Fabrication of PES-based super-hydrophilic ultrafiltration membranes by combining hydrous ferric oxide particles and UV irradiation

Abstract In this study, hydrous ferric oxide (HFO) particles were used to modify polyethersulfone (PES) ultrafiltration membranes, in view of obtaining super-hydrophilic membranes. The structure and size of HFO particles and the surface properties and morphology of the synthesized membranes were characterized using Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), dynamic light scattering (DLS), atomic force microscopy (AFM), scanning electron microscopy (SEM) and contact angle measurements. Membrane modification involved matrix modification, surface modification in the presence of a dopamine solution and UV light irradiation, and simultaneous modification of the surface and membrane matrix. The pure water flux, bovine serum albumin (BSA) rejection and antifouling properties were measured in a cross-flow filtration system to evaluate the membrane performance for each strategy. The effect of HFO particles on the super-hydrophilicization of the PES membranes was compared with the modified membrane surface using TiO2 and ZnO nanoparticles in the presence of a dopamine solution and UV irradiation. The effect of various parameters on the membrane performance such as concentration of the added HFO particles to the membrane matrix, UV irradiation exposure time and concentration of the HFO particles used in the coating of the membrane surface was examined. The synthesized membranes with 5 wt% HFO particles in the membrane matrix and covered with 0.5 wt% of these particles by UV irradiation for 10 minutes as the optimal conditions were found to have a high ability to reduce the contact angle to zero. This membrane was observed to have a relatively high water flux of 433.18 (l m-2 h-1) LMH despite having less porosity than the uncovered membrane. Its low fouling and high flux recovery ratio (FRR) after removing a high concentration of different oils indicated the excellent performance of this super-hydrophilic membrane in the separation of oil-water emulsions.