Effect of acid sites on catalytic destruction of trichloroethylene over solid acid catalysts

摘要

The catalytic destruction of trichloroethylene (TCE) over several solid acid catalysts (HZSM-5, gamma-Al2O3 and SBA-15/P) was evaluated under dry conditions. The activity order was found to be: HZSM-5 > SBA-15/P >gamma-Al2O3. It was reported that Bronsted and Lewis acid sites of catalysts both played an important role on TCE catalytic destruction, while the Bronsted acid sites were more decisive. Additionally, the formation of the polychlorinated by-product (tetrachloroethylene, PCE) over HZSM-5 and gamma-Al2O3 catalysts was observed and attributed to the presence of Lewis acid sites and basic O2-, and PCE was not detected over SBA-15/P catalyst due to the presence of only Bronsted acid sites. The TCE/O-2-TPSR studies demonstrated that the main oxidation products during TCE catalytic destruction are CO, CO2 and Cl-2, and the carbon in TCE was firstly converted to CO and then further oxidized into CO2 by gas phase O-2.