Sonophotocatalytic degradation of poly (vinyl pyrrolidone) (PVP) in the presence of TiO2 nanoparticles

The degradation of poly (vinyl pyrrolidone) (PVP) by means of ultrasound irradiation and its combination with heterogenous photocatalysis (TiO2 nanoparticles) was investigated. Emphasis was given on the effect of additive on degradation rate constants. 24 kHz of ultrasound irradiation was provided by a sonicator, while an ultraviolet source of 30 W was used for UV irradiation. To increase the efficiency of degradation process, degradation system was combined with TiO2 nanoparticles (0.1-0.6 g L-1) in the presence of UV irradiation. Sonophotocatalytic process led to complete PVP degradation in 150 min with the rate increasing with increasing catalyst loading. Sonophotocatalysis in the presence of nanoparticles was always faster than the respective individual processes. A synergistic effect between ultrasound and ultraviolet irradiation in the presence of TiO2 nanoparticles was suggested. The average molecular weight of ultrasonicated PVPs was determined by measurements of intrinsic viscosity of samples.