NO2在MgO颗粒物表面的非均相反应
组内消息 2014-12-01
结合原位漫反射红外傅里叶变换光谱(DRIFTS)与离子色谱(IC)技术确立了一种测定吸附系数真值的方法。
摘要：氧化镁(MgO)是大气中矿物气溶胶的重要组分之一, 对二次污染物的形成有着重要影响. 本研究采用原位漫反射红外傅里叶变换光谱(DRIFTS)与离子色谱(IC)技术, 研究了二氧化氮(NO2)在MgO颗粒表面的非均相反应. 探讨了无光照、紫外光照、臭氧(O3)、温度及相对湿度(RH)等对该反应的影响机制, 建立了新的测定摄取系数的方法. 结果表明, 无光照时, NO2在MgO颗粒表面生成的主要产物为硝酸盐和亚硝酸盐; 在NO2-MgO-O3和NO2-MgO-hn两种反应体系中主要产物均为硝酸盐, 生成的硝酸根峰面积分别是无光照条件下的1.54倍和3.04倍, O3和紫外光照对硝酸盐的生成均具有促进作用; 在紫外光照条件下, NO2在MgO颗粒物表面生成硝酸根的初始速率随温度的升高而呈单峰变化, 40℃时初始速率最大; 影响NO2与MgO颗粒物反应的敏感因素为紫外光照和臭氧, 其次为相对湿度和温度. 在25℃, RH为5%时, 无光照条件和紫外光照条件下反应初始摄取系数分别为9.01×10-4和5.65×10-3.
韩力慧, 陈媛媛, 贾龙, 程水源, 徐永福,等. NO2在MgO颗粒物表面的非均相反应. 中国科学 化学, 2014, 44(12),2004-2012
Heterogeneous reactions of NO2 on the surface of MgO particles
Abstract：MgO is one of the most important components of mineral aerosol, and it has an important influence on the formation of secondary pollutants. The heterogeneous reaction of NO2 on MgO particles was studied using in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and ion chromatography (IC). The influences of no ultraviolet radiation(UV), ultraviolet radiation(UV), ozone (O3), temperature and relative humidity (RH) on the reaction were investigated. A new method has firstly been established to determine uptake coefficients. The main products from the heterogeneous reaction of NO2 on MgO particles were nitrate and nitrite without UV. In NO2-MgO-O3 and NO2-MgO-hv reaction systems, the main product was nitrate, and its infrared adsorption peak areas were 1.54 and 3.04 times higher than that without UV, respectively. O3 and UV were in favor of the formation of nitrate. The initial rate of nitrate, due to the rise of temperature, showed a unimodal pattern with the maximum initial rate at 40℃ under UV. More sensitive factors affecting the reaction of NO2 on MgO particles are UV and ozone, followed by relative humidity and temperature. The initial reactive uptake coefficients of NO2 on MgO particles were determined to be 9.01×10-4 without UV and 5.65×10-3 with UV at 25℃ and 5% RH.
HAN LiHui, CHEN YuanYuan, JIA Long, CHENG ShuiYuan, XU YongFu,et al. Heterogeneous reactions of NO2 on the surface of MgO particles. Scientia Sinica Chimica, 2014, 44(12),2004-2012.
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