Clays and Clay Minerals, Vol. 58, No. 5, 682–690, 2010.
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Authors
Tao, Liang
Li, Fangbai
Wang, Yongkui
Sun, Kewen
Issue Date
2010
Type
Article
Language
Keywords
Periodicals , Geology , 2-nitrophenol , Adsorbed Fe(II) , Cyclic Voltammetry , Fe Oxides , Redox potential , Reductive Activity
Alternative Title
Reductive Activity Of Adsorbed Fe(ii) On Iron (oxyhydr)oxides For 2-nitrophenol Transformation
Abstract
Much attention has been paid to the adsorption of Fe(II) onto mineral surfaces as it is a crucial step in enhancing the reductive activity of Fe(II) species. The present study elucidates the role of Fe(II) adsorbed on Fe (oxyhydr)oxides (g-FeOOH, a-FeOOH, and a-Fe2O3) for the reductive transformation of 2-nitrophenol (2-NP), using cyclic voltammetry (CV). Studies of Fe(II) adsorption and 2-NP reduction kinetics showed that an increase in pH gave rise to an elevated density of adsorbed Fe(II) on mineral surfaces, which further resulted in an enhanced reaction rate of 2-NP reduction. In addition, CV tests showed that the enhanced activity of Fe(II) species is attributed to the negative shift of peak oxidation potential (EP) of the Fe(III)/Fe(II) couple. The dependence of adsorbed Fe(II) reactivity on pH values was proven by the three linear correlations obtained (ln k vs. pH, EP vs. pH, and ln k vs. EP). The present study demonstrated that the reductive activity of adsorbed Fe(II) species can be indicated by the EP value of active Fe(II) species. Moreover, the electrochemical approach can be used as an effective tool to study the reductive activity of adsorbed Fe(II) species in subsurface environments.
Description
gsccm58507-tao.pdf- 492KB
Citation
Clays and Clay Minerals, Vol. 58, No. 5, 682–690, 2010.
Publisher
The Clay Minerals Society
License
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