University/Institute:PD Division, Defence Research and Development Establishment, Gwalior 474002, India
A low-temperature vapor phase catalytic oxidation of dimethyl sulphide (DMS) with ozone over nano-sized Fe2O3–ZrO2 catalyst is carried out at temperatures of 50–200 ºC. Nanostructured Fe2O3–ZrO2 catalyst (FZN) is prepared by modified sol-gel method using citric acid as a chelating agent and conventional FZ catalyst is prepared with co-precipitation method. The catalysts are characterized using N2–BET surface area and pore size distributions, X-ray diffraction, TPR, TPD of DMS and NH3, SEM and TEM. The effects of operating temperature, ozone/DMS concentration and gas hourly space velocity (GHSV) on DMS removal efficiencies via catalytic ozonation are investigated. Relatively higher amount of ozone decomposition is observed on nanocatalyst compared to the co-precipitate catalyst from 50 ºC to 150 ºC. In contrast, at 200 ºC irrespective of the particle size, both catalysts performed similar activity. It clearly demonstrates that under ozone assisted catalytic oxidation over nanocatalyst offers the 100 % of DMS conversion at lower temperature. The synthesized nanocatalyst and ozone are observed highly efficient for low temperature catalytic oxidation of DMS. The stability test shows that the nanocatalyst have relatively high activity and stability under the reaction conditions. A plausible reaction mechanism has been proposed for the oxidation of DMS based on the possible reaction products.