Ultraviolet and infrared light decontamination and the secondary pollution products of G-series nerve agent simulant model molecules contaminating TiO2/Ti surfaces

Abstract Ultraviolet (UV) photodecontamination of chemical warfare agents (CWAs) has been an attractive way for decontamination of target areas unapproachable by a wet chemical method. Herein, decontamination was demonstrated using UV and infrared lamps and a home-built scanning 266-nm pulse laser under air and N2 conditions for the G-series nerve agent simulant model molecules of dimethyl methylphosphonate, dimethyl phosphite, diethyl methylphosphonate, and diethyl phosphite contaminating TiO2/Ti sheets. Volatile secondary photodecomposition products were examined by gas chromatography and mass spectrometry, and nonvolatile surface residues by X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction crystallography, and Fourier-transform infrared spectroscopy. The wavelength- and power-dependent mechanisms of the formation of diverse secondary products, the role of active O2−, h+ and •OH species, and the mechanisms of dissociative adsorption and photodecontamination were fully discussed and found valuable for the development of a remote laser photodecontamination method applicable to diverse CWA-contaminated target areas.