State Key Laboratory of Chemical Engineering, Co-Innovation Center of Chemical Science and Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology and School of Chemical Engineering and Technology , Tianjin University , Tianjin 300350 , China.
Brook Byer Institute for Sustainable Systems and School of Civil and Environmental Engineering , Georgia Institute of Technology , Atlanta , Georgia 30332 , United States.
Environ Sci Technol. 2018 May 15;52(10):5940-5948. doi: 10.1021/acs.est.7b06298. Epub 2018 Apr 24.
Developing effective technologies for treatment of spent etchant in printed circuit boards industries is of paramount for sustainable copper reuse and reducing copper discharge. We developed a novel closed-loop electrochemical cell for on-site regeneration of spent acidic cupric chloride etchant. It does not have any emissions and recycles all the copper using a three-dimensional graphite felt anode decorated with carbon nanotube (CNT/GF). The CNT/GF anode oxidizes Cu(I) to Cu(II) so that the spent cuprous chloride can be converted to cupric chloride and reused. The decorated CNT layer with abundant oxygen-containing functional groups significantly enhanced the electrocatalytic activity for Cu(II)/Cu(I) redox. The CuCl is oxidized to CuCl at the anode and the CuCl is reduced to Cu(0) at the cathode. The closed-loop cycle system converts the catholyte into the anolyte. On average, the energy consumption of Cu(I) oxidation by CNT/GF is decreased by 12%, comparing to that by untreated graphite felt. The oxidation rate of Cu(I) is determined by the current density, and there is no delay for the mass transport of Cu(I). This study highlights the outstanding electrocatalytic performance, the rapid mass-transfer kinetics, and the excellent stability of the CNT/GF electrode, and provides an energy-efficient and zero-emission strategy for the regeneration of etchant waste.
开发用于处理印刷电路板行业废蚀刻液的有效技术对于可持续的铜再利用和减少铜排放至关重要。我们开发了一种新型的闭环电化学电池，用于现场再生废酸性氯化铜蚀刻液。它没有任何排放物，并使用三维石墨毡阳极（涂有碳纳米管 (CNT/GF)）回收所有的铜。CNT/GF 阳极将 Cu(I)氧化为 Cu(II)，从而将废亚铜氯化物转化为氯化铜并重复使用。涂有 CNT 层的电极具有丰富的含氧官能团，显著提高了 Cu(II)/Cu(I)氧化还原的电催化活性。在阳极，CuCl 被氧化为 CuCl，在阴极，CuCl 被还原为 Cu(0)。闭环循环系统将阴极电解液转化为阳极电解液。平均而言，与未经处理的石墨毡相比，CNT/GF 对 Cu(I)氧化的能耗降低了 12%。Cu(I)的氧化速率由电流密度决定，并且 Cu(I)的传质没有延迟。这项研究突出了 CNT/GF 电极的出色电催化性能、快速传质动力学和优异的稳定性，为蚀刻液废物的再生提供了一种节能且零排放的策略。
