Efficient separation and extraction of copper ions from electroplating wastewater by capacitive deionization using...

As a hot issue, the scientific and effective separation and extraction of heavy metal ions from complex industrial effluent deserves wide investigation. Copper is an important valuable heavy metal in industrial wastewater. Selective extraction of copper ion (Cu²⁺) from effluent not only alleviates the shortage of resources, but also has economic and social benefits. In this study, we used capacitive deionization (CDI) to selectively extract Cu²⁺ from electroplating wastewater using the bimetallic sulfide CuFeS₂ electrode. The CuFeS₂ electrode showed good Cu²⁺ extraction performance and selectivity in a variety of cationic coexistence systems and real electroplating wastewater, indicating its potential for practical application. Specifically, the adsorption capacity of Cu²⁺ was up to 208.3 mg g^-1 in a 100 mg L^-1 CuSO₄ solution. The CuFeS₂ electrode removed more than 90 % of Cu²⁺ and had the highest partition coefficient (K_d) in a variety of cationic coexistence systems. The characterizations demonstrated that the excellent performance of CuFeS₂ electrode during the adsorption process was mainly due to the Faraday redox reaction. This work offers a novel approach and theoretical basis for extracting Cu²⁺ from electroplating wastewater by capacitive deionization.