Nanofiltration composite membranes of polyethersulfone and graphene oxide and sulfonated graphene oxide

In the present study, the polyethersulfone (PES) mixed matrix nanofiltration membranes with the embedding of the graphene oxide (GO) and sulfonated graphene oxide (s-GO) nanoparticles were fabricated via phase inversion method. The effect of GO and s-GO on the morphology and performance-fabricated PES membrane was evaluated in terms of pure water flux, dye retention, salt rejection, heavy metal removal, and antifouling properties. The fabricated membranes were characterized using FE-SEM, AFM, and water contact angle and porosity measurement. As a result, by adding GO and s-GO nanoparticles, the pure water flux (PWF) of mentioned membranes significantly improved due to the higher hydrophilicity. The increased hydrophilicity of the mentioned membranes was proved by the water contact angle data. The evaluation of nanofiltration performance was assessed by rejection measurement of cationic and anionic dyes. The rejection of heavy metals in the following order 97.5%, 87.8%, 76.3%, and 60.6% for Cr, Cd, Cu, and Ni, respectively, was obtained for the sample that contains 1 wt% s-GO. Moreover, other nanocomposite membranes showed relatively good results. The rejection results showed that GO and s-GO nanoparticles embedded membranes have higher dye retention ability than the bare PES. Fouling resistance of the membranes was evaluated by filtration of bovine serum albumin (BSA) solution. The results of antifouling properties showed that the membrane containing 0.5 wt% s-GO had the best fouling resistance.