Huang Yong H, Zhang Tian C
Department of Civil Engineering, University of Nebraska-Lincoln at Omaha Campus, Omaha, NE 68182-0178, USA.
Department of Civil Engineering, University of Nebraska-Lincoln at Omaha Campus, Omaha, NE 68182-0178, USA.
Water Res. 2006 Sep;40(16):3075-3082. doi: 10.1016/j.watres.2006.06.016. Epub 2006 Aug 9.
Batch tests were conducted to investigate reduction of nitrobenzene in a zerovalent iron system (Fe0) under various conditions. The results indicated that a limited amount of nitrobenzene (ArNO2) could be reduced to aniline by Fe0, but formation of a lepidocrocite (gamma-FeOOH) coating could significantly slow down the reaction. However, augmenting Fe0 with substoichiometric FeCl2 could dramatically accelerate the reaction. Surface-adsorbed Fe(II), not pH nor Cl-, was found to be responsible for rejuvenating the system. O2 and nitrobenzene could be concomitantly reduced by Fe0 in the presence of Fe2+. In the Fe0 system, both nitrobenzene and O2 favored formation of lepidocrocite; in the presence of aq. Fe(II), a stratified corrosion coating could develop, with magnetite (Fe3O4) as the inner layer and lepidocrocite as the outer layer. Fe2+ was not the main reductant for the reactions, but might accelerate the autoreduction of lepidocrocite to magnetite by the underlying Fe0. Our understanding on the role of Fe(II) in conjunction with a stratified, evolving corrosion coating may be useful for establishing an iron aquatic corrosion model.
进行了批次试验，以研究在各种条件下零价铁体系（Fe0）中硝基苯的还原情况。结果表明，Fe0可将有限量的硝基苯（ArNO2）还原为苯胺，但形成纤铁矿（γ-FeOOH）涂层会显著减缓反应。然而，用亚化学计量的FeCl2增强Fe0可显著加速反应。发现表面吸附的Fe（II）而非pH值或Cl-是使体系恢复活力的原因。在Fe2+存在的情况下，Fe0可同时还原O2和硝基苯。在Fe0体系中，硝基苯和O2都有利于纤铁矿的形成；在水合Fe（II）存在的情况下，可能会形成分层腐蚀涂层，内层为磁铁矿（Fe3O4），外层为纤铁矿。Fe2+不是反应的主要还原剂，但可能会加速纤铁矿被下层Fe0自动还原为磁铁矿的过程。我们对Fe（II）与分层、不断演变的腐蚀涂层的作用的理解可能有助于建立铁的水生腐蚀模型。
