X-ray Diffraction Microstructural Analysis of Swelling by Ethylene Glycol in Two Reference Clay Minerals |
| F. García Tomás a, M.A. Kojdecki b, P. Pardo c, R. Ibańez d, A. Álvarez Larena e, and J. Bastida a
aDepartment of Geology, Valencia University (UVEG), 46100 Burjasot (Valencia), Spain bInstitute of Mathematics and Cryptology, Military University of Technology, 00-908 Warsaw, Poland cDepartment of Inorganic Chemistry, UVEG, 46100 Burjasot (Valencia), Spain dMaterials Science Institute (ICMUV), UVEG, 46980 Paterna (Valencia), Spain eX Ray Diffraction Service, Faculty of Sciences, UAB, Bellaterra (Barcelona), Spain |
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| Kaolinite and montmorillonite are two clay minerals with different structures: dioctahedral 1:1 without layer charge and dioctahedral 2:1 with low layer charge. X-ray-diffraction microstructural analysis of two fractions of two reference clays (with kaolinite or montmorillonite) from the Clay Minerals Society Source Clay Repository were performed by the Voigt function method to provide microstructural data not available in the baseline studies of this Repository. A rough agreement was found between crystallite sizes determined from X-ray diffraction patterns and from images by field-emission scanning electron microscopy. In addition, the influence of swelling by ethylene-glycol on crystallite size was studied by the mentioned method. Two factors were found to affect the crystallite size variation in ethylene-glycol-treated clay minerals: (i) the increase of the unit cell in [001] direction due to the interlayer absorption of ethylene glycol molecules in the case of swelling minerals and (ii) the physisorption at the surfaces of the crystallites. Both effects operate in the case of montmorillonite, whereas just the latter one is expected in kaolinite. |
DOI: 10.12693/APhysPolA.130.876 PACS numbers: 68.37.Vj, 61.72.Dd |