Improving performance in algal organic matter filtration using polyvinylidene fluoride–graphene oxide nanohybrid membranes

Abstract

This study investigated the characteristics of various graphene oxide (GO) nanohybrid membranes and their performance in algal organic matter (AOM) filtration. The membranes were fabricated by phase inversion method. The effect of GO and its nanohybrids embedded in membranes was investigated in terms of wettability, porosity, pore size, surface charge, composition, morphology, permeability, fouling resistance and antimicrobial ability. In addition, the rejection of protein and carbohydrate as critical foulants in AOM was studied. Based on the findings, all the composite membranes showed lower flux decline than PVDF membrane. Composite membranes maintained higher protein (81–86%) and carbohydrate (77–83%) rejection compared with PVDF membrane (64% for protein and 63% for carbohydrate). However, the reversible to irreversible fouling ratio of PVDF, ZnO/GO-PVDF, Ag/GO-PVDF and GO-PVDF membranes was 3.07, 1.53, 0.86 and 1.09, respectively. This scenario implied that more hydrophilic substances in small molecular weight (MW) contained in AOM had plugged the composite membranes' pores and resulted in irreversible fouling. On the other hand, ZnO/GO-PVDF and Ag/GO-PVDF membranes exhibited superior antimicrobial ability and showed great potential in anti-biofouling mitigation.