Catalytic abatement of dichloromethane over transition metal oxide catalysts: Thermodynamic modelling and experimental studies

Dichloromethane (DCM) is a noxious chemical that is widely used in industry. The current work focuses on the catalytic abatement of DCM from industrial effluents to minimize its harmful effects to the environment and human wellbeing. Three transition metal oxide catalysts (V, Cu and Mn) supported on gamma-Al2O3 were synthetized for total oxidation of DCM in presence of steam. Thermodynamic modelling was used to reveal information related to the stability of the used transition metal oxides in the abatement conditions. The results showed that with 10 wt-% CuO and 10 wt-% V2O5 containing catalysts 100% conversion of DCM together with 90% HCl yield and insignificant by-product formation can be achieved at temperature around 500 degrees C. According to modelling, V2O5 should be stable at the conditions of DCM oxidation, while CuO would be more stable at higher temperature level (decomposition of CuCl2 starts at 300 degrees C). MnCl2 remains stable until 800 degrees C, which leads to deactivation of MnO2 catalyst. Presence of steam inhibits the poisoning of the materials by chlorine based on thermodynamic calculation. XRF analysis supports the results of thermodynamic modelling used MnO2 and CuO catalysts contain chlorine, which was not detected in case of V2O5/Al2O3. CuO/gamma-Al2O3 seems to be a good alternative to noble metal catalysts for the total oxidation of dichloromethane when used in the presence of steam and the temperatures above 300 degrees C to minimize Cl-poisoning. The outcomes of this study showed that the prepared metal oxides are promising catalysts to minimize pollution caused by chlorinated volatile organic compounds. (C) 2019 Elsevier Ltd. All rights reserved.