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

Abstract

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