Design of polymer composite-based porous membrane for in-situ photocatalytic degradation of adsorbed organic dyes

Dual functional separation membranes that enable the adsorption and subsequent degradation of organic dyes are highly demanded in the environmental remediation. In this study, the hybrid porous membrane has been fabricate via the phase inversion of an amphiphilic polymer (sulfonated polyarylene ether nitrile, abbreviated as SPEN) by using polyethylene glycol (PEG) and titanium dioxide TiO2 as sacrificial pore-forming agent and photocatalyst, respectively. Furthermore, we found that the loading content of PEG-TiO2 played the decisive role in modulation of the fine morphology and surface wettability of obtained hybrid porous membrane, which in turn determined their adsorption and photocatalytic degradation capacities towards organic dye of methyl blue (MB). More specifically, as the increasing of loading content of PEG-TiO2, the obtained hybrid porous membrane exhibited firstly increased and then decreased equilibrium water content (EWC) and porosity, leading to their similar variation of adsorption capacities towards MB. On the contrary, the increased loading content of PEG-TiO2 renders the obtained hybrid porous membrane with larger pore size and more hydrophilic surface, which contributed to the enhanced in-situ photocatalytic degradation of adsorbed MB, and as high as 99.9% adsorbed MB by hybrid porous membrane can be in-situ photo-catalytically degraded under optimized condition. Meanwhile, the MB adsorption and photocatalytic degradation capacities of the optimized hybrid porous membrane can be well preserved after re-generation for three times. Based on these results, the current work basically opens new ways to fabricate multifunctional re-useable porous membrane for environmental remediation application.

Automated summary

In this study, a dual functional hybrid porous membrane was fabricated using PEG and TiO2, which demonstrated capabilities for both adsorption and photocatalytic degradation of organic dyes. The loading content of PEG-TiO2 was found to significantly influence the morphology and wettability of the membrane, subsequently affecting its adsorption and photocatalytic degradation capacities towards methyl blue.