Photocatalytic degradation of chlorophenols using star block copolymers: Removal efficiency, by-products and toxicity of catalyst

Abstract

This study investigated the photocatalytic degradation of chlorophenols using two different types of porphyrin core star block copolymers (P-PSD and P-PD) with irradiation using visible light. Both P-PSD and P-PD catalysts show similar tendencies in the degradation of chlorophenols. Pentachlorophenol degraded faster than other chlorinated phenols (pentachlorophenol > 2,4,6-trichlorophenol > 2,4-dichlorophenol). The removal rate of chlorophenols using P-PSD was higher than the removal rate using P-PD, a difference which could be attributed to the hydrophobicity of P-PSD. The degradation intermediates and by-products of the chlorophenols were also identified. The analysis results revealed that the degradation of highly-chlorinated phenols was more rapid than the degradation of the less-chlorinated phenols, as confirmed by residual chlorinated compound and chloride ions that were released. The newly synthesized P-PSD catalyst is non-toxic to bacteria. For these reasons, the process of photocatalytic degradation using porphyrin core star block copolymers has potential advantages for the degradation of dissolved chlorophenol pollutants in water. (C) 2012 Elsevier B.V. All rights reserved.