有机硫酸酯定量方法优化及其在深圳市PM2.5中污染特征研究

发布时间：2018-06-08 17:53

  本文选题：深圳市PM2.5 + 有机硫酸酯　； 参考：《哈尔滨工业大学》2015年硕士论文

【摘要】：有机硫酸酯类物质(Organosulfates,OSs)是近几年来发现的一种存在于大气颗粒物上的新兴有机组分。有研究表明,在环境空气中SO_2浓度较高的地区,大气颗粒物中OSs的比重也较大。我国大气中SO_2污染严重,因此对我国大气颗粒物中OSs进行污染特征研究,评估OSs对大气颗粒物的贡献具有重要意义。本文建立了一种间接测定大气颗粒物中OSs的方法,通过间接地测定OSs的共有基团硫酸根的含量,并基于从烟雾箱获得的OSs中有机碳与有机硫的摩尔比,估算出OSs的含碳量。本文选用十二烷基硫酸钠作为OSs的替代标准物,建立和优化了OSs的解离方法,利用离子色谱测定解离前后颗粒物中硫酸根含量,同时通过差减法得到颗粒物中OSs中硫酸根的含量。为确定此方法在测定实际大气颗粒物中OSs含量的适用性,本文设计了一系列不同摩尔比的无机硫与有机硫的混合体系,评价了该方法用于测定混合体系中无机硫酸根(Inorganic Sulfates,IS)和总硫酸根(Total Sulfates,TS)的回收率和精密度,并对获得的OSs中硫酸根含量进行了误差分析。结果表明,本文建立的OSs中硫酸根定量方法的误差范围为5.74%～37.71%。本文选取α-蒎烯、β-蒎烯和异戊二烯三种生物源前体物臭氧氧化所生成的二次颗粒物作为研究对象,通过测定烟雾箱中在相同酸性不同硫含量无机种子气溶胶存在的条件下,三种生物源前体物臭氧氧化生成的颗粒物中有机硫与有机碳的变化量,确定OSs中有机碳与有机硫的相关性关系,实验数据的线性拟合结果表明OSs中有机碳与有机硫的摩尔比为10:1。另外,无机种子气溶胶酸度对二次有机气溶胶中有机硫酸根(Organic Sulfates,OS)含量和产率的影响大于其硫含量。本文针对深圳市四个不同特征污染源地区的PM2.5样品中OSs的污染特征进行了分析,发现深圳市冬季大气环境中OSs的质量浓度平均为2.71μgC/m~3,占颗粒物TOC的29.42%;深圳市夏季大气环境中OSs的质量浓度平均为1.18μgC/m~3,占颗粒物TOC的13.76%,占PM2.5质量的2.43%;四个不同特征污染源采样点的OSs的质量浓度大小依次为某电厂龙华西丽HITSZ,OSs占颗粒物TOC的大小依次为龙华某电厂西丽HITSZ。另外,对PM2.5各组分进行相关性分析,发现OSs中OS与颗粒物上的IS呈现显著正相关性,说明OSs可能是由IS通过一系列大气化学反应转化而形成的。
[Abstract]:Organic Sulfate compounds (Organo sulfates) is a new organic component found in atmospheric particulate matter in recent years. Some studies have shown that the proportion of OSs in atmospheric particulate matter is also larger in the area with higher concentration of SO2 in ambient air. So it is of great significance to study the characteristics of OSs pollution and evaluate the contribution of OSs to atmospheric particulates in China. In this paper, an indirect method for the determination of OSs in atmospheric particulates is established. By indirectly determining the content of common group sulfate in OSs, and based on the molar ratio of organic carbon to organic sulfur in OSs obtained from smoke box, the carbon content of OSs is estimated. In this paper, sodium dodecyl sulfate was chosen as the substitute standard of OSs, and the dissociation method of OSs was established and optimized. The content of sulfate in particles before and after dissociation was determined by ion chromatography. At the same time, the content of sulfate in OSs was obtained by differential subtraction. In order to determine the applicability of this method to the determination of OSs in actual atmospheric particulates, a series of mixed systems of inorganic and organic sulfur with different molar ratios have been designed in this paper. The method was used to determine the recovery and precision of Inorganic Sulfatesl (ISS) and Total Sulfatesl (TS) in the mixed system. The error analysis of the content of sulfate in the obtained OSs was carried out. The results show that the error range of the established quantitative method of sulfate in OSs is 5.74 ~ 37.71. The secondary particles produced by ozone oxidation of three biological precursors, 伪 -pinene, 尾 -pinene and isoprene, were selected as the research object. The change of organic sulfur and organic carbon in particulate matter produced by ozonation of three biological precursors and the correlation between organic carbon and organic sulfur in OSs were determined. The linear fitting results of experimental data showed that the molar ratio of organic carbon to organic sulfur in OSs was 10: 1. In addition, the effect of the acidity of inorganic seed aerosol on the content and yield of organic sulfate in secondary organic aerosol is greater than that of sulfur content. In this paper, the characteristics of OSs pollution in PM2.5 samples from four different pollution source areas in Shenzhen were analyzed. It was found that the average mass concentration of OSs in the atmospheric environment in winter in Shenzhen was 2.71 渭 g / m ~ (-1), accounting for 29.42% of the TOC of particulate matter, and that in the atmospheric environment of Shenzhen in summer was 1.18 渭 g C / m ~ (3), which accounted for 13.76 渭 g / m ~ (3) of TOC and 2.43% of the mass of PM2.5. The quality concentration of OSs at the source sampling point was in turn the size of the TOC of the particles occupied by HITSZOSs in a power plant was the same as that of Xiili HITSZ of a power plant in Longhua power plant. In addition, the correlation analysis of PM2.5 components showed that OS in OSs was positively correlated with is in particulate matter, which suggested that OSs might be formed by a series of atmospheric chemical reactions.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X513

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