Investigation of the Kinetics and Products Resulting from
the Reaction of Peroxone with Aminodinitrotoluenes
RONALD J. SPANGGORD, DAVID YAO, AND THEODORE MILL
INTRODUCTION AND BACKGROUND
The U.S. Army is interested in using Advanced Oxidation Technologies (AOTs) for the treat-
ment of wastes, residues, and contaminated groundwater resulting from past and present military
manufacturing and chemical handling practices. One AOT of interest is the use of peroxone. Per-
ratio at pH > 7, generates hydroxyl radical (HO), which is a powerful oxidant. Ozone is also a
strong oxidant of organic molecules in aqueous solution and offers competitive oxidative path-
ways in a peroxone system. Hydrogen peroxide may contribute to some oxidation of organics, but
because of the reactivity of ozone with hydrogen peroxide, ozone and hydroxyl radical will dom-
inate the oxidative process.
TNT (2,4,6-trinitrotoluene) is a major land contaminant at military installations, including TNT
manufacturing sites and load and pack (LAP) facilities. Once introduced into the soil, TNT can
undergo both aerobic and anaerobic microbial transformations that lead to 4-amino-2,6-dinitrotol-
uene (4-ADNT) and 2-amino-4,6-dinitrotoluene (2-ADNT). The structures of these chemicals are
shown below.
CH3
CH3
O2N
O2N
NO2
NH2
NH2
NO2
4-amino-2,6-dinitrotoluene
2-amino-4,6-dinitrotoluene
These compounds are currently being found in groundwater at munitions facilities. The use of an
AOT technology will involve the oxidation of TNT transformation products. It therefore becomes
important to understand oxidation rates, pathway, and stable end-products to make an assess-
ment of the safety of peroxone treatment of ADNT-contaminated waters.
Oxidation rates can be described by simple second-order rate expressions. The kinetic rate ex-
pressions for oxidation by ozone and hydroxyl radical processes are shown in eq 1 and 2. The
overall loss can be described by eq 3.
k1
ADNT + O3 ----------> Products
d[ADNT]/dt = k1[ADNT][O3]
(1)
k2
ADNT + HO --------> Products
d[ADNT]/dt = k2[ADNT][HO]
(2)
d[ADNT]/dt = k1[ADNT][O3] + k2[ADNT][HO] = (k1[O3] + k2[HO]) [ADNT]
(3)
Equation 3 shows that [O3] and [HO] and the rate constants (k1 and k2) will control the rate of
ADNT disappearance.
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