Polyethersulfone ultrafiltration membranes co-blended with amphiphilic polymers and nitrogen-doped titanium dioxide nanoparticles for anti-fouling and photocatalysis

Abstract

Polyethersulfone (PES) membranes have a high tendency to scale due to their inherent hydrophobicity, which limits their application and increases water treatment costs. To regulate the size of the pores of PES and prevent clogging, different qualities of poly(ethylene glycol)₃₈-block-poly(propylene glycol)₈ (PEG-PPG) were introduced and screened for the best ratios. Further introduced synthesized nitrogen-doped titanium dioxide (N-TiO₂), anti-fouling and photocatalytic PES ultrafiltration membranes (N-TiO₂@M) were prepared. N-TiO₂@M3 exhibited bovine serum albumin rejection rate of 93.8% and achieved a methylene blue photocatalytic efficiency of 95.3% after 120 min of operation. Furthermore, N-TiO₂@M4 showcased a water contact angle of 41.0°. Notably, the pure water flux of N-TiO₂@M4 surged by 499.3% compared to that of PES membrane. The fouling resistance ratio for membrane flux witnessed an increase from 70.0% to 82.7%, demonstrating the enhanced durability of N-TiO₂@M4. Moreover, the comprehensive analysis for N-TiO₂@M4 revealed a total contamination rate of 40.2%. The irreversible contamination rate of N-TiO₂@M4 after 1 h of ultraviolet light (UV) cleaning was 5.7%, and the irreversible contamination rate after 1 h of visible light irradiation was 6.7%. The method for mixing N-TiO₂ and PEG-PPG is straightforward and convenient, offering potential for the development of N-TiO₂@M with resistance to pollution and degradation in visible/UV light.