Abstract
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
H
2
O
2
: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
H
2
O
2
:Fe(II) molar ratios (4:1 to 8:1). Increasing the L:Fe ratio was
found to decrease the rate of H
2
O
2
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
H
2
O
2
injections in real water systems as well as packed column studies
for simulated groundwater injection.
