Interaction Mechanism Study on Simultaneous Removal of 1,2-Dichlorobenzene and NO over MnO<sub><i>x</i></sub>–CeO<sub>2</sub>/TiO<sub>2</sub> Catalysts at Low Temperatures
Qiulin Wang, Xiaoniu Huang, Yuheng Feng, Jianjian Zhou, Huancong Shi, Jing Jin
Abstract
To solve the multiple air pollution problems caused during waste incineration, simultaneous control of chlorinated aromatic pollutants (e.g., chlorobenzenes, chlorophenol, and dioxins) and nitrogen oxides (NOx) is of great significance. Titanium dioxide-supported manganese–cerium composite oxide (MnOx–CeO2/TiO2) catalysts with low-temperature activities were prepared and applied for simultaneous abatement of 1,2-dichorobenzene (o-DCBz) and NO. The interaction mechanism between o-DCBz catalytic oxidation and an NH3-SCR reaction was also studied based on the transient response experiments and several characterizations before/after the catalytic reaction. The optimum activity toward deNOx and catalytic oxidation of o-DCBz occurs both on a Mn0.15Ce0.1/Ti catalyst (i.e., Mn/Ti = 0.15, Ce/Ti = 0.1), and 97.1% of NO and 51.6% of o-DCBz are removed when the two reactions proceed independently at 150 °C. However, their simultaneous removal efficiencies are reduced mainly due to the competitive effect between o-DCBz catalytic oxidation and the NH3-SCR reaction for the limited surface acid sites and surface reactive oxygen species. In comparison, the NH3-SCR reaction is more likely to take place instead of o-DCBz catalytic oxidation, possibly because NH3 rather than o-DCBz can preferentially adsorb on the catalyst surface. In addition, the incomplete oxidation byproducts of o-DCBz residues on the catalyst surface and the chlorination of the active components of the catalyst caused by the chlorine atom from the dechlorination process of o-DCBz result in irreversible deactivation on the catalyst and lower the simultaneous abatement of o-DCBz and NO, especially at low temperatures.