Removal of Nickel and Boron from Plating Rinse Effluent by Electrochemical and Chemical Techniques

In this work, electrotreatment of nickel and boron containing plating rinse effluents was studied with mild steel and aluminum electrodes. Industrial effluent treatment directly by an electrochemical technique is capable of removing 80–85 % nickel. The residual nickel interfered with boron determination by curcumin method. The pH fall during electrotreatment in industrial effluent is due to electrodeposition of nickel at the cathode surface, evidenced by simulated effluent treatment. Nickel concentration can be reduced below the discharge limit from the industrial plating effluent by chemical precipitation and coagulation at pH above 8. Chemical precipitation showed maximum boron removal of about 50 %. Boron removal was 29.3–41.9 % and 20.6–33.1 % with ferric chloride and aluminum sulfate, respectively. A combination of chemical precipitation at pH 8.7 followed by electrotreatment reduces nickel to the discharge limit and also maximizes boron removal up to 59 %. The electrotreatment of nickel and boron containing plating rinse effluents is studied with mild steel and aluminum electrodes. The nickel concentration can also be reduced below the discharge limit from industrial plating effluent by chemical precipitation and coagulation. The optimum operating conditions for metal ion removal using both techniques are established.