[Mechanism of reductive dechlorination of trichlorophenol with different electron donors]

A test was conducted to examine the degradation effect and reductive dechlorination pathway of 2, 4, 6-trichlorophenol (2,4,6-TCP) in the presence of different electron donors, such as glucose, sodium lactate, sodium pyruvate and sodium acetate. The results showed that, compared with the effect of glucose, sodium lactate, sodium pyruvate and sodium acetate enhanced the dechlorination of 2, 4, 6-TCP effectively, among which sodium lactate could serve as a kind of hydrogen release compound, and the electrons required for reductive dechlorination were released in a sustained way. Substrate metabolism dehydrogenase activity was improved by the external electron donor; after reaction for 240 h, the activity of dehydrogenase was increased in the four electron donor systems, by 21.49%, 25.78%, 136.85% and 139.3%, respectively. The main reductive dechlorination products of 2,4,6-TCP included 2,4-dichlorophenol (2,4-DCP), 4-chlorophenol (4-CP) and phenol; when sodium acetate was used as the electron donor, 4-CP was the main degradation product, and the transformation ratio from 2,4,6-TCP to 4-CP was more than 22%.