EFFICIENT TREATMENT OF Ni II-CITRIC ACID COMPLEXES IN NICKEL PLATING EFFLUENT USING ELECTROCATALYTIC OXIDATION-SYNERGISTIC ELECTRODEPOSITION METHOD AND NICKEL RESOURCE RECOVERY

The chemical nickel plating process generates large volumes of wastewater. This wastewater contains NiII-citric acid complexes (Ni-Cit) that are difficult to treat. This study addressed the challenging Ni-Cit waste streams, focusing on development and implementation of a highly efficient and stable single-compartment approach for nickel recovery through electrocatalytic oxidation in synergistic electrodeposition. Our findings demonstrate that high-purity nickel (Ni) may be successfully recovered from Ni-Cit waste streams by combining electrocatalytic oxidation and electrodeposition. Scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) techniques were utilized to thoroughly examine the nickel recovered from the cathode. The study found that optimal electrochemical treatment was achieved with a current density of 100 mA cm–2, an initial pH of 4.05, and an initial Ni ion concentration of 0.01 M. Ni healing was achieved in 100% of cases after two hours of treatment. By investigating the degradation process of nickel waste solution complexed with citric acid, we proposed the mechanism of Ni-Cit electrocatalytic oxidation for complexation breakdown, and our findings provide a theoretical foundation for the effective treatment of nickel complex-containing wastewater and recovery of nickel metal monomers.