Pedosphere 21(6): 730--737, 2011
ISSN 1002-0160/CN 32-1315/P
©2011 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Effect of cobalt-doped framework on formation of todorokite from layered manganese oxides with Mg2+/Co2+ ions as template |
CUI Hao-Jie1,2 , LIU Fan2, TAN Wen-Feng2 and FENG Xiong-Han2 |
1 Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China);
2 Key Laboratory of Subtropical Agricultural Resources and Environment, Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070 (China) |
| ABSTRACT |
| Cobalt (Co) exists in significant quantities in naturally occurring manganese (Mn) oxides and alters the growth of Mn oxide crystals.Four-layered Mn oxides,Na-buserite (Na-bus) and three Co-doped Na-buserite samples prepared from oxidation of Mn (OH) 2 with 5%,10%,and 20% Co/(Mn+Co) molar ratios (5Co-Na-bus,10Co-Na-bus,and 20Co-Na-bus),were used to prepare todorokite,a common Mn oxide on the Earth's surface,using Mg2+/Co2+ ions as a template.The results showed that todorokites could be obtained by reflux treatment of Mg2+-exchanged non-doped Na-buserite and three Co-doped Na-buserites at atmospheric pressure.However,the formation of todorokites was prohibited by reflux treatment of Co2+-exchanged Na-bus,5Co-Na-bus,and 10Co-Na-bus samples.Instead,todorokite was obtained by the reflux treatment of Co2+-exchanged 20Co-Na-bus samples under atmospheric pressure.X-ray photoelectron spectroscopy analysis showed that doped Co existed as Co3+in the MnO6 layers of doped Na-buserites.The amount of substituted Co3+ in the MnO6 layers may play a key role in the conversion of buserite to todorokite using Co2+ ions as a template. |
| Key Words: Mn oxide, Na-buserite, reflux treatment, transformation, tunnel structure |
| Citation: Cui, H. J., Liu, F., Tan, W. F. and Feng, X. H. 2011. Effect of cobalt-doped framework on formation of todorokite from layered manganese oxides with Mg2+/Co2+ ions as template. Pedosphere. 21(6): 730-737. |
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