Heterogeneous and multiphase formation pathways of gypsum in the atmosphere.
Heterogeneous and multiphase formation pathways of gypsum in the atmosphere.
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DOI：
10.1039/c3cp53424c
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发表时间：
2013-10
期刊：
影响因子：
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通讯作者：
Qingxin Ma;Hong He;Yongchun Liu;Chang Liu;V. Grassian
中科院分区：
文献类型：
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作者：
Qingxin Ma;Hong He;Yongchun Liu;Chang Liu;V. Grassian
石膏是大气颗粒物的主要含硫成分。然而，到目前为止，它在大气中的形成途径仍然不清楚。在这项研究中，提出了几个潜在的重要的大气气溶胶中石膏的形成途径。结果表明，石膏是在硫酸盐和钙盐混合溶液的增湿-除湿过程中形成的。潮解层对于由Ca（2+）和SO 4（2-）离子形成石膏至关重要。特别地，吸湿组分如（NH 4）2SO 4和Ca（NO3）2的存在对于碳酸钙（CaCO 3）在SO2 + O3或SO2 + NO2以及无水硫酸钙（CaSO 4）在环境条件下非均相反应形成石膏（CaSO 4·2 H2O）时的转化是必需的。这项研究提供了明确的证据，表明气溶胶粒子的物理和化学处理过程中的协同效应对其最终化学成分、混合状态和吸湿行为有重大影响，而吸湿行为决定了所产生的气溶胶对环境和气候的影响。
Gypsum is a major sulphur-containing component of atmospheric particulate matter. To date, however, its formation pathways in the atmosphere are still not well known. In this study, several potentially important formation pathways of gypsum in atmospheric aerosols are proposed. We found that gypsum was formed in the humidifying-dehumidifying process of mixed sulphate and calcium salts. A deliquescent layer is crucial for the formation of gypsum from Ca(2+) and SO4(2-) ions. In particular, the presence of hygroscopic components, such as (NH4)2SO4 and Ca(NO3)2, is necessary for the conversion of calcium carbonate (CaCO3) upon heterogeneous reaction of either SO2 + O3 or SO2 + NO2 as well as anhydrous calcium sulphate (CaSO4) to form gypsum (CaSO4·2H2O) under ambient conditions. This study provides definitive evidence that synergistic effects in the physical and chemical processing of aerosol particles have a significant effect on their final chemical composition, mixing state and hygroscopic behaviour which dictates the environmental and climate impacts of the resulting aerosol.