TiO2/AgBr nanocomposite as a novel hydrophilic and photocatalytic modifier in the fabrication of polyethersulfone membrane for wastewater treatment

Abstract

Enhancing the performance of filtration membranes to improve their antifouling, permeability, and stability is a crucial objective. This can be acquired through the development of innovative materials and methods. With this in mind, the exertion of novel materials is considered a promising approach for modifying polymeric membranes. This study focuses on the potential of incorporating TiO2/AgBr photocatalytic nanocomposites to improve the hydrophilicity, antifouling, and permeability of polyethersulfone (PES) membranes. Following the synthesis of TiO2/AgBr, the study examines its impact on the performance of PES membranes by introducing various concentrations of TiO2/AgBr nanocomposite. Notably, the water contact angle significantly decreases from 68.5° to 44.2°, indicating an improvement in hydrophilicity. This enhanced overall porosity leads to almost a twofold increase in pure water permeability, with the bare membrane registering 78.3 L/m2h.bar and the membrane containing 0.2 wt% TiO2/AgBr achieving 152.4 L/m2h.bar. Due to the photocatalytic activity of TiO2/AgBr, the modified membranes demonstrate promoted antifouling performance, when UV irradiation is used in the washing step of the fouled membranes, as evidenced by the increased flux recovery ratio values, rising from 48 to 60.6 %. The rejection of two different dyes was assessed and the results of 83.9 % and 95.2 % rejection were obtained for Reactive Black 5 (RB5) and Lanasol Red 6G, respectively. Furthermore, the antibacterial activity of TiO2/AgBr was also indicated by confocal microscopy analysis. Thus, embedding TiO2/AgBr not only enhances antifouling properties but also improves the membranes’ ability to reject dyes effectively.