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CATALYTIC OXIDATION OF TOLUENE OVER MIXED Mn-M (M: Fe, Ni, Cu) OXIDES

Volatile organic compounds (VOCs) are recognized as the major contributors to global air pollution and the development of the effective methods and materials for the abatement of VOCs became of great importance. Among existing methods, such as incineration, condensation, adsorption, absorption and even plasma or photocatalysis, catalytic combustion is the most promising technology for VOC abatement [1], which can convert VOCs into harmless CO2 and water. Most of the catalysts used for VOC combustion are, generally, very active noble metals (Pt, Pd, etc), also very expensive. Many efforts have been made towards the design of cheaper catalyst materials based on the mixed transition metal oxides. Manganese oxides are reported to be among the most efficient transition-metal compounds in catalytic combustion [2, 3]. This paper deals with preparation, characterization and catalytic activity of the mixed manganese oxides, Mn-M (M: Fe, Ni, Cu) used for catalytic oxidation of toluene. Toluene, as one of the representative aromatic VOCs, extensively applied in different fields of industry was chosen as a model VOC compound. Catalysts were synthesized by the coprecipitation method and various techniques (XRD, SEM, N2 adsorption/desorption, etc.) were used for their characterization. Catalytic tests were performed in the fixed bed flow reactor and the influences of different reaction conditions on the catalytic performance were examined using gaseous mixture of toluene and nitrogen (242 ppm of toluene/nitrogen) and air as an oxidant. Tests were performed at different temperatures (373- 548 K) and various total flow rates of the reaction mixture (23-138 cm3 min-1) at the constant catalyst mass (0.05 g). Obtained mesoporous catalysts show low- temperature activities for the toluene oxidation with T90 temperatures corresponding to 90% of the toluene conversion observed at 450K and lower. [1] H. Huang, Q. Feng, D. Y. C. Leung, Catal. Sci. Technol. 5 (2015) 2649-2669. [2] M. R. Morales, B. P. Barbero, L.E. Cadús, Appl. Catal. B 74 (2007) 1-10. [3] J. Zhou, D. Wu, W. Jiang, Y. Li, Chem. Eng. Technol. 32 (2009) 1520-1526.

VOC ; toluene ; Mn-M (M: Fe ; Ni ; Cu)

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