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Wu Y, Tian Z, Li B, Gu J, Yuan H, Liu W, Ge H. Quantum chemical study on the catalytic debromination mechanism of brominated epoxy resins. JOURNAL OF HAZARDOUS MATERIALS 2024; 465:132943. [PMID: 38141316 DOI: 10.1016/j.jhazmat.2023.132943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 10/06/2023] [Accepted: 11/04/2023] [Indexed: 12/25/2023]
Abstract
The study employed Density Functional Theory (DFT) to investigate the catalytic debromination mechanism of brominated epoxy resins (BERs) by iron (Fe) and copper (Cu) catalysts. By introducing electric field (EF), intramolecular electron transfer and polarization effects on BERs debromination were explored and experimentally validated. Results indicated that the bond dissociation energy (BDE) of the C-Br bond was 312.27 kJ/mol without catalysis, while with Fe, Cu, and EF, it was 114.47 kJ/mol, 94.85 kJ/mol, and 292.59 kJ/mol, respectively, enhancing reactivity. EF parallel to the C-Br bond and oriented toward the C atom, altered electrostatic potential and dipole moment around C-Br bond, leading to 68.60% and 50.19% increment in electronic contribution difference and molecule polarity, respectively, thereby reducing the C-Br BDE. Fe and Cu facilitated electron transfers with BERs, inducing reactions between their negative electrostatic potentials and Br's positive potential, changing electron sharing, resulting in 19.87% and 12.11% increase in polarity, respectively, and further BDE reduction. Structural modifications by the EF and catalysts also intensified van der Waals forces with bromine atoms and decreased spatial hindrance, collectively making C-Br bond breakage easier. Experiments revealed the EF enhanced BERs' debromination efficiency but hindered Fe/Cu's catalysis at lower temperatures.
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Affiliation(s)
- Yufeng Wu
- Institute of Circular Economy, Beijing University of Technology, Beijing 100124, PR China; Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, PR China
| | - Zhongxun Tian
- Institute of Circular Economy, Beijing University of Technology, Beijing 100124, PR China; Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, PR China
| | - Bin Li
- Institute of Circular Economy, Beijing University of Technology, Beijing 100124, PR China; Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, PR China.
| | - Jing Gu
- Guangzhou Institute of Energy Conversion, The Chinese Academy of Sciences, Guangzhou 510070, PR China
| | - Haoran Yuan
- Guangzhou Institute of Energy Conversion, The Chinese Academy of Sciences, Guangzhou 510070, PR China
| | - Weijun Liu
- School of Mechanical and Automotive Engineering, Shanghai University of Engineering Science, Shanghai 201620, PR China
| | - Huijie Ge
- Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, PR China
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2
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Liu K, Wang M, Tsang DCW, Liu L, Tan Q, Li J. Facile path for copper recovery from waste printed circuit boards via mechanochemical approach. JOURNAL OF HAZARDOUS MATERIALS 2022; 440:129638. [PMID: 35933860 DOI: 10.1016/j.jhazmat.2022.129638] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 07/13/2022] [Accepted: 07/17/2022] [Indexed: 06/15/2023]
Abstract
Recycling copper (Cu0) from waste printed circuit boards (PCBs) is a prevalent challenge. Here, we propose a new pathway and reveal mechanisms for recovering Cu0 from waste PCBs via a mechanochemical approach. The successful application of mechanical force avoids using inorganic acid in the Cu0 recovery process. Our work demonstrates that ferric chloride (FeCl3) was superior to ferric sulfate and ferric nitrate as a solid-phase reagent for Cu0 recovery due to chloride complexation. Under the induction of mechanical force, the Cu0 in the waste PCBs was oxidized by Fe3+ and complexed by Cl¯ to form a meta-stable cuprous chloride, which was susceptible to leaching in an acidic liquid-phase system constructed by hydrolysis of ferric salt. Further mechanism analysis reveals that in the mechanochemical solid-phase reaction, Cu0, metallic impurities, metal oxides, and carbon materials from waste PCBs could also reduce Fe3+ to Fe2+. The optimum conditions for Cu0 recovery from waste PCB powder with FeCl3 as a solid-phase reagent were: rotational speed of 500 rpm, Cu0:Fe3+ molar ratio of 1:20, and reaction time of 120 min, achieving the highest recovery of 99.6 wt%. This study presents a facile path for Cu0 recovery from waste PCBs for resource circulation.
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Affiliation(s)
- Kang Liu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China; Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Mengmeng Wang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Daniel C W Tsang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China; Research Centre for Environmental Technology and Management, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China
| | - Lili Liu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Quanyin Tan
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
| | - Jinhui Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China.
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3
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Gao M, Bai L, Li X, Wang S, Song Z. Effects of polystyrene nanoplastics on lead toxicity in dandelion seedlings. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 306:119349. [PMID: 35487467 DOI: 10.1016/j.envpol.2022.119349] [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: 11/02/2021] [Revised: 04/19/2022] [Accepted: 04/20/2022] [Indexed: 06/14/2023]
Abstract
Increasing rates of commercialization and industrialization have led to the comprehensive evaluation of toxic effects of microplastics on crop plants. However, research on the impact of functionalized polystyrene nanoplastics on the toxicity of heavy metals remains limited. This study investigated the effects of polystyrene, carboxy-modified polystyrene, and amino-modified polystyrene on lead (Pb) toxicity in dandelion seedlings. The results showed that carboxy -modified polystyrene with a negative charge absorbed more Pb2+ than polystyrene and amino-modified polystyrene, and their maximum adsorption amounts were 5.328, 0.247, and 0.153 μg g-1, respectively. The hydroponic experiment demonstrated that single amino-modified polystyrene was more toxic to dandelion seedlings than polystyrene and carboxy-modified polystyrene. The presence of Pb2+ was found to increase antioxidant enzymes (superoxide dismutase and catalase) and non-antioxidant enzymes (glutathione and ascorbic acid) activities in response to excessive reactive oxygen species in dandelion leaves and roots treated with polystyrene and carboxy-modified polystyrene, while it did not change much when amino-modified polystyrene was added. Interestingly, compared with single Pb2+, the addition of amino-modified polystyrene with positive charges induced an obvious decrease in the above parameters; however, they declined slightly in the treatments with polystyrene and carboxy-modified polystyrene despite a stronger adsorption capacity for Pb2+. Similarly, the bioactive compounds, including flavonoids, polyphenols, and polysaccharides in dandelion, showed a scavenging effect on O2- and H2O2, thereby inhibiting the accumulation and reducing medicinal properties. This study found that the effects of microplastics on the uptake, distribution, and toxicity of heavy metals depended on the nanoparticle surface charge.
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Affiliation(s)
- Minling Gao
- Department of Civil and Environmental Engineering, Shantou University, No. 243 Daxue Road, Shantou, Guangdong Province, 515063, China
| | - Linsen Bai
- Department of Civil and Environmental Engineering, Shantou University, No. 243 Daxue Road, Shantou, Guangdong Province, 515063, China
| | - Xitong Li
- Department of Civil and Environmental Engineering, Shantou University, No. 243 Daxue Road, Shantou, Guangdong Province, 515063, China
| | - Shengli Wang
- School of Environmental Science and Engineering, Tiangong University, No. 399 Binshui West Road, Xiqing District, Tianjin, 300387, China
| | - Zhengguo Song
- Department of Civil and Environmental Engineering, Shantou University, No. 243 Daxue Road, Shantou, Guangdong Province, 515063, China.
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4
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Xian Y, Tao Y, Ma F, Zhou Y. Recovery of Metals from Heat-Treated Printed Circuit Boards via an Enhanced Gravity Concentrator and High-Gradient Magnetic Separator. MATERIALS (BASEL, SWITZERLAND) 2021; 14:4566. [PMID: 34443092 PMCID: PMC8399359 DOI: 10.3390/ma14164566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 07/31/2021] [Accepted: 08/03/2021] [Indexed: 11/16/2022]
Abstract
The recovery and reuse of waste printed circuit boards (PCBs) has attracted more and more attention from global researchers, as recycling of waste PCB metals is of great significance to the rational utilization of metal material resources. This study puts forward a clean and economical method in which enhanced gravity separation and wet high-gradient magnetic separation were combined to recover waste PCBs with heat treatment at a temperature of 240 °C. The heat treatment could improve the metal liberation effect of the PCBs, and the thermal behavior was measured by thermogravimetric analysis (TGA). The pyrolysis of the non-metal fraction (NMF) began around 300 °C, and the glass transition temperature of epoxy resin was 135.17 °C. The enhanced gravity separation technique was used for the separation of metals and NMF under the compound force field. The metals grade of the gravity concentrates fraction (GRF) was 82.97% under the optimal conditions, and the metals recovery reached 90.55%. A wet high-gradient magnetic separator was applied to classify the GRF into magnetic (MA) and non-magnetic (NMA) fractions, which could achieve iron and copper enrichment. After the three stages combined process, the copper and iron grades of the NMA and MA fractions were 70.17% and 73.42%, and the recovery reached 74.02% and 78.11%, respectively.
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Affiliation(s)
- Yushuai Xian
- Key Laboratory of Coal Processing and Efficient Utilization of Ministry of Education, China University of Mining and Technology, Xuzhou 221116, China; (Y.X.); (Y.Z.)
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, China
| | - Youjun Tao
- Key Laboratory of Coal Processing and Efficient Utilization of Ministry of Education, China University of Mining and Technology, Xuzhou 221116, China; (Y.X.); (Y.Z.)
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, China
| | - Fangyuan Ma
- Key Laboratory of Coal Processing and Efficient Utilization of Ministry of Education, China University of Mining and Technology, Xuzhou 221116, China; (Y.X.); (Y.Z.)
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, China
| | - You Zhou
- Key Laboratory of Coal Processing and Efficient Utilization of Ministry of Education, China University of Mining and Technology, Xuzhou 221116, China; (Y.X.); (Y.Z.)
- School of Metallurgy and Environment, Central South University, Changsha 410000, China
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Qin B, Lin M, Chen X, Xu Z, Fu Y, Hu J, Ruan J. A novel approach for determining the accurate debromination time in the ball-milling process of nonmetallic particles from waste printed circuit boards by computation. JOURNAL OF HAZARDOUS MATERIALS 2021; 410:124611. [PMID: 33246811 DOI: 10.1016/j.jhazmat.2020.124611] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 11/03/2020] [Accepted: 11/16/2020] [Indexed: 06/12/2023]
Abstract
Ball-milling technology is adopted for the debromination of nonmetallic particles of waste printed circuit boards. During the ball-milling process, too short ball-milling time causes insufficient debromination. Excessive ball-milling leads to the waste of resources and the destruction of the main structure of nonmetallic particles resin, unfavorable for the secondary utilization. However, how to determine debromination time of nonmetallic particles in ball-milling process has not been detailed studied. In this study, the ball-milling energy was coupled with the degradation energy of pentabromodiphenyl ether molecule to compute the time for each chemical bond to break. The ball-milling model was used to accurately compute effective mechanical ball-milling energy (1.234 × 10-3 J) generated by a single collision. The average bond energies of C‒O bond, C‒Br bond and C‒H bond (261.24, 302.05 and 489.50 kJ/mol) were analyzed by density functional theory. Under the conditions of 220 r/min and 1.2 g nonmetallic particles and NZVI (4:1). The C‒O bond, C‒Br bond, and C‒H bond fractured completely in turn at 2.25 h, 7.23 h (optimal debromination time), and 11.72 h. Based on the analysis of debromination pathways, it inferred that H2O, HBr, CH3Br, CH4, FeBr2, and graphite were generated. This paper develops a novel idea of the schedule of debromination time of nonmetallic particles, contributing to the directional removal of organic pollutants by ball-milling.
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Affiliation(s)
- Baojia Qin
- School of Environmental Science and Engineering, Sun Yat-Sen University, 135 Xingang Xi Road, Guangzhou 510275, 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
| | - Xi Chen
- School of Environmental Science and Engineering, Sun Yat-Sen University, 135 Xingang Xi Road, Guangzhou 510275, People's Republic of China
| | - Zhenming Xu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, People's Republic of China
| | - Yonggao Fu
- China National Electric Apparatus Research Institute Co., Ltd., People's Republic of China
| | - Jiaqi Hu
- China National Electric Apparatus Research Institute Co., Ltd., 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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Huang K, Zheng J, Yuan W, Wang X, Song Q, Li Y, Crittenden JC, Wang L, Wang J. Microwave-assisted chemical recovery of glass fiber and epoxy resin from non-metallic components in waste printed circuit boards. WASTE MANAGEMENT (NEW YORK, N.Y.) 2021; 124:8-16. [PMID: 33592321 DOI: 10.1016/j.wasman.2021.01.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 11/21/2020] [Accepted: 01/08/2021] [Indexed: 06/12/2023]
Abstract
An efficient, microwave-assisted chemical recovery approach for epoxy resin and glass fiber from non-metallic components (NMC) in waste printed circuit boards (WPCBs) for resource reutilization was developed in this research. HNO3 was selected as the chemical reagent because epoxy resin has low corrosion resistance to HNO3. The influence of reaction parameters such as reaction time, temperature, concentration of HNO3, liquid-solid ratio, and power of the microwave synthesizer on the separation efficiency of NMC (epoxy resin and glass fiber) and the reaction mechanism were investigated. The physical and chemical properties of NMC, reaction solvent, and decomposed products were analyzed using energy dispersive X-ray Spectroscopy (SEM-EDX) and Fourier transform infrared spectroscopy (FT-IR). The results showed that up to 88.42% of epoxy resin and glass fiber ((5 g) 10 mL/g) could be separated under the action of 300 W microwave power at 95 ℃ for 12 h and a HNO3 concentration of 7 mol/L. During the reaction, C-N bonds formed by the crosslinking agent and the three-dimensional network structure of the thermosetting epoxy resin were destroyed. The carbon chain structure and chemical properties of epoxy resin did not change significantly and the functional groups of ethyl acetate maintained the chemical structure before and after the reaction. This uncomplicated and efficient inorganic acid chemical microwave-assisted process holds promise for use as a feasible recovery technology for epoxy resin and glass fibers in NMC. The proposed process is particularly appealing because of its high selectivity, considerable economic advantages, and environmental benefits.
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Affiliation(s)
- Kaiyou Huang
- Shanghai Collaborative Innovation Centre for WEEE Recycling, Shanghai Polytechnic University, Shanghai 201209, China
| | - Jiongli Zheng
- Shanghai Collaborative Innovation Centre for WEEE Recycling, Shanghai Polytechnic University, Shanghai 201209, China
| | - Wenyi Yuan
- Shanghai Collaborative Innovation Centre for WEEE Recycling, Shanghai Polytechnic University, Shanghai 201209, China
| | - Xiaoyan Wang
- Shanghai Collaborative Innovation Centre for WEEE Recycling, Shanghai Polytechnic University, Shanghai 201209, China
| | - Qingbin Song
- Macau Environmental Research Institute, Macau University of Science and Technology, Macau, China
| | - Ying Li
- School of Environment and Safety Engineering, North University of China, Taiyuan 030051, China
| | - John C Crittenden
- Brook Byers Institute for Sustainable Systems and the Department of Civil and Environmental Engineering, Atlanta 30332, United States
| | - Lincai Wang
- Shanghai Collaborative Innovation Centre for WEEE Recycling, Shanghai Polytechnic University, Shanghai 201209, China
| | - Jingwei Wang
- Shanghai Collaborative Innovation Centre for WEEE Recycling, Shanghai Polytechnic University, Shanghai 201209, China
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7
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Huang K, Yuan W, Yang Y, Wang X, Xie J, Duan H, Li X, Wang L, Zhang C, Bai J, Wang J, Crittenden JC. Dissolution and separation of non-metallic powder from printed circuit boards by using chloride solvent. WASTE MANAGEMENT (NEW YORK, N.Y.) 2021; 123:60-68. [PMID: 33561771 DOI: 10.1016/j.wasman.2021.01.024] [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: 10/19/2020] [Revised: 01/05/2021] [Accepted: 01/18/2021] [Indexed: 06/12/2023]
Abstract
Non-metallic components (NMC) in waste printed circuit boards (WPCBs) are made of the thermosetting epoxy resin and glass fiber, which has been a research concern in the waste recycling area. The recycling of thermosetting epoxy resin is a serious challenge due to their permanent cross-linked structure. An efficient approach to chemical recycling of epoxy resin for resource reutilization was developed in this research. ZnCl2/CH3COOH aqueous solution was selected as catalysts system to decompose epoxy resin under a mild reaction condition. The influence of reaction parameters such as reaction temperature, time, liquid-solid ratio and ZnCl2 amount on the decomposition efficiency of epoxy resin and reaction mechanism were investigated. The physical and chemical properties of NMC, reaction solvent and decomposed products were analyzed using scanning electron microscope(SEM), Fourier transform infrared spectroscopy (FT-IR) and Gas chromatography-mass spectrometry (GC-MS). Results showed that up to 81.85% of epoxy resin could be dissolved by using a temperature of 190 °C during 8 h with a mixture of acetic acid (15 wt%): ZnCl2 (5 g) 20 mL/g. Incompletely coordinated zinc ions enables the cleavage of CN, CBr and CO bonds in the thermosetting brominated epoxy resin, which was mainly converted to phenol, 2-Bromophenol and 2, 4-Dibromophenol with high resource value. And the functional groups of ethyl acetate and acetic acid maintained chemical structure before and after reaction. This research provided a practical approach to the dissolution and reutilization of NMC in WPCBs.
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Affiliation(s)
- Kaiyou Huang
- Shanghai Collaborative Innovation Centre for WEEE Recycling, Shanghai Polytechnic University, Shanghai 201209, China
| | - Wenyi Yuan
- Shanghai Collaborative Innovation Centre for WEEE Recycling, Shanghai Polytechnic University, Shanghai 201209, China.
| | - Yuhan Yang
- Shanghai Collaborative Innovation Centre for WEEE Recycling, Shanghai Polytechnic University, Shanghai 201209, China
| | - Xiaoyan Wang
- Shanghai Collaborative Innovation Centre for WEEE Recycling, Shanghai Polytechnic University, Shanghai 201209, China
| | - Junying Xie
- Shanghai Collaborative Innovation Centre for WEEE Recycling, Shanghai Polytechnic University, Shanghai 201209, China
| | - Huabo Duan
- College of Civil Engineering, Shenzhen University, Shenzhen 518060, China
| | - Xiaodan Li
- China Northeast Municipal Engineering Design and Research Institute Co. Ltd, Changchun 130021, China
| | - Lincai Wang
- Shanghai Collaborative Innovation Centre for WEEE Recycling, Shanghai Polytechnic University, Shanghai 201209, China
| | - Chenglong Zhang
- Shanghai Collaborative Innovation Centre for WEEE Recycling, Shanghai Polytechnic University, Shanghai 201209, China
| | - Jianfeng Bai
- Shanghai Collaborative Innovation Centre for WEEE Recycling, Shanghai Polytechnic University, Shanghai 201209, China
| | - Jingwei Wang
- Shanghai Collaborative Innovation Centre for WEEE Recycling, Shanghai Polytechnic University, Shanghai 201209, China
| | - John C Crittenden
- Brook Byers Institute for Sustainable Systems and the Department of Civil and Environmental Engineering, Atlanta 30332, United States
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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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Liu F, Wan B, Wang F, Chen W. Effect of thermal shock process on the microstructure and peel resistance of single-sided copper clad laminates used in waste printed circuit boards. JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION (1995) 2019; 69:1490-1502. [PMID: 31566485 DOI: 10.1080/10962247.2019.1674751] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 08/21/2019] [Accepted: 09/13/2019] [Indexed: 06/10/2023]
Abstract
Efficient pre-processing is essential to the mechanical recovery of waste printed circuit boards (WPCBs). In this work, a thermal shock pretreatment was utilized to damage the interface between metals and nonmetals of single-sided copper clad laminates (SSCCLs), which are usually employed as the base material of printed circuit boards (PCBs). The effects of three thermal shock treatment parameters-i.e., peak temperature, holding time, and thermal shock cycle times-on the adhesion strength of SSCCLs were evaluated by orthogonal experiments. Microstructures and peel resistance of SSCCLs before and after thermal shock were characterized by scanning electron microscopy (SEM) and 90° peel test, respectively. Our results showed that the impact of three major factors that influence liberation efficiency was in the sequence of peak temperature > shock cycle times > holding time. Furthermore, the optimal thermal shock level could be achieved when the peak temperature was 300°C with the soaking time of 30 min and three cycle times. In the meantime, the corresponding peel strength of the SSCCLs (0.065 N/mm) was sharply decreased by 94% in comparison with those without thermal shock treatment. The manual dismantling experimental data verified the good feasibility of the optimal thermal shock process, suggesting that the copper foil could be readily dismantled from the substrate by hand after pretreatment, with a successful separation rate of 100% and a peeling efficiency of ~ 30 seconds per piece. Therefore, the optimal thermal shock process could notably improve liberation of metals and nonmetals, which would be helpful for efficient recycling of WPCBs.Implications: The interface between copper foil and laminate dielectric in a PCB can be weakened significantly via efficient thermal shock method. Thus, a good liberation could be achieved after thermal shock. In this work, a manual peeling of copper foil from the SSCCL substrates was achieved efficiently after optimal thermal shock pretreatment, confirming the feasibility of a shorter process of metal recovery from scrap SSCCLs without pulverization. The results will be useful for the pretreatment of recovery of the WPCBs.
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Affiliation(s)
- Fangfang Liu
- Guangdong Key Laboratory for Advanced Metallic Materials Processing, South China University of Technology, Guangzhou, Guangdong, People's Republic of China
- Department of Electromechanical Engineering, Guangdong University of Science and Technology, Dongguan, Guangdong, People's Republic of China
| | - Bingbing Wan
- School of Materials Science and Engineering, Dongguan University of Technology, Dongguan, Guangdong, People's Republic of China
| | - Fazhan Wang
- Guangdong Key Laboratory for Advanced Metallic Materials Processing, South China University of Technology, Guangzhou, Guangdong, People's Republic of China
| | - Weiping Chen
- Guangdong Key Laboratory for Advanced Metallic Materials Processing, South China University of Technology, Guangzhou, Guangdong, People's Republic of China
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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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11
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Sun J, Luo L. Subcellular Distribution and Chemical Forms of Pb in Corn: Strategies Underlying Tolerance in Pb Stress. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:6675-6682. [PMID: 29932337 DOI: 10.1021/acs.jafc.7b03605] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Studying the accumulation position and forms of heavy metals (HMs) in organisms and cells is helpful to understand the transport process and detoxification mechanism. As typical HMs, lead (Pb) subcellular content, localization, and speciation of corn subcellular fractions were studied by a series of technologies, including transmission electron microscopy, inductively coupled plasma mass spectrometry, and X-ray absorption near edge structure. The results revealed that the electrodense granules of Pb were localized in the cell wall, intercellular space, and plasma membranes. About 71% Pb was localized at the cell wall and soluble fraction. In cell walls, the total amount of pyromorphite and Pb carbonate was about 80% and the remaining was Pb stearate. In the nuclear and chloroplast fraction, which demonstrated significant changes, major speciations were Pb sulfide (72%), basic Pb carbonate (16%), and Pb stearate (12%). Pb is blocked by cell walls as pyromorphite and Pb carbonate sediments and compartmentalized by vacuoles, which both play an inportant role in cell detoxification. Besides, sulfur-containing compounds form inside the cells.
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Affiliation(s)
- Jianling Sun
- Beijing Municipal Research Institute of Environmental Protection , Beijing 100037 , People's Republic of China
| | - Liqiang Luo
- National Research Center for Geoanalysis , Beijing 100037 , People's Republic of China
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12
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Calgaro CO, Schlemmer DF, Bassaco MM, Dotto GL, Tanabe EH, Bertuol DA. Supercritical extraction of polymers from printed circuit boards using CO2 and ethanol. J CO2 UTIL 2017. [DOI: 10.1016/j.jcou.2017.10.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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13
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Tatariants M, Yousef S, Sidaraviciute R, Denafas G, Bendikiene R. Characterization of waste printed circuit boards recycled using a dissolution approach and ultrasonic treatment at low temperatures. RSC Adv 2017. [DOI: 10.1039/c7ra07034a] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
All the WPCB samples had similar structure, which comprises six layers of fiberglass (representing WPCB substrate), two copper foil layers (upper and lower layers), copper tracks, through-hole pads and two soldermask layers (upper and lower layers).
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Affiliation(s)
- Maksym Tatariants
- Department of Environmental Technology
- Faculty of Chemical Technology
- Kaunas University of Technology
- LT-50254 Kaunas
- Lithuania
| | - Samy Yousef
- Department of Production Engineering
- Faculty of Mechanical Engineering and Design
- Kaunas University of Technology
- LT-51424 Kaunas
- Lithuania
| | - Ruta Sidaraviciute
- Department of Environmental Technology
- Faculty of Chemical Technology
- Kaunas University of Technology
- LT-50254 Kaunas
- Lithuania
| | - Gintaras Denafas
- Department of Environmental Technology
- Faculty of Chemical Technology
- Kaunas University of Technology
- LT-50254 Kaunas
- Lithuania
| | - Regita Bendikiene
- Department of Production Engineering
- Faculty of Mechanical Engineering and Design
- Kaunas University of Technology
- LT-51424 Kaunas
- Lithuania
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14
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Feng Z, Velari S, Cossaro A, Castellarin-Cudia C, Verdini A, Vesselli E, Dri C, Peressi M, De Vita A, Comelli G. Trapping of Charged Gold Adatoms by Dimethyl Sulfoxide on a Gold Surface. ACS NANO 2015; 9:8697-709. [PMID: 26079254 DOI: 10.1021/acsnano.5b02284] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We report the formation of dimethyl sulfoxide (DMSO) molecular complexes on Au(111) enabled by native gold adatoms unusually linking the molecules via a bonding of ionic nature, yielding a mutual stabilization between molecules and adatom(s). DMSO is a widely used polar, aprotic solvent whose interaction with metal surfaces is not fully understood. By combining X-ray photoelectron spectroscopy, low temperature scanning tunneling microscopy, and density functional theory (DFT) calculations, we show that DMSO molecules form complexes made by up to four molecules arranged with adjacent oxygen terminations. DFT calculations reveal that most of the observed structures are accurately reproduced if, and only if, the negatively charged oxygen terminations are linked by one or two positively charged Au adatoms. A similar behavior was previously observed only in nonstoichiometric organic salt layers, fabricated using linkage alkali atoms and strongly electronegative molecules. These findings suggest a motif for anchoring organic adlayers of polar molecules on metal substrates and also provide nanoscale insight into the interaction of DMSO with gold.
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Affiliation(s)
- Zhijing Feng
- Physics Department, University of Trieste , Via A. Valerio 2, 34127 Trieste, Italy
- TASC Laboratory, Istituto Officina dei Materiali CNR-IOM , S.S. 14 km 163.5, 34149 Trieste, Italy
| | - Simone Velari
- Engineering and Architecture Department, University of Trieste , Via A. Valerio 6/1, 34147 Trieste, Italy
| | - Albano Cossaro
- TASC Laboratory, Istituto Officina dei Materiali CNR-IOM , S.S. 14 km 163.5, 34149 Trieste, Italy
| | - Carla Castellarin-Cudia
- TASC Laboratory, Istituto Officina dei Materiali CNR-IOM , S.S. 14 km 163.5, 34149 Trieste, Italy
| | - Alberto Verdini
- TASC Laboratory, Istituto Officina dei Materiali CNR-IOM , S.S. 14 km 163.5, 34149 Trieste, Italy
| | - Erik Vesselli
- Physics Department, University of Trieste , Via A. Valerio 2, 34127 Trieste, Italy
- TASC Laboratory, Istituto Officina dei Materiali CNR-IOM , S.S. 14 km 163.5, 34149 Trieste, Italy
| | - Carlo Dri
- Physics Department, University of Trieste , Via A. Valerio 2, 34127 Trieste, Italy
- TASC Laboratory, Istituto Officina dei Materiali CNR-IOM , S.S. 14 km 163.5, 34149 Trieste, Italy
| | - Maria Peressi
- Physics Department, University of Trieste , Via A. Valerio 2, 34127 Trieste, Italy
- CNR-IOM DEMOCRITOS , Area Science Park, S.S. 14 km 163.5, 34149 Trieste, Italy
- Consorzio Interuniversitario Nazionale per la Scienza e la Tecnologia dei Materiali (INSTM), Unità di ricerca di Trieste , Piazzale Europa 1, 34128 Trieste, Italy
| | - Alessandro De Vita
- Engineering and Architecture Department, University of Trieste , Via A. Valerio 6/1, 34147 Trieste, Italy
- Department of Physics, King's College London , Strand, London WC2R 2LS, United Kingdom
| | - Giovanni Comelli
- Physics Department, University of Trieste , Via A. Valerio 2, 34127 Trieste, Italy
- TASC Laboratory, Istituto Officina dei Materiali CNR-IOM , S.S. 14 km 163.5, 34149 Trieste, Italy
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15
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Chen M, Huang J, Ogunseitan OA, Zhu N, Wang YM. Comparative study on copper leaching from waste printed circuit boards by typical ionic liquid acids. WASTE MANAGEMENT (NEW YORK, N.Y.) 2015; 41:142-147. [PMID: 25869844 DOI: 10.1016/j.wasman.2015.03.037] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 03/19/2015] [Accepted: 03/25/2015] [Indexed: 06/04/2023]
Abstract
Waste printed circuit boards (WPCBs) are attracting increasing concerns because the recovery of its content of valuable metallic resources is hampered by the presence of hazardous substances. In this study, we used ionic liquids (IL) to leach copper from WPCBs. [BSO3HPy]OTf, [BSO3HMIm]OTf, [BSO4HPy]HSO4, [BSO4HMim]HSO4 and [MIm]HSO4 were selected. Factors that affect copper leaching rate were investigated in detail and their leaching kinetics were also examined with the comparison of [Bmim]HSO4. The results showed that all six IL acids could successfully leach copper out, with near 100% recovery. WPCB particle size and leaching time had similar influences on copper leaching performance, while IL acid concentration, hydrogen peroxide addition, solid to liquid ratio, temperature, showed different influences. Moreover, IL acid with HSO4(-) was more efficient than IL acid with CF3SO3(-). These six IL acids indicate a similar behavior with common inorganic acids, except temperature since copper leaching rate of some IL acids decreases with its increase. The results of leaching kinetics studies showed that diffusion plays a more important role than surface reaction, whereas copper leaching by inorganic acids is usually controlled by surface reaction. This innovation provides a new option for recovering valuable materials such as copper from WPCBs.
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Affiliation(s)
- Mengjun Chen
- Key Laboratory of Solid Waste Treatment and Resource Recycle (SWUST), Ministry of Education, Southwest University of Science and Technology, 59 Qinglong Road, Mianyang 621010, China.
| | - Jinxiu Huang
- Key Laboratory of Solid Waste Treatment and Resource Recycle (SWUST), Ministry of Education, Southwest University of Science and Technology, 59 Qinglong Road, Mianyang 621010, China
| | - Oladele A Ogunseitan
- Program in Public Health, Department of Population Health and Disease Prevention, and School of Social Ecology, University of California, Irvine, CA 92697-3957, USA
| | - Nengming Zhu
- Biogas Institute of Ministry of Agriculture, 13 4th Section Renmin South Road, Chengdu 610041, China
| | - Yan-min Wang
- School of Chemistry and Environmental Science, Shaanxi University of Technology, Hanzhong, Shaanxi 723001, China
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16
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Wath SB, Katariya MN, Singh SK, Vaidya AN. WITHDRAWN: Removal and separation of bromine epoxy resin for recovering valuable materials from waste printed circuit board using organic solvent. WASTE MANAGEMENT (NEW YORK, N.Y.) 2015:S0956-053X(15)00371-2. [PMID: 26050936 DOI: 10.1016/j.wasman.2015.05.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 05/15/2015] [Accepted: 05/15/2015] [Indexed: 06/04/2023]
Abstract
This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.
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Affiliation(s)
- Sushant B Wath
- CSIR-National Environmental Engineering Research Institute (NEERI), Nehru Marg, Nagpur 440 020, India.
| | - Mayuri N Katariya
- CSIR-National Environmental Engineering Research Institute (NEERI), Nehru Marg, Nagpur 440 020, India
| | - Sanjeev K Singh
- CSIR-National Environmental Engineering Research Institute (NEERI), Nehru Marg, Nagpur 440 020, India
| | - Atul N Vaidya
- CSIR-National Environmental Engineering Research Institute (NEERI), Nehru Marg, Nagpur 440 020, India
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17
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Guo J, Zhang R, Xu Z. PBDEs emission from waste printed wiring boards during thermal process. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:2716-2723. [PMID: 25629562 DOI: 10.1021/es5053599] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Polybrominated diphenyl ethers (PBDEs) contained in waste printed wiring board (PWB) matrix and surface dust can be emitted into the air during thermal process, which is widely used to detach the electronic components from the base boards of waste PWB. In this study, PBDEs concentrations in air and dust samples were detected in a PWB-heating workshop, and then heating experiments of PBDEs-containing materials in a quartz tube furnace were performed to investigate the PBDEs emission mechanism. The results showed that the mean concentrations of Σ8PBDEs in PM10 and TSP were 479 and 1670 ng/m(3), respectively. Compared with surface dust collected from waste PWB (15600 ng/g), PBDEs concentrations in dust from the workshop floor (31,100 ng/g), heating machine inside (84,700 ng/g), and the cyclone extractor (317,000 ng/g), were condensed after thermal process. Heating experiments showed that the emission rates of PBDEs from PBDEs-containing dust were obviously higher than those from PWB fragments in the first 1-h time. The cumulative amounts of PBDEs emitted from dust increased rapidly at first, and then leveled off to become asymptotic to the maximum amounts. At the temperature of 300 °C, the PBDEs emission from dust mainly occurred within the first 5 min, and the average emission rates for BDE-28, -47, and -99 among the first 5 min were 1230, 4480, and 1950 ng/(g·min), respectively. During the initial 1-h period, the trends of PBDEs emission from PWB fragments had a linear increase, and the emission rates of penta-BDE (BDE-47, -99, -100) at different temperatures were at a range of 9.75-11.5 ng/(g·min). All the results showed that PBDEs emission from PWB waste happened during thermal process, and management strategies were provided to reduce the occupational exposure level of PBDEs for workers.
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Affiliation(s)
- Jie Guo
- School of Environmental Science and Engineering, Shanghai Jiao Tong University , 800 Dongchuan Road, Shanghai 200240, People's Republic of China
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18
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Separation and recovery of fine particles from waste circuit boards using an inflatable tapered diameter separation bed. ScientificWorldJournal 2014; 2014:843579. [PMID: 25379546 PMCID: PMC4213985 DOI: 10.1155/2014/843579] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 08/19/2014] [Accepted: 08/27/2014] [Indexed: 11/18/2022] Open
Abstract
Recovering particle materials from discarded printed circuit boards can enhance resource recycling and reduce environmental pollution. Efficiently physically separating and recovering fine metal particles (-0.5 mm) from the circuit boards are a key recycling challenge. To do this, a new type of separator, an inflatable tapered diameter separation bed, was developed to study particle motion and separation mechanisms in the bed's fluid flow field. For 0.5-0.25 mm circuit board particles, metal recovery rates ranged from 87.56 to 94.17%, and separation efficiencies ranged from 87.71 to 94.20%. For 0.25-0.125 mm particles, metal recovery rates ranged from 84.76 to 91.97%, and separation efficiencies ranged from 84.74 to 91.86%. For superfine products (-0.125 mm), metal recovery rates ranged from 73.11 to 83.04%, and separation efficiencies ranged from 73.00 to 83.14%. This research showed that the inflatable tapered diameter separation bed achieved efficient particle separation and can be used to recover fine particles under a wide range of operational conditions. The bed offers a new mechanical technology to recycle valuable materials from discarded printed circuit boards, reducing environmental pollution.
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Lin KH, Chiang HL. Liquid oil and residual characteristics of printed circuit board recycle by pyrolysis. JOURNAL OF HAZARDOUS MATERIALS 2014; 271:258-265. [PMID: 24637450 DOI: 10.1016/j.jhazmat.2014.02.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 02/20/2014] [Accepted: 02/21/2014] [Indexed: 06/03/2023]
Abstract
Non-metal fractions of waste printed circuit boards (PCBs) were thermally treated (200-500°C) under nitrogen atmosphere. Carbon, hydrogen, and nitrogen were determined by elemental analyzer, bromine by instrumental neutron activation analysis (INAA), phosphorus by energy dispersive X-ray spectrometer (EDX), and 29 trace elements by inductively coupled plasma atomic emission spectrometer (ICP-AES) and mass spectrometry (ICP-MS) for raw material and pyrolysis residues. Organic compositions of liquid oil were identified by GC (gas chromatography)-MS, trace element composition by ICP system, and 12 water-soluble ions by IC (ionic chromatography). Elemental content of carbon was >450 mg/g, oxygen 300 mg/g, bromine and hydrogen 60 mg/g, nitrogen 30 mg/g, and phosphorus 28 mg/g. Sulfur was trace in PCBs. Copper content was 25-28 mg/g, iron 1.3-1.7 mg/g, tin 0.8-1.0mg/g and magnesium 0.4-1.0mg/g; those were the main metals in the raw materials and pyrolytic residues. In the liquid products, carbon content was 68-73%, hydrogen was 10-14%, nitrogen was 4-5%, and sulfur was less than 0.05% at pyrolysis temperatures from 300 to 500°C. Phenol, 3-bromophenol, 2-methylphenol and 4-propan-2-ylphenol were major species in liquid products, accounting for >50% of analyzed organic species. Bromides, ammonium and phosphate were the main species in water sorption samples for PCB pyrolysis exhaust.
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Affiliation(s)
- Kuo-Hsiung Lin
- Department of Environmental Engineering and Science, Fooyin University, Kaohsiung, Taiwan
| | - Hung-Lung Chiang
- Department of Health Risk Management, China Medical University, Taichung, Taiwan.
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20
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Ou Z, Li J. Synergism of mechanical activation and sulfurization to recover copper from waste printed circuit boards. RSC Adv 2014. [DOI: 10.1039/c4ra08265f] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
This work proposed a synergistic route of mechanic activation and sulfurization to recover copper from waste printed circuit boards for the first time and take successful use of free radical theory in assessing the synergism mechanism.
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Affiliation(s)
- Zhiyuan Ou
- State Key Joint Laboratory of Environment Simulation and Pollution Control
- School of Environment
- Tsinghua University
- Beijing, China
| | - Jinhui Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control
- School of Environment
- Tsinghua University
- Beijing, China
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