Preparation, stabilization and characterization of TiO2 on thin polyethylene films (LDPE): Photocatalytic applications

Abstract An innovative way to fix preformed nanocrystalline TiO 2 on low-density polyethylene film (LDPE-TiO 2 ) is presented. The LDPE-TiO 2 film was able to mediate the complete photodiscoloration of Orange II using about seven times less catalyst than a TiO 2 suspension and proceeded with a photonic efficiency of ∼0.02. The catalyst shows photostability over long operational periods during the photodiscoloration of the azo dye Orange II. The LDPE-TiO 2 catalyst leads to full dye discoloration under simulated solar light but only to a 30% TOC reduction since long-lived intermediates generated in solution seem to preclude full mineralization of the dye. Physical insight is provided into the mechanism of stabilization of the LDPE-TiO 2 composite during the photocatalytic process by X-ray photoelectron spectroscopy (XPS). The adherence of TiO 2 on LDPE is investigated by electron microscopy (EM) and atomic force microscopy (AFM). The thickness of the TiO 2 film is seen to vary between 1.25 and 1.69 μm for an unused LDPE-TiO 2 film and between 1.31 and 1.50 μm for a sample irradiated 10 h during Orange II discoloration pointing out to a higher compactness of the TiO 2 film after the photocatalysis.