Modification of SnO2 nanoparticles by conjugated derivative of polyvinyl chloride for efficient photocatalytic reduction of Cr(VI) under visible-light

Conjugated derivative (CPVC) from thermal dehydrochlorination of polyvinyl chloride (PVC) was tried to modify SnO2 nanoparticles for developing a high efficiency visible-light-activated photocatalyst for the treatment of Cr(VI) wastewaters. CPVC modified SnO2 nanoparticles (SnO2/CPVC) were synthesized via the following procedures: (i) mixing of SnO2 nanoparticles and PVC in tetrahydrofuran solution, then evaporation of tetrahydrofuran to produce SnO2/PVC nanocomposite, and (ii) thermal treatment of the SnO2/PVC nanocomposite at 150 °C for 2 h to transform its PVC into conjugated CPVC. The as-synthesized products were characterized using X-ray diffraction, Raman spectroscopy, high resolution transmission electron microscopy, UV-vis diffuse reflectance spectra, transient photocurrent measurement, and electrochemical impedance spectroscopy. The photocatalytic tests indicated that SnO2/CPVC nanocomposite had exceptionally higher (about 14 times) photocatalytic activity than SnO2 nanoparticles in the reduction of aqueous Cr(VI) under visible-light (λ > 420 nm) irradiation. This work is the first report of SnO2/CPVC as photocatalyst for the reduction of Cr(VI), and also useful for developing new efficient visible-light-activated photocatalysts using low cost polyvinyl chloride.