Oxidative treatment of high explosives contaminated wastewater

Abstract

The oxidation of high explosives (HE), TNT, RDX and HMX, contaminated water has been studied under different conditions. Catalytic and advanced oxidation employing ultraviolet and hydrogen peroxide were investigated. Catalytic and non-catalytic wet oxidation of HE were carried over a 4.45 wt% Pt/TiO 2 catalyst with a particle diameter of less than 105 μm in a batch reactor at moderate pressure (⩽35 atm) and temperature (⩽200°C). Ultraviolet photolysis in combination with hydrogen peroxide oxidation was carried out in a pyrex glass reactor with a total volume of 310 ml at ambient conditions. The irradiation in the photoreactor was obtained by a low-pressure mercury lamp that emits about 90% of its radiation at 254 nm with a 15 W power input. Catalytic and non-catalytic oxidation results indicate that the reaction rate is very much temperature dependent, virtually pressure independent, and mildly dependent on the amount of catalyst. The presence of catalyst resulted in about 20°C advantage in catalytic oxidation when compared to homogeneous wet oxidation. Also RDX/HMX oxidation was relatively easy without the presence of a catalyst at temperatures as low as 85°C and complete oxidation occurs at above 110°C in less than 30 min. Direct photolysis of RDX/HMX was accomplished in about 20 min whereas TNT was the most stable compound and the presence of hydrogen peroxide was essential to reach total oxidation in a reasonable time.