Treatment of lead frame nickel-plating wastewater with newly designed electrodeposition reactor

Nickel pollution is usually caused by several industrial processes such as electroplating, plastics manufacturing, nickel-cadmium batteries, fertilizers, pigments, mining and metallurgy, and it may cause severe damage to lungs, kidneys, gastrointestinal distress, e.g., nausea, vomiting, diarrhea, pulmonary fibrosis, renal edema, and skin dermatitis. Moreover, it is also a known carcinogen. Therefore, it is necessary to develop effective and inexpensive methods to remove and/or recover nickel. In this work, electrotreatment of a high strength industrial lead frame nickel-plating waste- water ([Ni] = 16000 mg L^-1) was studied with newly designed electrodeposition reactor. The electrolyte was circulated rapidly past the anode and cathode at a higher flow rate, allowing for improvements in efficiency and recovery, and then nickel electrodeposited on the surface of cathode. The effect of solution pH and current density was investigated as well. The results showed that the pH decreased during the electrotreatment, which is due to the production of H+ on the anode surface, and the lower current density was accompanied with the higher current efficiency. In this study, the optimum pH value was found in the range of 2-2.5. Under the optimum conditions, over 99.9% nickel would be removed.