机动车尾气排放中的气态污染物与金属氧化物之间的反应机制研究

Reaction Mechanism between Gaseous Pollutants and Metal Oxides in Vehicle Exhaust

硝酸盐和硫酸盐是大气细颗粒物中的重要组成部分,以往研究发现机动车尾气排放的气态污染物(NO_(X)、SO_(2))对大气颗粒物的生成有一定的贡献,但忽视了机动车排放的金属氧化物对硝酸盐和硫酸盐生成的促进作用,因此本文对机动车排放的气态污染物与金属氧化物(MgO、MnO_(2)、Al_(2)O_(3)、ZnO、CuO和Cr_(2)O_(3))之间的反应原理进行了分析。研究表明,在不同混合气体条件下,NO_(X)、SO_(2)与上述不同金属氧化物反应生成的物种(硝酸盐、硫酸盐)促进了大气颗粒物的生成。同时,从金属氧化物表面物种的生成反应来看,各金属氧化物的非均相反应能力存在差异,且Cr_(2)O_(3)非均相反应较强烈。通过研究,丰富了机动车排放的颗粒物组分对硝酸盐、硫酸盐物种的形成机制的探讨。

Nitrate and sulfate are important components of fine particulate matter in the atmosphere.Previous studies have found that gaseous pollutants(NO_(X),SO_(2))from vehicle exhaust emissions contribute to the generation of atmospheric particulate matter to a certain extent,but neglected the promotion effect of metal oxides from vehicle emissions on the generation of nitrate and sulfate.Therefore,the reaction principle between gaseous pollutants emitted from motor vehicles and metal oxides(MgO,MnO_(2),Al_(2)O_(3),ZnO,CuO and Cr_(2)O_(3))was analyzed in this paper.The results show that the species(nitrate,sulfate)generated by the reaction of NO_(x),SO_(2)and the above different metal oxides promote the generation of atmospheric particles under different mixed gas conditions.At the same time,from the perspective of the formation reactions of species on the surface of metal oxides,the heterogeneous reaction ability of metal oxides is different.Cr_(2)O_(3)heterogeneous reaction is strong This study enriched the discussion on the formation mechanism of nitrate and sulfate species in particulate matter emitted from motor vehicles.