Removal of zinc and nickel ions by complexation–membrane filtration process from industrial wastewater Original Research Article

Many industrial wastewater streams contain toxic metal cations, for example, Ni2+, Zn2+, etc. or their oxyanions in up to few hundred mg/dm3, which must be removed before water recycling or discharging directly into surface waters. The conventional processes to treat this kind of wastewater are, e.g. chemical precipitation, ion exchange, membrane separations (such as electrodialysis, nanofiltration, reverse osmosis and ultrafiltration), adsorption or biosorption. In this work a membrane technique, ultrafiltration, completed with complexation was investigated. During the experiments, impact of conditions of membrane, pH and polymer/metal ratio have been investigated. The study series were carried out both of zinc and nickel. According to our studies, the most effective composition both tested metals is the following: PES-10 membrane, PAA complexation agent and pH>8. The volume ratio of the polymer bounding agent and metal ion because of environmental and economical aspects should be about unit.