Investigation of a TiO2 photocatalyst immobilized with poly(vinyl alcohol)

[Display omitted] •Preparation of a TiO2-PVA composite foil by a simple solution casting method.•The structure of the polymer changes during thermal treatment.•The degradation products formed interfere with the photocatalytic application.•Highly conjugated degradation products were detected during the structural studies.•After pre-treatment the composite can decompose a surfactant in multiple cycles. Immobilization of TiO2 photocatalyst was realized with application of poly(vinyl alcohol) (PVA). However, these PVA-based foils were too instable to be used for photocatalytic water cleaning. Their stability could be significantly enhanced by a thermal treatment, but this procedure generated various water-soluble derivatives such as aldehydes, ketones, and aromatic species. Photocatalytic pre-treatment of the foils proved to be suitable to remove these products from the surface of the composite. After three subsequent pre-treating cycles of irradiation and rinsing, the PVA-TiO2 foil became applicable for photocatalytic degradation of Triton X-100, a widely used non-ionic detergent. The composite catalyst kept its stability and efficiency even after some cycles of re-usage, while its surface underwent a perceptible, although quantitatively negligible degradation.