Protein mediated textile dye filtration using graphene oxide–polysulfone composite membranes

Here we report graphene oxide (GO) concentration dependent protein binding (BSA) and dye filtration (RO-16) capabilities of polysulfone–GO composite membranes under different pH conditions (2, 7 and 10). The membranes were fabricated with different GO concentrations (1, 2, 4 and 8% w/w) and were successfully characterized for their physical and chemical properties, as well as for their performance ability. The best BSA binding and dye rejection rates were observed with 2% GO membrane at pH = 10, which were 95% and 78.26% respectively, suggesting that 2% is the optimal concentration. Further, considering the fact that RO-16 dye is acidic friendly, contact time studies were carried out with 2% GO membranes at pH = 2 and pH = 10. It was observed that 2% GO–polysulfone membrane at pH = 2 shows the highest dye rejection rate of 87.4%, supporting the importance of contact time in filtration technology.