Development and characterization of polyethersulfone-based nanofiltration membrane with stability to hydrogen peroxide

Polyethersulfone-based nanofiltration membranes have been shown to be appropriate to purify wastewater; however, the presence of powerful oxidants (or disinfecting agents) such as hydrogen peroxide can negatively affect the required membrane physicochemical properties, impair its structural morphology and, ultimately, shorten its lifespan. In this work, to overcome such problems, TiO2 nanoparticles (anatase form, < 25 nm) were introduced via blending in order to prepare PES(TiO2) membrane. Pristine and commercial PES nanofiltration (PES 10 and NP030) membranes were used as references. All membranes were immersed in a H2O2 (1 or 5 wt% H2O2) solution for predefined time periods. The process performance of the membranes in terms of water flux and rejection of target solutes was then studied to evaluate their tolerance to H2O2. In addition, the hydrophilicity, process performance and morphology of the membranes were characterized by measuring water contact angles, by performing filtration experiments, and by SEM, respectively. All membranes were found to be tolerant to 1 wt% H2O2 for a minimum of 20 days. The referenced membranes showed a significant loss in performance after being immersed in 5 wt% H2O2. The results demonstrated that the PES(TiO2) composite membranes have a better H2O2 tolerance compared to the reference membranes. The PES(TiO2) membrane was found to have a high water permeability (33.4 L/(m2 h bar)) and a high solute rejection (94.9% for Direct Red 23). Therefore, this membrane can be considered a promising candidate for possible use in treating industrial wastewater effluents containing H2O2.