Synthesis and characterization of novel PES/GO-g-PSS mixed matrix membranes with outstanding antifouling and dye rejection properties

In this study, a novel mixed matrix ultrafiltration membrane based on polyethersulfone (PES) was prepared by embedding graphene oxide-g-polystyrene sulfonate (GO-g-PSS) nanoplates into the polymer matrix by using the phase inversion method. The GO-g-PSS nanoplates were synthesized by using the ATRP method, based on which the ATRP initiator was first grafted onto pre-modified graphene oxide (GO-NH2), and subsequently, the polymerization process was carried out in the presence of monomers. Water contact angle and porosity measurements were both employed for characterization of the prepared membranes. Additionally, the structure and morphology of all the prepared membranes were evaluated by using scanning electron microscopy (SEM) and atomic force microscopy (AFM). It was also found that, using these nanoparticles, water flux, porosity and hydrophilicity of membranes remarkably increased. Moreover, the more the modified GO loading amount increased, the more the roughness of the prepared membranes increased. The performance of all the prepared membranes was also investigated in terms of rejection, flux recovery and fouling parameters. Accordingly, the retention of two dyes and bovine serum albumin (BSA) molecules was tested, by which the effects of mean pore size, dimensions of permeated molecules and hydrophilicity of the membrane surface were analyzed. It was demonstrated by the fouling test that the 0.75wt% GO-g-PSS/PES membrane sample could provide the highest F-RR value (89.9%) and the lowest irreversible fouling resistance (R-ir) value (10.1%).

Automated summary

A novel mixed matrix ultrafiltration membrane based on PES embedded with GO-g-PSS nanoplates was prepared, showing increased water flux, porosity, and hydrophilicity. Higher loading of modified GO led to increased surface roughness of the membranes. The membranes demonstrated improved performance in rejection, flux recovery and fouling resistance.