Removal of hazardous chlorinated VOCs over Mn-Cu mixed oxide based catalyst

MnCuOx/TiO2 supported catalyst was synthesized by the incipient wetness impregnation method. The catalyst was then tested for the oxidation of chlorobenzene (CB) used as a Cl-VOC model. The results showed that MnCuOx/TiO2 is very active for CB oxidation since a total conversion (exclusively into H2O, CO2 and Cl-2) was reached at 350 degrees C without formation of any other harmful organic compounds and no catalyst deactivation was observed. This performance was attributed to the formation Mn1.6CU1.4O4 spinel phase. However, at lower temperatures, some deactivation occurred before a steady-state is reached. At 300 degrees C, the CB conversion decreased and stabilised at 75% after 5 h and a small amount of HCl and traces of CO were detected. The reason why HCl was not detected at temperatures higher than 350 degrees C was explained by Deacon reaction. SEM/EDS analysis revealed the presence of chlorine uniformly dispersed on the catalyst surface. The formation of chlorinated compound (MnCUOx-aCl2a/TiO2), which is presumed to be responsible of the catalyst partial deactivation, was confirmed by other analysis experiments (TG/DTA, TPR). The catalyst regeneration under air at 350 degrees C allowed the system to recover the initial activity in spite of the fact that the chlorine was not completely removed from the catalyst. (C) 2009 Elsevier B.V. All rights reserved.