Electrochemical evidences for promoted interfacial reactions: the role of Fe(II) adsorbed onto gamma-Al2O3 and TiO2 in reductive transformation of 2-nitrophenol.
Electrochemical evidences for promoted interfacial reactions: the role of Fe(II) adsorbed onto gamma-Al2O3 and TiO2 in reductive transformation of 2-nitrophenol.
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DOI：
10.1021/es8033445
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发表时间：
2009-04
影响因子：
11.4
通讯作者：
Fangbai Li;Liang Tao;C. Feng;Xiang-zhong Li;K. Sun
中科院分区：
文献类型：
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作者：
Fangbai Li;Liang Tao;C. Feng;Xiang-zhong Li;K. Sun
本研究旨在用电化学方法阐明矿物表面吸附的Fe(II)在2-硝基苯酚(2-NP)还原转化中的作用。Fe(11)吸附和2-NP还原动力学研究表明，γ-Al_2O_3和TiO等矿物的一致性以及溶液的pH值是决定Fe(11)吸附行为和影响2-NP还原速率常数(K)的关键因素。此外，采用循环伏安法(CV)和电化学阻抗谱(EIS)两种电化学方法表征了Fe(II)在有矿物涂层电极和无矿物涂层电极上的反应性。电化学证据表明，溶液pH对络合物Fe(II)的氧化电位(EP)有显著影响，2-NP的还原转化增强可能与Fe(II)表面络合物的EP降低和Fe(III)/Fe(II)对的电荷转移电阻(R(CT))降低有关。对这些关系进行了定量研究。在pH 6.7时，测得的EP和R(CT)按非矿物(k×10~(-2)，0.64>；0.077分钟(-L))的顺序递减。
This study was aimed at elucidating the role of adsorbed Fe(II) on minerals in the reductive transformation of 2-nitrophenol (2-NP) by using electrochemical methods. The studies of Fe(ll) adsorption and 2-NP reduction kinetics showed that the identity of minerals such as gamma-Al2O3 and TiO and the solution pH were crucial factors to determine the Fe(ll) adsorption behavior and to influence the rate constant (k) of 2-NP reduction. Furthermore, two electrochemical methods, cyclic voltammetry (CV) and electrochemical impedance spectrometry (EIS), were applied to characterize the Fe(II) reactivity with both the mineral-coated and mineral-free electrodes. The electrochemical evidence confirmed that the peak oxidation potential (Ep) of complex Fe(II) can be significantly affected by the solution pH;the enhanced reductive transformation of 2-NP can be related to the reduced Ep of surface-complex Fe(II) and the reduced charge transfer resistance (R(CT)) of the Fe(III)/Fe(II) couple. All these relationships were studied quantitatively. At pH 6.7, the measured Ep and R(CT) decreased in the order TiO2/GC gamma-Al2O3 > nonmineral (k x 10-2, 7.91 > 0.64 > 0.077 min(-l)).