Direct evidence of transformation fr

Direct evidence of transformation from smectite to palygorskite:TEM investigation

Palygorskite clays sampled from palygorskite clay deposits in Jiangsu and Anhui provinces were investigated by transmission electron microscopy (TEM). Many intergrowth phenomena of special ultra-microstructure between smectite and palygorskite were found. The ultra-microstructure indicates that palygorsite fiberrous crystals grow along (001) of primary smectite through structural transformation and decomposition of the primary smectite. According to field investigation and X-ray diffraction (XRD) analyses, the transformation mechanism and process can be described as: formation of smectite from basalt weathering deposited in localization basin; evaporation of lake water in aridity environment causing pH increase and concentration of magnesium ion in interstice water of sediment smectite in the lake basin. Under alkaline conditions, magnesium ion occupied interlayer positions of the smectite. Because of the misfit between magnesium octahedral sheet and smectite layer, magnesium ion interaction with smectire layers caused the 'smectite to transform into palygorskite, and resulted in the formation of smectite and palygorskite complex particulates, and even smaller secondary smectite crystal plates. The transformation of smectite structure resulted in the formation of nanometer minerals with large specific surface area and excellent property of physics and chemistry in smectite-palygorskite mixing clay. The results from TEM investigation are important for understanding properties of palygorskite clay and application.

作 者： Chen Tianhu XU Huifang LU Anhuai Xu Xiaochun Peng Shuchuan Yue Shucang   作者单位： Chen Tianhu(College of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China;Department of Geology and Geophysics, University of Wisconsin, Madison, W153706, USA)

XU Huifang(Department of Geology and Geophysics, University of Wisconsin, Madison, W153706, USA)

LU Anhuai(Department of Geology, Peking University, Beijing 100871, China)

Xu Xiaochun,Peng Shuchuan,Yue Shucang(College of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China) 

刊 名： 中国科学D辑（英文版）  SCI 英文刊名： SCIENCE IN CHINA SERIES D  年，卷(期)： 2004 47(11)  分类号： P6  关键词： palygorskite   smectite   transmission electron microscopy   X-ray diffraction   nanometer mineralogy  

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