UV light decontamination and secondary pollution products of G-series chemical warfare model molecules contaminated on Mo and MoOx surfaces

Abstract

Understanding decomposition mechanism and analysis of secondary products for a chemical warfare agent (CWA) simulant on a contaminated target area are very important for better treatments of contaminated primary and secondary pollutants, and the development of a decontamination method. Herein, UV light (lamp and 266-nm laser high power pulses) photodecomposition method was introduced for the decontamination of G-series dimethyl methylphosphonate, dimethyl phosphite, diethyl methylphosphonate, and diethyl phosphite CWA model molecules contaminated on Mo and MoOx surfaces under various conditions. The secondary gas products were fully examined by gas chromatography and mass spectrometry, and the surface residues were also examined by scanning electron microscopy, Fourier-transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction analysis, and X-ray photoelectron spectroscopy before and after UV decontamination. Density function theory was employed to calculate the bond dissociation energies of the major chemical bonds for the CWA simulants. The full database for the photodecontamination products, the decomposition mechanism, the bond energies, and the roles of active species of O2−, h+ or OH reported in the present study provide valuable information on the development of future remote UV laser CWA decontamination system.