Catalytic removal of 1,2-dichloroethane over LaSrMnCoO6/H-ZSM-5 composite: insights into synergistic effect and pollutant-destruction mechanism

Abstract

La_xSr_2−xMnCoO₆ materials with different Sr contents were prepared by a coprecipitation method, with LaSrMnCoO₆ found to be the best catalyst for 1,2-dichloroethane (DCE) destruction (T₉₀ = 509 °C). As such, a series of LaSrMnCoO₆/H-ZSM-5 composite materials were rationally synthesized to further improve the catalytic activity of LaSrMnCoO₆. As expected, the introduction of H-ZSM-5 could remarkably enlarge the surface area, increase the number of Lewis acid sites, and enhance the mobility of the surface adsorbed oxygen species, which consequently improved the catalytic activity of LaSrMnCoO₆. Among all the composite materials, 10 wt% LaSrMnCoO₆/H-ZSM-5 possessed the highest catalytic activity, with 90% of 1,2-DCE destructed at 337 °C, which is a temperature reduction of more than 70 °C and 170 °C compared with that of H-ZSM-5 (T₉₀ = 411 °C) and LaSrMnCoO₆ (T₉₀ = 509 °C), respectively. Online product analysis revealed that CO₂, CO, HCl, and Cl₂ were the primary products in the oxidation of 1,2-DCE, while several unfavorable reaction by-products, such as vinyl chloride, 1,1,2-trichloroethane, trichloroethylene, perchloroethylene, and acetaldehyde, were also formed via dechlorination and dehydrochlorination processes. Based on the above results, the reaction path and mechanism of 1,2-DCE decomposition are proposed.