Sonophotocatalytic Degradation of Poly (Vinyl Pyrrolidone) in the Presence of Fe (III)/H2O2

Abstract

The degradation of poly (vinyl pyrrolidone) (PVP) by means of ultrasound irradiation and its combination with homogeneous photocatalysis (photo-Fenton) 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 16 W was used for UV irradiation. To increase the efficiency of degradation process, degradation system was combined with Fe (III) (2.510-4mol/L) and H2O2 (0.020 - 0.118 mol/L) in the presence of UV irradiation and the rate of degradation process change from 4.07x10-5 to 8.24x10-5 mol15 l-1.5 min-1. Photo-Fenton process led to complete PVP degradation in 150 min with the rate increasing with increasing catalyst loading. Sonophotocatalysis in the presence of Fe (III)/H2O2 was always faster than the respective individual processes. A negative order for the dependence of the reaction rate on total molar concentration of PVP solution within the degradation process was suggested. Results of this study indicate that the presence of catalyst in the reaction medium can be utilized to reduce molecular weight of PVP while maintaining the power of irradiated ultrasound.