Superhydrophilic PVDF membrane fabricated on modified TiO₂/CS-SDAEM nanoparticles deposited on GA/CNTs hydrophilic layer to achieve self-cleaning photodegradation and low contamination rate for dyestuff separation

In this work CS-SDAEM polymer brushes with long-chain structure were synthesized, and TiO₂/CS-SDAEM nanoparticles were prepared by modifying them on the TiO₂ surface. The prepared modified membrane can effectively degrade dyes through photocatalysis and can reduce the contamination rate of the membrane during use. The separation membrane achieves efficient removal of contamination by self-cleaning. The results of the membrane surface analysis test show that the formation of coordination bonds between o-benzenetriol of GA and TiO₂, and the chemical reaction between CS and GA, which promote the stability between coating components. The results of filtering tests show that with the excellent anti-fouling performance of long-chain polymer brush, the photodegradability of TiO₂ and a large number of hydrophilic groups contained in GA and CS, PVDF- TiO₂/CS-SDAEM membranes overcome the above shortcomings and achieve super-hydrophilicity, anti-fouling and self-cleaning. In addition, DFT model simulations of photocatalytic processes show that there is a charge transfer between CS and TiO₂, which increases the width of the high light absorption band and improves the efficiency of photodegradation. Modified membranes achieve efficient self-cleaning processes and low flux decline rates, which hold great promise for use in real wastewater application scenarios.