Hydrothermal Treatment of C−N−O−H Wastes: Reaction Kinetics and Pathways for Hydrolysis Products of High Explosives

Abstract

Bench-scale studies demonstrated the efficacy of hydrothermal oxidation for the treatment of wastes derived from the alkaline hydrolysis of the high explosive PBX 9404 (94% HMX, 3% nitrocellulose, and 3% chloroethyl phosphate). Specifically, chemical kinetics studies were used to deduce major global reaction pathways, and to develop a kinetic model. Although the hydrolysis liquor is a complicated waste matrix, a three-parameter kinetic model captured major reaction paths. The kinetic model used total organic carbon (TOC) as a bulk parameter for dissolved organic materials, while NOx- was used to represent the oxidized nitrogen species in solution (NO2- and NO3-). With the use of the kinetic model, an optimal treatment strategy using two oxidation stages was derived. The first stage involved balancing NOx- and O2 redox chemistry to minimize aqueous nitrogen in the effluent, while the second stage mineralized the remaining TOC.