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Improvement of the performance of PES nanocomposite membrane incorporated with citric acid-modified graphene oxide for the removal of heavy metals

This work reports the preparation of a high performance polyethersulfone mixed matrix nanocomposite membrane incorporated with citric acid-decorated graphene oxide (GO-CA). The effect of the additive on morphology, performance and antifouling properties of the prepared membranes was investigated using common available techniques. Scanning electron microscopy images illustrated no cracks on the top of the surface, showing favorable dispersing of GO-CA in the bulk of the modified membranes. In addition, the retention ability of the membranes towards Cr3+ and Pb2+ ions was increased to over four times at appropriate dosages of GO-CA. In this regard, the mixed matrix membranes composed of GO-CA nanosheets showed a remarkable and desired antifouling properties (over 99.4% in comparison with 86.2% for the pristine membrane) during filtration of bovine serum albumin solution. The results clearly indicated that the alteration of roughness and hydrophilicity causes the suppression of fouling owing to the presence of GO-CA. Eventually, the alteration in surface charge (Donnan exclusion) and pore size (steric hindrance) of the membranes composed of GO-CA determined the value of rejection.