Catalytic ozonation of dichloromethane at low temperature and even room temperature on Mn-loaded catalysts

Five Mn-loaded catalysts were synthesized on gamma-Al2O3, TiO2, ZrO2, nano gamma-Al2O3 and nanoZrO(2) supports. The catalytic ozonation of DCM (dichloromethane) was evaluated under industrial conditions (i.e., temperature, O-3 input, H2O and SO2 content). According to results, >90% DCM conversion without O-3 residue was achieved for all samples at 120 degrees C and an O-3/DCM ratio of 6. At 20-120 degrees C, the highest Mn3+ content, abundant surface oxygen species and more weak acid sites led to the best performance of Mn/nanoAl(2)O(3) (M/A-II). At 20 degrees C and 120 degrees C, 80% and 95% DCM can be degraded respectively on M/A-II at 20 degrees C with matched surface oxygen species and acidity. An O-3/DCM ratio of 6 was optimal for performance and economy. For the effects of complex exhaust, both H2O and SO2 deactivated M/A-II. The H2O-induced deactivation was recoverable and also removed surface-deposited chlorine-containing species, enhancing the HCl selectivity. Finally, the Cl equilibrium of the reaction was comprehensively analyzed.

Automated summary

Five Mn-loaded catalysts were synthesized on different supports and their catalytic ozonation performance for DCM was evaluated under industrial conditions. The results showed that all catalysts achieved over 90% DCM conversion, with Mn/nanoAl2O3 exhibiting the best performance. Both H2O and SO2 affected the catalyst activity, with the inhibition caused by H2O being reversible.