Characterization of Ni-rich hexagonal birnessite and its geochemical effects on aqueous Pb2+/Zn2+ and As(III)

	Characterization of Ni-rich hexagonal birnessite and its geochemical effects on aqueous Pb2+/Zn2+ and As(III)
	Yin, H; Tan, WF; Zheng LR(郑黎荣); Zheng, LR; Cui, HJ; Qiu, GH; Liu, F; Feng, XH
刊名	GEOCHIMICA ET COSMOCHIMICA ACTA
	2012
卷号	93 页码:47-62
英文摘要	Hexagonal birnessite is the most ubiquitous manganese oxide in geological environments. It is often highly enriched in trace metal ions such as Ni and plays an important role in metal(loids) geochemistry. Nanostructured birnessites containing different amounts of Ni were synthesized by addition of Ni2+ to initial reactants. Powder X-ray diffraction (XRD), element analysis, field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), X-ray absorption spectroscopy (XAS) and isothermal adsorption and oxidation of metal(loids) were carried out to investigate the effects of Ni doping on the substructure and physicochemical properties of birnessite, and Ni crystal chemistry in birnessite. These Ni-rich birnessites have Ni contents as high as 2.99% (Ni5) and 6.08% (Ni10) in weight. EXAFS results show that Ni5 has 23.7% of the total Ni (0.71 wt.%) and Ni10 has 34.5% of the total Ni (2.10 wt.%) in Mn octahedral layer with the remaining Ni located at vacancies and edge sites. The Ni-rich birnessites have weaker crystallinity and thermal stability, fewer layers stacked along the c axis, similar to 1.5-2.7 times larger surfaces areas, and a higher Mn average oxidation numbers (AONs) compared to the birnessite without Ni. Additionally, the doping of Ni during birnessite crystallization enhances the formation of vacancies in the layer; however, adsorption capacities for Pb2+ and Zn2+ by these Ni-rich birnessites are reduced, mainly because of vacancies and edge sites occupation by a large amount of Ni. The Ni-rich birnessites exhibit much higher oxidation capability and can completely oxidize As(III) in solution at rapid initial reaction rates under the experimental condition. The results indicate that incorporation of Ni into the natural birnessite in ferromanganese nodules may be achieved both by direct coprecipitation with Mn to build the layers and migration over time from adsorbed Ni on the surface into the layer structure. It is also implied that Ni doping in birnessite has great impact on the geochemical behaviors of heavy metals, either in adsorption or oxidation reactions. (C) 2012 Elsevier Ltd. All rights reserved.
学科主题	Geochemistry & Geophysics
收录类别	SCI
WOS记录号	WOS:000308426800004
公开日期	2016-05-03
内容类型	期刊论文
源URL	[http://ir.ihep.ac.cn/handle/311005/223793]
专题	中国科学院高能物理研究所
推荐引用方式 GB/T 7714	Yin, H,Tan, WF,Zheng LR,et al. Characterization of Ni-rich hexagonal birnessite and its geochemical effects on aqueous Pb2+/Zn2+ and As(III)[J]. GEOCHIMICA ET COSMOCHIMICA ACTA,2012,93:47-62.
APA	Yin, H.,Tan, WF.,郑黎荣.,Zheng, LR.,Cui, HJ.,...&Feng, XH.(2012).Characterization of Ni-rich hexagonal birnessite and its geochemical effects on aqueous Pb2+/Zn2+ and As(III).GEOCHIMICA ET COSMOCHIMICA ACTA,93,47-62.
MLA	Yin, H,et al."Characterization of Ni-rich hexagonal birnessite and its geochemical effects on aqueous Pb2+/Zn2+ and As(III)".GEOCHIMICA ET COSMOCHIMICA ACTA 93(2012):47-62.