Copper Removal from Aqueous Solution by Polymer-Enhanced Ultrafiltration Method Using Polyacrylic Acid (PAA) and Polyvinyl Alcohol (PVA) Polymers

Abstract

Abstract The presence of heavy metals with low concentrations in water sources can cause problems for human beings, the environment, and animals; so heavy metals should be eliminated from different wastewaters before discharging into water sources. Copper is one of the heavy metals which can cause several problems in low concentrations for animals and especially problems for plants. There are different methods for copper removal from aqueous solutions such as adsorption, chemical precipitation, photocatalysis, ion exchange, membrane filtration, etc. Ultrafiltration (UF) is a kind of membrane filtration. Polymer-enhanced ultrafiltration (PEUF) is able to overcome the limitation of removing heavy metals in UFs and achieve a high removal of heavy metals. In this research, polyacrylic acid (PAA) and polyvinyl alcohol (PVA) polymers, were used separately with UF to remove copper (Cu) from aqueous solutions. Effects of parameters such as pH, copper concentration, the weight ratio of polymer to copper (P/Cu), ionic strength of the influent solution, and filtration pressure on PEUF performance were examined. Also, response surface analyses were applied to see the simultaneous effect of two parameters. Copper removal of more than 67% was obtained by the use of a 5 kiloDalton (kDa) UF membrane without using a polymer which is a relatively high amount. In some conditions, the study has achieved more than 90% copper removal.