A new idea for efficient copper recovery from wastewater by electrodeposition: Adsorption pretreatment

The rapidly growing electroplating industry has led to the discharge of large amounts of wastewater containing heavy metals. Electrodeposition techniques can recover metals from wastewater, which have economic and environmental benefits. However, the application of electrodeposition involves high energy costs facing actual industrial wastewater. This is closely related to the complex nature of the wastewater, which contains high levels of inorganic and organic impurities, which is significantly inconsistent with the water used in the laboratory simulation. In this study, only a simple adsorption process for pretreatment can remove 76 % of the TOC and reduce the electrical conductivity by 38 %. The electrodeposition could reduce the ineffective energy consumption by 60 %–80 % from 10 kw∙h/kg to 6–7 kw∙h/kg for actual wastewater, compared to the effective energy consumption of 5 kw∙h/kg for simulated wastewater, demonstrating that the adsorption pretreatment had a positive effect on the deposition of Cu. Notably, the results of SEM and optical microscope indicated that a more compact copper texture was obtained after pretreatment, and the findings of EDS and XRD showed that both simulated and actual wastewater yielded high-purity metallic Cu. This work provided an effective way to promote the application of electrodeposition in real wastewater treatment.