An ecologically effective water treatment technique using electrochemically generated hydroxyl radicals for in situ destruction of organic pollutants: Application to herbicide 2,4-D
Ma. Oturan, An ecologically effective water treatment technique using electrochemically generated hydroxyl radicals for in situ destruction of organic pollutants: Application to herbicide 2,4-D, J APPL ELEC, 30(4), 2000, pp. 475-482
The electrochemical production of Fenton's reagent by simultaneous reductio
n of dioxygen and ferric ions on a carbon felt electrode, permits a control
led, in situ generation of hydroxyl (OH.) radicals. The possibility of usin
g electrochemically produced OH. radicals for solving environmental problem
s is investigated. Continuous and controlled production of hydroxyl radical
s was achieved by electrochemical reduction of O-2 in the presence of a cat
alytic amount of ferric or ferrous ion. These radicals are used for remedia
tion of water containing toxic-persistent-bioaccumulative organic pollutant
s through their transformation into biodegradable compounds or through thei
r mineralization into H2O and CO2. A widely used herbicide, 2,4-dichlorophe
noxyacetic acid (2,4-D), was selected as a model for a toxic organic pollut
ant. High pressure liquid chromatography (HPLC) was used to quantify the di
stribution of the hydroxylated products obtained. Rate constants for the hy
droxylation reactions of 2,4-D, 2,4-dichlorophenol (2,4-DCP), 2,4-dichloror
esorcinol (2,4-DCR) and 4,6-dichlororesorcinol (4,6-DCR) were determined. T
he mineralization of 2,4-D and its derivatives was followed by total organi
c carbon (TOC) measurements. More than 95% of 2,4-D and the intermediates g
enerated during the electrolysis can be mineralized.