Degradation of diethyl sulfide vapors with manganese oxide catalysts supported on zeolite-13X: The influence of process parameters and mechanism in presence of ozone

Vapour phase catalytic degradation of diethyl sulfide (DES) (simulant of a potential chemical warfare agent: sulfur mustard) at higher concentration (∼1200 ppm) is carried out in a fixed bed flow reactor over Mn/zeolite-13X catalysts of different manganese contents. The reaction is studied in the temperature range of 60-180 °C using ozone as the oxidizing agent. The influence of various process parameters such as reaction temperature, metal content, gas hourly space velocities (GHSV), ozone-to-DES mole ratio and water vapor are studied for getting maximum activity of the catalysts. Results reveal that reaction temperature and water vapor has significant effect on the conversion of DES and stability of the catalyst. Higher ozone-to-DES mole ratio facilitates the complete mineralization of DES at mild reaction conditions. The major products identified in the gas phase degradation of DES are carbon oxides, ethylene, acetaldehyde, acetic acid, sulfur dioxide and diethyl sulfone. Traces of diethyl sulfoxide, ethanol, thioethanol, methane thiol, formic acid are also identified in GC-MS analyses. The plausible degradation pathway is proposed based on the products identified by analyses results. The Mn/zeolite-13X catalysts of different composition are prepared by wet impregnation method and characterized by different characterization techniques.