Mechanism Of Nitrate Formation On The Surface Of Albite (Orthoclase) Multiphase Particles

Although China’s air quality has improved in recent years,large-scale haze weather still occurs across the country,and the operation of China’s economy and society has been seriously affected.Although the concentration of SO₂ gas has been effectively controlled,the concentrations of O₃ and NO₂ are still high,so it is necessary to further study the reaction between NO₂ and O₃ in the atmosphere.Inorganic particulate matter in the atmosphere is the carrier or catalyst of gaseous pollutants,which can be converted into secondary inorganic particles through heterogeneous reaction,resulting in more serious air pollution.Albite（orthoclase）,one of the main minerals in atmospheric mineral dust,has rarely been studied in atmospheric heterogeneous reaction.Therefore,this study constructed the composite interface of inorganic gas（NO₂/NO₂+O₃）-secondary polar particulate matter-mineral particles to explore the influence of atmospheric secondary inorganic particles on the formation of nitrate on the surface of albite（orthoclase）.In this study,albite（orthoclase）particles,NO₂,O₃ and typical secondary inorganic particles（Na₂SO₄,Na NO₃,NH₄Cl）were selected as research objects to explore their role in heterogeneous reactions,and the influence of different environmental conditions（light and humidity）on heterogeneous reaction.The main conclusions are as follows:（1）Under ultraviolet irradiation,the albite and orthoclase reached saturation after 180min reaction at the relative humidity of 54%and 75%,respectively.The surface nitrate yield reached 14.27 ppm and 7.67 ppm,respectively.Albite is 1.86 times that of orthoclase.At high relative humidity,due to the adsorption of NO₂ on the surface of albite（orthoclase）,the generated N₂O₄ will undergo disproportionation reaction to form NO₃^-and NO₂^-,and generate·OH with H₂O on the mineral surface,and oxidize NO₂^-to NO₃^-.Meanwhile,due to the fracture of Na-O,K-O and Al-O bonds,the dissolved Na⁺,K⁺and Al³⁺in albite and orthoclase combine with the generated NO₃^-to generate Na NO₃,KNO₃ and Al（NO₃）₃.（2）The yield of NO₃^-on the surface of albite（orthoclase）loaded with Na₂SO₄,Na NO₃and NH₄Cl is 1.02,1.44 and 1.37 times that of single albite,and 1.34,1.33 and 1.79 times that of NO₃^-on the surface of orthoclase.The loading of secondary inorganic particles is conducive to the adsorption and conversion of NO₂ on the surface of albite（orthoclase）.The promoting effect is NH₄Cl>Na NO₃>Na₂SO₄.Physical adsorption of NO₂ reacts with H₂O on the surface to generate HNO₃ and HNO₂,and then reacts with dissolved metal ions on the surface of albite（orthoclase）to generate Na NO₃,KNO₃,Al（NO₃）₃ and nitrite.Nitrate and nitrite can react with Na₂SO₄ to form K₂SO₄ and Al₂（SO₄）₃.When Na NO₃ is loaded on the surface of albite（orthoclase）,the loaded NO₃-under ultraviolet irradiation will photolysis and eventually form·OH,and then the gaseous NO₂ will be oxidized to HNO₃ and react with metal ions to form Na NO₃,KNO₃ and Al（NO₃）₃.albite（orthoclase）-NH₄Cl particles react with NO₂,and NO₂ combines NO₃^-generated by adsorption and transformation with NH₄⁺to form NH₄NO₃particles.（3）O₃ can significantly promote the adsorption and conversion of NO₂ on the surface of albite（orthoclase）and its multiphase particles.O₃ can directly react with NO₂ and the resulting N₂O₅ can adsorb the surface of albite（orthoclase）and react with it to produce Na NO₃,KNO₃and Al（NO₃）₃.After loading Na₂SO₄,the HNO₃ generated by NO₂ adsorption on the surface of albite（orthoclase）can further react with Na₂SO₄ to produce Na NO₃ and Na HSO₄.The generated HSO₄^-is converted to SO₄^2-by·OH produced by the photolysis of O₃,and Na NO₃is generated continuously in the reaction cycle.After loading NH₄Cl,NH₃ escaping from NH₄Cl hydrolysis of albite（orthoclase）can react with O₃ to directly generate NH₄NO₃.