Hydrothermal degradation of adsorbed sulfur mustard on activated carbon

✍ Scribed by Ruth Osovsky; Doron Kaplan; Hadar Rotter; Shai Kendler; Michael Goldvaser; Yossi Zafrani; Ishay Columbus

• Publisher: Elsevier Science
• Year: 2011
• Tongue: English
• Weight: 846 KB
• Volume: 49
• Category: Article
• ISSN: 0008-6223
• DOI: 10.1016/j.carbon.2011.05.028

✦ Synopsis

Thermal and hydrothermal degradations of adsorbed sulfur mustard (HD) on activated carbon particles from a chemical protective over-garment were studied. Carbon loaded with 5 wt.% HD was heated in a closed reactor at temperatures up to 160 °C for 0.5-6 h and analyzed by solid-state 13 C MAS NMR. On dry carbon at room temperature, HD was stable for months. On a thoroughly pre-wetted carbon, adsorbed HD partially degraded to thiodiglycol (TDG) and TDG-sulfoxide (TDG-SO) within 2-3 months. Heating dry HD-loaded carbon to 160 °C caused partial degradation within 4 h to 1,4-thioxane, along with 1,4-dithiane and vinyl sulfides. Complete degradation within 2.5 h to the same products occurred upon hydrothermal treatment of the HD-loaded carbon, using a water/carbon ratio of 0.3:1. With higher water/carbon ratios of 0.6:1-5:1 at temperatures of 120 °C and above, adsorbed HD hydrolyzed rapidly within 0.5 h. The latter reaction led to the formation of TDG concurrent with either thioxane (at 160 °C) or TDG-SO and TDG-dimer (at 120 °C). The mechanisms of the observed degradation processes are discussed.