Chelate-Modified Fenton Reaction for the Degradation of Trichloroethylene in Aqueous and Two-Phase Systems

被引:91
|
作者
Lewis, Scott
Lynch, Andrew
Bachas, Leonidas [2 ]
Hampson, Steve
Ormsbee, Lindell
Bhattacharyya, Dibakar [1 ]
机构
[1] Univ Kentucky, Dept Chem & Mat Engn, Kentucky Res Consortium Energy & Environm, Lexington, KY 40506 USA
[2] Univ Kentucky, Dept Chem, Lexington, KY 40506 USA
关键词
iron; citrate; TCE droplet; DNAPL; groundwater; hydroxyl radical; ADVANCED OXIDATION PROCESSES; HYDROGEN-PEROXIDE; CATALYTIC DECOMPOSITION; MASS-TRANSFER; DESTRUCTION; OZONE; GROUNDWATER; PARTICLES; STABILITY; MECHANISM;
D O I
10.1089/ees.2008.0277
中图分类号
X [环境科学、安全科学];
学科分类号
08 ; 0830 ;
摘要
The primary objective of this research was to model and understand the chelate-modified Fenton reaction for the destruction of trichloroethylene (TCE) present in both the aqueous and organic (in the form of droplets) phases. The addition of a nontoxic chelate (L), such as citrate or gluconic acid, allows for operation at near-neutral pH and controlled release of Fe(II)/Fe(III). For the standard Fenton reaction at low pH in two-phase systems, an optimum H2O2:Fe(II) molar ratio was found to be between 1:1 and 2:1. Experimentation proved the chelate-modified Fenton reaction effectively dechlorinated TCE in both the aqueous and organic phases at pH 6-7 using low H2O2: Fe(II) molar ratios (4:1 to 8:1). Increasing the L: Fe ratio was found to decrease the rate of H2O2 degradation in both Fe(II) and Fe(III) systems at near-neutral pH. Generalized models were developed to predict the concentration of TCE in the aqueous phase and TCE droplet radius as a function of time using literature-reported hydroxyl radical reaction kinetics and mass transfer relationships. Additional aspects of this work include the reusability of the Fe-citrate complex under repeated H2O2 injections in real water systems as well as packed column studies for simulated groundwater injection.
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页码:849 / 859
页数:11
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