Photocatalytic activity and biodegradation of polyhydroxybutyrate films containing titanium dioxide

Abstract

This study aims to evaluate the photocatalytic activity and biodegradation of polyhydroxybutyrate (PHB) films containing titanium dioxide (TiO 2). Nanosized TiO 2 photocatalysts were immobilized onto PHB film to overcome the difficulty of the recovery process. PHB is a suitable base material as it is naturally biodegradable and is produced from renewable resources. The photocatalytic degradation of organic compounds, photocatalytic sterilization activity and biodegradation rate in garden soil of PHB–TiO 2 composite films were investigated. After an hour under solar illumination, 96% of methylene blue solution was decolorized. The antibacterial activity against Escherichia coli ( E. coli) using PHB–TiO 2 composite film exhibited enhanced photocatalytic sterilization activity over time. As for the ability to biodegrade, PHB–TiO 2 composite films placed on soil surface with no direct solar illumination showed slower degradation rate compared to those receiving direct solar illumination. Interestingly, the latter composite films showed faster degradation rates compared to pure PHB films indicating that the degradation is mainly due to photocatalytic activity. PHB–TiO 2 composite films buried in soil generally showed slower degradation rates compared to pure PHB films and were dependent on the soil microbial activity.