Hydrophilic photocatalytic membrane via grafting conjugated polyelectrolyte for visible-light-driven biofouling control

Abstract

The photocatalytic membrane (PM) is a promising platform to impart membranes with an anti-biofouling property. However, the fabrication of effective PMs remains challenging because the physical loading of photoactive materials on the membrane can cause pore blocking and layer delamination due to repetitive operations. In this study, we demonstrate a chemical grafting of conjugated polyelectrolytes (CPEs) on a PVDF membrane surface to generate visible-light-active PMs with high stability. Using chemical tethering of CPE on the membrane followed by anion exchange, the surficial hydrophilicity of PM is improved significantly without compromising its porosity and water permeability. The hydrophilic PM exhibits excellent performance for photo-degradation of organic dyes, photo-reduction of Cr(VI), and photocatalytic inactivation of mixed-culture biofilm under visible light irradiation. The anti-biofouling property enables > 97 % flux recovery in repeated filtration cycles through the visible light treatment, even after it is fouled with a super-saturated bacterial feed solution (10(9) CFU/mL).