Synergistic photocatalytic-photothermal contribution induced by Pd-TiO2/PEDOT immobilized in PVDF membrane for enhanced water purification

The photocatalytic membrane systems show great potential for water purification and wastewater treatment with efficient energy utilization. Herein, we develop a synergistic photocatalytic-photothermal route, based on Pd-TiO2/PEDOT composite immobilized in PVDF membrane, for effective water permeability and reutilization property. Novel Pd-TiO2/PEDOT/PVDF ultrafiltration membrane is prepared by the phase inversion method with immobilizing Pd-TiO2/PEDOT obtained by ultrasonic irradiation. During the removal of HA under light irradiation, Pd-TiO2/PEDOT/PVDF membrane presents an unexpected increasing in water flux, when compared to pristine PVDF, Pd-TiO2/PVDF and PEDOT/PVDF membranes, with the highest normalized flux reaches up to 2.1 and remains as 1.3 even after 300 min of irradiation. This significantly enhances the water transport, along with the achieved high rejection and anti-fouling performance. It can be attributed to synergistic photocatalytic-photothermal effect of Pd-TiO2/PEDOT, which is realized by their strong interaction and uniform distribution. The addition of PEDOT promotes photocatalytic effect of Pd-TiO2 by enhancing separation of photo-induced charges. High photothermal conversion efficiency of Pd-TiO2/PEDOT and low temperature difference in Pd-TiO2/PEDOT/PVDF membrane facilitate effective thermal storage, beneficial for water transport. Meanwhile, thermal energy promotes generation of more ∙OH and ∙O2– radicals to remove pollutants. Synergistic photocatalytic-photothermal contribution in Pd-TiO2/PEDOT/PVDF membrane shows significant potential for practical application.