Anodic oxidation process for the degradation of 2, 4-dichlorophenol in aqueous solution and the enhancement of biodegradability

Degradation of 2, 4-dichlorophenol (2, 4-DCP) in aqueous media by anodic oxidation using Ti-based oxide electrode has been studied. Additionally, the influence of anodic oxidation on the biodegradability of 2, 4-DCP solution was investigated. It was found that alkaline media was suitable for the anodic oxidation of 2, 4-DCP, while acidic media tended to cause more 2, 4-DCP volatizing. The poor degradation of 2, 4-DCP was ascribed to the direct anodic oxidation at lower anodic potential, while the indirect anodic oxidation was responsible for the better degradation at higher anodic potential with a high power consumption. The variation of COD and the characteristic of UV-vis spectra indicated that some organic intermediates were produced during the course of the degradation of 2, 4-DCP. The obvious inhibition of microbial activity was observed when 2, 4-DCP concentration was about 100 mg/L. The anodic oxidation process was able to enhance the biodegradability of 2, 4-DCP solution and this enhancement became greater with the extension of anodic oxidation treatment. This work suggests that the anodic oxidation with the Ti/IrO2/RuO2/TiO2 electrode generally applied in chemical industry is a promising alternative for the pretreatment of the wastewaters containing chlorophenols.