Industrial-scale highly efficient nickel recovery from electroplating wastewater using resin adsorption followed by aeration mixing acid regeneration

Abstract

Cation-exchange resins have been used to recover nickel from electroplating wastewater, but resin regeneration often consumes a large amount of acid and alkali, resulting in low Ni(II) concentrations in regenerating solution. In this study, the industrial-scale Ni(II) recovery from electroplating wastewater using resin adsorption and regeneration was investigated. Two cation-exchange resin tanks and one chelated resin tank in series effectively reduced the nickel concentrations to below 0.1 mg/L. The spent resin could be efficiently regenerated by a novel aeration mixing method, greatly reducing acid and alkali consumption in comparison with the traditional downstream regeneration method. The spent resin was successfully regenerated by 2 bed volume (BV) of 6 % HCl, and the acid utilization ratio was above 99 %. More than 60 g/L of Ni(II) ions in regenerating solution was stably obtained, which benefited the subsequent nickel recovery by electrodeposition. Similarly, H2SO4 was also effective for Ni(II) desorption from the spent resins. The adsorption and regeneration cost was calculated to be ¥ 5.5–9.5/m3 for the electroplating wastewater containing 200–800 mg/L Ni(II) ions, much lower than that by chemical precipitation. This study provided an effective resin regeneration method to consume less regenerants and obtain higher Ni(II) concentrations, making the Ni(II) recovery cost-effective.