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Rao MD, Meshram RB, Singh KK, Morrison CA, Love JB. Life cycle analysis on sequential recovery of copper and gold from waste printed circuit boards. WASTE MANAGEMENT (NEW YORK, N.Y.) 2023; 171:621-627. [PMID: 37837909 DOI: 10.1016/j.wasman.2023.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Revised: 09/21/2023] [Accepted: 10/05/2023] [Indexed: 10/16/2023]
Abstract
Informal recycling activities of waste printed circuit boards, such as pyrolysis and landfilling, cause severe environmental harm to society. Pyrolysis of resin and polymer fraction leads to the generation of toxic effluents, and landfilling causes the leaching of heavy metals into the groundwater. A sustainable and eco-friendly way to recover base and precious elements will be an economically attractive option. Current research studied the cradle-to-gate environmental impacts of the sequential recovery of copper and gold through delamination, leaching, solvent extraction, electrowinning and cementation from waste printed circuit boards with the help of life cycle assessment.GaBi software was utilized to assess environmental impacts such as global warming, abiotic depletion (fossil), acidification potential and human toxicity potential during the process. Inventory data was collected by conducting several experiments and from optimizing parameters for recycling and separating 4.53 g of copper and 2.25 mg of gold from 16 g of component-free waste printed circuit boards. Results indicate that the chemical pre-treatment or delamination process for separating metal clads from the non-metallic fraction is primarily involved in the impact category. The higher impact during delamination is due to electricity consumption. The proposed study also corroborates the industrial viability of recycling valuable metals from waste printed circuit boards to minimize the environmental impacts. The outcomes of this work could be beneficial in creating the environmental guiding principle for WPCBs recycling plants.
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Affiliation(s)
- Mudila Dhanunjaya Rao
- CSIR-National Metallurgical Laboratory, Jamshedpur 831007, India; Department of Metallurgical Engineering, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005, India.
| | - Rohit B Meshram
- CSIR-National Metallurgical Laboratory, Jamshedpur 831007, India
| | - Kamalesh K Singh
- Department of Metallurgical Engineering, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005, India.
| | - Carole A Morrison
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, The King's Buildings, David Brewster Road, Edinburgh EH9 3FJ, UK
| | - Jason B Love
- EaStCHEM School of Chemistry, University of Edinburgh, Joseph Black Building, The King's Buildings, David Brewster Road, Edinburgh EH9 3FJ, UK
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Haghi M, Fotovat F, Yaghmaei S. Co-pyrolysis of paper-laminated phenolic printed circuit boards and calcium-based additives in fixed and fluidized bed reactors. WASTE MANAGEMENT (NEW YORK, N.Y.) 2023; 171:532-544. [PMID: 37806161 DOI: 10.1016/j.wasman.2023.09.041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 09/27/2023] [Accepted: 09/30/2023] [Indexed: 10/10/2023]
Abstract
This study compares the impact of the calcium-based additives and the pyrolyzer on the recovery and the halide content of the oil produced from the pyrolysis of paper-laminated phenolic resin printed circuit boards (FR2-PCB). The preliminary experiments showed that the maximum liquid recovery (40.6%) was achieved in a fluidized bed pyrolyzer containing a 50:50 mixture of CaO and Ca(OH)2 operating at T = 620 °C and PCB-to-additive ratio (FR2/A) = 5.4 g/g for 22 min. Extra tests were then carried out under these conditions in fixed and fluidized bed pyrolyzers to separately explore the impact of CaO, Ca(OH)2, and CaO + Ca(OH)2 on the liquid recovery (LR) and the halogen content of the non-solid products. In the fluidized bed, LR in the presence of CaO, Ca(OH)2, and CaO + Ca(OH)2 was 34.5%, 41.2%, and 38.9 wt%, respectively. The fraction of phenolic compounds in the pyrolysis oil ranged from 86% to 93%, about 1-3% higher than the corresponding values in the fixed bed. Using additives led to lower halide content in the pyrolysis oil of the fluidized bed than that of the fixed bed. However, the opposite trend was observed in the absence of additives. Regardless of the type of pyrolyzer, Ca(OH)2 was more successful than CaO in increasing LR, whereas CaO was more effective than Ca(OH)2 in pyrolysis oil dechlorination. Co-pyrolysis of FR2-PCB and CaO + Ca(OH)2 in a fluidized bed reactor was identified as a practical approach to enhance the recovery of pyrolysis oil comprising only 5% of the original halogen content of the feedstock.
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Affiliation(s)
- Mahdi Haghi
- Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran, Iran
| | - Farzam Fotovat
- Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran, Iran.
| | - Soheila Yaghmaei
- Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran, Iran
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Gautam P, De AK, Rao MD, Sinha I, Behera CK, Singh KK. Waste remediation: Low-temperature synthesis of hybrid Cu(OH) 2/CuO and CuO nanostructures from spent printed circuit boards and their dye degradation studies. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023:10.1007/s11356-023-29005-7. [PMID: 37542015 DOI: 10.1007/s11356-023-29005-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 07/22/2023] [Indexed: 08/06/2023]
Abstract
The demand for environmentally friendly and sustainable resource utilization techniques for recycling waste printed circuit boards is significant due to their status as valuable secondary resources, containing high-purity copper and precious metals. In this context, Cu(OH)2/CuO and CuO nanostructures were fabricated using alkaline precipitation and low-temperature aging methods using the strip solution originated from laboratory-scale spent mobile phone printed circuit board recovery process. XRD, FTIR, FESEM-EDX, and TEM were utilized to characterize the as-recovered nanoproducts. A hybrid structure of Cu(OH)2/CuO was formed at 70°, and monoclinic CuO phase was formed at 80 °C aging time. The results show that Cu(OH)2/CuO nanoflakes have an average crystallite size of 24.06 nm and a particle width of 22 ± 3 nm. Cu(OH)2/CuO nanoflakes formed at 70 °C aging temperature and 24-h residence time have finer crystallite and particle sizes than CuO-ridged nanospheres formed at 80 °C aging temperature. The optical band gap energy of Cu(OH)2/CuO and CuO nanostructures formed was found to be 2.28 eV and 2.22 eV, respectively. The hybrid Cu(OH)2/CuO nanostructure photocatalyzed the decomposed 97.28% rhodamine blue using a visible light source, whereas the CuO nanostructure degraded only 14.64% rhodamine blue dye under similar conditions. A surfactant-less hybrid structure is developed without the use of any chemical precursor. Thus, a high value-added product is produced using one waste material to remove another waste in wastewater treatment.
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Affiliation(s)
- Pushpa Gautam
- Department of Metallurgical Engineering, Indian Institute of Technology (Banaras Hindu University) Varanasi, Varanasi, 221005, India.
| | - Arup Kumar De
- Department of Metallurgical Engineering, Indian Institute of Technology (Banaras Hindu University) Varanasi, Varanasi, 221005, India
| | | | - Indrajit Sinha
- Department of Chemistry, Indian Institute of Technology (Banaras Hindu University) Varanasi, Varanasi, 221005, India
| | - Chhail Kumar Behera
- Department of Metallurgical Engineering, Indian Institute of Technology (Banaras Hindu University) Varanasi, Varanasi, 221005, India
| | - Kamalesh Kumar Singh
- Department of Metallurgical Engineering, Indian Institute of Technology (Banaras Hindu University) Varanasi, Varanasi, 221005, India
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Grigorescu RM, Ghioca P, Iancu L, David ME, Ion RM, Gabor RA, Nicolae CA, Teodorescu-Slamnoiu S, Alexandrescu E. Electric and electronic equipment waste: reuse in elastomeric composites. JOURNAL OF POLYMER RESEARCH 2023. [DOI: 10.1007/s10965-022-03432-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Yao Y, He J, Yang B, Zhao Y, Zhu L. Study on particle characteristics and metal distribution of waste printed circuit boards based on a shear crusher. POWDER TECHNOL 2022. [DOI: 10.1016/j.powtec.2022.118103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Lin KH, Tsai JH, Lan CL, Chiang HL. The effect of microwave pyrolysis on product characteristics and bromine migration for a non-metallic printed circuit board. WASTE MANAGEMENT (NEW YORK, N.Y.) 2022; 153:147-155. [PMID: 36096042 DOI: 10.1016/j.wasman.2022.08.030] [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: 06/16/2022] [Revised: 08/17/2022] [Accepted: 08/29/2022] [Indexed: 06/15/2023]
Abstract
At present, it is necessary to carry out environmentally friendly treatment of non-metallic fractions (NMFs) of waste printed circuit board (WPCB) to improve resource utilization. NMFs of WPCB are pyrolyzed by microwave heating to determine the effect of different operating conditions on the characteristics of pyrolysis products. The results show that yields for residue, oil and gas are 59.03-67.63, 7.10-28.46 and 4.86-33.88 wt%. A high temperature promotes a decrease in oil yield and an increase in non-condensable gas yield. An increase in the NaOH dose results in a more significant cracking of the oil to gas. Increasing the concentration of NaOH increases the mass fraction of the total Br in residues (from 23.62 to 86.94 %), so the addition of NaOH is beneficial to the fixation of Br. A kinetics study shows that there are two thermal decomposition regions (398-625 K and 675-925 K), and NaOH-catalyzed pyrolysis reduces the activation energy to 18.91 and 31.95 kJ mol-1, respectively. The formation of Br-containing substances in the pyrolysis oil and gas can be inhibited if the bromine fixation in pyrolysis residue increases. NaOH-catalyzed pyrolysis can reduce bromine and also reduce energy recovery efficiency. This pyrolysis process still requires further research to improve the recovery of energy and valuable materials.
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Affiliation(s)
- Kuo-Hsiung Lin
- Department of Environmental Engineering and Science, Fooyin University, Kaohsiung 831301, Taiwan
| | - Jiun-Horng Tsai
- Department of Environmental Engineering, National Cheng Kung University, Tainan 701401, Taiwan; Research Center for Climate Change and Environment Quality, National Cheng Kung University, Tainan 701401, Taiwan
| | - Chen-Laun Lan
- Department of Environmental Engineering and Science, Fooyin University, Kaohsiung 831301, Taiwan
| | - Hung-Lung Chiang
- Department of Safety Health and Environmental Engineering, National Yunlin University of Science and Technology, Yunlin 640301, Taiwan
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Fedorova MI, Levina AV, Zakhodyaeva YA, Voshkin AA. Extracting Transition Metals from HCl Solutions by Means of Polypropylene Glycol 425. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A 2022. [DOI: 10.1134/s0036024422080106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Cao R, Zhou R, Liu Y, Ma D, Wang J, Guan Y, Yao Q, Sun M. Research on the pyrolysis characteristics and mechanisms of waste printed circuit boards at fast and slow heating rates. WASTE MANAGEMENT (NEW YORK, N.Y.) 2022; 149:134-145. [PMID: 35728477 DOI: 10.1016/j.wasman.2022.06.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 05/24/2022] [Accepted: 06/12/2022] [Indexed: 06/15/2023]
Abstract
The pyrolysis treatment of waste printed circuit boards (WPCBs) shows great potential for sustainable treatment and hazard reduction. In this work, based on thermogravimetry (TG), pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), and density functional theory (DFT), the thermal weight loss, product distribution, and kinetics of WPCBs pyrolysis were studied by single-step and multi-step pyrolysis at fast (600 °C/min) and slow (10 °C/min) heating rates. The heating rates of TG and Py-GC/MS were the same for each group of experiments. In addition, the bond dissociation energy (BDE) of WPCBs polymer monomers was calculated by DFT method. Compared with slow pyrolysis, the final weight loss of fast pyrolysis is reduced by 0.76 wt%. The kinetic analysis indicates that the activation energies of main pyrolysis stages range from 98.29 kJ/mol to 177.59 kJ/mol. The volatile products of fast pyrolysis are mainly phenols and aromatics. With the increase of multi-step pyrolysis temperature, the order of the escaping volatiles is phenols, hydrocarbyl phenols, aromatics, and benzene (or diphenyl phenol). The pyrolysis residue of WPCBs may contains phenolics and polymers. Based on the free radical reactions, the mechanism and reaction pathways of WPCBs pyrolysis were deduced by the DFT. Moreover, a large amount of benzene is produced by pyrolysis, and its formation mechanism was elaborated.
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Affiliation(s)
- Rui Cao
- School of Chemical Engineering, Northwest University, International Science & Technology Cooperation Base of MOST for Clean Utilization of Hydrocarbon Resources, Chemical Engineering Research Center of the Ministry of Education for Advanced Use Technology of Shanbei Energy, Shaanxi Research Center of Engineering Technology for Clean Coal Conversion, Collaborative Innovation Center for Development of Energy and Chemical Industry in Northern Shaanxi, Xi'an 710069, Shaanxi, China
| | - Ruishi Zhou
- School of Chemical Engineering, Northwest University, International Science & Technology Cooperation Base of MOST for Clean Utilization of Hydrocarbon Resources, Chemical Engineering Research Center of the Ministry of Education for Advanced Use Technology of Shanbei Energy, Shaanxi Research Center of Engineering Technology for Clean Coal Conversion, Collaborative Innovation Center for Development of Energy and Chemical Industry in Northern Shaanxi, Xi'an 710069, Shaanxi, China
| | - Yongqi Liu
- School of Chemical Engineering, Northwest University, International Science & Technology Cooperation Base of MOST for Clean Utilization of Hydrocarbon Resources, Chemical Engineering Research Center of the Ministry of Education for Advanced Use Technology of Shanbei Energy, Shaanxi Research Center of Engineering Technology for Clean Coal Conversion, Collaborative Innovation Center for Development of Energy and Chemical Industry in Northern Shaanxi, Xi'an 710069, Shaanxi, China
| | - Duo Ma
- School of Chemical Engineering, Northwest University, International Science & Technology Cooperation Base of MOST for Clean Utilization of Hydrocarbon Resources, Chemical Engineering Research Center of the Ministry of Education for Advanced Use Technology of Shanbei Energy, Shaanxi Research Center of Engineering Technology for Clean Coal Conversion, Collaborative Innovation Center for Development of Energy and Chemical Industry in Northern Shaanxi, Xi'an 710069, Shaanxi, China
| | - Jing Wang
- School of Chemical Engineering, Northwest University, International Science & Technology Cooperation Base of MOST for Clean Utilization of Hydrocarbon Resources, Chemical Engineering Research Center of the Ministry of Education for Advanced Use Technology of Shanbei Energy, Shaanxi Research Center of Engineering Technology for Clean Coal Conversion, Collaborative Innovation Center for Development of Energy and Chemical Industry in Northern Shaanxi, Xi'an 710069, Shaanxi, China
| | - Yulei Guan
- School of Chemical Engineering, Northwest University, International Science & Technology Cooperation Base of MOST for Clean Utilization of Hydrocarbon Resources, Chemical Engineering Research Center of the Ministry of Education for Advanced Use Technology of Shanbei Energy, Shaanxi Research Center of Engineering Technology for Clean Coal Conversion, Collaborative Innovation Center for Development of Energy and Chemical Industry in Northern Shaanxi, Xi'an 710069, Shaanxi, China
| | - Qiuxiang Yao
- School of Science, Xijing University, Xi'an Key Laboratory of Advanced Photo-electronics Materials and Energy Conversion Device, Xi'an 710123, Shaanxi, China.
| | - Ming Sun
- School of Chemical Engineering, Northwest University, International Science & Technology Cooperation Base of MOST for Clean Utilization of Hydrocarbon Resources, Chemical Engineering Research Center of the Ministry of Education for Advanced Use Technology of Shanbei Energy, Shaanxi Research Center of Engineering Technology for Clean Coal Conversion, Collaborative Innovation Center for Development of Energy and Chemical Industry in Northern Shaanxi, Xi'an 710069, Shaanxi, China.
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Recovery of Rare-Earth Elements from Printed Circuit Boards by Vacuum Pyrolysis and Multiple Electrostatic Separation. Processes (Basel) 2022. [DOI: 10.3390/pr10061152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The influence of the multi-stage electrostatic separation (ESS) of mechanically treated and magnetically separated waste electronic material and the pyrolysis of the selected ESS fraction on the distribution of metal elements (MEs), elements contained in refractory oxides (EROs), bromine (Br), and rare-earth elements (REEs) contained in waste electronic material was studied. The concentration of MEs, Br, and EROs in the tested samples was determined by X-ray fluorescence analysis, and the concentration of REEs and uranium was determined by inductively coupled plasma mass spectrometry (ICP-MS). The analysis of the distribution of elements during the multi-stage ESS showed that MEs were predominantly distributed in the conductive fraction and Br, EROs, and REEs were distributed in the nonconductive fraction. The nonconductive fraction (NC2) of the two-stage ESS was subjected to a low-temperature vacuum pyrolysis (T = 550 °C, p = 10 mbar). The distribution of pyrolysis products of the NC2 fraction was determined. The main products of the vacuum pyrolysis experiments were the solid residue phase (54.4 wt.%) and oils (35.4 wt.%). It has been proven that pyrolysis can significantly increase the concentration of MEs, EROs, and REEs in raw materials, thereby providing a method for cost-effectively obtaining of REEs from waste printed circuit boards.
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Karan P, Chakraborty R. E-waste derived silica-alumina for eco-friendly and inexpensive Mg-Al-Ti photocatalyst towards glycerol carbonate (electrolyte) synthesis: Process optimization and LCA. WASTE MANAGEMENT (NEW YORK, N.Y.) 2022; 140:213-224. [PMID: 34836726 DOI: 10.1016/j.wasman.2021.11.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 10/21/2021] [Accepted: 11/13/2021] [Indexed: 06/13/2023]
Abstract
Valorization ofe-waste, i.e. waste printed circuit board (WPCB) through mechano-chemical activation to obtain silica as the catalyst support and alumina as the catalyst precursor for eco-friendly synthesis of inexpensive highly proficient photocatalyst has been explored. The WPCB derived silica-supported layered double oxide photocatalyst (MATLSW) and its counterpart (MATLSC) involving commercial silica and alumina precursors were synthesized through the wet-impregnation method under energy-efficient solar simulated quartz halogen lamp (SSQHL) irradiations to improve its photocatalytic properties compared to conventional methods. The prepared MATLSWpossessed a significantly low band-gap-energy (1.58 eV) that rendered efficient photocatalysis in the green-synthesis of glycerol carbonate (GC) (an effective electrolyte). The catalytic performance of the optimal MATLSWresulted in a superior yield of GC (98.68%) compared to that rendered by MATLSCcatalyst (GC yield: 96.56%) at optimal process conditions. Detailed life cycle assessment (LCA) of the entire process (deploying Ecoinvent 3.5 database) dictated conducive environmental impacts concerning 1 kg GC synthesis alongside a scale-up study for 1 MT GC synthesis encompassing silica-alumina extraction from WPCB, MATLSW preparation, and employment of SSQHL-radiated batch reactor (SSQHLBR) (56.64% less energy consumption than conventional). The overall process deploying the novel MATLSWin conjunction with the effectual reactor demonstrated superiority over the conventional GC synthesis process through appreciable reductions of environmental impact parameters, namely GWP, FDP, and HTP by 5.78%, 3.60%, and 5.72% respectively. The developed green process for e-waste utilization can procreate an effective waste management protocol towards a cleaner world.
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Affiliation(s)
- Poulami Karan
- Chemical Engineering Department, Jadavpur University, Kolkata 700032, India
| | - Rajat Chakraborty
- Chemical Engineering Department, Jadavpur University, Kolkata 700032, India.
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Yaashikaa PR, Priyanka B, Senthil Kumar P, Karishma S, Jeevanantham S, Indraganti S. A review on recent advancements in recovery of valuable and toxic metals from e-waste using bioleaching approach. CHEMOSPHERE 2022; 287:132230. [PMID: 34826922 DOI: 10.1016/j.chemosphere.2021.132230] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 08/30/2021] [Accepted: 09/08/2021] [Indexed: 05/15/2023]
Abstract
This review is intent on the environmental pollution generated from printed circuit boards and the methods employed to retrieve valuable and hazardous metals present in the e-wastes. Printed circuit boards are the key components in the electronic devices and considered as huge e-pollutants in polluting our surroundings and the environment as a whole. Composing of toxic heavy metals, it causes serious health effects to the plants, animals and humans in the environment. A number of chemical, biological and physical approaches were carried out to recover the precious metals and to remove the hazardous metals from the environment. Chemical leaching is one of the conventional PCBs recycling methods which was carried out by using different organic solvents and chemicals. Need of high cost for execution, generation of secondary wastes in the conventional methods, forces to discover the advanced recycling methods such as hydrometallurgical, bio-metallurgical and bioleaching processes to retrieve the valuable metals generate through e-wastes. Among them, bioleaching process gain extra priority due to its higher efficiency of metal recovery from printed circuit boards. There are different classes of microorganisms have been utilized for precious metal recovery from the PCBs through bioleaching process such as chemolithoautotrophy, heterotrophy and different fungal species including Aspergillus sp. and Penicillium sp. The current status and scope for further studies in printed circuit boards recycling are discussed in this review.
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Affiliation(s)
- P R Yaashikaa
- Department of Biotechnology, Saveetha School of Engineering, SIMATS, Chennai, 602105, India
| | - B Priyanka
- Department of Biotechnology, Saveetha School of Engineering, SIMATS, Chennai, 602105, India
| | - P Senthil Kumar
- Department of Chemical Engineering, Sri Sivasubramaniya Nadar College of Engineering, Chennai, 603110, India; Centre of Excellence in Water Research (CEWAR), Sri Sivasubramaniya Nadar College of Engineering, Chennai, 603110, India.
| | - S Karishma
- Department of Biotechnology, Rajalakshmi Engineering College, Chennai, 602105, India
| | - S Jeevanantham
- Department of Biotechnology, Rajalakshmi Engineering College, Chennai, 602105, India
| | - Sravya Indraganti
- Department of Chemical Engineering, Sri Sivasubramaniya Nadar College of Engineering, Chennai, 603110, India; Centre of Excellence in Water Research (CEWAR), Sri Sivasubramaniya Nadar College of Engineering, Chennai, 603110, India
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Kokare S, Asif FMA, Mårtensson G, Shoaib-ul-Hasan S, Rashid A, Roci M, Salehi N. A comparative life cycle assessment of stretchable and rigid electronics: a case study of cardiac monitoring devices. INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCE AND TECHNOLOGY : IJEST 2022; 19:3087-3102. [PMID: 34054976 PMCID: PMC8150627 DOI: 10.1007/s13762-021-03388-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 04/20/2021] [Accepted: 05/07/2021] [Indexed: 05/20/2023]
Abstract
Stretchable electronics is a new innovation and becoming popular in various fields, especially in the healthcare sector. Since stretchable electronics use less printed circuit boards (PCBs), it is expected that the environmental performance of a stretchable electronics-based device is better than a rigid electronics-based device that provides the same functionalities. Yet, such a study is rarely available. Thus, the main purpose of this research is to perform a comparative life cycle analysis of stretchable and rigid electronics-based devices. This research combines both the case study approach and the research review approach. For the case study, a cardiac monitoring device with both stretchable and rigid electronics is used. The ISO 14044:2006 standard's prescribed LCA approach and ReCiPe 2016 Midpoint (Hierarchist) are followed for the impact assessment using the SimaPro 9.1 software. The LCA results show that the stretchable cardiac monitoring device has better environmental performance in all eighteen impact categories. This research also shows that the manufacturing process of stretchable electronics has lower environmental impacts than those for rigid electronics. The main reasons for the improved environmental performance of stretchable electronics are lower consumption of raw material as well as decreased energy consumption during manufacturing. Based on the LCA results of a cardiac monitoring device, the study concludes that stretchable electronics and their manufacturing process have better environmental performance in comparison with the rigid electronics and their manufacturing process.
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Affiliation(s)
- S. Kokare
- Department of Production Engineering, KTH Royal Institute of Technology, Brinellvägen 68, 100 44 Stockholm, Sweden
| | - F. M. A. Asif
- Department of Production Engineering, KTH Royal Institute of Technology, Brinellvägen 68, 100 44 Stockholm, Sweden
| | - G. Mårtensson
- Department of Protein Science, KTH Royal Institute of Technology, Mycronic AB Nytorpsvägen 9, 183 03 Täby, Sweden
| | - S. Shoaib-ul-Hasan
- Department of Production Engineering, KTH Royal Institute of Technology, Brinellvägen 68, 100 44 Stockholm, Sweden
| | - A. Rashid
- Department of Production Engineering, KTH Royal Institute of Technology, Brinellvägen 68, 100 44 Stockholm, Sweden
| | - M. Roci
- Department of Production Engineering, KTH Royal Institute of Technology, Brinellvägen 68, 100 44 Stockholm, Sweden
| | - N. Salehi
- Department of Production Engineering, KTH Royal Institute of Technology, Brinellvägen 68, 100 44 Stockholm, Sweden
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Wang C, Sun R, Xing B. Copper recovery from waste printed circuit boards by the flotation-leaching process optimized using response surface methodology. JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION (1995) 2021; 71:1483-1491. [PMID: 33433266 DOI: 10.1080/10962247.2021.1874568] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 12/04/2020] [Accepted: 12/27/2020] [Indexed: 06/12/2023]
Abstract
Recycling of waste printed circuit boards (PCBs) receives increasing attention due to abundant metallic resources and significant environmental threats. This work proposes a process for copper recovery from PCBs by froth flotation and oxidation leaching. Copper grade is improved from 38.70% to 68.34% with the recovery of 88.76% by froth flotation, and froth flotation is significantly influenced by copper liberation and particles dispersion of PCB powders. Process variables of oxidation leaching are examined by response surface methodology (RSM). A reliable mathematical model is obtained to predict the response as a function of independent variables and their interactions. Oxidation leaching is remarkably influenced by experimental variables, and the interactions between sulfuric acid and hydrogen peroxide are significant. Optimum conditions are achieved as sulfuric acid 1.0 mol/L, hydrogen peroxide 17%, temperature 50°C, and time 234 minutes, and the maximum leaching ratio of Cu is up to 99.94%, indicating that oxidation leaching is an effective method for Cu recovery from PCBs.Implications: Recycling of waste printed circuit boards (PCBs) receives increasing attention due to abundant metallic resources and significant environmental threats. This work proposes a novel process for copper recovery from PCBs by froth flotation and oxidation leaching. Froth flotation is efficient to enrich copper in metal fractions. Process variables of oxidation leaching are examined by response surface methodology (RSM). A reliable mathematical model is obtained to predict the response as a function of independent variables and their interactions. The froth flotation-oxidation leaching process is practicable and effective for copper recovery from waste printed circuit boards. This study significantly contributes to recycling metal resources from waste PCBs. We believe that this work will attract a broad readership and lead others to follow our approach.
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Affiliation(s)
- Chongqing Wang
- School of Chemical Engineering, Zhengzhou University, Zhengzhou, People's Republic of China
| | - Ruirui Sun
- School of Chemical Engineering, Zhengzhou University, Zhengzhou, People's Republic of China
| | - Baolin Xing
- School of Chemical Engineering, Zhengzhou University, Zhengzhou, People's Republic of China
- Henan Key Laboratory of Coal Green Conversion, College of Chemistry and Chemical Engineering, Henan Polytechnic University, Jiaozuo, People's Republic of China
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Liu J, Jiang Q, Wang H, Li J, Zhang W. Catalytic effect and mechanism of in-situ metals on pyrolysis of FR4 printed circuit boards: Insights from kinetics and products. CHEMOSPHERE 2021; 280:130804. [PMID: 33965868 DOI: 10.1016/j.chemosphere.2021.130804] [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: 02/01/2021] [Revised: 04/02/2021] [Accepted: 04/30/2021] [Indexed: 06/12/2023]
Abstract
Pyrolysis is a promising method for the recovery of waste printed circuit boards (WPCBs), but few researches have noticed the influence of in-situ metals. This study conducted a series of comparisons between metal-free leftover pieces (LP) and intact boards (IB), including pyrolysis characteristics, volatile emission, kinetics, and thermodynamic parameters. The thermo-gravimetry (TG) analyses indicated that both the samples presented predominant mass loss in narrow temperature intervals, and characteristic pyrolysis temperatures of IB were approximately 15 °C lower than those of LP. Dominant constituents in evolved gases were detected by Fourier-transform infrared spectrometry as CO2, phenol, bromophenol, ethers, ketones, and aldehydes, and metals accelerated the generation of light hydrocarbons and aromatic compounds. The activation energy and thermodynamic parameters were calculated and compared, and the results verified the presence of in-situ metals led to a lower energy barrier and higher reaction extent. Moreover, conversion behaviors of Cu, Fe, Sn, and Pb manifested the formation of metal bromides and implied the reduction of brominated volatiles. The obtained results confirmed the catalytic effect of in-situ metals on PCBs pyrolysis and their bromine fixation abilities. This study contributes to fundamental knowledge that can be used to guide the pyrolysis of WPCBs.
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Affiliation(s)
- Jingxin Liu
- School of Environmental Engineering, Wuhan Textile University, Wuhan, 430073, China; Engineering Research Centre for Clean Production of Textile Dyeing and Printing, Ministry of Education, Wuhan Textile University, Wuhan, 430073, China
| | - Qihao Jiang
- School of Environmental Engineering, Wuhan Textile University, Wuhan, 430073, China
| | - Hanlin Wang
- School of Environmental Engineering, Wuhan Textile University, Wuhan, 430073, China
| | - Jinping Li
- School of Environmental Engineering, Wuhan Textile University, Wuhan, 430073, China; Engineering Research Centre for Clean Production of Textile Dyeing and Printing, Ministry of Education, Wuhan Textile University, Wuhan, 430073, China
| | - Wenjuan Zhang
- School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing, 100083, China.
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15
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Arya S, Patel A, Kumar S, Pau-Loke S. Urban mining of obsolete computers by manual dismantling and waste printed circuit boards by chemical leaching and toxicity assessment of its waste residues. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 283:117033. [PMID: 33887669 DOI: 10.1016/j.envpol.2021.117033] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 03/23/2021] [Accepted: 03/28/2021] [Indexed: 05/11/2023]
Abstract
Waste residues and acidic effluents (post-processing of E-waste) released into the local surroundings cause perilous environmental threats and potential risks to human health. Only limited research and information are available toward the sustainable management of waste residues generated post resource recovery of E-waste components. In the present study, the manual processing of obsolete computer (keyboard, monitor, CPU, and mouse) and chemical leaching of waste printed circuit boards (WPCBs) (motherboard, hard drive, DVD drive, and power supply) were performed for urban mining. The toxicity characteristics of typical pollutants in the residues of the WPCBs (post chemical leaching) were studied by toxicity characteristics leaching procedure (TCLP) test. Manual dismantling techniques resulted in an efficient urban mining concept with an overall average profit estimation of INR 2513.73/US$ 34.59. The chemical leaching of WPCBs showed a high concentration of metal leaching like Cu (229662 ± 575.3 mg/kg) and Pb (36785.67 ± 13.07 mg/kg) in the motherboard after stripping epoxy coating. The toxicity test revealed that the concentration of Cu (245.746 ± 0.016 mg/l) in the treated waste residue and Cu (430.746 ± 0.0015 mg/l) and Pb (182.09 ± 0.0035 mg/l) in the non-treated waste residue exceeded the threshold limit. The concentrations of other elements As, Cd, Co, Cr, Ag, Mn, Zn, Ni, Fe, Se, and In were within the permissible limit. Hence, the waste residue stands non-hazardous except Cu and Pb. Stripping out the epoxy coating of WPCBs enhances the metal leaching concentrations. The study highlighted that efficient and appropriate E-waste urban mining has immense potential in tracing the waste scrap into secondary resources. This study also emphasized that the final processed waste residue (left unattended or discarded due to lack of appropriate skill and technology) can be taken into consideration and exploited for value-added materials.
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Affiliation(s)
- Shashi Arya
- CSIR-National Environmental Engineering Research Institute (CSIR-NEERI), Nehru Marg, Nagpur, Maharashtra, 440 020, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201 002, Uttar Pradesh, India
| | - Aneri Patel
- CSIR-National Environmental Engineering Research Institute (CSIR-NEERI), Nehru Marg, Nagpur, Maharashtra, 440 020, India
| | - Sunil Kumar
- CSIR-National Environmental Engineering Research Institute (CSIR-NEERI), Nehru Marg, Nagpur, Maharashtra, 440 020, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201 002, Uttar Pradesh, India.
| | - Show Pau-Loke
- Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga-43500 Semenyih, Selangor Darul Ehsan, Malaysia
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Willner J, Fornalczyk A, Jablonska-Czapla M, Grygoyc K, Rachwal M. Studies on the Content of Selected Technology Critical Elements (Germanium, Tellurium and Thallium) in Electronic Waste. MATERIALS 2021; 14:ma14133722. [PMID: 34279300 PMCID: PMC8269855 DOI: 10.3390/ma14133722] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 05/30/2021] [Accepted: 06/28/2021] [Indexed: 11/24/2022]
Abstract
The article draws attention to the problem of the presence of metals: germanium (Ge), tellurium (Te), thallium (Tl), and others (Cd, Ba, Co, Mn, Cr, Cu, Ni, Pb, Sr, and Zn) in selected waste of electrical and electronic equipment (WEEE). As a result of the growing demand for new technologies, the global consumption of TECs has also been increasing. Thus, the amount of metals in circulation, of which the impacts on the environment have not yet been fully understood, is constantly increasing. Due to the low content of these metals in WEEE, they are usually ignored during e-waste analyses. The main aim of this study was to determine the distribution of Ge, Te, and Tl (and other elements) in ground sieve fractions (1.0, 0.5, 0.2, and 0.1 mm) of selected electronic components (solar lamps, solar cell, LED TV screens, LCD screens, photoresistors, photodiodes, phototransistors) and to determine the possible tendency of the concentrations of these metals in fractions. This problem is particularly important because WEEE recycling processes (crushing, grinding, and even collection and transport operations) can lead to dispersion and migration of TCE pollutants into the environment. The quantitative composition of e-waste was identified and confirmed by ICP-MS, ICP-OES and SEM-EDS, and XRD analyses. It was found that Ge, Te, and Tl are concentrated in the finest fractions of ground e-waste, together with Cd and Cr, which may favor the migration of these pollutants in the form of dust during storage and processing of e-waste.
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Affiliation(s)
- Joanna Willner
- Faculty of Materials Engineering, Silesian University of Technology, 40-019 Katowice, Poland;
| | - Agnieszka Fornalczyk
- Faculty of Materials Engineering, Silesian University of Technology, 40-019 Katowice, Poland;
- Correspondence:
| | - Magdalena Jablonska-Czapla
- Institute of Environmental Engineering, Polish Academy of Sciences, 41-819 Zabrze, Poland; (M.J.-C.); (K.G.); (M.R.)
| | - Katarzyna Grygoyc
- Institute of Environmental Engineering, Polish Academy of Sciences, 41-819 Zabrze, Poland; (M.J.-C.); (K.G.); (M.R.)
| | - Marzena Rachwal
- Institute of Environmental Engineering, Polish Academy of Sciences, 41-819 Zabrze, Poland; (M.J.-C.); (K.G.); (M.R.)
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17
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Impact of Grinding of Printed Circuit Boards on the Efficiency of Metal Recovery by Means of Electrostatic Separation. MINERALS 2021. [DOI: 10.3390/min11030281] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This paper analyses the impact of the method of grinding printed circuit boards (PCBs) in a knife mill on the efficiency and purity of products obtained during electrostatic separation. The separated metals and plastics and ceramics can be used as secondary raw materials. This is in line with the principle of circular economy. Three different screen perforations were used in the mill to obtain different sizes of ground grains. Moreover, the effect of cooling the feed to cryogenic temperature on the final products of separation was investigated. The level of contamination of the concentrate, intermediate, and waste obtained as a result of the application of fixed, determined electrostatic separation parameters was assessed using ICP-AES, SEM–EDS, XRD, and microscopic analysis as well as specific density. The yields of grain classes obtained from grinding in a knife mill were tested through sieve analysis and by using a particle size analyser. The test results indicate that using a knife mill with a 1 mm screen perforation along with cooling the feed to cryogenic temperature significantly improves the efficiency of the process. The grinding products were characterised by the highest release level of the useful substance—metals in the free state. The purity of the concentrate and waste obtained from electrostatic separation was satisfactory, and the content of the intermediate, in which conglomerates of solid metal–plastic connections were present, was very low. The yield of concentrate and waste amounted to 26.2% and 71.0%, respectively. Their purity, reflected in the content of the identified metals (valuable metals), was at the level of 93.3% and 0.5%, respectively. In order to achieve effective recovery of metals from PCBs by means of electrostatic separation, one should strive to obtain a feed composed of grains <1000 μm and, optimally, <800 μm.
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Annamalai M, Gurumurthy K. Characterization of end-of-life mobile phone printed circuit boards for its elemental composition and beneficiation analysis. JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION (1995) 2021; 71:315-327. [PMID: 32841086 DOI: 10.1080/10962247.2020.1813836] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 08/03/2020] [Accepted: 08/07/2020] [Indexed: 06/11/2023]
Abstract
Globally, waste electrical and electronic equipment is one of the fastest-growing waste sectors. Mobile phones constitute the major portion of the telecommunication e-waste category. Over the years, waste mobile phones were considered as a potential source of secondary metals. This study aims to determine the physical and chemical composition of the discarded mobile phones and to evaluate its recovery potential. The printed circuit boards from the discarded (waste) mobile phones (MPCB) were collected and samples of different sizes 3 × 3 cm, 2 mm, 1 mm, 500 µm, and 150 µm were obtained after milling and sieving. Elemental composition revealed the presence of base metals, Cu, Zn, Fe, Ni, and Pb, in higher quantities with a significant amount of precious metals Au and Ag. Amount of base metals present in different MPCB size fractions was found in the order 3 × 3 cm > 2 mm > 1 mm > 500 µm >150 µm. The amount of precious metals like Ag and Au was found to be higher in large-sized MPCB fractions. FTIR studies declared the presence of polymers like ABS, PC, and HIPs in MPCB samples. TCLP tests for toxic metals revealed that MPCBs contained high concentrations of cadmium, lead, and mercury highlighting their hazardous potential. The ultimate analysis revealed that NMF has a GCV of 12.34 MJ/kg and a volatile content of 42.25%, which can be a potential source of energy that can be recovered through the gasification or pyrolysis process. Overall, the comprehensive characterization of waste MPCBs will systematically provide a better understanding of e-waste recycling processes for beneficiation purpose and sustainable resource utilization.Implications: A comprehensive characterization of waste mobile phone printed circuit boards for its elemental composition was performed. Mechanical treatment steps before MPCBs processing increased the exposure of metals resulting in a higher concentration of metals in acid-digested samples. The elemental analysis of MPCBs revealed that MPCBs possessed significant quantities of base and precious metals. The amount of precious metals like Ag and Au was also found in higher ranges in large-sized MPCB fractions, which elucidated fact to be considered in the pre-treatment process for metal recoveries. The high content of base and precious metals in waste mobile phones displayed their economic potential in the market. This new source may compensate for the escalating global demand for gold and silver. Results from the study indicated that MPCBs can serve as an excellent secondary source for various metals and as an efficient alternative fuel.
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Affiliation(s)
- Mohan Annamalai
- School of Biosciences and Technology, Vellore Institute of Technology, Vellore, India
| | - Kalaichelvan Gurumurthy
- VIT School of Agriculture Innovations and Advanced Learning, Vellore Institute of Technology, Vellore, India
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Grigorescu RM, Ghioca P, Iancu L, David ME, Andrei ER, Filipescu MI, Ion RM, Vuluga Z, Anghel I, Sofran IE, Nicolae CA, Gabor AR, Gheboianu A, Bucurica IA. Development of thermoplastic composites based on recycled polypropylene and waste printed circuit boards. WASTE MANAGEMENT (NEW YORK, N.Y.) 2020; 118:391-401. [PMID: 32942222 DOI: 10.1016/j.wasman.2020.08.050] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 07/27/2020] [Accepted: 08/25/2020] [Indexed: 06/11/2023]
Abstract
In the last several years, the electronic waste, especially printed circuit boards have significantly increased over the world, generating one of the highest rates of solid waste. The recycling process of the printed circuit boards implies mainly the recovery of metals and glass fibers, while the reuse of the polymeric support has remained largely in the phase of research. In this paper, the non-metallic part of printed circuit boards was used as filler (up to 30%), but also to improve the fire resistance of thermoplastic composites based on recycled polypropylene and diene block-copolymers. The synergy between the elastic effect of elastomers and the reinforcing effect of the waste powder into the thermoplastic matrix was studied by mechanical and dynamo-mechanical analysis, X-ray diffraction, optical microscopy, micro-calorimetry and thermo-gravimetrical analysis. Improved mechanical properties, especially impact strength was observed. The compatibization of components considering the interactions between the ethylene-butylene blocks from the hydrogenated and maleinized styrene-butadiene block-copolymer and recycled polypropylene, respectively between the MA groups and the functionalities of the waste powder, evidenced by FTIR, was highlighted by changes in the X-ray pattern and an increased fire resistance and thermal stability.
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Affiliation(s)
- Ramona Marina Grigorescu
- National Institute for Research & Development in Chemistry & Petrochemistry, ICECHIM, 202 Splaiul Independentei, 060021 Bucharest, Romania.
| | - Paul Ghioca
- National Institute for Research & Development in Chemistry & Petrochemistry, ICECHIM, 202 Splaiul Independentei, 060021 Bucharest, Romania
| | - Lorena Iancu
- National Institute for Research & Development in Chemistry & Petrochemistry, ICECHIM, 202 Splaiul Independentei, 060021 Bucharest, Romania; Valahia University, Doctoral School of Materials Engineering Department, 13 Aleea Sinaia, 130004 Targoviste, Romania
| | - Madalina Elena David
- National Institute for Research & Development in Chemistry & Petrochemistry, ICECHIM, 202 Splaiul Independentei, 060021 Bucharest, Romania; Valahia University, Doctoral School of Materials Engineering Department, 13 Aleea Sinaia, 130004 Targoviste, Romania
| | - Elena Ramona Andrei
- National Institute for Research & Development in Chemistry & Petrochemistry, ICECHIM, 202 Splaiul Independentei, 060021 Bucharest, Romania
| | - Mircea Ioan Filipescu
- National Institute for Research & Development in Chemistry & Petrochemistry, ICECHIM, 202 Splaiul Independentei, 060021 Bucharest, Romania
| | - Rodica-Mariana Ion
- National Institute for Research & Development in Chemistry & Petrochemistry, ICECHIM, 202 Splaiul Independentei, 060021 Bucharest, Romania; Valahia University, Doctoral School of Materials Engineering Department, 13 Aleea Sinaia, 130004 Targoviste, Romania
| | - Zina Vuluga
- National Institute for Research & Development in Chemistry & Petrochemistry, ICECHIM, 202 Splaiul Independentei, 060021 Bucharest, Romania
| | - Ion Anghel
- Police Academy "Alexandru Ioan Cuza", Fire Officers Faculty, Str. Morarilor 3, Sector 2, 022451 Bucharest, Romania
| | - Ioana-Emilia Sofran
- Police Academy "Alexandru Ioan Cuza", Fire Officers Faculty, Str. Morarilor 3, Sector 2, 022451 Bucharest, Romania
| | - Cristian-Andi Nicolae
- National Institute for Research & Development in Chemistry & Petrochemistry, ICECHIM, 202 Splaiul Independentei, 060021 Bucharest, Romania
| | - Augusta Raluca Gabor
- National Institute for Research & Development in Chemistry & Petrochemistry, ICECHIM, 202 Splaiul Independentei, 060021 Bucharest, Romania
| | - Anca Gheboianu
- Valahia University, Institute of Multidisciplinary Research for Science and Technology, 13 Aleea Sinaia, 130004 Târgoviste, Romania
| | - Ioan Alin Bucurica
- Valahia University, Institute of Multidisciplinary Research for Science and Technology, 13 Aleea Sinaia, 130004 Târgoviste, Romania
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20
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Xiong J, Yu S, Wu D, Lü X, Tang J, Wu W, Yao Z. Pyrolysis treatment of nonmetal fraction of waste printed circuit boards: Focusing on the fate of bromine. WASTE MANAGEMENT & RESEARCH : THE JOURNAL OF THE INTERNATIONAL SOLID WASTES AND PUBLIC CLEANSING ASSOCIATION, ISWA 2020; 38:1251-1258. [PMID: 31902310 DOI: 10.1177/0734242x19894621] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Advanced thermal treatment of electronic waste offers advantages of volume reduction and energy recovery. In this work, the pyrolysis behaviour of nonmetallic fractions of waste printed circuit boards was studied. The fate of a bromine and thermal decomposition pathway of nonmetallic fractions of waste printed circuit boards were further probed. The thermogravimetric analysis showed that the temperatures of maximum mass loss were located at 319°C and 361°C, with mass loss of 29.6% and 50.6%, respectively. The Fourier transform infrared Spectroscopy analysis revealed that the spectra at temperatures of 300°C-400°C were complicated with larger absorbance intensity. The nonmetallic fractions of waste printed circuit boards decomposed drastically and more evolved products were detected in the temperature range of 600°C-1000°C. The gas chromatography-mass spectrometry analysis indicated that various brominated derivates were generated in addition to small molecules, such as CH4, H2O and CO. The release intensity of CH4 and H2O increased with temperature increasing and reached maximum at 600°C-800°C and 400°C-600°C. More bromoethane (C2H5Br) was formed as compared with HBr and methyl bromide (CH3Br). The release intensity of bromopropane (C3H7Br) and bromoacetone (C3H5BrO) were comparable, although smaller than that of bromopropene (C3H5Br). More dibromophenol (C6H4Br2O) was released than that of bromophenol (C6H5BrO) in the thermal treatment. During the thermal process, part of the ether bonds first ruptured forming bisphenol A, propyl alcohol and tetrabromobisphenol A. Then, the tetrabromobisphenol A decomposed into C6H5BrO and HBr, which further reacted with small molecules forming brominated derivates. It implied debromination of raw nonmetallic fractions of waste printed circuit boards or pyrolysis products should be applied for its environmentally sound treating.
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Affiliation(s)
- Jingjing Xiong
- College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou, China
| | - Shaoqi Yu
- College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou, China
| | - Daidai Wu
- Chinese Academy of Sciences, Guangzhou Institute of Energy Conversion, Guangzhou, China
| | - Xiaoshu Lü
- Department of Electrical Engineering and Energy Technology, University of Vaasa, Vaasa, Finland
- Department of Civil Engineering, Aalto University, Espoo, Finland
- Construction Engineering College, Jilin University, Chang Chun, China
| | - Junhong Tang
- College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou, China
| | - Weihong Wu
- College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou, China
| | - Zhitong Yao
- College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou, 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: 36] [Impact Index Per Article: 9.0] [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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Yao Z, Xiong J, Yu S, Su W, Wu W, Tang J, Wu D. Kinetic study on the slow pyrolysis of nonmetal fraction of waste printed circuit boards (NMF-WPCBs). WASTE MANAGEMENT & RESEARCH : THE JOURNAL OF THE INTERNATIONAL SOLID WASTES AND PUBLIC CLEANSING ASSOCIATION, ISWA 2020; 38:903-910. [PMID: 31918637 DOI: 10.1177/0734242x19896630] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In this study, the pyrolysis behaviour of nonmetal fraction of waste printed circuit boards (NMF-WPCBs) was studied based on five model-free methods and distributed activation energy model (DAEM). The possible decomposition mechanism was further probed using the Criado method. Thermogravimetric analysis indicated that the NMF-WPCBs pyrolysis process could be divided into three stages with temperatures of 37-330°C, 330-380°C and 380-1000°C. The mass loss at different heating rate was determined as 26.85-29.98%, 13.47-24.21% and 20.43-23.36% for these stages, respectively. The activation energy (Eα) from various model-free methods first increased with degree of conversion (α) increasing from 0.05 to 0.275, and then decreased beyond this range. The coefficient (R) from the Flynn-Wall-Ozawa (FWO) method was higher, and the resulting Eα fell into the range of 214.947-565.660 kJ mol-1. For the DAEM method, the average Eα value was determined as 337.044 kJ mol-1, comparable with 329.664 kJ mol-1 from the FWO method. The thermal decomposition kinetics of NMF-WPCBs could be better described by the second-order reaction.
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Affiliation(s)
- Zhitong Yao
- College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou, China
| | - Jingjing Xiong
- College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou, China
| | - Shaoqi Yu
- College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou, China
| | - Weiping Su
- College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou, China
| | - Weihong Wu
- College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou, China
| | - Junhong Tang
- College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou, China
| | - Daidai Wu
- Chinese Academy of Sciences, Guangzhou Institute of Energy Conversion, Guangzhou, China
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23
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Xing M, Li Y, Zhao L, Song X, Fu Z, Du Y, Huang X. Swelling-enhanced catalytic degradation of brominated epoxy resin in waste printed circuit boards by subcritical acetic acid under mild conditions. WASTE MANAGEMENT (NEW YORK, N.Y.) 2020; 102:464-473. [PMID: 31743837 DOI: 10.1016/j.wasman.2019.11.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 11/08/2019] [Accepted: 11/10/2019] [Indexed: 06/10/2023]
Abstract
Waste printed circuit boards (WPCBs) contain a large amount of brominated epoxy resins (BERs), which may cause environmental problems. However, BERs degradation under mild conditions is challenging due to the good thermal and chemical stabilities of BERs. This study proposes a mild and efficient method that uses subcritical acetic acid (220 °C-260 °C, 2.6-3.6 MPa) to decompose BERs. BERs swell quickly at 200 °C and are thoroughly decomposed into bisphenol A and phenol at 220 °C when the acetic acid mass concentration and holding time are fixed at 49.90% and 1 h, respectively. Experimental results show that subcritical acetic acid has excellent swelling and catalytic degradation effects on BERs. The quick swelling of BERs allows the free migration of the catalyst in the epoxy network and thus significantly enhances the catalytic degradation effect. Therefore, BERs can be thoroughly decomposed by subcritical acetic acid under mild conditions. Temperature and acetic acid concentration are the major parameters that control the resin degradation rate. Bromine-free oil phase products are obtained at ≥240 °C. The possible decomposition pathway of BERs in subcritical acetic acid is also investigated. Most of the bromine is transformed into HBr and enriched in the aqueous phase. In conclusion, the proposed mild method could be used as a novel practical and industrial procedure for the degradation and debromination of BERs.
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Affiliation(s)
- Mingfei Xing
- Institute of Resource and Environment, Henan Polytechnic University, Jiaozuo 454000, Henan, China.
| | - Yu Li
- Institute of Resource and Environment, Henan Polytechnic University, Jiaozuo 454000, Henan, China
| | - Lei Zhao
- Zhengzhou Quality and Technical Supervision and Inspection Center, Zhengzhou 450006, Henan, China
| | - Xiaoyan Song
- College of Geosciences and Engineering, North China University of Water Resources and Electric Power, Zhengzhou 450046, Henan, China
| | - Zegang Fu
- Institute of Resource and Environment, Henan Polytechnic University, Jiaozuo 454000, Henan, China
| | - Yajie Du
- Institute of Resource and Environment, Henan Polytechnic University, Jiaozuo 454000, Henan, China
| | - Xingyu Huang
- Institute of Resource and Environment, Henan Polytechnic University, Jiaozuo 454000, Henan, China; School of Environment Science and Spatial Informatics, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China.
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Advanced Recovery Techniques for Waste Materials from IT and Telecommunication Equipment Printed Circuit Boards. SUSTAINABILITY 2019. [DOI: 10.3390/su12010074] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Waste from information technology (IT) and telecommunication equipment (WITTE) constitutes a significant fraction of waste from electrical and electronic equipment (WEEE). The presence of rare metals and hazardous materials (e.g., heavy metals or flame retardants) makes the necessary recycling procedures difficult and expensive. Important efforts are being made for Waste Printed Circuit Board (WPCB) recycling because, even if they only amount to 5–10% of the WITTE weight, they constitute up to 80% of the recovered value. This paper summarizes the recycling techniques applicable to WPCBs. In the first part, dismantling and mechanical recycling techniques are presented. Within the frame of electro-mechanical separation technology, the chain process of shredding, washing, and sieving, followed by one or a combination of magnetic, eddy current, corona electrostatic, triboelectrostatic, or gravity separation techniques, is presented. The chemical and electrochemical processes are of utmost importance for the fine separation of metals coming from complex equipment such as WPCBs. Thermal recycling techniques such as pyrolysis and thermal treatment are presented as complementary solutions for achieving both an extra separation stage and thermal energy. As the recycling processes of WPCBs require adequate, efficient, and ecological recycling techniques, the aim of this survey is to identify and highlight the most important ones. Due to the high economic value of the resulting raw materials relative to the WPCBs’ weight and composition, their recycling represents both a necessary environmental protection action, as well as an economic opportunity.
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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: 22] [Impact Index Per Article: 4.4] [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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Cesaro A, Belgiorno V, Gorrasi G, Viscusi G, Vaccari M, Vinti G, Jandric A, Dias MI, Hursthouse A, Salhofer S. A relative risk assessment of the open burning of WEEE. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:11042-11052. [PMID: 30793245 PMCID: PMC6469622 DOI: 10.1007/s11356-019-04282-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 01/16/2019] [Indexed: 05/11/2023]
Abstract
Waste electric and electronic equipment (WEEE) represents a potential secondary source of valuable materials, whose recovery is a growing business activity worldwide. In low-income countries, recycling is carried out under poorly controlled conditions resulting in severe environmental pollution. High concentrations of both metallic and organic pollutants have been confirmed in air, soil, water, and sediments in countries with informal recycling areas. The release of these contaminants into the environment presents a risk to the health of the exposed population that has been widely acknowledged but still needs to be quantified. The aim of this work was to evaluate the relative risk from inhalation associated with the open burning of different kinds of WEEE. The shrinking core model was applied to estimate the concentration of the metals which would be released into the environment during the incineration of different types of WEEE. In addition, the potential generation of dioxins during the same informal practice was estimated, based on the plastic content of the WEEE. The results provided for the first time a comparative analysis of the risk posed from the open burning of WEEE components, proposing a methodology to address the absolute risk assessment to workers from the informal recycling of WEEE.
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Affiliation(s)
- Alessandra Cesaro
- Sanitary Environmental Engineering Division (SEED), Department of Civil Engineering, University of Salerno, via Giovanni Paolo II, 84084, Fisciano, SA, Italy.
| | - Vincenzo Belgiorno
- Sanitary Environmental Engineering Division (SEED), Department of Civil Engineering, University of Salerno, via Giovanni Paolo II, 84084, Fisciano, SA, Italy
| | - Giuliana Gorrasi
- Department of Industrial Engineering, University of Salerno, via Giovanni Paolo II, 84084, Fisciano, SA, Italy
| | - Gianluca Viscusi
- Department of Industrial Engineering, University of Salerno, via Giovanni Paolo II, 84084, Fisciano, SA, Italy
| | - Mentore Vaccari
- Department of Civil, Environmental, Architectural Engineering and Mathematics, University of Brescia, via Branze 43, 25123, Brescia, Italy
| | - Giovanni Vinti
- Department of Civil, Environmental, Architectural Engineering and Mathematics, University of Brescia, via Branze 43, 25123, Brescia, Italy
| | - Aleksander Jandric
- Waste Management Institute, BOKU University, Muthgasse 107, 1190, Vienna, Austria
| | - Maria Isabel Dias
- Centro de Ciências e Tecnologias Nucleares - C2TN, Campus Tecnológico e Nuclear, Polo de Loures, Instituto Superior Técnico, Estrada Nacional 10, km 139,7, Bobadela, 2696-066, Loures, Portugal
| | - Andrew Hursthouse
- University of the West of Scotland Paisley Campus, Paisley, PA1 2BE, UK
| | - Stefan Salhofer
- Waste Management Institute, BOKU University, Muthgasse 107, 1190, Vienna, Austria
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Tatariants M, Yousef S, Sakalauskaitė S, Daugelavičius R, Denafas G, Bendikiene R. Antimicrobial copper nanoparticles synthesized from waste printed circuit boards using advanced chemical technology. WASTE MANAGEMENT (NEW YORK, N.Y.) 2018; 78:521-531. [PMID: 32559941 DOI: 10.1016/j.wasman.2018.06.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 06/08/2018] [Accepted: 06/09/2018] [Indexed: 06/11/2023]
Abstract
Waste Printed Circuit Boards (WPCBs) were classified as one of the most important resources for urban mining containing high purity Copper (Cu) and other valuable materials. Recently, a dissolution recycling approach enhanced by ultrasonic treatment succeeded in the liberation of Cu foils from WPCBs as received. This research aims to synthesize Copper Nanoparticles (Cu-NPs) from the recovered Cu by using an advanced chemistry approach to obtain nano-product with high added value taking into consideration environmental risks. The experiments were carried out on the Cu foils recovered from the three types of WPCBs with different purity of Cu (Motherboard, Video Card, and Random Access Memory (RAM)). The synthesis process was performed in two stages: (a) preparation of Copper (II) Sulfate aqueous solutions from the recovered Cu and (b) chemical reduction of solutions for synthesis of Cu-NPs by using Native Cyclodextrins (NCDs), particularly ß-NCD as stabilizers. The efficiency of the developed approach for raw material of different purity was assessed and the final yield and the estimated recovery cost of synthesized Cu-NPs were calculated with high accuracy as well as the properties of the synthesized Cu-NPs. The obtained Cu-NPs were examined using SEM-EDS, TEM, XRD, Raman Spectroscopy, and TGA. To maximize the potential biomedical application benefits, the antibacterial activity of Cu-NPs was investigated by the standard microdilution method for E. coli, P. aeruginosa, and S. aureus bacterial cultures. The results showed that the produced Cu-NPs had an average size of 7 nm and yield 90%, while the preparation costs were 6 times lower in comparison to the commercial counterparts. In addition, the results indicated that the synthesized Cu-NPs from RAM sample had a good antimicrobial action.
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Affiliation(s)
- Maksym Tatariants
- Department of Environmental Technology, Faculty of Chemical Technology, Kaunas University of Technology, LT-51424 Kaunas, Lithuania
| | - Samy Yousef
- Department of Production Engineering, Faculty of Mechanical Engineering and Design, Kaunas University of Technology, LT-51424 Kaunas, Lithuania; Department of Production Engineering and Printing Technology, Akhbar Elyom Academy 6th of October, Egypt.
| | | | | | - Gintaras Denafas
- Department of Environmental Technology, Faculty of Chemical Technology, Kaunas University of Technology, LT-51424 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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