Solid-phase photocatalytic degradation of polystyrene plastic with TiO2 as photocatalyst

Solid-phase photocatalytic degradation of polystyrene (PS) plastic with TiO₂ as photocatalyst was investigated in the ambient air under ultraviolet light irradiation. Higher weight loss rate, lower average molecular weight, increased carbonyl peak intensity, less volatile organics and more CO₂ emitted with irradiation in PS-TiO₂ composite sample compared to pure PS sample were observed. These facts indicated the higher photodegradation rate of PS-TiO₂ sample than that of PS sample, and emphasized the potential of the composite sample in bring about complete photodegradation of polystyrene plastic. It is implied that the degradation initially occurred over TiO₂ particles, followed by the diffusion reaction with the aid of reactive oxygen species generated on TiO₂ particle surface.