Mechanisms of Mn(II) catalytic oxidation on ferrihydrite surfaces and the formation of manganese (oxyhydr)oxides

doi:10.1016/j.gca.2017.04.044

IHEP OpenIR > 核技术应用研究中心

	Mechanisms of Mn(II) catalytic oxidation on ferrihydrite surfaces and the formation of manganese (oxyhydr)oxides
	Lan, S; Wang, XM; Xiang, QJ; Yin, H; Tan, WF; Qiu, GH; Liu, F; Zhang, J; Feng, XH; Zhang J(张静)
	2017
发表期刊	GEOCHIMICA ET COSMOCHIMICA ACTA (IF:4.609[JCR-2016],4.847[5-Year])
ISSN	0016-7037
EISSN	1872-9533
卷号	211 页码:79-96
文章类型	Article
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.
关键词	Mn(II) oxidation Ferrihydrite Iron oxides Manganese oxides Interfacial catalysis Electrochemical electron transfer
DOI	10.1016/j.gca.2017.04.044
关键词[WOS]	FE(II)-CATALYZED TRANSFORMATION ; ENVIRONMENTAL SIGNIFICANCE ; REDUCTIVE TRANSFORMATION ; ELECTRICAL-PROPERTIES ; MINERAL SURFACES ; AQUEOUS MN(II) ; OXIDES ; IRON ; BIRNESSITE ; REACTIVITY
收录类别	SCI ; SCOPUS ; ADS
语种	英语
WOS研究方向	Geochemistry & Geophysics
WOS类目	Geochemistry & Geophysics
WOS记录号	WOS:000405786800006
ADS Bibcode	2017GeCoA.211...79L
ADS URL	https://ui.adsabs.harvard.edu/abs/2017GeCoA.211...79L
ADS引文	https://ui.adsabs.harvard.edu/abs/2017GeCoA.211...79L/citations
引用统计	正在获取... 被引频次：115 [ADS]
文献类型	期刊论文
条目标识符	https://ir.ihep.ac.cn/handle/311005/284777
专题	核技术应用研究中心实验物理中心多学科研究中心
作者单位	中国科学院高能物理研究所
第一作者单位	中国科学院高能物理研究所
推荐引用方式 GB/T 7714	Lan, S,Wang, XM,Xiang, QJ,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	Lan, S.,Wang, XM.,Xiang, QJ.,Yin, H.,Tan, WF.,...&张静.(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	Lan, S,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.

条目包含的文件
文件名称/大小	文献类型	版本类型	开放类型	使用许可

20170725.pdf（3914KB）	期刊论文	出版稿	限制开放	CC BY-NC-SA	请求全文
20170725-A.doc（3155KB）	期刊论文	出版稿	限制开放	CC BY-NC-SA	请求全文