Article
Chemistry, Analytical
Fu-Rong Xiu, Qingyun Bai, Chuanzhong Chen, Yingying Qi, Siyi Wang, Xiaochun Tan
Summary: In this study, a novel resource conversion strategy using subcritical water-CuO process was developed to produce high-purity phenolic chemicals from waste printed circuit boards. The SubCW-CuO process showed high selectivity and efficiency in producing high-purity phenol and p-cresol products, while effectively fixing bromine.
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
(2022)
Article
Engineering, Environmental
Jingxin Liu, Hanlin Wang, Wenjuan Zhang, Teng Wang, Meng Mei, Si Chen, Jinping Li
Summary: This study investigates the pyrolysis mechanism of printed circuit boards (PCBs) with and without the presence of iron catalyst. It is found that iron can accelerate the pyrolysis reaction and facilitate the conversion of organic bromides to inorganic bromides. Retaining iron is beneficial for energy saving and environmental protection in WPCBs pyrolysis.
JOURNAL OF HAZARDOUS MATERIALS
(2022)
Article
Engineering, Environmental
Ye Chen, Jiakuan Yang, Sha Liang, Jingping Hu, Huijie Hou, Bingchuan Liu, Keke Xiao, Wenbo Yu, Huali Deng
Summary: A method using an enhanced subcritical water process with alkaline additive was proposed for efficient removal of brominated epoxy resins from waste printed circuit boards. The alkaline additive contributes to the removal of bromine by destroying the structure of fiberglass, releasing the resins and facilitating debromination. This approach offers a mild and efficient method for debromination of WPCBs.
RESOURCES CONSERVATION AND RECYCLING
(2021)
Article
Engineering, Chemical
Kai Dean Kang, I. M. S. K. Ilankoon, Meng Nan Chong, Ta Yeong Wu
Summary: This study investigates value recovery using coarse printed circuit boards (PCBs) through organic swelling pre-treatment. The experiment demonstrates the effectiveness of organic swelling in causing cracks and delamination in the multi-layered structure of the PCBs. Copper concentrate with high copper contents can be obtained by performing organic swelling for coarse PCBs. The weakened PCBs after organic swelling can be subjected to a less energy-intensive mechanical method to yield embedded copper foils.
MINERALS ENGINEERING
(2023)
Article
Engineering, Environmental
Kaiyou Huang, Jiongli Zheng, Wenyi Yuan, Xiaoyan Wang, Qingbin Song, Ying Li, John C. Crittenden, Lincai Wang, Jingwei Wang
Summary: An efficient microwave-assisted chemical recovery approach has been developed for recycling epoxy resin and glass fiber from waste printed circuit boards. The results showed that under certain conditions, epoxy resin and glass fiber can be efficiently separated while maintaining the chemical properties of the epoxy resin intact.
Article
Green & Sustainable Science & Technology
Jie Zhu, Zichun Yao, Zhihao Huang, Siyaxuan Xiong, Yetao Tang, Zhenming Xu, Jujun Ruan
Summary: This study accurately analyzed the capture capacity and mechanism of CaCO3 and activated carbon to bromides through quantum chemistry calculation and wet experiments, providing scientific information and approach to the safe resource recovery of waste brominated resin.
JOURNAL OF CLEANER PRODUCTION
(2022)
Article
Engineering, Environmental
Shuyu Chen, Run Li, Yaqi Shen, Lu Zhan, Zhenming Xu
Summary: This study conducted thermogravimetric analysis and kinetic analysis, revealing the positive self-catalytic influence of co-existing metals in waste printed circuit boards (WPCBs) during pyrolysis. It provides a theoretical basis for understanding the catalytic influence of these metals during the pyrolysis process.
FRONTIERS OF ENVIRONMENTAL SCIENCE & ENGINEERING
(2022)
Article
Chemistry, Multidisciplinary
Carlos A. Navarro, Yijia Ma, Katelyn H. Michael, Hanna M. Breunig, Steven R. Nutt, Travis J. Williams
Summary: The presented catalytic, aerobic conditions enable depolymerization of amine-linked epoxy thermoset matrix polymers commonly found in high-performance CFRP materials. Unlike other recycling methods, this process retains the aligned and woven fibers in the same pattern as the parent material and recovers valuable materials from the thermoset matrix.
Article
Green & Sustainable Science & Technology
Gerard Gandon-Ros, Aurora Soler, Ignacio Aracil, Maria Francisca Gomez-Rico, Juan A. Conesa
Summary: This study focused on debromination of waste printed circuit boards (WCBs) under hydrothermal treatment. Experiments were conducted in two different high-pressure reactors, resulting in high debromination efficiency.
JOURNAL OF CLEANER PRODUCTION
(2021)
Article
Engineering, Environmental
Ruitong Gao, Binyang Liu, Lu Zhan, Jie Guo, Jie Zhang, Zhenming Xu
Summary: The study indicated that copper (Cu) has a catalytic effect during the pyrolysis of waste printed circuit boards (WPCBs), promoting the conversion of organic bromides to Br-2 and HBr, and reducing the apparent activation energy.
JOURNAL OF HAZARDOUS MATERIALS
(2021)
Article
Engineering, Environmental
Bruno Monteiro, Liliana M. Martelo, Paulo M. S. Sousa, Margarida M. S. M. Bastos, Helena M. V. M. Soares
Summary: The study evaluated the efficiency of microwave assistance in delaminating waste printed circuit boards, showing microwave to be the most effective method. Optimized parameters resulted in faster and more efficient delamination of WPCBs into metallic and non-metallic components.
Article
Engineering, Environmental
Tianhao Zhang, Xiao Mao, Juanshen Qu, Yang Liu, Asif Ali Siyal, Wenya Ao, Jie Fu, Jianjun Dai, Zhihui Jiang, Zeyu Deng, Yongmeng Song, Daiying Wang, Chtaeva Polina
Summary: Microwave-assisted pyrolysis of waste printed circuit boards was studied, showing that increasing temperature led to higher pyrolysis conversion rates and changes in oil composition. Addition of ZSM-5 and kaolin promoted recombination reactions of pyrolysis products, increasing certain aromatic compounds in the oil while reducing non-condensable gases. Additionally, higher pyrolysis temperatures enhanced transfer of bromine, leading to improved bromine fixation efficiency in pyrolysis residues.
JOURNAL OF HAZARDOUS MATERIALS
(2021)
Article
Polymer Science
Xiongfei Zhang, Chuang Ma, Peiyu Liu, Dan Huang, Pengyun Li
Summary: Due to its high crosslinking density, compact structure, and stable performance, epoxy resin is difficult to degrade, leading to serious environmental pollution problems. In this study, the degradation of amine-cured epoxy resin was investigated using dipropylene glycol dimethyl ether as a swelling agent and nitric acid as an oxidant. The results showed that the degradation rate achieved using the swelling agent-assisted oxidation degradation method was significantly higher than that achieved using only oxidation degradation. The molecular weight of the degradation product was relatively dispersed, composed of low molecular polymer and small fragments, with the molecular weight of the low molecular polymer being approximately 2167. The degradation products primarily contained 4-isopropyl-phenol and (allyloxy)benzene rings. This work provides a new approach to address the degradation, recycling, and pollution of epoxy resin.
EUROPEAN POLYMER JOURNAL
(2023)
Article
Engineering, Environmental
Kaiyou Huang, Wenyi Yuan, Yuhan Yang, Xiaoyan Wang, Junying Xie, Huabo Duan, Xiaodan Li, Lincai Wang, Chenglong Zhang, Jianfeng Bai, Jingwei Wang, John C. Crittenden
Summary: This research developed an efficient method for chemical recycling of thermosetting epoxy resin using ZnCl2/CH3COOH aqueous solution as catalysts system, decomposing epoxy resin under mild reaction conditions. It provided a practical approach for the dissolution and reutilization of non-metallic components in waste printed circuit boards (WPCBs).
Article
Chemistry, Multidisciplinary
Yujiao Kan, Fangyuan Zheng, Ruxin Zhang
Summary: This study investigated the impact of separation technologies for PCBs on the preparation, characterization, and application of pyrolytic carbon. The results showed that pyrolytic carbons prepared from the non-magnetic fraction exhibited better pore characteristics and adsorption properties compared to those prepared from the non-conductive fraction. Additionally, the adsorption process of ciprofloxacin by the pyrolytic carbons was found to be spontaneous and endothermic.
Article
Engineering, Environmental
Xiaojian Liu, Bei Wang, Yayun Ma, Xiangyang Zhou, Juan Yang, Yuehui He, Jingjing Tang, Fanyun Su, Wan Yang
Summary: This study proposes a combined process of reduction roasting of herb-medicine residue and oxalic acid leaching to improve the recovery efficiency of lithium from spent lithium-ion batteries. By utilizing the reducing gas produced from the pyrolysis of herb-medicine residue, the layered structure of the cathode powder is destroyed and converted into Li2CO3, Ni, Co, and MnO. Additionally, selective extraction of lithium is achieved using oxalic acid, and the efficiency and kinetics of lithium extraction are improved under the combined action of herb-medicine residue and oxalic acid.
Article
Engineering, Environmental
Muxina Konarova, Nuno Batalha, Gabriel Fraga, Mohamed H. M. Ahmed, Steven Pratt, Bronwyn Laycock
Summary: This study presents a proof of concept for a technology that integrates PET recovery from mixed plastic waste and plastic pyrolysis. By depolymerizing PET into TPA using a low volatility oil as medium, it achieves low-pressure operation and a selective separation and recovery of TPA from the product mix. Full PET conversion and high TPA recovery were achieved, making it an effective solution for processing mixed waste streams and improving the yield and quality of liquid product from thermal pyrolysis compared to untreated feedstock.
Article
Engineering, Environmental
Zhenhua Sun, Jing Li, Xuejiang Wang, Siqing Xia, Jianfu Zhao
Summary: This study investigated the influence of in-situ formed MgFe2O4 on the hydrothermal treatment of swine manure. The results showed that the in-situ formation of MgFe2O4 improved the dehydration and decarboxylation of organic components in swine manure, thereby improving its carbonization degree. Furthermore, it enhanced the stabilization of heavy metals and the retention of phosphorus. MgFe2O4 modified hydrochars exhibited remarkable adsorption capacity for Pb(II) and Cu(II) without any leaching of heavy metals.
Article
Engineering, Environmental
Yijing Jiang, Boyang Leng, Jingxin Xi
Summary: The increased generation of municipal solid waste has had a significant impact on the economy, environment, and public health. The current waste treatment process has limitations. By developing a comprehensive social costing model, this study assesses the impacts of municipal solid waste management throughout its life cycle and provides policymakers with best practices and feasibility information.
Article
Engineering, Environmental
Marina Hernandes de Paula e Silva, Ricardo Coser Mergulha, Jose Geraldo Vidal Vieira, Andrea Brasco Pampanelli, Rodrigo Salvador, Diogo Aparecido Lopes Silva
Summary: This study developed and implemented a self-assessment tool to assist companies in decision-making processes for establishing circular flows based on Lean Manufacturing and Circular Economy principles. The tool utilized a maturity model and was applied to nine companies of varying characteristics. The findings revealed that certain companies showed higher maturity in water-waste and chemical-emissions management, with larger enterprises focusing on these strategies. However, many companies lacked sufficient training and employee awareness prior to seeking cleaner alternatives, and comprehensive actions to manage the product lifecycle were lacking. To address these gaps, the tool provided tailored recommendations for each company to improve their processes, products, and value chain.
Article
Engineering, Environmental
Gamze Dogdu, Turgay Pekdemir, Sanaz Lakestani, Seyda Karabork, Osman Cavus
Summary: This paper presents data on food waste associated with mini size food packaging services, highlighting the difficulties in emptying the food and consumer wastefulness as the main causes. These findings have significant implications for the sustainability of food and relevant packaging.
Article
Engineering, Environmental
Qingxia Li, Xin Kong, Yuxin Chen, Jianan Niu, Jia Jing, Jin Yuan, Yifeng Zhang
Summary: This study investigates how to enhance methane production from food waste after hydrothermal pretreatment. The results demonstrate a significant increase in methane yield when zero-valent iron and magnetite are used together, and high organic loading is favorable for methane production. Microbial diversity analysis further reveals the dominant pathways and metabolic processes involved in methane generation.
Article
Engineering, Environmental
D. H. H. Sim, I. A. W. Tan, L. L. P. Lim, E. T. Lau, B. H. Hameed
Summary: The development of controlled-release fertilizer formulation is important for preventing environmental pollution caused by nutrient leaching and volatilization. This study combined biochar-based fertilizer with encapsulation technology to improve the nutrient release mechanism. Optimal conditions for synthesizing urea-impregnated biochar (UIB) were determined using central composite design, and the release of nitrogen was described by mathematical models. Results showed that encapsulated UIB (EUIB) achieved complete release of nitrogen in water and exhibited improved water retention in sandy-textural soil. Therefore, EUIB derived from peppercorn waste has the potential to be used as a sustainable controlled-release fertilizer for agriculture.
Article
Engineering, Environmental
Yuchuan Wang, Neslihan Akdeniz
Summary: Incorporating biochar into composting systems can increase compost temperatures. This study developed a heat transfer model for a biochar-amended co-composting system and found that biochar increased thermal conductive losses but also enhanced microbial activity, resulting in an overall increase in total heat unit. When biochar was applied on the surface, it mainly functioned as an insulator.
Article
Engineering, Environmental
George Tsalis, Birger Boutrup Jensen, Jessica Aschemann-Witzel
Summary: This paper empirically explores the relationship between retail price promotions and household food waste. The results show that households with a higher proportion of discount food purchases and environmental awareness tend to waste less food, while larger households and those lacking food handling skills tend to waste more food.
Article
Engineering, Environmental
Lukas Friederici, Arne Koch, Patrick Martens, Jana Pantzke, Sebastiano Di Bucchianico, Thorsten Streibel, Christopher P. Rueger, Ralf Zimmermann
Summary: The increasing demand for lightweight materials has led to a rise in fiber-reinforced plastic (FRP) production. However, the properties and compositional range of FRPs pose challenges to recycling strategies. Pyrolysis has emerged as a promising method for separating the fibers from the polymer matrix. This study investigated the pyrolysis process using thermal analysis and high-resolution mass spectrometry, and also assessed the toxicity of the recovered fibers using an in vitro model.
Review
Engineering, Environmental
Devika Kannan, Shakiba Khademolqorani, Nassibeh Janatyan, Somaieh Alavi
Summary: This paper introduces Smart Waste Management (SWM) that applies Industry 4.0 technologies in waste management. A framework called SWM4.0 is developed, which highlights the importance of smart people, smart cities, smart enterprises, and smart factories in achieving successful waste management. The paper also suggests future research directions and managerial implications.