Effect of copper content on the pyrolysis process of organic components in waste printed circuit boards: Based on experimental and quantum chemical DFT simulations
{"title":"Effect of copper content on the pyrolysis process of organic components in waste printed circuit boards: Based on experimental and quantum chemical DFT simulations","authors":"","doi":"10.1016/j.cjche.2024.04.024","DOIUrl":null,"url":null,"abstract":"<div><p>In recent years, scientists have become increasingly concerned in recycling electronic trash, particularly waste printed circuit boards (WPCBs). Previous research has indicated that the presence of Cu impacts the pyrolysis of WPCBs. However, there may be errors in the experimental results, as printed circuit boards (PCBs) with copper and those without copper are produced differently. For this experiment, we blended copper powder with PCB nonmetallic resin powder in various ratios to create the samples. The apparent kinetics and pyrolysis properties of four resin powders with varying copper concentrations were compared using nonisothermal thermogravimetric analysis (TG) and thermal pyrolysis-gas chromatography mass spectrometry (Py-GC/MS). From the perspective of kinetics, the apparent activation energy of the resin powder in the pyrolysis reaction shows a rise (0.1<α<0.2)-stable (0.2<α<0.4)-accelerated increase (0.4<α<0.8)- decrease (0.8<α<0.9) process. After adding copper powder, the apparent activation energy changes more obviously when (0.2<α<0.4). In the early stage of the pyrolysis reaction (0.1<α<0.6), the apparent activation energy is reduced, but when α = 0.8, it is much higher than that of the resin sample without copper. Additionally, it is discovered using thermogravimetric analysis and Py-GC/MS that copper shortens the temperature range of the primary pyrolysis reaction and prevents the creation of compounds containing bromine. This inhibition will raise the temperature at which compounds containing bromine first form, and it will keep rising as the copper level rises. The majority of the circuit board molecules have lower bond energies when copper is present, according to calculations performed using the Gaussian09 software, which promotes the pyrolysis reaction.</p></div>","PeriodicalId":9966,"journal":{"name":"Chinese Journal of Chemical Engineering","volume":null,"pages":null},"PeriodicalIF":3.7000,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Chinese Journal of Chemical Engineering","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S100495412400185X","RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENGINEERING, CHEMICAL","Score":null,"Total":0}
引用次数: 0
Abstract
In recent years, scientists have become increasingly concerned in recycling electronic trash, particularly waste printed circuit boards (WPCBs). Previous research has indicated that the presence of Cu impacts the pyrolysis of WPCBs. However, there may be errors in the experimental results, as printed circuit boards (PCBs) with copper and those without copper are produced differently. For this experiment, we blended copper powder with PCB nonmetallic resin powder in various ratios to create the samples. The apparent kinetics and pyrolysis properties of four resin powders with varying copper concentrations were compared using nonisothermal thermogravimetric analysis (TG) and thermal pyrolysis-gas chromatography mass spectrometry (Py-GC/MS). From the perspective of kinetics, the apparent activation energy of the resin powder in the pyrolysis reaction shows a rise (0.1<α<0.2)-stable (0.2<α<0.4)-accelerated increase (0.4<α<0.8)- decrease (0.8<α<0.9) process. After adding copper powder, the apparent activation energy changes more obviously when (0.2<α<0.4). In the early stage of the pyrolysis reaction (0.1<α<0.6), the apparent activation energy is reduced, but when α = 0.8, it is much higher than that of the resin sample without copper. Additionally, it is discovered using thermogravimetric analysis and Py-GC/MS that copper shortens the temperature range of the primary pyrolysis reaction and prevents the creation of compounds containing bromine. This inhibition will raise the temperature at which compounds containing bromine first form, and it will keep rising as the copper level rises. The majority of the circuit board molecules have lower bond energies when copper is present, according to calculations performed using the Gaussian09 software, which promotes the pyrolysis reaction.
期刊介绍:
The Chinese Journal of Chemical Engineering (Monthly, started in 1982) is the official journal of the Chemical Industry and Engineering Society of China and published by the Chemical Industry Press Co. Ltd. The aim of the journal is to develop the international exchange of scientific and technical information in the field of chemical engineering. It publishes original research papers that cover the major advancements and achievements in chemical engineering in China as well as some articles from overseas contributors.
The topics of journal include chemical engineering, chemical technology, biochemical engineering, energy and environmental engineering and other relevant fields. Papers are published on the basis of their relevance to theoretical research, practical application or potential uses in the industry as Research Papers, Communications, Reviews and Perspectives. Prominent domestic and overseas chemical experts and scholars have been invited to form an International Advisory Board and the Editorial Committee. It enjoys recognition among Chinese academia and industry as a reliable source of information of what is going on in chemical engineering research, both domestic and abroad.