The electrochemical method was used to remove nickel ion from spent electroless nickel plating bath (pH=5 3). An electrolytic cell was composed of a porous nickel foam cathode and an inert RuO 2/Ti anode. Nickel ions were reduced and deposited on the surface of the nickel foam cathode. The effect of current density (i), linear velocity of wastewater(v), gap between cathode and anode(d C/A) and reaction time(t) on nickel removal rate and current efficiency were studied. As reaction time prolonged, nickel removal rate increased while current efficiency decreased. And larger v and smaller d C/A can enhance nickel removal rate and increase current efficiency by promoting mass transfer and dropping concentration polarization. The effect of current density on nickel removal by electrochemistry was related to other parameters. After three hours’ electrolysis with i=1 0 A/dm2, v=18 5 cm/min and d C/A=0 5 cm, nickel removal rate and current efficiency reached 85 6% and 29 1%, respectively.
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