Enhanced Degradation of RDX by Shewanella putrefaciens CN32 and Iron Bearing Soil Minerals

We demonstrated that reductive degradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (Royal Demolition Explosive, RDX) can be enhanced by bio-reduced iron-bearing soil minerals (IBSMs) using Shewanella putrefaciens CN32 (CN32). The highest rate constant was obtained by bio-reduced lepidocrocite (0.1811 h-1) during RDX degradation, followed by magnetite (0.1700 h-1), green rust (0.0757 h-1), hematite (0.0495 h-1), and goethite (0.0394 h1 ). Significant increase of Fe(II) was observed during the reductive degradation of RDX by bio-reduced IBSMs. X-ray diffraction and electron microscope analyses were conducted for identification of degradation mechanism of RDX in this study. Hexahydro-1-nitroso-3,5dinitro-1,3,5triazine, Hexahydro-1,3-dinitroso-5-nitro-1,3,5triazine, and Hexahydro-1,3,5trinitroso-1,3,5triazine were detected as products during RDX degradation.