Sustainable self-floating lignocellulosic biomass-TiO2@Aerogel for outdoor solar photocatalytic Cr(VI) reduction

To overcome the common drawbacks of suspended TiO2 photocatalysis system, a water-floating Lignocellulosic Biomass-TiO2-Aerogel with a low density was synthesized via in situ polymerization for Cr(VI) reduction under visible light. Two forms of floating photocatalysts were designed, i.e., pill form (surface area: 5 cm(2), mass: 0.89 g), and rod form (surface area: 9.8 cm(2), mass: 1.3 g). Materials were characterized by X-ray diffraction, Scanning Electron Microscopy and UV-vis diffuse reflectance spectroscopy. Lignocellulosic Biomass-TiO2-Aerogel exhibits an excellent visible light response with a band gap of 2.76 eV. The total reduction of 200 mL of Cr(VI) (10 ppm, pH: 3) was obtained within 30 min under visible light ( > 420 nm) using pill or rod floating materials. This photocatalyst showed a relatively good recycling ability and an excellent buoyancy which make it a promising candidate for outdoor real-world application.