title: Degradation characteristics of 2,4-dichlorophenoxyacetic acid in electro-biological system.
abstract: The reductive degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) was studied in an electro-biological system, a biological system and an electric catalytic system, respectively. Electrochemical characteristics were monitored by cyclic voltammetry and the intermediate products of 2,4-D degradation were determined by high speed liquid chromatography (HPLC). The results showed that all 2,4-D degradations in the three systems conformed to the kinetics characteristics of one-order reaction, and the degradation kinetics constants were 28.74 × 10(-2) h(-1), 19.73 × 10(-2) h(-1) and 3.54 × 10(-2) h(-1), respectively. The kinetics constant in the electro-biological system was higher than the sum in the other two systems by 19%. The electrochemical assistance provided the electrons and accelerated the electron transfer rate in the microbial degradation of 2,4-D. The degradation resulted from the microbial reduction strengthened by the electrochemical assistance. The electron transfer existed between the electrode, cytochrome, NAD and the pollutants. A long-range electron transfer process could be achieved on the multi-phase interfaces between the electrode, bacteria and the pollutants.
authors.affiliation: Tianjin Key Laboratory of Aquatic Science and Technology, Tianjin Institute of Urban Construction, Tianjin 300384, China. Electronic address: jinglizhangczp@126.com.
authors.forename: Jingli
authors.initials: J
authors.lastname: Zhang
authors.forename: Zhanping
authors.initials: Z
authors.lastname: Cao
authors.forename: Hongwei
authors.initials: H
authors.lastname: Zhang
authors.forename: Lianmei
authors.initials: L
authors.lastname: Zhao
authors.forename: Xudong
authors.initials: X
authors.lastname: Sun
authors.forename: Feng
authors.initials: F
authors.lastname: Mei
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D055664:Electrochemical Techniques / Q000379:methods*; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D013056:Spectrophotometry, Ultraviolet; D014961:X-Ray Diffraction
chemical_list: D015084:2,4-Dichlorophenoxyacetic Acid
keywords: 2,4-Dichlorophenoxyacetic acid; Degradation pathway; Electro-biological system; Electron transfer