Waste Management ( IF 8.1 ) Pub Date : 2021-02-13 , DOI: 10.1016/j.wasman.2021.01.010 Kaiyou Huang , Jiongli Zheng , Wenyi Yuan , Xiaoyan Wang , Qingbin Song , Ying Li , John C. Crittenden , Lincai Wang , Jingwei Wang
An efficient, microwave-assisted chemical recovery approach for epoxy resin and glass fiber from non-metallic components (NMC) in waste printed circuit boards (WPCBs) for resource reutilization was developed in this research. HNO3 was selected as the chemical reagent because epoxy resin has low corrosion resistance to HNO3. The influence of reaction parameters such as reaction time, temperature, concentration of HNO3, liquid-solid ratio, and power of the microwave synthesizer on the separation efficiency of NMC (epoxy resin and glass fiber) and the reaction mechanism were investigated. The physical and chemical properties of NMC, reaction solvent, and decomposed products were analyzed using energy dispersive X-ray Spectroscopy (SEM-EDX) and Fourier transform infrared spectroscopy (FT-IR). The results showed that up to 88.42% of epoxy resin and glass fiber ((5 g) 10 mL/g) could be separated under the action of 300 W microwave power at 95 ℃ for 12 h and a HNO3 concentration of 7 mol/L. During the reaction, C-N bonds formed by the crosslinking agent and the three-dimensional network structure of the thermosetting epoxy resin were destroyed. The carbon chain structure and chemical properties of epoxy resin did not change significantly and the functional groups of ethyl acetate maintained the chemical structure before and after the reaction. This uncomplicated and efficient inorganic acid chemical microwave-assisted process holds promise for use as a feasible recovery technology for epoxy resin and glass fibers in NMC. The proposed process is particularly appealing because of its high selectivity, considerable economic advantages, and environmental benefits.
中文翻译:
微波辅助从废印刷电路板中的非金属成分中回收玻璃纤维和环氧树脂
这项研究开发了一种有效的微波辅助化学回收方法,用于从废印刷电路板(WPCB)中的非金属成分(NMC)中回收环氧树脂和玻璃纤维,以进行资源再利用。选择HNO 3作为化学试剂是因为环氧树脂对HNO 3的耐腐蚀性较低。反应时间,温度,HNO 3浓度等反应参数的影响研究了微波合成器的液固比和功率对NMC(环氧树脂和玻璃纤维)的分离效率及反应机理的影响。使用能量色散X射线光谱(SEM-EDX)和傅立叶变换红外光谱(FT-IR)分析了NMC,反应溶剂和分解产物的物理和化学性质。结果表明,在95℃,300 W微波功率和HNO 3的作用下,最多可分离出88.42%的环氧树脂和玻璃纤维((5 g)10 mL / g)。浓度为7 mol / L。在反应过程中,由交联剂形成的CN键和热固性环氧树脂的三维网络结构被破坏。环氧树脂的碳链结构和化学性质没有明显变化,乙酸乙酯的官能团在反应前后保持了化学结构。这种简单,有效的无机酸化学微波辅助工艺有望成为NMC中环氧树脂和玻璃纤维的可行回收技术。所提出的方法特别吸引人,因为它具有高选择性,可观的经济优势和环境效益。