Minimizing chemicals usage for TiO2 immobilisation onto commercial PES membrane employing in-situ polymerisation long-term performance and stability evaluation

The strong integration of TiO2 nanoparticles (NPs) into the membrane surface to impart antibacterial functionality is often challenging due to the agglomeration of nanoparticles and often requires a labour-intensive, multi-step process. To tackle this challenge, we developed a practical, simple, and scalable method to firmly adhere TiO2 NPs on a commercial polyether sulfone (PES) membrane using a one-step dip coating process harnessing polydopamine as an adhesive agent. The process was optimized with regards to the reaction time. A range of analytical methods were utilized for a thorough examination of the surface chemistry and the structural properties of the produced membranes. The experimental results revealed that the modification at the optimum reaction time of 30 min enhanced the hydrophilicity of the PES membranes as confirmed by the decrease of contact angle. As a result, the modified membranes exhibited a significant improvement in membrane permeability with 12 times higher water permeation flux (962 LMH for pDA-f-TiO2-PES30) compared to the pristine PES membranes (79.9 LMH). The static adsorption of BSA on the surface of membranes was reduced from (60 ug/cm2 for pristine PES to 21 ug/cm2 for pDA-f-TiO2-PES120). The modified PES membranes displayed a higher flux recovery ratio (97%) and fouling reversibility (98.62%) than pristine PES membrane (37.63%). Also, the coated PES membranes bestowed a good antibacterial property relative to the pristine one. The membranes showed better physical and chemical stability compared to unmodified PES membranes. Thus, the proposed coating method proved to be a practical and effective TiO2 immobilization approach for improving membrane lifespan and its fouling resistance.

Journal article