Combination of multi-oxidation process and electrolysis for pretreatment of PCB industry wastewater and recovery of highly-purified copper

Abstract

Current approach for wastewater treatment in the field of printed circuit board (PCB) is uneconomical and resource-wasting, which has turned into a heavy burden for the enterprise. Therefore, it is highly urgent to develop a cost-efficient and sustainable strategy for the remediation of PCB wastewater. In this work, a multi-oxidation coupled with electrolysis approach was proposed for the decontamination of PCB wastewater and recovery of copper element simultaneously. Based on this multi-oxidation of UV/KMnO4/Na2S2O8/H2O2, the chelate bonds of Cu and organic ligands can be effectively broken to release numerous free Cu2+ ions, and chemical oxygen demand (COD) of PCB wastewater sharply decreased from 32,800 to 1680 mg/L, leading to a high COD removal efficiency of 94.9%. Subsequently, as high as 90.1% of free Cu2+ ions can be easily transformed into high-value Cu element by a simple electrodeposition process. The degradation products in different oxidation systems were identified by the LC–MS/MS. The degradation pathway has also been proposed. The relationships among the recovery efficiency of copper, electrode distance and power consumption were studied. Based on the analysis of techno-economic benefits, the net income of this proposed coupling technology in engineering application reached up to ¥1414800.