Fabrication of reusable polymer nanocomposite films made of thermoplastic polyurethane and modified BiVO4 for photodegradation of Malachite Green

Semiconducting BiVO4, is successfully prepared by solid-state route and attempts are taken to dope vanadium sites by titanium ions to produce BiV1-xTixO4 (x = 5%, 10% and 15%). The products are analyzed using powder X-ray diffraction, Raman spectroscopy, scanning electron microscopy and energy dispersive spectroscopy. The average particle sizes are in the range of 71-82 nm. Using diffuse reflectance spectroscopy, the band gaps are estimated and fall in visible range (2.11-2.41 eV). These nanomaterials are investigated for the photodegradation of malachite green dye solution that can find application in wastewater treatment and their efficiencies are investigated by time-dependent UV-Visible spectroscopy. 15% titanium doped BiVO4 (BVO-15) showed the highest efficiency by completely degrading malachite green in 180 min under visible light irradiation. In such heterogenous processes, separation of the used nanocatalysts remain a challenge. To address this, reusable polymer nanocomposite films are prepared using thermoplastic polyurethane (TPU) to immobilize BVO-15. The polymer nanocomposite film with 0.10 g of catalyst in 1 g of TPU showed maximum efficiency (similar to 96%). The powder and film catalysts are investigated for three cycles and found to be effective. Thus, they show remarkable photocatalytic activity, stability and reusability that make them suitable for the wastewater treatment.