Influence of pollutant concentration on the separation efficiency of chelating membranes for removing simultaneously metal ions and proteins from simulated industrial wastewater

BACKGROUND A novel chelating membrane was fabricated for removing simultaneously metal ions (Cd2+, Pb2+ and Cu2+) and proteins (bovine serum albumin and lysozyme) from simulated industrial effluent. The purpose of the study was to investigate the influence of pollutant concentration on the separation efficiency of the chelating membrane for pollutants. RESULTS (i) The removal of metal ions mainly relies on the adsorption capacity of the chelating membrane, and seems to be independent of the concentration of protein. (ii) The retention of proteins depends mainly on their concentration in solution. (iii) When the wastewater contains high concentration of metal ions (C = 100 mg L-1) and low concentration of proteins (C = 10 mg L-1), the chelating membrane exhibits overall poor separation performance, with a low ion removal efficiency (55-70%) and a low protein rejection rate (ca 60%). (iv) When the wastewater contains low concentration of metal ions (C = 10 mg L-1) and high concentration of proteins (C = 100 mg L-1), the chelating membrane exhibits overall excellent separation performance, with ion removal rates of higher than 90% (except for Cd2+) and protein rejection rates of higher than 90%. CONCLUSIONS The separation efficiency of the chelating membrane for metallic and organic pollutants greatly depends on the pollutant concentration in the wastewater. This study provides a theoretical basis for membrane technology for removing simultaneously heavy metals and organic pollutants in wastewater. (c) 2022 Society of Chemical Industry (SCI).