. 4.5, Mineral de la Reforma 42184, Hidalgo, Mexico; (J.H.-Á.); (E.C.-S.); (A.A.-F.); (M.A.V.-R.)
| | - Eduardo Cerecedo-Sáenz
- Academic Area of Earth Science and Materials, Institute of Basis Sciences and Engineering, Autonomous University of the State of Hidalgo, Highway Pachuca-Tulancingo km. 4.5, Mineral de la Reforma 42184, Hidalgo, Mexico; (J.H.-Á.); (E.C.-S.); (A.A.-F.); (M.A.V.-R.)
| | - Alberto Arenas-Flores
- Academic Area of Earth Science and Materials, Institute of Basis Sciences and Engineering, Autonomous University of the State of Hidalgo, Highway Pachuca-Tulancingo km. 4.5, Mineral de la Reforma 42184, Hidalgo, Mexico; (J.H.-Á.); (E.C.-S.); (A.A.-F.); (M.A.V.-R.)
| | - Maria A. Veloz-Rodríguez
- Academic Area of Earth Science and Materials, Institute of Basis Sciences and Engineering, Autonomous University of the State of Hidalgo, Highway Pachuca-Tulancingo km. 4.5, Mineral de la Reforma 42184, Hidalgo, Mexico; (J.H.-Á.); (E.C.-S.); (A.A.-F.); (M.A.V.-R.)
| | - Norman Toro
- Faculty of Engineering and Architecture, Universidad Antonio Prat, Iquique 1100000, Chile;
| | - Maria del P. Gutiérrez-Amador
- Apan High School, Autonomous University of the State of Hidalgo, Highway Apan-Calpulalpan km. 8, Apan 43920, Hidalgo, Mexico;
| | - Otilio A. Acevedo-Sandoval
- Academic Area of Chemistry, Institute of Basis Sciences and Engineering, Autonomous University of the State of Hidalgo, Highway Pachuca-Tulancingo km. 4.5, Mineral de la Reforma 42184, Hidalgo, Mexico
- Correspondence: (E.S.-R.); (O.A.A.-S.); Tel.: +52-771-207-4171 (E.S.-R.); +52-771-151-7643 (O.A.A.-S.)
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18
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Andrade DF, Castro JP, Garcia JA, Machado RC, Pereira-Filho ER, Amarasiriwardena D. Analytical and reclamation technologies for identification and recycling of precious materials from waste computer and mobile phones. CHEMOSPHERE 2022; 286:131739. [PMID: 34371353 DOI: 10.1016/j.chemosphere.2021.131739] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 07/20/2021] [Accepted: 07/28/2021] [Indexed: 06/13/2023]
Abstract
Waste electrical and electronic equipment (WEEE) is one of the world's fastest-growing class of waste. WEEE contain a large amount of precious materials that have aroused the interest to develop new recycling technologies. Hence, effective recycling strategies are extremely necessary to promote the proper handling of these materials as well as for environmentally sound recovery of secondary raw resource. This paper reviews important existing methods and emerging technologies in WEEE management, with special emphasis in characterization, extraction and reclamation of precious materials from waste computer and mobile phones. Traditional pyrometallurgical and hydrometallurgical technologies still play a central role in the recovery of metals. More recently, emerging greener recycling technologies using microorganisms (i.e. biometallurgical), plasma arc fusion method and pretreatments (i.e. ultrasound and mechanochemical technologies) combined with other recycling methods (e.g. hydrometallurgical), and using less toxic solvents such as ionic liquids (ILs) and deep eutectic solvents (DESs) have also been attempted to recycle metals from computer and mobile phone scrap. The role of analytical method development, especially using spectroanalytical methods for chemical inspection and e-waste sorting process at industrial applications is also discussed. This confirmed that most direct sampling techniques such as laser-induced breakdown spectroscopy (LIBS) and X-ray fluorescence (XFR) have several advantages over traditional sorting methods including rapid analytical response, without use of chemical reagents or waste generation, and greater reclamation of precious and critical materials in the WEEE stream.
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Affiliation(s)
- Daniel Fernandes Andrade
- Group of Applied Instrumental Analysis, Department of Chemistry, Federal University of São Carlos, Rod Washington Luiz, km 235, 13565905, São Carlos, SP, Brazil; School of Natural Science, Hampshire College, 01002, Amherst, MA, USA
| | - Jeyne Pricylla Castro
- Group of Applied Instrumental Analysis, Department of Chemistry, Federal University of São Carlos, Rod Washington Luiz, km 235, 13565905, São Carlos, SP, Brazil
| | - José Augusto Garcia
- Group of Applied Instrumental Analysis, Department of Chemistry, Federal University of São Carlos, Rod Washington Luiz, km 235, 13565905, São Carlos, SP, Brazil; SG Soluções Científicas, 13560660, São Carlos, SP, Brazil
| | - Raquel Cardoso Machado
- Group of Applied Instrumental Analysis, Department of Chemistry, Federal University of São Carlos, Rod Washington Luiz, km 235, 13565905, São Carlos, SP, Brazil
| | - Edenir Rodrigues Pereira-Filho
- Group of Applied Instrumental Analysis, Department of Chemistry, Federal University of São Carlos, Rod Washington Luiz, km 235, 13565905, São Carlos, SP, Brazil
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Dismantling of Waste Printed Circuit Boards with the Simultaneous Recovery of Copper: Experimental Study and Process Modeling. MATERIALS 2021; 14:ma14185186. [PMID: 34576406 PMCID: PMC8465044 DOI: 10.3390/ma14185186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 09/01/2021] [Accepted: 09/06/2021] [Indexed: 11/24/2022]
Abstract
The study was carried out with the aim to demonstrate the applicability of a combined chemical–electrochemical process for the dismantling of waste printed circuit boards (WPCBs) created from different types of electronic equipment. The concept implies a simple and less polluting process that allows the chemical dismantling of WPCBs with the simultaneous recovery of copper from the leaching solution and the regeneration of the leaching agent. In order to assess the performance of the dismantling process, various tests were performed on different types of WPCBs using the 0.3 M FeCl3 in 0.5 M HCl leaching system. The experimental results show that, through the leaching process, the electronic components (EC) together with other fractions can be efficiently dismounted from the surface of WPCBs, with the parallel electrowinning of copper from the copper rich leaching solution. In addition, the process was scaled up for the dismantling of 100 kg/h WPCBs and modeled and simulated using process flow modelling software ChemCAD in order to assess the impact of all steps and equipment on the technical and environmental performance of the overall process. According to the results, the dismantling of 1 kg of WPCBs requires a total energy of 0.48 kWh, and the process can be performed with an overall low environmental impact based on the obtained general environmental indexes (GEIs) values.
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20
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Yao Z, Zhong Q, Xiao J, Ye S, Tang L, Zhang Z. An environmental-friendly process for dissociating toxic substances and recovering valuable components from spent carbon cathode. JOURNAL OF HAZARDOUS MATERIALS 2021; 404:124120. [PMID: 33068991 DOI: 10.1016/j.jhazmat.2020.124120] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/29/2020] [Accepted: 09/25/2020] [Indexed: 06/11/2023]
Abstract
Spent carbon cathode (SCC), a hazardous solid waste discharged from the aluminum electrolysis industry, has a serious environmental pollution risk. This study aims to explore an environmental friendly process for dissociating toxic substances and recovering valuable components from SCC. Parameters of molten salt-assisted roasting and water leaching were optimized. A possible dissociation mechanism of toxic substances was proposed. Results showed that 99.12% of cyanide was decomposed and 96.63% of fluoride was leached under optimal conditions. The recovery route of fluoride was designed according to the solution equilibrium chemical calculation and the difference in solubility and particle size between the recovered products. Exhaust gas with a high concentration of CO and CO2 was used for the carbonation of the leaching solution to recover cryolite. Effects of reaction conditions on precipitation mass and phase composition of recovered cryolite were investigated in detail. Characterization results indicated that the crystallinity and particle size of cryolite recovered under optimal conditions were extremely similar to those of commercial products. Finally, NaF and Na2CO3 were separated and recovered via evaporative crystallization combined with selective filtration. This proposed process with circular economy and green chemistry characteristics is expected to recover valuable components while minimizing environmental hazards of SCC.
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Affiliation(s)
- Zhen Yao
- School of Metallurgy and Environment, Central South University, Changsha 410083, PR China; School of Materials and Architectural Engineering, Guizhou Normal University, Guiyang 550001, PR China
| | - Qifan Zhong
- School of Metallurgy and Environment, Central South University, Changsha 410083, PR China; National Engineering Laboratory for Efficient Utilization of Refractory Nonferrous Metal Resources, Central South University, Changsha 410083, PR China.
| | - Jin Xiao
- School of Metallurgy and Environment, Central South University, Changsha 410083, PR China; National Engineering Laboratory for Efficient Utilization of Refractory Nonferrous Metal Resources, Central South University, Changsha 410083, PR China.
| | - Shengchao Ye
- School of Metallurgy and Environment, Central South University, Changsha 410083, PR China
| | - Lei Tang
- School of Metallurgy and Environment, Central South University, Changsha 410083, PR China
| | - Zhenhua Zhang
- School of Metallurgy and Environment, Central South University, Changsha 410083, PR China
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21
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Hu J, Tang Y, Ai F, Lin M, Ruan J. Biofilm for leaching precious metals from waste printed circuit boards using biocyanidation technology. JOURNAL OF HAZARDOUS MATERIALS 2021; 403:123586. [PMID: 32795820 DOI: 10.1016/j.jhazmat.2020.123586] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 07/23/2020] [Accepted: 07/25/2020] [Indexed: 06/11/2023]
Abstract
Presently, biocyanidation technology is being usually adopted to recover precious metals from an increasing quantity of waste printed circuit boards. The main aim of this work was to investigate the biofilm formation of Pseudomonas and its ability to leach precious metals. Based on batch experiments, strain 113 showed the highest biofilm-forming activity in optimal culture conditions of pH 7.0, 25 °C, and 1/25 NB medium among the Pseudomonas strains isolated. Both low concentrations of Cu2+ (500 ppm) and Ag+ (2.5 ppm) promoted biofilm formation. Under the optimal culture conditions for biofilm formation, the concentration of CN- was up to 5.0 ppm. In the continuous silver leaching experiment, the Ag+ concentration reached 4.0 ppm and the leaching efficiency was 14.7 % at 7 d. The results of this study may contribute to the construction of a bioreactor used for continuous leaching of waste printed circuit boards in an attempt to recover precious metals. Our results may also aid in the industrialization of biocyanidation technology.
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Affiliation(s)
- Jian Hu
- School of Environmental Science and Engineering, Yangzhou University, 196 Huayang Xi Road, Yangzhou, People's Republic of China.
| | - Yun Tang
- School of Environmental Science and Engineering, Yangzhou University, 196 Huayang Xi Road, Yangzhou, People's Republic of China
| | - Fangqiu Ai
- School of Environmental Science and Engineering, Yangzhou University, 196 Huayang Xi Road, Yangzhou, People's Republic of China
| | - Mi Lin
- School of Environmental Science and Engineering, Sun Yat-Sen University, 135 Xingang Xi Road, Guangzhou, 510275, People's Republic of China
| | - Jujun Ruan
- School of Environmental Science and Engineering, Sun Yat-Sen University, 135 Xingang Xi Road, Guangzhou, 510275, People's Republic of China.
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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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23
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Zhang S, Zhu N, Mao F, Zhang J, Huang X, Li F, Li X, Wu P, Dang Z. A novel strategy for harmlessness and reduction of copper smelting slags by alkali disaggregation of fayalite (Fe 2SiO 4) coupling with acid leaching. JOURNAL OF HAZARDOUS MATERIALS 2021; 402:123791. [PMID: 33254800 DOI: 10.1016/j.jhazmat.2020.123791] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 08/07/2020] [Accepted: 08/17/2020] [Indexed: 06/12/2023]
Abstract
Copper smelting slags are difficult to achieve harmlessness and reduction because of the presence of abundant of fayalite (Fe2SiO4). This work proposed a novel strategy for harmlessness and reduction of copper smelting slags by alkali disaggregation of Fe2SiO4 coupling with acid leaching. The disaggregation changed the Fe2SiO4 phase by NaOH and released the embedded harmful and valuable metals. The evaluation of disaggregation effect mainly depends on further acid treatment. Especially the total leaching efficiency of As, Zn, Fe, Cu and Pb was achieved 99.7%, 62.5%, 41.5%, 99.9% and 99.1% under diluted HNO3-H2O2 system, respectively. Compared with the non-disaggregated control, the efficiency was accordingly increased by 73.3%, 71.1%, 18.6%, 72.2% and 22.4%. Meanwhile, the content of As, Cu and Pb in the slags decreased from 1165.5 mg/kg, 30085.9 mg/kg and 5008.8 mg/kg to as low as 5.2 mg/kg, 21.2 mg/kg and 15.6 mg/kg, respectively. Interestingly, the strategy brought out 48.1% of the weight reduction of the copper smelting slags. The favorable effect was mainly attributed to the broken of Fe-O-Si bond thereafter improving the acid leaching activation. Therefore, the proposed strategy could potentially be a new method to realize harmlessness and reduction of copper smelting slags.
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Affiliation(s)
- Sihai Zhang
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, PR China
| | - Nengwu Zhu
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, PR China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Cluster Ministry of Education, Guangzhou, 510006, PR China; Guangdong Environmental Protection Key Laboratory of Solid Waste Treatment and Recycling, Guangzhou, 510006, PR China; Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling, Guangzhou, 510006, PR China.
| | - Fulin Mao
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, PR China
| | - Jianyi Zhang
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, PR China
| | - Xixian Huang
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, PR China
| | - Fei Li
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, PR China
| | - Xinyu Li
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, PR China
| | - Pingxiao Wu
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, PR China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Cluster Ministry of Education, Guangzhou, 510006, PR China
| | - Zhi Dang
- School of Environment and Energy, South China University of Technology, Guangzhou, 510006, PR China; The Key Lab of Pollution Control and Ecosystem Restoration in Industry Cluster Ministry of Education, Guangzhou, 510006, PR China
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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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25
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Gao R, Liu B, Zhan L, Guo J, Zhang J, Xu Z. In-situ debromination mechanism based on self-activation and catalysis of Ca(OH) 2 during pyrolysis of waste printed circuit boards. JOURNAL OF HAZARDOUS MATERIALS 2020; 392:122447. [PMID: 32193111 DOI: 10.1016/j.jhazmat.2020.122447] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 02/29/2020] [Accepted: 02/29/2020] [Indexed: 06/10/2023]
Abstract
Completely and deeply removed bromide from waste printed circuit boards (WPCBs) is necessary due to their toxicity and carcinogenicity. To achieve this purpose, calcium hydroxide (Ca(OH)2) as a debromination agent was added during pyrolysis process of WPCBs. The results showed that hydrogen bromide (HBr), 4-bromophenol, 2-bromophenol and 2,4-dibromophenol were the main bromide species in pyrolysis products. The Ca(OH)2 plays a significant role for removing HBr and organic bromide, but not affects products yield. Optimal removal efficiency for 4-bromophenol, 2-bromophenol and 2,4-dibromophenol reached 87.5 %, 74.6 % and 54.5 %, respectively. And debromination efficiency was related to the steric hindrance caused by bromide atoms. The Ca(OH)2 can be activated by captured HBr and its thermal decomposition. And the newly-generated calcium bromide and calcium oxide significantly facilitate debromination due to their high surface energy and reactivity. The debromination mechanism was clarified by experiments coupled with computational chemistry: the coordination of bromide and calcium to form [Ph-Br···Ca2+] or [Ph-Br···Caatom]. Then, electrons were delivered form bromide atom to Ca2+ or Caatom, which resulted in the stretch and weaken the C-Br bond. Hence, the C-Br bond was more easily to break. This work can provide support for designing novel and efficient debromination agents applied for high-temperature system.
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Affiliation(s)
- Ruitong Gao
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, PR China
| | - Binyang Liu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, PR China
| | - Lu Zhan
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, PR China
| | - Jie Guo
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, PR China
| | - Jie Zhang
- Instrumental Analysis Center, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, PR China
| | - Zhenming Xu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, PR China.
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26
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Mandadi GK, Asmatulu R, Khan WS, Asmatulu E. Fast and affordable recycling approach to electronic waste above the melting point using induction heat combined with centrifugal forces. ASIA-PAC J CHEM ENG 2020. [DOI: 10.1002/apj.2483] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Gopi K. Mandadi
- Department of Mechanical EngineeringWichita State University Wichita KS 67260 United States
| | - Ramazan Asmatulu
- Department of Mechanical EngineeringWichita State University Wichita KS 67260 United States
| | - Waseem S. Khan
- Department of Mechanical and Mechatronics EngineeringFujairah Men's College, Higher Colleges of Technology Fujairah United Arab Emirates
| | - Eylem Asmatulu
- Department of Mechanical EngineeringWichita State University Wichita KS 67260 United States
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27
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Gao R, Zhan L, Guo J, Xu Z. Research of the thermal decomposition mechanism and pyrolysis pathways from macromonomer to small molecule of waste printed circuit board. JOURNAL OF HAZARDOUS MATERIALS 2020; 383:121234. [PMID: 31563045 DOI: 10.1016/j.jhazmat.2019.121234] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 09/05/2019] [Accepted: 09/13/2019] [Indexed: 06/10/2023]
Abstract
Pyrolysis is an important pre-treatment technology for pyrometallurgy, which could reduce pollution and recover materials from waste printed circuit boards (WPCBs). However, present studies on mechanism of pyrolysis were insufficient, which results in the unclear of controlling reaction rate and inhibiting side reaction. To further develop pyrolysis technology, the in-depth research on the pyrolysis mechanism is necessary. In this study, we investigated the thermal decomposition process and pyrolysis pathways from macromonomers to products of WPCBs. The results showed that HBr was produced at the initial stage of pyrolysis. Then, the resin body depolymerized into macromonomers, followed by random rupture and free radical reactions to form pyrolysis products. Besides, possible mechanism for bisphenol A thermal decomposing was analyzed by bond energy. The results suggested that methyl groups in bisphenol A would be preferentially removed because of low bond energy. The six possible pathways may occur simultaneously when energy sufficient. Moreover, the mechanism function was determined by Škvára-Šesták method as: G(α)=-ln 1-α2, which indicated pyrolysis reaction agreed with the model of random nucleation followed by random growth. This study provided the theoretical basis for pollution control, process optimization and reactor design of WPCBs pyrolysis.
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Affiliation(s)
- Ruitong Gao
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, PR China
| | - Lu Zhan
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China
| | - Jie Guo
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, PR China
| | - Zhenming Xu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China.
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28
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Environmentally friendly synthesis of copper nanoparticles from waste printed circuit boards. Sep Purif Technol 2020. [DOI: 10.1016/j.seppur.2019.115860] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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29
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Qi Y, Yi X, Zhang Y, Meng F, Shu J, Xiu F, Sun Z, Sun S, Chen M. Effect of ionic liquid [MIm]HSO 4 on WPCB metal-enriched scraps refined by slurry electrolysis. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:33260-33268. [PMID: 31520374 DOI: 10.1007/s11356-019-06337-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 08/26/2019] [Indexed: 06/10/2023]
Abstract
Waste printed circuit boards (WPCBs) are usually dismantled, crushed, and sorted to WPCB metal-enriched scraps, still containing an amount of non-metallic materials. This research used slurry electrolysis to refine these WPCB metal-enriched scraps and to examine if a standard ionic liquid, [MIm]HSO4, can replace H2SO4 in the system. The impact of the refinement process on metal migration and transformation is discussed in detail. The results demonstrated that metals in WPCB metal-enriched scraps could be successfully refined using slurry electrolysis, and [MIm]HSO4 can be used to replace H2SO4 in the system. When 80% of H2SO4 was replaced by [MIm]HSO4 (electrolyte of 200 mL, 30 g/L CuSO4·5H2O, 60 g/L NaCl, 130 g/L H2SO4, and 1.624 A for 4 h), the total metal recovery rate is 85%, and the purity, current efficiency, and particle size of cathode metal powder were 89%, 52%, and 3.77 μm, respectively. Moreover, the microstructure of the cathode metal powder was dendritic in the H2SO4-CuSO4-NaCl slurry electrolysis system, whereas at an 80% [MIm]HSO4 substitution rate slurry electrolysis system, the cathode metal powder was irregular and accumulated as small-sized spherical particles. Thus, replacing inorganic leaching solvents with ionic liquids may provide a potential choice for the resources in WPCB metal-enriched scraps.
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Affiliation(s)
- Yaping Qi
- Key Laboratory of Solid Waste Treatment and Resource Recycle, Ministry of Education, Southwest University of Science and Technology, Mianyang, 621010, China
| | - Xiaoxia Yi
- Key Laboratory of Solid Waste Treatment and Resource Recycle, Ministry of Education, Southwest University of Science and Technology, Mianyang, 621010, China
| | - Yugai Zhang
- Key Laboratory of Solid Waste Treatment and Resource Recycle, Ministry of Education, Southwest University of Science and Technology, Mianyang, 621010, China
| | - Fansong Meng
- Key Laboratory of Solid Waste Treatment and Resource Recycle, Ministry of Education, Southwest University of Science and Technology, Mianyang, 621010, China
| | - Jiancheng Shu
- Key Laboratory of Solid Waste Treatment and Resource Recycle, Ministry of Education, Southwest University of Science and Technology, Mianyang, 621010, China
| | - Furong Xiu
- College of Geology & Environmental, Xi'an University of Science and Technology, Xi'an, 710054, China
| | - Zhi Sun
- Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China
| | - Shuhui Sun
- Institute National de la Recherché Scientifique-Énergie, Matériaux et Télécommunications, Varennes, QC, J3X 1S2, Canada
| | - Mengjun Chen
- Key Laboratory of Solid Waste Treatment and Resource Recycle, Ministry of Education, Southwest University of Science and Technology, Mianyang, 621010, China.
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30
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Dai S, Zheng Y, Zhao Y, Chen Y, Niu D. Molten hydroxide for detoxification of chlorine-containing waste: Unraveling chlorine retention efficiency and chlorine salt enrichment. J Environ Sci (China) 2019; 82:192-202. [PMID: 31133264 DOI: 10.1016/j.jes.2019.03.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 03/08/2019] [Accepted: 03/11/2019] [Indexed: 06/09/2023]
Abstract
Hazardous waste dechlorination reduces the potential of creating dioxins during the incineration process. To investigate the salt effect on waste dechlorination, molten hydroxides with a low melting temperature were utilized for the pre-dechlorination and decomposition of chlorine-containing organic wastes (COWs) including trichlorobenzene (TCB), perchloroethylene, hexachlorobenzene and chlordane. The results showed that a eutectic mixture of caustic sodium and potassium hydroxides (41 wt.% NaOH and 59 wt.% KOH) led to a low melting point below 300°C and a relatively high chlorine retention efficiency (CRE) with TCB as a representative COWs. The amounts of hydroxides, reaction time, and temperature all had notable influence on CRE. When the mass ratio of hydroxides to TCB reached 30:1, approximately 98.1% of the TCB was destroyed within 2.5 hr at 300°C with CRE of 71.6%. According to the residue analysis, the shapes of reaction residues were irregular with particles becoming swollen and porous. The benzene ring and C-Cl bonds disappeared, while carboxyl groups formed in the residues. The stripped chlorine was retained and condensed to form chloride salts, and the relative abundance of the chloride ions associated with the mass of TCB in residues increased from 0 to 75.0% within the 2.5 hr reaction time. The observed concentration of dioxins in residues was 5.6 ngTEQ/kg. A reaction pathway and possible additional reactions that occur in this dechlorination system were proposed. Oxidizing agents may attack TCB and facilitate hydrogenation/dechlorination reactions, making this process a promising and environmentally friendly approach for chlorine-containing organic waste treatment.
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Affiliation(s)
- Shijin Dai
- College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
| | - Yilin Zheng
- College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Youcai Zhao
- College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Yu Chen
- College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China
| | - Dongjie Niu
- College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China.
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31
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Korf N, Løvik AN, Figi R, Schreiner C, Kuntz C, Mählitz PM, Rösslein M, Wäger P, Rotter VS. Multi-element chemical analysis of printed circuit boards - challenges and pitfalls. WASTE MANAGEMENT (NEW YORK, N.Y.) 2019; 92:124-136. [PMID: 31160021 DOI: 10.1016/j.wasman.2019.04.061] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 04/24/2019] [Accepted: 04/30/2019] [Indexed: 06/09/2023]
Abstract
Printed circuit boards (PCB) are an essential component of electrical and electronic equipment (EEE) and account for roughly 5% of the mass of EEE. Knowledge about the chemical composition of PCB is crucial to enable an enhanced recycling, especially for elements considered critical regarding their economic importance and supply risk (e.g. precious metals or specialty metals such as tantalum, germanium, gallium). No standard reference methods exist for determining the chemical composition of PCB. Previously published element mass fractions cover a wide range and were produced with numerous methods for sample preparation, digestion, and measurement. This impedes comparability of PCB composition from different studies. To investigate sample- and element-specific effects of applied methods a PCB sample from desktop PC was analysed in two separate labs. One lab applied sample- and element-specific validated methods (aqua regia, HF, H2SO4 blend; ICP-OES, QQQ-ICP-MS), providing reference values, the other applied routine in-house methods (aqua regia; ICP-OES, ICP-MS) to assess the validity of in-house methods for chemical analysis of PCB. A t-test was used to identify elements depicting significant differences between validated and in-house methods. For base metals, in-house methods led to comparable results. For precious, specialty, and hazardous metals as well as REE investigated in this study, significant differences were detected. With respect to all results for in-house methods in this study, the combination of aqua regia and ICP-OES led to less significant differences than aqua regia and ICP-MS. The results show that sample- and element-specific quality assurance is crucial to prevent analytical bias.
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Affiliation(s)
- Nathalie Korf
- Chair of Circular Economy and Recycling Technology at Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany.
| | - Amund N Løvik
- Technology and Society Laboratory at Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| | - Renato Figi
- Advanced Analytical Technologies at Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland
| | - Claudia Schreiner
- Advanced Analytical Technologies at Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland
| | - Claudia Kuntz
- Chair of Circular Economy and Recycling Technology at Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Paul Martin Mählitz
- Chair of Circular Economy and Recycling Technology at Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Matthias Rösslein
- Particles-Biology Interactions Laboratory at Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| | - Patrick Wäger
- Technology and Society Laboratory at Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland
| | - Vera Susanne Rotter
- Chair of Circular Economy and Recycling Technology at Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
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32
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Hubau A, Chagnes A, Minier M, Touzé S, Chapron S, Guezennec AG. Recycling-oriented methodology to sample and characterize the metal composition of waste Printed Circuit Boards. WASTE MANAGEMENT (NEW YORK, N.Y.) 2019; 91:62-71. [PMID: 31203943 DOI: 10.1016/j.wasman.2019.04.041] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 04/18/2019] [Accepted: 04/19/2019] [Indexed: 06/09/2023]
Abstract
As spent printed circuit boards (PCBs) are among the most valuable components in waste electrical and electronic equipment (WEEE), their recovery makes economic and strategic sense. However, their composition varies considerably depending on the location, year and type of appliance in which they were used. Developing new treatment processes requires representative sampling of spent PCBs from large samples and accurate determination of their raw material composition. This study aimed to characterize spent PCBs by milling, sampling and leaching with an appropriate reagent. Sampling was performed on 526 kg of spent PCBs, to obtain different samples milled at 750 µm in order to access the metals. The samples were leached with aqua regia and the metal contents of the leachates were determined. For most metals, the analyses of 40 g-samples of spent PCBs showed limited variation in the composition of the different samples. These results concurred well with other studies reported in the literature.
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Affiliation(s)
- Agathe Hubau
- BRGM, F-45060 Orléans, France; Chimie ParisTech, PSL Research University, CNRS, Institut de Recherche de Chimie Paris (IRCP), F-75005 Paris, France.
| | | | - Michel Minier
- Chimie ParisTech, PSL Research University, CNRS, Institut de Recherche de Chimie Paris (IRCP), F-75005 Paris, France
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33
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Dai S, Zheng Y, Zhao Y, Li Q, Niu D. Dechlorination and conversion mechanism of trichlorobenzene as a model compound of chlorine-containing wastes by different base-catalyzed combinations. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:9480-9489. [PMID: 30726536 DOI: 10.1007/s11356-019-04221-2] [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: 10/26/2018] [Accepted: 01/10/2019] [Indexed: 06/09/2023]
Abstract
Chlorine-containing organic waste (COWs) is a big threat for the waste incineration because of the dioxin generation and equipment corrosion. Recently, dechlorination and detoxification of COWs is emergent in order to lower the environmental risk and treatment costs. In this study, base-catalyzed decomposition processes with different hydroxides, hydrogen donors, and catalysts were conducted for pre-treatment of COWs to reduce organic chlorine content, with the TCB as a model compound and industrial rectification residues for verification. Results showed that maximum chlorine retention efficiency (CRE) of four alkalis followed the order of KOH > NaOH-KOH > NaOH > Mg(OH)2, which were 98.3%, 93.4%, 97.2%, and 1.5%, respectively, and could be expressed as an apparent first-order reaction. The differences were resulted from the varying ionic potentials of the metal cations. Hydrogen donors (glycol, glycerol, paraffin oil, and PEG 200) acted as effective dechlorination regents follow the order of PEG > glycol > paraffin oil > glycerol. In addition, Fe, Ni, Cu, and activated carbon catalysts increased the CRE by 68.9% to 92.4%, 91.9%, 89.2%, and 73.3%, respectively. Residue analysis through X-ray diffraction and Fourier transform infrared spectroscopy revealed that KCl, sodium oxalate, and phenol were the main products and a plausible stepwise dechlorination pathway was proposed. The effectiveness of three optimized combinations including NaOH/PEG, KOH/PEG, and NaOH-KOH/PEG (with the Fe catalyst) was confirmed by using them for dechlorinating rectification residues, and they restrained 98.2%, 91.2%, and 94.6% of the chlorine, respectively. The organochlorine content decreased from 19.2 to 1.8% within 180 min, while inorganic chorine content increased from 1.5 to 18.9%, indicating the potential for COWs dechlorination.
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Affiliation(s)
- Shijin Dai
- College of Environmental Science and Engineering, Tongji University, Siping Rd. 1239, Shanghai, 200092, China
| | - Yilin Zheng
- College of Environmental Science and Engineering, Tongji University, Siping Rd. 1239, Shanghai, 200092, China
| | - Youcai Zhao
- College of Environmental Science and Engineering, Tongji University, Siping Rd. 1239, Shanghai, 200092, China
- Shanghai Institute of Pollution Control and Ecological Security, 1515 North Zhongshan Rd. (No. 2), Shanghai, 200092, China
| | - Qiang Li
- China Everbright Greentech Limited, Shenzhen, 518040, China
| | - Dongjie Niu
- College of Environmental Science and Engineering, Tongji University, Siping Rd. 1239, Shanghai, 200092, China.
- Shanghai Institute of Pollution Control and Ecological Security, 1515 North Zhongshan Rd. (No. 2), Shanghai, 200092, China.
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34
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Liu K, Yang J, Hou H, Liang S, Chen Y, Wang J, Liu B, Xiao K, Hu J, Deng H. Facile and Cost-Effective Approach for Copper Recovery from Waste Printed Circuit Boards via a Sequential Mechanochemical/Leaching/Recrystallization Process. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:2748-2757. [PMID: 30698959 DOI: 10.1021/acs.est.8b06081] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The recovery of copper (Cu0) from waste printed circuit boards (WPCBs) is a great challenge as a result of its heterogeneous structural properties, with a mixture of metals, epoxy resin, and fiberglass. In this study, a three-step sequential process, including mechanochemical processing, water leaching, and recrystallization, for Cu0 recovery from WPCB powder is reported. Potassium persulfate (K2S2O8), instead of acid/alkali reagents, was employed as the sole reagent in the cupric sulfate (CuSO4) regeneration process. Complete oxidation of Cu0 in the WPCBs to copper oxide (CuO) and CuSO4 was first achieved during mechanochemical processing with K2S2O8 as the solid oxidant, and the K2S2O8 was simultaneously converted to sulfate compounds [K3H(SO4)2] via a solid-solid reaction with epoxy resin (C nH mO y) as the hydrogen donator under mechanical force. The rapid leaching of Cu species in the forms of CuO and CuSO4 was therefore easily realized with pure water as a nontoxic leaching reagent. The kinetics of the leaching process of Cu species was confirmed to follow the shrinking nucleus model controlled by solid-film diffusion. Finally, CuSO4·5H2O was successfully separated by cooling crystallization of the hot saturated solution of sulfate salt [K2Cu(SO4)2·6H2O]. An efficient conversion of Cu0 to CuSO4·5H2O product, for WPCB recycling, was therefore established.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Huali Deng
- Dongjiang Environmental Protection Company, Limited , Shenzhen , Guangdong 518000 , People's Republic of China
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35
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Gao R, Xu Z. Pyrolysis and utilization of nonmetal materials in waste printed circuit boards: Debromination pyrolysis, temperature-controlled condensation, and synthesis of oil-based resin. JOURNAL OF HAZARDOUS MATERIALS 2019; 364:1-10. [PMID: 30336331 DOI: 10.1016/j.jhazmat.2018.09.096] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 08/23/2018] [Accepted: 09/30/2018] [Indexed: 06/08/2023]
Abstract
The rapid replacement of electric and electronic equipment has produced large amount of waste printed circuit boards (WPCBs). At present, physical and mechanical methods are widely used to recover valuable metals from WPCBs. Unfortunately, produced nonmetal materials (NMMs) were typically hazardous waste and were usually disposed by landfill. Considering the characteristics of structure and composition of NMMs, debromination pyrolysis was regarded as the appropriate technique to decompose organics. However, pyrolysis oil and pyrolysis residue were still typically hazardous and difficult to disposal or recycle. Hence, we proposed a novel integrated method to reuse NMMs. The results showed that temperature-controlled condensation method was effective to separate pyrolysis oil. Besides, bromine was removed from organics and formed CaBr2. Pyrolysis oil was used to synthesize oil-based resin. FT-IR, 1H and 13C NMR and TG analysis results indicated that oil-based resin had the same structure and thermostability with commercial resin, which suggested that oil-based rein had economic value. In addition, CaBr2 in residual could be recycled by water leaching and filter residues can be used as ideal reinforcing material for building materials. This study raises a comprehensive method to utilize NMMs and recover value materials effectively, sustainably and environmentally friendly.
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Affiliation(s)
- Ruitong Gao
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, PR China
| | - Zhenming Xu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 20092, PR China.
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36
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Chen B, He J, Xi Y, Zeng X, Kaban I, Zhao J, Hao H. Liquid-liquid hierarchical separation and metal recycling of waste printed circuit boards. JOURNAL OF HAZARDOUS MATERIALS 2019; 364:388-395. [PMID: 30384249 DOI: 10.1016/j.jhazmat.2018.10.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 10/08/2018] [Accepted: 10/09/2018] [Indexed: 06/08/2023]
Abstract
Waste electrical and electronic equipment is rapidly increasing worldwide, resulting in a large quantity of waste printed circuit boards (WPCBs). There is a great challenge on how to efficiently separate mixed metals in WPCBs, which consists of more than 10 elements including hazardous Cr, Pb and Cd. In this work, based on atomic interactions, a method of liquid-liquid hierarchical separation is developed to separate the mixed metals dissociated from the pyrolyzed WPCBs of mobile phones. The hierarchical separation of L→LFe-rich + LCu,Pb-rich, LCu,Pb-rich→LCu-rich + LPb-rich and LPb-rich→SCu-dendritical + L'Pb-rich produces four immiscible Fe-rich, Cu-rich, Cu-dendritical and Pb-rich substances. The separation rate between these substances can reach more than 96% in a super-gravity field of G = 1000g. Other metals selectively distribute in the four substances. The Fe-rich substance collects Cr, Co, Ni and Si. Almost all of Au and Ag are trapped in the Cu-rich and Cu-dendritical substances. The low-melting-point metals, i.e. Bi, Cd, In and Sn, are located in the Pb-rich substance. This work provides a green shortcut for efficiently separating and recycling overall metals in WPCBs.
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Affiliation(s)
- Bin Chen
- Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, China; School of Materials Science and Engineering, University of Science and Technology of China, Shenyang, 110016, China
| | - Jie He
- Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, China.
| | - Yaoyao Xi
- Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, China
| | - Xiangfeng Zeng
- Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China
| | - Ivan Kaban
- IFW Dresden, Institute for Complex Materials, Helmholtzstr. 20, Dresden, 01069, Germany
| | - Jiuzhou Zhao
- Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, China.
| | - Hongri Hao
- Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, China
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37
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Dai SJ, Zhao YC, Niu DJ, Li Q, Chen Y. Preparation and reactivation of magnetic biochar by molten salt method: Relevant performance for chlorine-containing pesticides abatement. JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION (1995) 2019; 69:58-70. [PMID: 30095366 DOI: 10.1080/10962247.2018.1510441] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2018] [Revised: 08/02/2018] [Accepted: 08/07/2018] [Indexed: 06/08/2023]
Abstract
Molten salt has been regarded as a versatile and environmental-friendly method for the material preparation and waste destruction. In this work, molten FeCl3 was utilized for the generation of magnetic biochar (MBC) derived from simultaneous activation and magnetization of biomass. The sample characterization indicated that MBC had a rough surface with BET surface area of 404 m2/g and total pore volume of 0.35cm3/g. Highly dispersed Fe3O4 and nitrogen could be deposited on the surface, leading to an excellent magnetization property. The MBC exhibited a great 2,4-Dichlorophenol (2.4-DCP) and atrazine removal performance in solution with the maximum adsorption capacity achieved 298.12 mg/g and 102.17 mg/g. Kinetics results demonstrated that MBC adsorption met the Pseudo-first-order model better. Molten NaOH-Na2CO3 was provided for the re-activation of exhausted MBC. 2,4-DCP was firstly desorbed from the MBC and subsequently destructed by the active species in the melt medium. Chlorine can be captured in the molten alkaline medium from the XRD pattern of residues.The MBC could be easily recovered with a yield of 98.2% and fixed carbon content of 61.0% after the molten salt regeneration process. With no 2,4-DCP detected, 65.5% and 31.69% of initial Cl was found in washing water and residues with the molten NaOH-Na2CO3, respectively. After 4 cycles of regeneration and adsorption, 60.55%-72.22% of initial adsorption capacity can be kept. This preparation and regeneration method can be an effective way to reduce the risk of secondary pollution of chlorinated organic compounds during adsorbent regeneration.Implications: Molten salt (MS) is a salt or multiple salts with a low melting point, and has been applied in many sectors and is regarded as a crucial role in terms of energy, environmental, and resource sustainability. In our paper, magnetic biochar was prepared by one-step activation and magnetization of fir dust using molten FeCl3∙6H2O. Meanwhile, a regeneration method using molten alkaline salt was provided. Magnetic biochar generated in our study performed well in the 2,4-dichlorophenol and atrazine adsorption. After four cycles of regeneration and adsorption, 72.2% of initial 2,4-DCP adsorption capacity can be kept.
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Affiliation(s)
- Shi-Jin Dai
- State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai China
| | - You-Cai Zhao
- State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai China
- College of Environmental Science and Engineering, Tongji University, Shanghai, China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai PR China
| | - Dong-Jie Niu
- College of Environmental Science and Engineering, Tongji University, Shanghai, China
- Shanghai Institute of Pollution Control and Ecological Security, Shanghai PR China
| | - Qiang Li
- China Everbright Greentech Limited, Shenzhen China
| | - Yu Chen
- State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai China
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Correa MMJ, Silvas FPC, Aliprandini P, Moraes VTD, Dreisinger D, Espinosa DCR. SEPARATION OF COPPER FROM A LEACHING SOLUTION OF PRINTED CIRCUIT BOARDS BY USING SOLVENT EXTRACTION WITH D2EHPA. BRAZILIAN JOURNAL OF CHEMICAL ENGINEERING 2018. [DOI: 10.1590/0104-6632.20180353s20170144] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Silva WC, de Souza Corrêa R, da Silva CSM, Afonso JC, da Silva RS, Vianna CA, Mantovano JL. Recovery of base metals, silicon and fluoride ions from mobile phone printed circuit boards after leaching with hydrogen fluoride and hydrogen peroxide mixtures. WASTE MANAGEMENT (NEW YORK, N.Y.) 2018; 78:781-788. [PMID: 32559970 DOI: 10.1016/j.wasman.2018.06.049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Revised: 05/21/2018] [Accepted: 06/25/2018] [Indexed: 06/11/2023]
Abstract
The recovery of copper, nickel, zinc, silicon, iron, aluminum, tin and fluoride ions from fluoride leach liquors of non-ground printed circuit boards (PCBs) from mobile phones is described in detail. These PCBs were leached with HF + H2O2 mixtures after previous treatment with 6 mol L-1 NaOH (removal of the solder mask). A combination of solvent extraction (SX) and precipitation techniques was used. 99.5 wt% zinc, copper and nickel, in this order, were extracted in one stage (Zn, Ni) or two stages (Cu) with di-2-ethylhexylphosphoric acid (D2EHPA) diluted in kerosene (25 °C, A/O = 1 v/v) after adjusting the pH of the leachate. They were easily stripped by aqueous H2SO4. Iron, aluminum and tin did not interfere because they were masked by fluoride ions. Iron and aluminum were precipitated together as Na3FeF6 + Na3AlF6 by careful addition of aqueous NaOH. Silicon, tin and fluoride ions were recovered together (Na2SiF6 + Na2SnF6 + NaF) by careful evaporation of the aqueous solution after SX of nickel. The tin salt was leached from this solid by absolute ethanol. High HF concentration (10 mol L-1) in the leachant affected SX of Cu(II) and precipitation of iron/aluminum flurocomplexes since some NaF partially precipitated at acidic pH.
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Affiliation(s)
- Walner Costa Silva
- Analytical Chemistry Department, Institute of Chemistry, Federal University of Rio de Janeiro, Av. Athos da Silveira Ramos, 149, Room A509, 21941-909 Ilha do Fundão, Rio de Janeiro, Brazil
| | - Roger de Souza Corrêa
- Analytical Chemistry Department, Institute of Chemistry, Federal University of Rio de Janeiro, Av. Athos da Silveira Ramos, 149, Room A509, 21941-909 Ilha do Fundão, Rio de Janeiro, Brazil
| | - Calvin Sampaio Moreira da Silva
- Analytical Chemistry Department, Institute of Chemistry, Federal University of Rio de Janeiro, Av. Athos da Silveira Ramos, 149, Room A509, 21941-909 Ilha do Fundão, Rio de Janeiro, Brazil
| | - Júlio Carlos Afonso
- Analytical Chemistry Department, Institute of Chemistry, Federal University of Rio de Janeiro, Av. Athos da Silveira Ramos, 149, Room A509, 21941-909 Ilha do Fundão, Rio de Janeiro, Brazil.
| | - Rubens Souza da Silva
- Chemistry and Nuclear Materials Department, Institute of Nuclear Engineering, Rua Hélio de Almeida, 75, 21941-906 Ilha do Fundão, Rio de Janeiro, Brazil
| | - Cláudio Augusto Vianna
- Chemistry and Nuclear Materials Department, Institute of Nuclear Engineering, Rua Hélio de Almeida, 75, 21941-906 Ilha do Fundão, Rio de Janeiro, Brazil
| | - José Luiz Mantovano
- Chemistry and Nuclear Materials Department, Institute of Nuclear Engineering, Rua Hélio de Almeida, 75, 21941-906 Ilha do Fundão, Rio de Janeiro, Brazil
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Lin C, Chi Y, Jin Y, Jiang X, Buekens A, Zhang Q, Chen J. Molten salt oxidation of organic hazardous waste with high salt content. WASTE MANAGEMENT & RESEARCH : THE JOURNAL OF THE INTERNATIONAL SOLID WASTES AND PUBLIC CLEANSING ASSOCIATION, ISWA 2018; 36:140-148. [PMID: 29307304 DOI: 10.1177/0734242x17748364] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Organic hazardous waste often contains some salt, owing to the widespread use of alkali salts during industrial manufacturing processes. These salts cause complications during the treatment of this type of waste. Molten salt oxidation is a flameless, robust thermal process, with inherent capability of destroying the organic constituents of wastes, while retaining the inorganic ingredients in the molten salt. In the present study, molten salt oxidation is employed for treating a typical organic hazardous waste with a high content of alkali salts. The hazardous waste derives from the production of thiotriazinone. Molten salt oxidation experiments have been conducted using a lab-scale molten salt oxidation reactor, and the emissions of CO, NO, SO2, HCl and dioxins are studied. Impacts are investigated from the composition of the molten salts, the types of feeding tube, the temperature of molten carbonates and the air factor. Results show that the waste can be oxidised effectively in a molten salt bath. Temperature of molten carbonates plays the most important role. With the temperature rising from 600 °C to 750 °C, the oxidation efficiency increases from 91.1% to 98.3%. Compared with the temperature, air factor has but a minor effect, as well as the composition of the molten salts and the type of feeding tube. The molten carbonates retain chlorine with an efficiency higher than 99.9% and the emissions of dioxins are below 8 pg TEQ g-1 sample. The present study shows that molten salt oxidation is a promising alternative for the disposal of organic hazardous wastes containing a high salt content.
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Affiliation(s)
- Chengqian Lin
- 1 State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, P.R China
| | - Yong Chi
- 1 State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, P.R China
| | - Yuqi Jin
- 1 State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, P.R China
| | - Xuguang Jiang
- 1 State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, P.R China
| | - Alfons Buekens
- 1 State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, P.R China
- 2 Chemical Engineering Department, Vrije University Brussel, Brussels, Belgium
| | - Qi Zhang
- 3 Zhejiang Best Energy and Environment Co. Ltd, Hangzhou, P.R China
| | - Jian Chen
- 3 Zhejiang Best Energy and Environment Co. Ltd, Hangzhou, P.R China
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Wang L, Li Q, Li Y, Sun X, Li J, Shen J, Han W, Wang L. A novel approach for recovery of metals from waste printed circuit boards and simultaneous removal of iron from steel pickling waste liquor by two-step hydrometallurgical method. WASTE MANAGEMENT (NEW YORK, N.Y.) 2018; 71:411-419. [PMID: 29030122 DOI: 10.1016/j.wasman.2017.10.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 09/17/2017] [Accepted: 10/03/2017] [Indexed: 06/07/2023]
Abstract
Waste printed circuit boards (WPCBs) and steel pickling waste liquor (SPWL) have received extensive attention in recent years because of its harmfulness and resource. In this work, two-step leaching process was carried out by using SPWL as the leaching agent. A series of continuously domesticated bacteria were used for bioleaching and the bacterial strain was identified as Acidithiobacillus ferrooxidans (A. ferrooxidans) by 16S rDNA gene sequence analysis. The vast majority of the metals in WPCBs were recovered by two-step leaching, such as Cu, Pb, Zn, Sn, Al, Ni. Meanwhile, a large amount of iron was removed from SPWL, which greatly reduces the burden of the subsequent treatment. Pulp density and pH were optimized to achieve maximum recovery of copper and simultaneous removal of iron in bioleaching. It was found that the optimum conditions were pulp density 60 g/L and pH 0.5-1.0. Nearly 100% of copper was recovered and 51.94% of iron was removed under optimum conditions. The kinetic experiments showed that the rate of copper leaching was controlled by external diffusion rather than internal diffusion, because the acidic environment of the leachate prevented the formation of the precipitate and maintained it in a smaller size.
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Affiliation(s)
- Lili Wang
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu Province, China
| | - Qiao Li
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu Province, China
| | - Yi Li
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu Province, China
| | - Xiuyun Sun
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu Province, China.
| | - Jiansheng Li
- Engineering Research Center for Chemical Pollution Control (Ministry of Education), School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu Province, China
| | - Jinyou Shen
- Engineering Research Center for Chemical Pollution Control (Ministry of Education), School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu Province, China
| | - Weiqing Han
- Engineering Research Center for Chemical Pollution Control (Ministry of Education), School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu Province, China
| | - Lianjun Wang
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu Province, China; Engineering Research Center for Chemical Pollution Control (Ministry of Education), School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu Province, China
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42
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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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Xiu FR, Weng H, Qi Y, Yu G, Zhang Z, Zhang FS, Chen M. A novel recovery method of copper from waste printed circuit boards by supercritical methanol process: Preparation of ultrafine copper materials. WASTE MANAGEMENT (NEW YORK, N.Y.) 2017; 60:643-651. [PMID: 27876566 DOI: 10.1016/j.wasman.2016.11.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Revised: 10/31/2016] [Accepted: 11/01/2016] [Indexed: 06/06/2023]
Abstract
In this study, supercritical methanol (SCM) process was successfully used for the preparation of ultrafine copper materials from waste printed circuit boards (PCBs) after nitric acid pretreatment. Waste PCBs were pretreated twice in nitric acid. Sn and Pb were recovered by the first nitric acid pretreatment. The leach liquor with a high concentration of copper ions after the second nitric acid leaching was subjected to SCM process. The mixture of Cu and Cu2O with poor uniformity of particle size was formed due to the effect of ferric iron contained in the leach liquor of waste PCBs, while more uniform and spherical Cu particles with high monodispersity and smaller size could be prepared after the removal of Fe. The size of Cu particles increased obviously with the decline of SCM temperature, and particles became highly aggregated when the reaction temperature decreased to 300°C. The size of Cu particles decreased markedly with the decrease of initial concentration of copper ion in the leach liquor of waste PCBs. It is believed that the process developed in this study is simple and practical for the preparation of ultrafine copper materials from waste PCBs with the aim of recycling these waste resources as a high value-added product.
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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
| | - Mengjun Chen
- Key Laboratory of Solid Waste Treatment and Resource Recycle (SWUST), Ministry of Education, Southwest University of Science and Technology, Mianyang 621010, People's Republic of China
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Awasthi AK, Zeng X, Li J. Integrated bioleaching of copper metal from waste printed circuit board-a comprehensive review of approaches and challenges. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:21141-21156. [PMID: 27678000 DOI: 10.1007/s11356-016-7529-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 08/26/2016] [Indexed: 05/24/2023]
Abstract
Waste electrical and electronic equipment (e-waste) is the most rapidly growing waste stream in the world, and the majority of the residues are openly disposed of in developing countries. Waste printed circuit boards (WPCBs) make up the major portion of e-waste, and their informal recycling can cause environmental pollution and health risks. Furthermore, the conventional disposal and recycling techniques-mechanical treatments used to recover valuable metals, including copper-are not sustainable in the long term. Chemical leaching is rapid and efficient but causes secondary pollution. Bioleaching is a promising approach, eco-friendly and economically feasible, but it is slower process. This review considers the recycling potential of microbes and suggests an integrated bioleaching approach for Cu extraction and recovery from WPCBs. The proposed recycling system should be more effective, efficient and both technically and economically feasible.
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Affiliation(s)
- Abhishek Kumar Awasthi
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Rm. 805, Sino-Italian Environment and Energy Efficient Building, Beijing, 100084, China
| | - Xianlai Zeng
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Rm. 805, Sino-Italian Environment and Energy Efficient Building, Beijing, 100084, China
| | - Jinhui Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Rm. 805, Sino-Italian Environment and Energy Efficient Building, Beijing, 100084, China.
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Cayumil R, Khanna R, Rajarao R, Mukherjee PS, Sahajwalla V. Concentration of precious metals during their recovery from electronic waste. WASTE MANAGEMENT (NEW YORK, N.Y.) 2016; 57:121-130. [PMID: 26712661 DOI: 10.1016/j.wasman.2015.12.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Revised: 12/02/2015] [Accepted: 12/05/2015] [Indexed: 05/22/2023]
Abstract
The rapid growth of electronic devices, their subsequent obsolescence and disposal has resulted in electronic waste (e-waste) being one of the fastest increasing waste streams worldwide. The main component of e-waste is printed circuit boards (PCBs), which contain substantial quantities of precious metals in concentrations significantly higher than those typically found in corresponding ores. The high value and limited reserves of minerals containing these metals makes urban mining of precious metals very attractive. This article is focused on the concentration and recovery of precious metals during pyro-metallurgical recycling of waste PCBs. High temperature pyrolysis was carried out for ten minutes in a horizontal tube furnace in the temperature range 800-1350°C under Argon gas flowing at 1L/min. These temperatures were chosen to lie below and above the melting point (1084.87°C) of copper, the main metal in PCBs, to study the influence of its physical state on the recovery of precious metals. The heat treatment of waste PCBs resulted in two different types of solid products, namely a carbonaceous non-metallic fraction (NMFs) and metallic products, composed of copper rich foils and/or droplets and tin-lead rich droplets and some wires. Significant proportions of Ag, Au, Pd and Pt were found concentrated within two types of metallic phases, with very limited quantities retained by the NMFs. This process was successful in concentrating several precious metals such as Ag, Au, Pd and Pt in a small volume fraction, and reduced volumes for further processing/refinement by up to 75%. The amounts of secondary wastes produced were also minimised to a great extent. The generation of precious metals rich metallic phases demonstrates high temperature pyrolysis as a viable approach towards the recovery of precious metals from e-waste.
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Affiliation(s)
- R Cayumil
- Centre for Sustainable Materials Research and Technology (SMaRT), School of Materials Science and Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - R Khanna
- Centre for Sustainable Materials Research and Technology (SMaRT), School of Materials Science and Engineering, The University of New South Wales, Sydney, NSW 2052, Australia.
| | - R Rajarao
- Centre for Sustainable Materials Research and Technology (SMaRT), School of Materials Science and Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
| | - P S Mukherjee
- Advanced Materials Technology Department, CSIR-Institute of Minerals and Materials Technology, Bhubaneswar 751013, India
| | - V Sahajwalla
- Centre for Sustainable Materials Research and Technology (SMaRT), School of Materials Science and Engineering, The University of New South Wales, Sydney, NSW 2052, Australia
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Kaya M. Recovery of metals and nonmetals from electronic waste by physical and chemical recycling processes. WASTE MANAGEMENT (NEW YORK, N.Y.) 2016; 57:64-90. [PMID: 27543174 DOI: 10.1016/j.wasman.2016.08.004] [Citation(s) in RCA: 215] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Revised: 08/02/2016] [Accepted: 08/04/2016] [Indexed: 05/11/2023]
Abstract
This paper reviews the existing and state of art knowledge for electronic waste (e-waste) recycling. Electrical and/or electronic devices which are unwanted, broken or discarded by their original users are known as e-waste. The main purpose of this article is to provide a comprehensive review of e-waste problem, strategies of e-waste management and various physical, chemical and metallurgical e-waste recycling processes, their advantages and disadvantages towards achieving a cleaner process of waste utilization, with special attention towards extraction of both metallic values and nonmetallic substances. The hazards arise from the presence of heavy metals Hg, Cd, Pb, etc., brominated flame retardants (BFRs) and other potentially harmful substances in e-waste. Due to the presence of these substances, e-waste is generally considered as hazardous waste and, if improperly managed, may pose significant human and environmental health risks. This review describes the potential hazards and economic opportunities of e-waste. Firstly, an overview of e-waste/printed circuit board (PCB) components is given. Current status and future perspectives of e-waste/PCB recycling are described. E-waste characterization, dismantling methods, liberation and classification processes are also covered. Manual selective dismantling after desoldering and metal-nonmetal liberation at -150μm with two step crushing are seen to be the best techniques. After size reduction, mainly physical separation processes employing gravity, electrostatic, magnetic separators, froth floatation, etc. have been critically reviewed here for separation of metals and nonmetals, along with useful utilizations of the nonmetallic materials. The recovery of metals from e-waste material after physical separation through pyrometallurgical, hydrometallurgical or biohydrometallurgical routes is also discussed along with purification and refining. Suitable PCB recycling flowsheets for industrial applications are also given. It seems that hydrometallurgical route will be a key player in the base and precious metals recoveries from e-waste. E-waste recycling will be a very important sector in the near future from economic and environmental perspectives. Recycling technology aims to take today's waste and turn it into conflict-free, sustainable polymetallic secondary resources (i.e. Urban Mining) for tomorrow. Recycling technology must ensure that e-waste is processed in an environmentally friendly manner, with high efficiency and lowered carbon footprint, at a fraction of the costs involved with setting multibillion dollar smelting facilities. Taking into consideration our depleting natural resources, this Urban Mining approach offers quite a few benefits. This results in increased energy efficiency and lowers demand for mining of new raw materials.
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Affiliation(s)
- Muammer Kaya
- Mining Engineering Department, Eskişehir Osmangazi University, Eskişehir, Turkey.
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Liu J, Guo X, Liu Y, Jiang X, Huang G. Effects of alkali-salt fusion process on recovery of amphoteric metals from waste printed circuit boards. ACTA ACUST UNITED AC 2016. [DOI: 10.1080/03719553.2016.1209921] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- J. Liu
- School of Metallurgy & Environment, Central South University, Changsha 410083, China
| | - X. Guo
- School of Metallurgy & Environment, Central South University, Changsha 410083, China
| | - Y. Liu
- School of Metallurgy & Environment, Central South University, Changsha 410083, China
| | - X. Jiang
- School of Metallurgy & Environment, Central South University, Changsha 410083, China
| | - G. Huang
- School of Metallurgy & Environment, Central South University, Changsha 410083, China
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Wang C, Zhao W, Wang J, Chen L, Luo CJ. An innovative approach to predict technology evolution for the desoldering of printed circuit boards: A perspective from China and America. WASTE MANAGEMENT & RESEARCH : THE JOURNAL OF THE INTERNATIONAL SOLID WASTES AND PUBLIC CLEANSING ASSOCIATION, ISWA 2016; 34:491-501. [PMID: 27067430 DOI: 10.1177/0734242x16640330] [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: 06/05/2023]
Abstract
The printed circuit boards basis of electronic equipment have seen a rapid growth in recent years and played a significant role in modern life. Nowadays, the fact that electronic devices upgrade quickly necessitates a proper management of waste printed circuit boards. Non-destructive desoldering of waste printed circuit boards becomes the first and the most crucial step towards recycling electronic components. Owing to the diversity of materials and components, the separation process is difficult, which results in complex and expensive recovery of precious materials and electronic components from waste printed circuit boards. To cope with this problem, we proposed an innovative approach integrating Theory of Inventive Problem Solving (TRIZ) evolution theory and technology maturity mapping system to forecast the evolution trends of desoldering technology of waste printed circuit boards. This approach can be applied to analyse the technology evolution, as well as desoldering technology evolution, then research and development strategy and evolution laws can be recommended. As an example, the maturity of desoldering technology is analysed with a technology maturity mapping system model. What is more, desoldering methods in different stages are analysed and compared. According to the analysis, the technological evolution trends are predicted to be 'the law of energy conductivity' and 'increasing the degree of idealisation'. And the potential technology and evolutionary state of waste printed circuit boards are predicted, offering reference for future waste printed circuit boards recycling.
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Affiliation(s)
- Chen Wang
- School of Manufacturing Science & Engineering, Sichuan University, Chengdu, China
| | - Wu Zhao
- School of Manufacturing Science & Engineering, Sichuan University, Chengdu, China
| | - Jie Wang
- School of Manufacturing Science & Engineering, Sichuan University, Chengdu, China
| | - Ling Chen
- Division of Production and Materials Engineering, Lund University, Lund, Sweden
| | - Chun-Jing Luo
- School of Manufacturing Science & Engineering, Sichuan University, Chengdu, China
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A simple and nearly-closed cycle process for recycling copper with high purity from end life printed circuit boards. Sep Purif Technol 2016. [DOI: 10.1016/j.seppur.2016.03.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Stuhlpfarrer P, Luidold S, Antrekowitsch H. Recycling of waste printed circuit boards with simultaneous enrichment of special metals by using alkaline melts: A green and strategically advantageous solution. JOURNAL OF HAZARDOUS MATERIALS 2016; 307:17-25. [PMID: 26775099 DOI: 10.1016/j.jhazmat.2015.12.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Revised: 12/01/2015] [Accepted: 12/07/2015] [Indexed: 06/05/2023]
Abstract
The increasing consumption of electric and electronic equipment has led to a rise in toxic waste. To recover the metal fraction, a separation of the organic components is necessary because harmful substances such as chlorine, fluorine and bromine cause ecological damage, for example in the form of dioxins and furans at temperature above 400°C. Hence, an alternative, environmentally friendly approach was investigated exploiting that a mixture of caustic soda and potassium hydroxide in eutectic composition melts below 200°C, enabling a fast cracking of the long hydrocarbon chains. The trials demonstrate the removal of organic compounds without a loss of copper and precious metals, as well as a suppressed formation of hazardous off-gases. In order to avoid an input of alkaline elements into the furnace and ensuing problems with refractory materials, a washing step generates a sodium and potassium hydroxide solution, in which special metals like indium, gallium and germanium are enriched. Their concentrations facilitate the recovery of these elements, because otherwise they become lost in the typical recycling processes. The aim of this work was to find an environmental solution for the separation of plastics and metals as well as a strategically important answer for the recycling of printed circuit boards and mobile phones.
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Affiliation(s)
- Philipp Stuhlpfarrer
- Montanuniversitaet Leoben, Chair of Nonferrous Metallurgy, Department of Metallurgy, Franz-Josef-Straße 18, 8700 Leoben, Austria.
| | - Stefan Luidold
- Montanuniversitaet Leoben, Chair of Nonferrous Metallurgy, Department of Metallurgy, Franz-Josef-Straße 18, 8700 Leoben, Austria
| | - Helmut Antrekowitsch
- Montanuniversitaet Leoben, Chair of Nonferrous Metallurgy, Department of Metallurgy, Franz-Josef-Straße 18, 8700 Leoben, Austria
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