Authors

Abstract

Nano TiO₂ , one of the most effective photocatalysts, has extensive use in fields such as air purification, sweage treatment, water spitting, reduction of CO₂, and solar cells. Nowadays, the most promising method to recycle nano TiO₂ during the photocatalysis is to immobilize TiO₂ onto matrix, such as polyvinyl alcohol (PVA). However, due to the slow water permeability of PVA after cross-linking, the pollutants could not contact with nano TiO₂ photocatalyst in time. To overcome this problem, we dispersed calcium carbonate particles into a PVA-TiO₂ mixture and then filmed the glass. PVA-TiO₂-CaCO₃ films were obtained by drying. Through thermal treatment, we obtained the cross-linked PVA-TiO₂-CaCO₃ films. Finally, the calcium carbonate in the film was dissolved by hydrochloric acid, and the porous PVA-TiO₂ composite photocatalyst was obtained. The results show the addition of CaCO₃ has no obvious effect on PVA cross-linking and that a large number of cavities have been generated on the surface and inside of porous PVA-TiO₂ hybrid hydrogel film. The size of the holes is about 5-15µm, which is consistent with that of CaCO₃.The photocatalytic rate constant of porous PVA-TiO₂ hybrid hydrogel film is 2.49 times higher than that of nonporous PVA-TiO₂ hybrid hydrogel film.

Keywords

Hybrid Hydrogel, Photocatalysis, TiO₂, PVA