Eco-Friendly Hydrophilic Membranes for Sustainable Pervaporative Removal of Heavy Metals from Industrial Wastewater

Abstract In this study, the removal of certain metals from synthetic and real wastewater samples with different contamination levels is investigated using hydrophilic membranes through the pervaporation method. Poly(vinyl alcohol) (PVA), κ-carrageenan (κ-CRG), sodium alginate (ALG), and chitosan (CS) are separately grafted with ethylene glycol dimethacrylate (EGDMA) using cerium ammonium nitrate (CAN), ammonium persulfate (APS), and benzoyl peroxide (BPO) as initiators, resulting in the synthesis of PVA-g-EGDMA, κ-CRG-g-EGDMA, ALG-g-EGDMA, and CS-g-EGDMA graft copolymers. Blend membranes are prepared by mixing each hydrophilic graft copolymer with PVA at ratios of 1/1 and 2/1, namely PVA/PVA-g-EGDMA, PVA/κ-CRG-g-EGDMA, PVA/ALG-g-EGDMA, and PVA/CS-g-EGDMA. The membranes are characterized by Atomic Force Microscopy (AFM) and contact angle measurements. Pervaporation experiments are carried out to remove Cr 6+ , Cd 2+ , Ni 2+ , and Pb 2+ ions from wastewater samples. The rejection (%R) values obtained with the hydrophilic membranes range between 162 and 236 for Cr 6+ , 157–210 for Cd 2+ , 102–135 for Ni 2+ , and 108–142 for Pb 2+ , while the flux values are in the range of 0.01–1.36 kg/m²h. The best pervaporation performance is achieved with the PVA/κ-CRG-g-EGDMA membrane.