Comparison of Different Modification Processes of a Polyethersulfone Ultrafiltration Membrane for Sulfamethoxazole Removal

Nowadays there is a growing interest in membrane modification processes, to improve their characteristics, the effectiveness of their treatments and reduce the possible fouling. In this sense, in this work a modification of an ultrafiltration membrane with tree different materials has been carried out: reduced graphene oxide (rGO), chitosan and MgCl2. For both the native and the modified membranes, a study has been carried out to remove the emerging contaminant sul-fomethoxazole. SEM and SEM-EDX analyses have been performed to confirm membrane surface modifications. In the characterization of the membranes, it is noteworthy that the values of the permeability coefficient, Aw, have been lower in the modified membranes, which is unexpected. Regarding the pollutant removal tests, the influence of pressure and initial concentration on permeate flows and rejections has been studied. Native membrane shows the highest permeate flow values. Comparing the modified membranes, the highest rejection values are obtained with the rGO-modified membrane, which can be explained by its greater hydrophilic character. Finally, a fouling study has been carried out, verifying that in almost all cases such fouling occurs after the passage of the pollutant, due to the blockage of the membrane pores.