Superhydrophilic and polyporous nanofibrous membrane with excellent photocatalytic activity and recyclability for wastewater remediation under visible light irradiation

Wastewater remediation via photocatalysis for the environmentally friendly degradation of organic contaminants has attracted increasing attention in recent years. Nevertheless, the efficiency of such a promising technology is still unsatisfactory due to the low light utilization, poor hydrophilicity, easy aggregation, and difficult recycling of powder photocatalyst materials. In this study, we developed a versatile strategy for the design of superhydrophilic and polyporous nanofibrous membrane with excellent photocatalytic activity and outstanding recyclability via the combination of loading modified photocatalyst and constructing hydrophilic channels in the electrospinning nanofibers. A novel graphitic carbon nitride photocatalyst with the simultaneous introduction of boron-doped and nitrogen-deficient structure (B-C3N4) was synthesized firstly, and then blended with polyethersulfone and Poly(vinylpyrrolidone) (PVP) to fabricate composite nanofibrous membrane via electrospinning technology. After a simple water extraction process to remove PVP, a highly Polyporous and superhydrophilic nanofibrous membrane (PBCN) was obtained. The resulting mesopores and channels existing in the nanofibers could facilitate the diffusion of contaminant molecules, expose more photocatalysis sites of B-C3N4, and finally improve the photocatalytic activity. Especially, thanks to the continuous removal of residue PVP in PBCN, it was provided with a sustaining enhancement of reusability during the repetitive reuse process, which was superior to most of the traditional wastewater remediation materials. In addition, a possible photocatalytic mechanism for degrading organic contaminants by the PBCN was proposed. In this work, we not only prepared superhydrophilic, polyporous and visible light responsive nanofibrous membrane for the photocatalytic degradation of various organic contaminants, but also introduced a novel approach towards the design of advanced nanofibrous materials for diverse catalysis, adsorption and separation applications in environment remediation.