Calcined electroplating sludge as a novel bifunctional material for removing Ni(II)-citrate in electroplating wastewater

Abstract

Electroplating sludge as the hazardous waste produced from the electroplating wastewater treatment plants, is also precious resources of various transition metals. In this study, the novel calcined electroplating sludge (CES) was prepared via facile calcination and subsequently used as an effective bifunctional material for removing Ni(II)-citrate in electroplating wastewater. The CES displayed a high removal efficiency of Ni(II)-citrate in the CES/H2O2 system via oxidative degradation of complex compounds and adsorptive removal of Ni2+. The high removal efficiency could be ascribed to the excellent catalysis and adsorption ability of the CES. The Fe and Cu oxides in the CES were considered as reactive components for the activation of H2O2 to degrade the complex compound, while the oxygen-containing functional groups on the CES surfaces were responsible for the adsorption of Ni2+. Various parameters affecting Ni(II)-citrate in the electroplating wastewater removal efficiency were tested. With the addition of 50 mmol/L H2O2 and 1.5 g/L CES, 87% of the total nickel could be removed within 50 min when the total nickel concentration in the Ni(II)-citrate containing electroplating wastewater was 283 mg/L. This study provides a new method for the treatment of electroplating wastewater containing nickel-organic complexes by the electroplating sludge wastes. This technology can reduce the treatment cost of electroplating wastewater and achieve the concept of disposal waste with waste.