Copper sulphide/cuprous sulphide doped zero-valent iron@carbon (ZVI@C/CuS/Cu2S) activate PMS for rapid and effective decomposition of Ni-EDTA

Ni-EDTA is widely present in electroplating effluents. It cannot be effectively removed by traditional wastewater treatment methods due to its chemical stability. In this study, copper sulphide/cuprous sulphide doped zero-valent iron@carbon (ZVI@C/CuS/Cu₂S) was prepared to active peroxymonsulphate (PMS) to decomposition Ni-EDTA. The ZVI@C/CuS/Cu₂S + PMS process shows excellent performance under neutral or even alkaline conditions. This is due to the acceleration of ZVI electron transport by CuS/Cu₂S, the autocatalysis of CuS/Cu₂S itself, and the synergistic effect of CuS/Cu₂S and Ni-EDTA. The removal efficiency of 50 ppm Ni-EDTA electroplating effluents reached 99.53% at 10 min, and the discharge water can meet the Chinese emission standard. The influences of the main parameters such as initial pH value, catalyst, PMS and initial Ni-EDTA concentration on removal efficiency was systematically investigated.