Study on the Heterogeneous Reaction of SO₂ and NO₂ on Coal Ash

Harmful substances such as sulfur dioxide produced by coal combustion are the main source of air pollution. The heterogeneous reaction of polluting gases and coal ash particles has an important impact on atmospheric pollution. The sulphate formed by the oxidation of SO2 from coal combustion is combined with the dust generated by coal combustion, resulting in a large amount of adsorbed water on the surface becoming agglomerated nucleus, which forms a dense fog, affects the visibility of the atmosphere, and endangers human health. The existing research results show that serious damage to personnel is not only polluted gases such as SO2 and primary particulate matter directly discharged from coal combustion, but mainly secondary particles such as sulfate and nitrate formed by chemical reaction of SO2 and NO2 on the surface of particulate matter. Studying the formation process of secondary particulate matter on the surface of coal ash is crucial to improve the atmospheric environment around the power plant and other institutions. The heterogeneous reaction of mixed gas SO2, NO2 and air on the surface of the coal ash particles was investigated based on the laboratory-built aerosol reactor under ambient temperature and pressure conditions. Experimental studies have found that the relative humidity, light conditions and gas concentration will affect the process of SO2 and NO2 gas in the heterogeneous transformation of coal ash into secondary particles.