Decomplexation of Ni(II)-citrate and recovery of nickel from chelated nickel containing electroplating wastewater by peroxymonosulfate with nickel

In this work, Ni(II) was used as peroxymonosulfate (PMS) activator for decomplexation of Ni(II)-citrate, and subsequently applied for the decomplexation of chelated nickel in the electroless nickel plating wastewater. Effect of the co-existed substances (HCO3−, HPO32−, H2PO2−, and P2O74−) on the decomplexation of Ni(II)-citrate were evaluated. Interestingly, except for H2PO2−, the presence of HCO3−, HPO32−, and P2O74− enhanced the decomplexation efficiency of Ni(II)-citrate via promoting the decomposition of PMS. Based on the radical quenching experiments and electron spinning resonance (ESR) spectra analysis, OH, SO4‐, and 1O2 were the primary reactive species involved in the decomplexation reaction process. Furthermore, after the decomplexation of the electroless nickel plating wastewater by PMS, the recovery of nickel was successfully achieved via adsorption coupled with electrodeposition, and 93.1% nickel recovery could be accomplished with initial Ni(II) eluent concentration of 32.5 g/L. Therefore, this study provides a green and promising approach for the application of advanced oxidation processes based on PMS activation, and has the potential to convert recoverable resources into value-added products from electroplating wastewater.