Electrospinning preparation of TPU/TiO2/PANI fiber membrane with enhanced dye degradation and photocatalytic Cr(VI) reduction

The efficient elimination of toxic dye and Cr(VI) from wastewater by photocatalysis is still a challenge due to the unsatisfactory photocatalytic efficiency and difficult separation of the photocatalyst . Herein, the thermoplastic polyurethane (TPU) fiber membrane was prepared by electrospinning and then titanium dioxide (TiO 2 ) nanoparticles were loaded on the fiber membrane by ultrasonic-assisted method, followed by in-situ polymerizations of polyaniline (PANI) on the surface of the membrane. The synergistic effect of TiO 2 and PANI results in faster charge migration and more efficient separation of photogenerated charge carriers. Photocatalytic experiments revealed that TPU/TiO 2 /PANI fiber membranes were highly efficient for dye degradation and Cr(VI) reduction under visible light irradiation. 99.7 % of Congo red was degraded by TPU/TiO 2 /PANI membrane within 30 min, and the reaction rate reached 0.2 min −1 . The Cr(VI) reduction efficiency was up to 99.0 % within 25 min with a reaction rate of 0.128 min −1 . Additionally, the TPU/TiO 2 /PANI membrane exhibited a low loss in catalytic activity even after recycling 10 times, suggesting superior recycling stability compared to TPU/TiO 2 membrane. The result of the electron spin resonance (ESR) experiment showed that superoxide radicals (-O 2 - ) and hydroxyl radicals (-OH - ) were involved in the photocatalytic degradation process. The prepared TPU/TiO 2 /PANI fiber membrane combined with excellent photocatalytic capacity, good stability and easy recovery makes it a good candidate for removing dye and Cr(VI) from wastewater.