Mechanisms of Mn(II) catalytic oxidation on ferrihydrite surfaces and the formation of manganese (oxyhydr)oxides
文献类型：期刊论文
| 作者 | Qiu, GH; Liu, F; Zhang, J ; Feng, XH; Zhang J(张静); Wang, XM; Lan, S; Xiang, QJ; Yin, H; Tan, WF
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| 刊名 | GEOCHIMICA ET COSMOCHIMICA ACTA
 |
| 出版日期 | 2017 |
| 卷号 | 211页码:79-96 |
| 关键词 | Mn(II) oxidation Ferrihydrite Iron oxides Manganese oxides Interfacial catalysis Electrochemical electron transfer |
| ISSN号 | 0016-7037 |
| DOI | 10.1016/j.gca.2017.04.044 |
| 文献子类 | Article |
| 英文摘要 | Oxidation of Mn(II) is an important process that controls the mobility and bioavailability of Mn, as well as the formation of Mn (oxyhydr) oxides in natural systems. It was found that the surfaces of minerals, such as iron (oxyhydr) oxides, can accelerate Mn(II) oxidation to a certain degree, but the underlying mechanism has not been clearly understood. This study explores the reaction pathways and mechanisms of Mn(II) oxidation on ferrihydrite surfaces at neutral pH, commonly found in natural environments, by comparisons with montmorillonite, amorphous Al(OH)(3), goethite, and magnetite using macroscopic experiments and spectroscopic analyses. Results show that when Mn(II) concentrations are below 4 mM, macroscopic Mn (II) adsorption on the three iron (oxyhydr) oxide surfaces conforms well to the Langmuir equation, with ferrihydrite showing the highest adsorption capacity. With Mn(II) concentrations ranging within 6-24 mM, the adsorbed Mn(II) is mainly oxidized into manganite (c-MnOOH) and/or feitknechtite (b-MnOOH) by dissolved O-2, and Mn(II) removal on a unit mass basis in the presence of magnetite is the highest compared with ferrihydrite and goethite. Ferrihydrite, a semiconductor material, shows stronger catalytic ability for Mn(II) oxidation on the same surface area than insulator minerals (i. e., montmorillonite and amorphous Al(OH)(3)). Additionally, the products of Mn(II) oxidation in the presence of semiconductor iron (oxyhydr) oxides (i. e., ferrihydrite, goethite, or magnetite) at the same Fe/Mn molar ratio include both manganite and a small amount of Mn(IV) minerals, and the Mn average oxidation states (Mn AOSs) of these products follow the order: magnetite > goethite > ferrihydrite. Magnetite and goethite, with relatively smaller SSAs and lower band gap energies, exhibit greater catalysis for Mn(II) oxidation than ferrihydrite at the same Fe/Mn ratio, which goes against the conventional interfacial effect and is related to the electrochemical properties. Thus, the Mn(II) catalytic oxidation by O-2 on ferrihydrite surfaces should include an electrochemical pathway, i. e., electron transfer (ET) in the Mn(II)-Conduction Band (CB) Ferrihydrite-O-2 complexes, in addition to the conventional two interfacial catalytic pathways, i. e., ET in the Mn(II)-Fe(II, III)-O-2 complexes and direct ET in the Mn(II)-O-2 complexes. These results reveal new implications for understanding the processes and mechanisms of Mn(II) oxidation on iron (oxyhydr) oxide surfaces and the abiotic formation of Mn (oxyhydr) oxides in surface environments. (C) 2017 Elsevier Ltd. All rights reserved. |
| 电子版国际标准刊号 | 1872-9533 |
| WOS关键词 | FE(II)-CATALYZED TRANSFORMATION ; ENVIRONMENTAL SIGNIFICANCE ; REDUCTIVE TRANSFORMATION ; ELECTRICAL-PROPERTIES ; MINERAL SURFACES ; AQUEOUS MN(II) ; OXIDES ; IRON ; BIRNESSITE ; REACTIVITY |
| WOS研究方向 | Geochemistry & Geophysics |
| 语种 | 英语 |
| WOS记录号 | WOS:000405786800006 |
| 源URL | [http://ir.ihep.ac.cn/handle/311005/284777]  |
| 专题 | 高能物理研究所_核技术应用研究中心 高能物理研究所_实验物理中心 高能物理研究所_多学科研究中心 |
| 作者单位 | 中国科学院高能物理研究所 |
| 推荐引用方式 GB/T 7714 | Qiu, GH,Liu, F,Zhang, J,et al. Mechanisms of Mn(II) catalytic oxidation on ferrihydrite surfaces and the formation of manganese (oxyhydr)oxides[J]. GEOCHIMICA ET COSMOCHIMICA ACTA,2017,211:79-96. |
| APA | Qiu, GH.,Liu, F.,Zhang, J.,Feng, XH.,张静.,...&Tan, WF.(2017).Mechanisms of Mn(II) catalytic oxidation on ferrihydrite surfaces and the formation of manganese (oxyhydr)oxides.GEOCHIMICA ET COSMOCHIMICA ACTA,211,79-96. |
| MLA | Qiu, GH,et al."Mechanisms of Mn(II) catalytic oxidation on ferrihydrite surfaces and the formation of manganese (oxyhydr)oxides".GEOCHIMICA ET COSMOCHIMICA ACTA 211(2017):79-96. |
入库方式： OAI收割
来源：高能物理研究所
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