THE CATALYTIC OZONE OXIDATION OF AQUEOUS
SOLUTIONS OF HYDRAZINE, MONOMETHYL HYDRAZINE AND
UNSYMMETRICAL DIMETHYLHYDRAZINE
Raymond A. Sierka, Professor
Civil Engineering Department
University of Arizona
Tucson, Arizona 85721
William F. Cowen, Senior Analytical Chemist
Catalytic, Inc.
Philadelphia, Pennsylvania  19102
INTRODUCTION
The hydrazine family of fuels includes hydrazine (H), monomethylhydrazine (MMH)
and unsymmetrical dimethylhydrazine (UDMH) as well as mixtures of the above.
The United States Air Force is responsible for the procurement, storage and transport
of hydrazine fuels not only for its own systems, such as Minuteman III and the F-l 6, but
also for NASA and the space shuttle program. During the course of these operations there
is a potential for environmental degradation. For example, accidental spdls could occur
directly from tank traders and tank cars or when transfer lines are connected or disconnected during loading and unloading. Since the transport container must be sampled at the
site of production as well as the destination point, the problem of proper disposal of these
materials and residual purged liquids must be carefuUy considered.
This research centered on the treatment of aqueous solutions of H, MMH and UDMH
by ozone. A parametric study was conducted to evaluate the effect of ultraviolet (UV)
light as a catalyst, pH, solution concentration, reactor inlet ozone gas phase concentration
and superficial gas velocity. Additionally, the effect of gas sparging (air or oxygen) in the
presence and absence of UV light was evaluated. Finally, the partial oxidation products
of ozone treated hydrazine fuels were characterized and aquatic toxicity testing accomphsh-
ed.
EXPERIMENTAL APPARATUS
The basic apparatus used for all experiments is presented in a process flow diagram
shown in Figure 1.
All experiments were conducted in a semi-batch mode, that is, a constant liquid volume
and a continuous supply of gas. Two reactors were employed in this work. The primary
reactor was the Life Systems Modified Torricelli Ozone Contactor (LMTOC) and the second
one was an ozone-ultrasonic reactor. The information generated with the latter reactor
is not reported in this paper. The reader is referred to Reference 1 for results obtained with
the ozone-ultrasound catalyzed system.
The basic design characteristics and construction materials of the LMTOC are listed in
Table I. More complete design and development information can be found elsewhere [2,3].
A grace ozonator Model LG-2-L2 was used to produce ozone. The unit contained two
corona cells and was designed to operate at gas pressures to 15 psig, with gas flows from
10 to 100 SCFH and an electrical power input from 0 to 200 watts per corona ceU.
Ozone was produced from both air and oxygen. For runs when an ozone concentration
of 13 mg/l gas or less (approximately 1% ozone in air) was desired, air was the ozonator
feed gas. Air was compressed in a Puregas Compressor Model 4 HCJ-12-M 400 X and passed
through 0.25-in. stainless steel tubing to the ozonator at 15 psig. Tank oxygen, (extra-dry
grade) was supplied to the ozonator in the same manner as the air. Oxygen feed gas permitted the production of higher concentrations of ozone (i.e., approximately 2% ozone in
oxygen) than with air for the same electrical power input to the generator.
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