Removal of Heavy Metals from Electroplating Wastewater by Thin-Film Composite Nanofiltration Hollow-Fiber Membranes

In this study, thin-film composite nanofiltration (NF) hollow-fiber membranes were used to remove heavy metals from actual electroplating wastewater. The effects of the operating pressure, feed temperature, and feed pH on the membrane performance for the treatment of electroplating wastewater were investigated. The rejection rates for chromium, copper, and nickel ions reached 95.76%, 95.33%, and 94.99%, respectively, at 0.4 MPa. With a rise in the feed temperature, the permeate flux increased while the rejection rates of heavy metals did not significantly change. It was evident that the feed pH greatly affected the permeate flux and heavy-metal rejection as well. In addition, all of the rejection rates of heavy metals by the membrane were over 94.8% throughout the electroplating wastewater concentration process. Also, the NF hollow-fiber membrane showed good stability in electroplating wastewater with a pH value of 2.31.