Method for Degrading Aromatic Explosive Solutions

The present invention relates to a method for disposing of waste discharges containing aromatic explosives, such as TNT, and more particularly to a method of degrading explosive molecules so that the resulting effluent can be dumped without creating hazard or pollution.

The most common method for disposing of waste discharges containing explosives is to dump them without any treatment. This is undesirable both ecologically and from a safety point of view. Although, the explosive material can be separated from the fluid, which is usually water, by passing the effluent through an activated charcoal or resin column, the filter medium and the explosives absorbed create another disposal method.

The present invention relates to a method for disposing of waste discharges containing aromatic explosives, such as trinitrotoluene, dinitrotoluene, cyclotetramethylenetetrainitramine, cyclotrimethylenetrinitramine, and mixtures of these explosives. A water solution of explosives is mixed with a small amount of an additive, such as acetone or hydrogen peroxide and this mixture is then subjected to ultraviolet light. The subjecting of the additive to ultraviolet light produces a free radical which then strips off a hydrogen molecule from the other organic molecules present and creates an unstable intermediate product. Further exposure of this unstable intermediate product with ultraviolet light reduces the product to carbon dioxide and ammonia.

It is therefore a general object of the present invention to provide a relatively inexpensive method for disposing of waste discharges containing aromatic explosives.

Another object of the present invention is to provide an ecologically acceptable method of disposing of aqueous solutions of explosives by degrading the explosive molecules.

Other objects, advantages, and novel features of the present invention will become apparent from the following detailed description of the invention.

A water solution of explosives to be treated is placed in a mixing vessel and between 1 and 2 percent of either acetone or hydrogen peroxide is added to the water solution. This mixed solution is then transferred by pump or gravity to an exposure chamber having ultraviolet light. Photodecomposition of both the explosive and the additive takes place.

The method of the present invention has been found effective against trinitrotoluene (TNT), dinitrotoluene (DNT), cyclotetramethylenetetranitramine (HMX), cyclotrimethylenetrinitramine (RDX) and mixtures of these explosives. The photochemical reaction mechanisms are not fully understood but are thought to be as follows:

in the above equations (2) and (5), the radicals CH.sub.3.sup.. and OH.sup.. strip off a hydrogen molecule from the explosive compound to produce an unstable intermediate product which, when subjected to ultraviolet light, degrades the unstable intermediate product into carbon dioxide and ammonia.

The following examples are provided to illustrate the invention:

An exposure chamber was constructed and was comprised of a fluorescent light fixture which housed a germicidal lamp which emitted short wavelength ultraviolet light. The lamp was surrounded by a pyrex sleeve which had an inlet port on one end and an outlet port on the opposite end. A water solution of TNT (100 ppm) was placed in a mixing vessel and 1 %, by weight, of acetone was added. This mixture was pumped from the mixing vessel through the pyrex sleeve and then back into the mixing vessel. After 3 hours, all TNT and conversion products were eliminated.

A water solution of TNT (100 ppm) was mixed with 1 % hydrogen peroxide and pumped through the exposure chamber described in EXAMPLE I. After 24 hours, the TNT was eliminated and the total organic carbon was reduced from an initial 36.5 mg/1 to 0.6 mg/1.

Although the invention has been described with reference to a particular embodiment, it will be apparent that various pumping and exposure arrangement can be made to practice the invention on a large-scale production basis.