Heterogeneous Reactions Of SO₂,NO₂ And Acetic Acid On The Surface Of Typical Mineral Aerosol

Aerosol is a huge dispersion system formed by various solid or liquid particles dispersed in the atmospheric environment.Mineral aerosol is one of the important components of atmospheric aerosol and one of the most active aerosols.Heterogeneous reactions of atmospheric trace pollutant gases including organic and inorganic pollutant gases on the surface of mineral aerosols can change the chemical composition of atmospheric aerosols,affect the oxidative capacity and chemical balance in atmospheric chemistry,and endanger human health.Moreover,it can change the optical properties and hygroscopicity of aerosols,worsen regional and global atmospheric environment and change global climate.So far,research on the heterogeneous reactions of trace pollutant gases on the surface of mine aerosols has been extensive and in-depth,but there is still much research space for the synergistic or competitive effects of organic and inorganic pollutant gases on the surface of mineral aerosols.In this research,diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)technology is used to carry out a series of studies on the competitive and synergistic impacts of NO2,SO2 and HAc on the surface of typical mineral aerosols in atmospheric heterogeneous reactions.At the same time,the effects of environmental factors such as relative humidity and solar radiation on heterogeneous reactions were explored.The competitive reactions of SO2 and HAc on the surface of α-Al2O3 and CaCO3 particles were studied,and the competitive effects between sulfite and acetate on the surface of different particles in the heterogeneous reaction were explored.On the surface of α-Al2O3 particles,acetate and sulfite can compete for surface-active sites,resulting in a decrease in the total amount of acetates.On the surface of CaCO3 particles,the heterogeneous reaction of SO2 can be impeded by coexisting acetic acid,resulting in a drastic reduction of the number of sulfitesThe effects of NO2 and SO2 particles on the heterogeneous reaction of HAc on the surface of α-Al2O3 particles in the presence and absence of simulated solar radiation were researched,and the role and effect of pre-adsorption in the heterogeneous reaction in the atmosphere was explored.It can be seen that solar radiation stimulates the formation of more acetate and nitrate.At the same time,it can promote the conversion of sectional sulfite to sulfate in the heterogeneous reaction of SO2 on α-Al2O3 particles.Pre-adsorbed species like nitrate,sulfite or sulfate play a significant role in the heterogeneous reaction of acetic acid on the surface of α-Al2O3 particles,which have conspicuous inhibition influence on the formation of acetate.When α-Al2O3 particles are pre-adsorbed by different types of substances or not,simulated radiation can promote the growth of different amounts of acetate.The effects of NO2 and HAc on the heterogeneous reaction of SO2 on the surface of CaCO3 particles in the presence and absence of simulated solar radiation with different relative humidity were studied,and different chemical mechanisms of competitive and synergistic reactions were researched.On the surface of CaCO3 particles,moderate relative humidity can promote the formation of sulfite and acetate.Also,solar radiation can promote the conversion of sulfite to sulfate,but the production of nitrate has been suppressed.The coexistence of NO2 with SO2 promotes the heterogeneous reaction between SO2 and CaCO3 particles.On the contrary,acetic acid plays a suppressive role.In the presence of water,it can reduce the inhibitory effect of acetic acid and produce a certain number of sulfites.The experimental results were summarized and the reaction mechanism was deducedThis research focuses on the mix pollution of two types of organic and inorganic pollutants on the surface of typical mineral particles in the atmosphere.The competitive reaction,synergistic reactions and pre-adsorption impacts are discussed separately.Environmental factors such as solar radiation,relative humidity can also have significant effects on the heterogeneous reaction.This study revealed the complexities of heterogeneous conversion processes,which provides a variety of ideas and possibilities for the formation of related inorganic and organic salts in the atmosphere.