Remediating hexahydro‐1,3,5‐trinitro‐1,2,5‐trazine‐contaminated water and soil by fenton oxidation

Abstract

AbstractSoils surrounding the former Nebraska Ordnance Plant (NOP) and other military installations are highly contaminated with hexahydro‐1,3,5‐trinitro‐1,3,5‐triazine (RDX). Because RDX is mobile in soil and recalcitrant at high concentrations, soil remediation is needed to reduce environmental hazards. Conventional treatment by incineration is costly and often creates strong public opposition. We propose an alternative treatment using the Fenton reagent (Fe2 + H2O2) to remediate RDX‐contaminated water and soil. Treating an aqueous solution of RDX with the Fenton reagent resulted in complete RDX destruction within 24 h. Ultraviolet irradiation in combination with Fenton reagent enhanced both RDX transformation and mineralization. Mass balance experiments with 14C‐RDX indicated that, within 12 h of Fenton oxidation, 76% of the initial 14C activity was lost from solution, the majority of which (68%) was recovered as 14CO2. Additional products resulting from Fenton oxidation of RDX included NH+4, NO−3, and formic acid; we also present evidence that methylene dinitramine is formed. The U.S. EPA remediation goal (5.8 mg RDX/kg) for the NOP site was achieved when the Fenton reagent was added incrementally to RDX‐contaminated soil slurries at elevated temperature (45°C). These results support the use of the Fenton reaction for remediating RDX‐contaminated water and soil.