The effects of iron(II) on the kinetics of arsenic oxidation and sorption on manganese oxides

JOURNAL OF COLLOID AND INTERFACE SCIENCE

卷:457

Article

Wu, Yun¹  Li, Wei^1,2  Sparks, Donald L.¹ 

[1] Univ Delaware, Delaware Environm Inst, Environm Soil Chem Res Grp, Newark, DE 19716 USA

[2] Nanjing Univ, Sch Earth Sci & Engn, Minist Educ, Key Lab Surficial Geochem, Nanjing 210046, Jiangsu, Peoples R China

关键词: Arsenic;    Iron;    Stirred-flow;    Oxidation;    Sorption;    Kinetics;    delta-MnO2;   

DOI  :  10.1016/j.jcis.2015.07.022

来源: Elsevier

【 摘 要 】

In this study, As(III) oxidation kinetics by a poorly-crystalline phyllomanganate (delta-MnO2) in the presence and absence of dissolved Fe(II) was investigated using stirred-flow and batch experiments. Chemically synthetic delta-MnO2 was reacted with four influent solutions, containing the same As(III) concentration but different Fe(II) concentrations, at pH 6. The results show an initial rapid As(III) oxidation by delta-MnO2, which is followed by an appreciably slow reaction after 8 h. In the presence of Fe(II), As(III) oxidation is inhibited due to the competitive oxidation of Fe(II) as well as the formation of Fe(III)-(hydr)oxides on the delta-MnO2 surface. However, the sorption of As(III), As(V) and Mn(II) are increased, for the newly formed Fe(III)-(hydr)oxides provide additional sorption sites. This study suggests that the competitive oxidation of Fe(II) and consequently the precipitation of Fe(III) compounds on the delta-MnO2 surface play an important role in As(III) oxidation and As sequestration. Understanding these processes would be helpful in developing in situ strategies for remediation of As-contaminated waters and soils. (C) 2015 Elsevier Inc. All rights reserved.

【 授权许可】

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