Transformation of Polycyclic Aromatic Hydrocarbons and Formation of Environmentally Persistent Free Radicals on Modified Montmorillonite: The Role of Surface Metal Ions and Polycyclic Aromatic Hydrocarbon Molecular Properties
Transformation of Polycyclic Aromatic Hydrocarbons and Formation of Environmentally Persistent Free Radicals on Modified Montmorillonite: The Role of Surface Metal Ions and Polycyclic Aromatic Hydrocarbon Molecular Properties
复制标题
改性蒙脱土上多环芳烃的转化和环境持久性自由基的形成：表面金属离子和多环芳烃分子性质的作用
DOI：
10.1021/acs.est.8b00425
复制
发表时间：
2018-05-15
影响因子：
11.4
通讯作者：
Sharma, Virender K.
中科院分区：
文献类型：
--
作者：
Jia, Hanzhong;Zhao, Song;Sharma, Virender K.
本文研究了过渡金属离子[Fe(III)、Cu(II)、Ni(II)、Co(II)或Zn(II)]在室温(23℃)下对蒙脱石粘土表面多环芳烃(菲、菲、苯并[a]菲、芘和苯并[a]芘)的转化。这些多环芳烃的衰减遵循一级动力学，观察到的速率常数(k(Obs)，day(-1))与金属离子存在的关系遵循Fe(III)&Gt；Cu(II)&Gt；Ni(II)&Gt；Co(II)&Gt；Zn(II)的顺序。K(OBS)值与多环芳烃的氧化电位和金属离子的氧化还原电位呈良好的线性关系。值得注意的是，这些多环芳烃的转化会导致环境持久性自由基(EPFR)的形成，这是由于它们对人类健康的不利影响而引起的主要关注。采用密度泛函理论进行势能面(PES)计算，以了解改性粘土上多环芳烃在粘土表面形成自由基的机理和Kobs的变化趋势。这些EPFR的产率和稳定性随母体多环芳烃和金属离子的不同而不同。结果表明，金属在多环芳烃在共污染场地引起的EPFR的形成和去向中可能起到了作用。
This paper presents the transformation of PAHs (phenanthrene, anthracene, benzo[a]anthracene, pyrene, and benzo[a]pyrene) on montmorillonite clays that are modified by transition-metal ions [Fe(III), Cu(II), Ni(II), Co(II), or Zn(II)] at room temperature (similar to 23 degrees C). The decay of these PAHs follows first-order kinetics, and the dependence of the observed rate constants (k(obs), day(-1)) on the presence of metal ions follows the order Fe(III) > Cu(II) > Ni(II) > Co(II) > Zn(II). The values of k(obs) show reasonable linear relationships with the oxidation potentials of the PAHs and the redox potentials of the metal ions. Notably, transformation of these PAHs results in the formation of environmentally persistent free radicals (EPFRs), which are of major concern due to their adverse effects on human health. The potential energy surface (PES) calculations using density functional theory were performed to understand the trends in kobs and the plausible mechanisms for radical formation from the PAHs on modified clays. The yields and stability of these EPFRs from anthracene and benzo[a]pyrene on clay surfaces varies with both the parent PAH and the metal ion. The results demonstrated the potential role of metals in the formation and fate of PAH-induced EPFR at co-contaminated sites.