Zero-Valent Iron Supported Microbial Reductive Dechlorination of 2,4-Dichlorophenol

Abstract

The experiment was conducted to examine the potential of zero-valent iron (Fe⁰) as the sole electron donor for reductive dechlorination of 2,4-dichlorophenol by mixed culture. The optimal conditions and the sustainability of 2,4-dichlorophenol dechlorination in Fe⁰+microbe system were also investigated. The results showed that, Fe⁰ was an effective electron donor to stimulate reductive dechlorination of 2,4-dichlorophenol and 2,4-dichlorophenol (30 mg L^-1) could be transformed completely within 68 h. The rate was similar to that with acetate or lactate as electron donor, while the rate was slow with glucose as electron donor. The quantity of Fe⁰, inoculation added and pH had a significant effect on 2,4-dichlorophenol dechlorination. The optimal quantity of Fe⁰, inoculation added and initial pH was 2.0 g L^-1, 646.4 mg volatile suspended solid L^-1 and 8, respectively. Fe⁰ sustained 2,4-dichlorophenol dechlorination over a long period. 4-Chlorophenol was the intermediate roduct from 2,4-dichlorophenol, but it was difficult to be further degraded.