Oxidative degradation of 2,4.6-trinitrotoluene by ozone in an electrohydraulic discharge reactor

The electrohydraulic discharge process in the presence of ozone has been used to investigate the rapid degradation and mineralization of aqueous 2,4,6-trinitrotoluene (TNT) solutions that were directly exposed to high-energy electrical discharges between two submerged electrodes. The 165 mu M solutions of TNT we re competely ( > 90%) mineralized over the course of 300 electrical discharges of 7 kJ each. The kinetics of TNT degradation were investigated as a function of the aqueous-phase ozone concentration, pH, discharge energy, and electrode gap length. The rate of TNT degradation increases with an increase in aqueous-phase ozone concentration of up to 150 mu M, an increase in pH from 3.0 to 7.9, an increase in discharge energy from 5.5 to 9 kJ, and a decrease in the electrode gap length from 10 to 6 mm. The rapid rates of mineralization (e.g. 12 ms) are attributed to the action of UV light in the reactor chamber on O-3 to produce a high flux of hydroxyl radicals per discharge (1 mu M discharge(-1)). The primary reaction intermediates were 2,4,6-trinitrobenzaldehyde and trinitrobenzene.