A Study On The Treatment Of Nickel Electroplating Rinse Water By Twice Nanofiltration And Electrolysis

On the purpose of recycling metal and wastewater,this paper discussed the reuse strategy of electroplating nickel rinse water using a nanofiltration process. The study evaluated the effect of temperature,pressure,feed rate,Ni²⁺ concentration, and additive on rejection of nickel and permeate flux. Experimental data indicate that the optimal operating condition is at a pressure of 2.0MPa, temperature of 25℃, and feed rate of 2400L/h, at which the average rejection of nickel is greater than 99 %. A solution with a nickel concentration of 30 mg/L was concentrated more than 600 times by twice nanofiltration, resulting in its concentration up to 17679 mg/ L. At this concentration, the nickel can be reused for electroplating. The first 98.38% permeate pool of the nanofiltration had a nickel concentration less than 1mg/L. The following 9.62% permeate pool had a concentration less than 2.3mg/L, and the last 2.88% permeate pool had a concentration less than 15mg/L. The first permeate pool meets the discharge specification, while the following pools can be recycled to the feed in the nanofiltration process. A high permeate flux was maintained throughout the entire filtration process even at high nickel concentrations in the feed. On the basis of successful experiments , a project with 200 m3/ d for treating electroplating nickel patching liquor, the application of the separation technology with nanofiltration membrane in the treatment of electroplating nickel rinse wateris not only reasonable technically but also feasible economically. The results demonst rated that metallic nickel with good quality could be retrieved by this way under the condition of high current density, and the current efficiency was also high. Then recovering of 90% metallic Ni from concentrated electroplating nickel rinse water by electrolysis . The best electrolytic paramelers are experimentally established.This TFC?-S nanofiltration process is suitable for industrial production due to its process simplicity and low capital and operational costs. The experimental results provide basis and references for the designand operation of actual systems. The application of membrane separation technique in treatment of electroplating wastewater will produce remarkable social benefits.