Kinetics and mechanism of the enhanced reductive degradation of nitrobenzene by elemental iron in the presence of ultrasound
Kinetics and mechanism of the enhanced reductive degradation of nitrobenzene by elemental iron in the presence of ultrasound
复制标题
DOI：
10.1021/es990385p
复制
发表时间：
2000-05-01
影响因子：
11.4
通讯作者：
Hoffmann, MR
中科院分区：
文献类型：
--
作者：
Hung, HM;Ling, FH;Hoffmann, MR
超声分解、元素铁 (Fe-0) 还原以及这两种过程的组合被用来促进水中硝基苯 (NB) 和苯胺 (AN) 的降解。在超声波存在下，Fe-0 还原硝基苯的速率得到提高。超声降解硝基苯的一级速率常数 k(US) 为 1.8 x 10(-3) min(-1)，而在 Fe-0 存在的情况下，发现速率要快得多。每个系统中苯胺降解率相似的观察结果表明，超声处理过程不受 Fe-0 存在的影响。观察到的硝基苯降解速率的提高主要归因于声空化对 Fe-0 表面的连续清洁和化学活化，以及反应物、中间体和产物在溶液相和 Fe-0 表面之间的质量传输速率的加快。亚硝基苯和苯胺（Fe-0 还原产生的主要反应中间体）的相对浓度在超声波存在下发生显着改变。
Sonolysis, reduction by elemental iron (Fe-0), and a combination of the two processes were used to facilitate the degradation of nitrobenzene (NB) and aniline (AN) in water. The rates of reduction of nitrobenzene by Fe-0 are enhanced in the presence of ultrasound. The first-order rate constant, k(US),for nitrobenzene degradation by ultrasound is 1.8 x 10(-3) min(-1), while in the presence of Fe-0, the rate was found to be substantially faster. The observation of similar degradation rates for aniline in each system suggests that the sonication process was not affected by the presence of Fe-0. The observed rate enhancements for the degradation of nitrobenzene can be attributed primarily to the continuous cleaning and chemical activation of the Fe-0 surfaces by acoustic cavitation and to accelerated mass transport rates of reactants, intermediates, and products between the solution phase and the Fe-0 surface. The relative concentrations of nitrosobenzene and aniline, the principal reaction intermediates generated by Fe-0 reduction, are altered substantially in the presence of ultrasound.