Tailoring lixiviant properties to optimise selectivity in E-waste recycling
Tailoring lixiviant properties to optimise selectivity in E-waste recycling
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DOI：
10.1039/d2su00038e
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发表时间：
2023-01-12
期刊：
影响因子：
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通讯作者：
Abbott, Andrew P.
中科院分区：
文献类型：
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作者：
Hartley, Jennifer M.;Scott, Sean;Abbott, Andrew P.
电子垃圾产生的规模使得技术金属的选择性回收成为一个重要的研究课题。以前的研究表明，深度共晶溶剂（DESs）可以快速消化金，在本研究中，研究了不同的水和乙二醇含量对DESs中选择性回收金属能力的影响。结果发现，由于溶液粘度的降低，水含量的增加导致铜的金属蚀刻速率增加，但由于氯化物和氧化物/氢氧化物化学之间的竞争导致钝化膜的形成，镍、银和金的蚀刻速率降低。以碘为催化剂，研究了不同溶剂组成下的形态形成。两种三卤化物的比例基本上不受溶剂组成的影响，但由于氯浓度较低导致碘的溶解度降低，在20%的水中检测到分子碘的存在。结果表明，在低含水量条件下，溶剂的物理性质对金属蚀刻速率的影响最为重要，而在高含水量条件下，氧化物/氢氧化物化学的影响更为显著，从而使pcb中铜的选择性金属蚀刻成为可能。水在DES中的存在通过钝化层的形成赋予了金属蚀刻的选择性。
The scale of E-waste production makes the selective recovery of technology metals an important research topic. It has previously been shown that deep eutectic solvents, DESs, can be used to rapidly digest gold and in the current study the effect of varying water and ethylene glycol content on the ability to selectively recover metals in DESs was investigated. It was found that increased water content resulted in an increase in metal etching rates for copper due to the decreasing viscosity of the solution, but etching rates of nickel, silver and gold were decreased due to the competition between chloride and oxide/hydroxide chemistry causing passivating films to form. Iodine was used as a catalyst and speciation was investigated in different solvent compositions. The ratio of the two trihalide species was mostly unaffected by solvent composition, but the presence of molecular iodine was detected with 20 wt% water due to decreased iodine solubility resulting from lower chloride concentration. It was determined that solvent physical properties were most important for metal etching rates at low water content, but at high water content the effect of oxide/hydroxide chemistry was more significant, resulting in the possibility of selective metal etching of copper from PCBs.The presence of water in a DES imparts selectivity to metal etching via the formation of passivation layers.