Microwave-assisted catalytic oxidation of gaseous toluene with a Cu-Mn-Ce/cordierite honeycomb catalyst

Abstract

A novel Cu-Mn-Ce/cordierite honeycomb catalyst was prepared by an incipient wetness method and the catalyst was characterized. The active ingredients were present as various spinel species of Cu, Mn and Ce oxides with different valences and they were unevenly dispersed over the surface of the catalyst. The catalytic oxidation of gaseous toluene was primarily investigated using a fixed bed reactor under microwave heating in the continuous flow mode. Under the optimal conditions of 6.7 wt-% loading of the active component, a bed temperature of 200°C, a flow rate of 0.12 m³·h⁻¹ and an initial concentration of toluene of 1000 mg·m⁻³, the removal and mineralization efficiencies of toluene were 98% and 70%, respectively. Thus the use of the microwave effectively improved the oxidation of toluene and this is attributed to dipole polarization and hotspot effects. After four consecutive cycles (a total of 1980 min), the Cu-Mn-Ce/cordierite catalyst still exhibited excellent catalytic activity and structural stability, and the toluene removal was higher than 90%. This work demonstrates the possibility of treating volatile organic compounds in exhaust gases by microwave-assisted catalytic oxidation.

Key words： microwave; catalytic oxidation; toluene; Cu-Mn-Ce/cordierite; mineralization

Acknowledgements

This work was supported by the key technological innovation team of Shaanxi Province (2017KCT-19-01) and the innovative research team of Xi’an University of Architecture and Technology.

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