Effect of Cobalt-Doped Framework on Formation of Todorokite from Layered Manganese Oxides with Mg^(2+)/Co^(2+) Ions as Template  

作　　者：CUI Hao-Jie LIU Fan TAN Wen-Feng FENG Xiong-Han 

机构地区：[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）

出　　处：《Pedosphere》2011年第6期730-737,共8页土壤圈（英文版）

基　　金：Supported by the National Natural Science Foundation of China(Nos.41001139 and 40771102)

摘　　要：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 MnOs 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.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.

关 键 词：Mn oxide Na-buserite reflux treatment transformation tunnel structure 

分 类 号：TQ137.12[化学工程—无机化工] S718.554[农业科学—林学]