Emission Control of Toluene in Iron Ore Sintering Using Catalytic Oxidation Technology: A Critical Review

Abstract

Iron ore sintering flue gas containing large amounts of volatile organic compounds (VOCs) can form secondary photochemical smog and organic aerosols, thus posing a serious threat to human health and the ecological environment. Catalytic combustion technology has been considered as one of the most prospective strategies for VOC elimination. This paper focuses on a review of studies on catalytic removal of typical VOCs (toluene) on transition metal oxide catalysts in recent years, with advances in single metal oxides, multi-oxide composites, and supported metal oxide catalysts. Firstly, the catalytic activities of a series of catalysts for toluene degradation are evaluated and compared, leading to an analysis of the key catalytic indicators that significantly affect the efficiency of toluene degradation. Secondly, the reaction pathway and mechanism of toluene degradation are systematically introduced. Considering the site space and investment cost, the conversion of VOC pollutants to harmless substances using existing selective catalytic reduction (SCR) systems has been studied with considerable effort. Based on the current development of simultaneous multi-pollutant elimination technology, the interaction mechanism between the NH3-SCR reaction and toluene catalytic oxidation on the surface is discussed in detail. Finally, views on the key scientific issues and the challenges faced, as well as an outlook for the future, are presented. This overview is expected to provide a guide for the design and industrial application of NO/VOC simultaneous removal catalysts.