Photocatalytic degradation of polyvinylpyrrolidone in aqueous solution using TiO2/H2O2/UV system

The photocatalytic degradation of high molecular weight polyvinylpyrrolidone (PVP), a water-soluble polymer, using a TiO2/H2O2/UV system was studied in an annular photoreactor using a mercury vapor lamp (125W) as the radiation source. The effect of the initial hydrogen peroxide concentration and the operating conditions, such as initial concentration of PVP, photocatalyst dosage and initial pH, on the reaction rate was also evaluated. It was observed that the efficiency of the TiO2/H2O2/UV system was 33% higher than that of a system without H2O2, reaching total organic carbon removals of above 80% in 6h of reaction, depending on the experimental conditions. The optimal photocatalyst dosage was found to be 0.50gL(-1). Also, the results demonstrate that the reaction rate increases as the pH and initial concentration of PVP decrease. This treatment can be carried out successfully under optimal conditions and enhance the biodegradability of the organic matter remaining at the end of the application of the TiO2/H2O2/UV system, as assessed by biochemical oxygen demand/chemical oxygen demand measurements.