Electron-beam treatment of aromatic hydrocarbons that can be air-stripped from contaminated groundwater. 2. Gas-phase studies.
Electron-beam treatment of aromatic hydrocarbons that can be air-stripped from contaminated groundwater. 2. Gas-phase studies.
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可以从受污染的地下水中气提的芳香烃的电子束处理。
DOI：
10.1021/es020930d
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发表时间：
2003
影响因子：
11.4
通讯作者：
C. von Sonntag
中科院分区：
文献类型：
--
作者：
L. Prager;G. Mark;H. Mätzing;H. Paur;J. Schubert;F. Frimmel;S. Hesse;H. Schuchmann;M. N. Schuchmann;C. von Sonntag
挥发性芳烃的电子束降解（苯、甲苯、乙苯、二甲苯：BTEX），其在本工作中已经通过将所需芳族化合物引入空气流或另一种气体（例如氧气）中来模拟，基本上通过将 *OH基团加成到芳环上来引发，产生羟基环己二烯基基团，其在加入氧时形成相应的过氧自由基。如以苯作为BTEX代表的一些详细研究，这些的各种反应导致级联反应中的许多氧化产物，包括在初始芳族化合物的高周转率的普遍条件下的产物分解。重要的是，羟基环己二烯基过氧自由基的形成是部分可逆的，因此在这些系统中具有显著存在的羟基环己二烯基自由基的反应也必须考虑在内。在气相中，与水相相反（见第1部分），羟基环己二烯基自由基的反应导致低聚产物，这些低聚产物除了离子簇外，似乎还有助于观察到的气溶胶的成核。当空气用于汽提时，观察到各种硝化产物，其中包括硝基苯酚。然而，这些研究并没有明确的中试阶段，因为使用平行进行的生物反应器进行的BTEX降解是如此成功，以至于EB技术被认为是非竞争性的。至于后者，需要昂贵的设备，包括汽提塔、EB机和气溶胶沉淀器。凝结的气溶胶是生物抗性的，需要进一步处理以解毒。
The electron-beam (EB) degradation of volatile aromatics (benzene, toluene, ethylbenzene, xylenes: BTEX) in groundwater strip gas, which in the present work has been modeled by the introduction of the desired aromatic(s) to a stream of air or another gas, such as oxygen, is initiated essentially by the addition of *OH radicals to the aromatic ring, giving rise to hydroxycyclohexadienyl radicals, which form the corresponding peroxyl radicals upon addition of oxygen. As studied in some detail with benzene as a BTEX representative, various reactions of these lead to numerous oxidation products in a cascade of reactions, including the decomposition of products under the prevailing conditions of high turnover of the initial aromatic. Importantly, hydroxycyclohexadienylperoxyl radical formation is partly reversible, and the reactions of the hydroxycyclohexadienyl radicals, which thus have a significant presence in these systems, must therefore also be taken into consideration. In the gas phase, in contrast to the aqueous phase (see Part 1), the reactions of the hydroxycyclohexadienyl radicals lead to oligomeric products that appear to contribute, in addition to ionic clusters, to nucleation for the aerosols observed. Various nitrated products, among them nitrophenols, are observed when air is used for the stripping. However, these studies did not clear the pilot plant stage, since BTEX degradation using a bioreactor carried out in parallel was so successful that the EB technology was judged to be noncompetitive. As for the latter, expensive equipment consisting of a stripper, the EB machine, and an aerosol precipitator would be required. The condensed aerosols are biorefractory and would require further treatment for detoxification.