TiO2 nanoparticle stability via polyacrylic acid-binding on the surface of polyethersulfone membrane: Long-term evaluation

Abstract

Immobilization of photocatalysts on the membrane surface is a promising approach that produces photocatalytic membranes that could help advance wastewater treatment. This work examined the stability of TiO2 nanoparticles binding to the PES membrane surface via polyacrylic acid. For this aim, the corona-induced grafting technique was used for graft polymerization of PAA to introduce strong binding sites for TiO2 deposition on the PES surface. The stability test was performed in a cross-flow system, which indicated minimal leaching after 72 h of filtration. The results evidenced the firm attachment of TiO2 on the membrane surface after long-term operation. PAA grafted membranes with TiO2-deposited membranes showed better hydrophilicity and higher water flux. Compared to the unmodified PES membrane, the maximum flux of the TiO2 deposited membrane increased by 85 %. Moreover, the photocatalytic ability of the photocatalytic membranes to remove phenol was evaluated under UV irradiation. The prepared membranes showed good photocatalytic performance after three hours of continuous operation. The highest phenol degradation was achieved by PES-PAA-TiO2-0.1 %wt, indicating 62 % removal of the pollutant after three hours. With its remarkable stability during filtration and outstanding photocatalytic performance, the prepared membrane illustrates the excellent potential for long-term processes that could minimize nanoparticles leaching.