Catalytic oxidation of trace concentrations of trichloroethylene over Cr2O3 and 5% Cr2O3 on ?-Al2O3

This research addressed the ability of Cr2O3 and 5% Cr2O3/γ-Al2O3 to catalytically oxidize trichioroethylene (TCE). Various types of Cr2O3 catalysts were compared with Pt, CuO and Fe2O3 which were previously tested in our laboratory. A number of sample catalysts containing 5% Cr2O3 on γ-Al2O3 were synthesized for this research. Different procedures were evaluated in the synthesis in order to find which procedure gives the most active catalyst. The oxidation of TCE was used as a diagnostic reaction to evaluate catalytic activity. The catalytic oxidation of trichioroethylene was conducted in a tubular reactor system in order to evaluate the activity of the catalysts as a function of temperature and space velocity. Gas chromatography with electron capture and flame ionization detectors was used for quantitative analysis of feed and product streams. The results showed that commercial powdered chromium oxide had lower light-off temperature than powdered iron oxide, but needed a temperature of 600 °C to achieve 99% conversion of trichioroethylene, while Fe2O3 showed similar conversion of TCE at 550 °C when 111 ppm TCE are reacted at a space velocity 17,400 v/v/h. In addition TCE was converted by powered Cr2O3 to an unknown byproduct which was detected by GCECD. Results with supported Cr2O3 on γ-Al2O3 showed that over 99% conversion of trichioroethylene was achieved at 400 °C for the same space velocity. A comparison of catalytic kinetics for oxidation of TCE showed that the best 5 % Cr2O3/γ-Al2O3 catalyst synthesized in this research is slightly more active than 1.5 % Pt/γ-Al2O3. Based on the results presented here, additional research on the new catalyst is warranted. In particular, lifetime comparisons between the new catalyst and 1.5 % Pt/γ-Al2O3 need to be conducted