Kinetics of RDX degradation by zero-valent iron (ZVI)

Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is a common groundwater contaminant at military facilities. The current research has been conducted to evaluate the use of zero-valent iron (ZVI) for the remediation of water contaminated with RDX. RDX was found to degrade rapidly in the presence of ZVI. The observed first-order kinetic constant for RDX reduction follows an enzymatic-like kinetic model with respect to the ZVI concentration. At low ZVI concentrations, RDX reduction follows pseudo first order kinetics with respect to ZVI concentration; while at high ZVI concentrations the RDX reduction is zero-order. Nitroso compounds (MNX, DNX, and TNX), nitrate, nitrite and nitrous oxide were identified as the main by-products for the RDX reduction by ZVI. The nitroso compounds were found to undergo reduction by ZVI.