Insight into the enhanced performance of toluene removal from simulated flue gas over Mn-Cu oxides modified activated coke

Abstract

A series of bimetallic oxides of manganese and copper with different loading of copper loaded on activated coke (MnxCuy/AC) were synthesized by ultrasound-assisted equivalent volume impregnation method for toluene oxidation in simulated flue gas at 150–300 °C. The physicochemical properties of samples have been investigated by means of XRD, SEM, BET, XPS, H2-TPR and DRIFT. Mn6Cu5/AC exhibited the enhanced toluene removal efficiency (99.38%) at 270 °C, as well as satisfactory reusability and durability. The excellent activity of Mn6Cu5/AC was connected with the highly uniform distribution of active components and the larger specific surface area, which confirmed the synergistic interaction between MnOx and CuOx, thus leading to the stronger reducibility and the good oxygen mobility. In addition, SO2 and NO played a hindering role due to the competitive adsorption of active sites in pure N2, whereas the negative effect would be reduced by the introduction of O2. Besides, the influence of H2O on toluene removal was complex. Moreover, the reaction process obtained from DRIFT indicated that toluene can be rapidly adsorbed and activated to form the benzaldehyde and maleic anhydride species on Mn6Cu5/AC, and finally be further oxidized into CO2 and H2O. Finally, the mechanism of toluene oxidation over Mn6Cu5/AC was proposed.