Iron(III)-induced activation of chloride and bromide from modeled salt pans.
Iron(III)-induced activation of chloride and bromide from modeled salt pans.
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DOI：
10.1021/jp508006s
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发表时间：
2015-05
期刊：
影响因子：
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通讯作者：
J. Wittmer;S. Bleicher;C. Zetzsch
中科院分区：
文献类型：
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作者：
J. Wittmer;S. Bleicher;C. Zetzsch
海洋喷雾气溶胶、盐田和其他含盐表面上卤化物的光化学导致形成活性卤素物种。我们研究了原子氯（Cl）和溴（Br）在气相中的存在下，实验室模拟的盐田组成的氯化钠掺杂氯化铁（III）六水合物（0.5和2重量%）的光化学形成。将样品铺在Teflon板上，并在Teflon烟雾室中在纯化的加湿空气中暴露于模拟阳光下，在ppb水平的碳氢化合物测试混合物的存在下，通过自由基时钟法测定Cl、Br和OH的形成。在Fe（III）光解还原为Fe（II）的驱动下，在低NOX、初始无O3的环境中，Fe（III）掺杂NaCl盐样品的生成速率（高达10（7）atoms cm（-3）s（-1））超过纯NaCl样品上Cl的释放一个数量级以上。在溴化物掺杂的样品（0.5重量%的NaBr），一部分的Cl释放被取代Br时，Fe（III）的存在。添加硫酸钠，草酸钠，草酸，和邻苯二酚的NaCl/FeCl 3样品被发现抑制氯化物的活化。
The photochemistry of halides in sea spray aerosol, on salt pans, and on other salty surfaces leads to a formation of reactive halogen species. We investigated the photochemical formation of atomic chlorine (Cl) and bromine (Br) in the gas phase in the presence of laboratory-modeled salt pans consisting of sodium chloride doped with iron(III) chloride hexahydrate (0.5 and 2 wt %). The samples were spread on a Teflon sheet and exposed to simulated sunlight in a Teflon smog chamber in purified, humidified air in the presence of a test mixture of hydrocarbons at the ppb level to determine Cl, Br, and OH formation by the radical clock method. Driven by the photolytic reduction of Fe(III) to Fe(II), the production rates of the Fe(III)-doped NaCl salt samples (up to10(7) atoms cm(-3) s(-1)) exceeded the release of Cl above a pure NaCl sample by more than an order of magnitude in an initially O3-free environment at low NOX. In bromide-doped samples (0.5 wt % NaBr), a part of the Cl release was replaced by Br when Fe(III) was present. Additions of sodium sulfate, sodium oxalate, oxalic acid, and catechol to NaCl/FeCl3 samples were found to restrain the activation of chloride.