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

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.