High Co-doping promotes the transition of birnessite layer symmetry from orthogonal to hexagonal
文献类型：期刊论文
| 作者 | Yin, H; Liu, Y; Koopal, LK; Feng, XH; Chu, SQ; Zhu, MQ; Liu, F; Chu SQ(储胜启) |
| 刊名 | CHEMICAL GEOLOGY
 |
| 出版日期 | 2015 |
| 卷号 | 410页码:12-20 |
| 关键词 | Birnessite Layer symmetry Transition metals Powder XRD X-ray absorption spectroscopy |
| 英文摘要 | Despite its presence in limited amounts, birnessite has a wide spread distribution and is often highly enriched in tracemetals such as Co in diverse geological environments. This study investigated the effects of Co doping on the layer structure and properties of birnessites synthesized through the oxidation of Mn2+ by O-2 under alkaline conditions, by using powder X-ray diffraction (XRD) and X-ray absorption spectroscopy (both XANES and EXAFS). The Co doped, high-pH birnessites are composed of platy crystals, and have lower crystallinity, larger specific surface areas (SSAs) and higher Mn average oxidation states (AOSs) than pure birnessite. Cobalt Kedge EXAFS analysis reveals that no CoOOH is formed, and similar to 76% of the total Co is located in the layers of the Co-doped birnessites. Careful examination of these Co-doped samples by XRD and EXAFS analyses demonstrates that the presence of Co during the synthesis of high-pH birnessite promotes the structural transition of the birnessite layer symmetry from orthogonal to hexagonal. This is due to the decrease in Mn(III) in the layers of the doped solids, leading to the attenuation of Jahn-Teller effect. The decrease in Mn(III) in the layers might be attributed to the substitution of Mn(III) by Co(III) in the layers. The competitive adsorption of Co2+/3+ with Mn2+ might also decrease the oxidation of Mn2+ to Mn(III) and the subsequent migration of Mn(III) into the birnessite layers. The results provide new insights into the interaction mechanisms between transition metals and birnessite-like minerals, and improve our understanding of the abiotic oxidation of Mn2+ as well as the prevalence of birnessites with hexagonal symmetry in natural environments. (C) 2015 Elsevier B.V. All rights reserved. |
| 学科主题 | Geochemistry & Geophysics |
| 类目[WOS] | Geochemistry & Geophysics |
| 收录类别 | SCI ; EI |
| WOS记录号 | WOS:000359064300002 |
| 公开日期 | 2016-05-03 |
| 源URL | [http://ir.ihep.ac.cn/handle/311005/228677]  |
| 专题 | 高能物理研究所_多学科研究中心 |
| 推荐引用方式 GB/T 7714 | Yin, H,Liu, Y,Koopal, LK,et al. High Co-doping promotes the transition of birnessite layer symmetry from orthogonal to hexagonal[J]. CHEMICAL GEOLOGY,2015,410:12-20. |
| APA | Yin, H.,Liu, Y.,Koopal, LK.,Feng, XH.,Chu, SQ.,...&储胜启.(2015).High Co-doping promotes the transition of birnessite layer symmetry from orthogonal to hexagonal.CHEMICAL GEOLOGY,410,12-20. |
| MLA | Yin, H,et al."High Co-doping promotes the transition of birnessite layer symmetry from orthogonal to hexagonal".CHEMICAL GEOLOGY 410(2015):12-20. |
入库方式： OAI收割
来源：高能物理研究所
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