Removal of trace copper from simulated nickel electrolytes using a new chelating resin

A novel tert-butyl 2-picolyamino-N-acetate-functionalized chelating resin (abbreviated as PS-AMPY) with high selectivity was synthesized for the removal of trace copper from simulated nickel electrolytes. In the single metal solution, the adsorption of Cu (II) was described by the Langmuir isotherm model, while the adsorption of Ni (II) was fitted well to the Langmuir isotherm model and Freundlich isotherm model, and the maximum adsorption capacities for Cu (II) and Ni (II) were 1.22 mmol/g and 0.44 mmol/g, respectively. Kinetic experiments could be represented by the pseudo-second-order model, and the thermodynamic parameters showed that the adsorption of Cu (II) and Ni (II) was an endothermic and spontaneous process. Besides, the highest selectivity coefficient was up to 2242 for Cu (II) versus Ni (II) in the binary metal solutions. The dynamic column adsorption and regeneration studies confirmed that the PS-AMPY resin had the potential to be used as an effective adsorbent for the removal and selective recovery of Cu (II) from simulated nickel electrolytes. Moreover, the residual concentration of Cu (II) in the purified nickel electrolyte was reduced to <3 mg/L within the first 18 BV, and the mass ratio of Cu/Ni was 20 in the saturated resin, which completely satisfied the industrial requirements of the nickel electro-refining process to prepare high-purity nickel product from simulated nickel electrolytes. In addition, the interactions between PS-AMPY resin and Cu (II) were investigated by X-ray photoelectron spectroscopy (XPS).