FTIR and XRD investigations of tetracycline intercalation in smectites
Li, Zhaohui (China University of Geosciences. Faculty of Earth Sciences)
Kolb, Vera M. K. (University of Wisconsin Parkside. Chemistry Department)
Jiang, Wei-Teh (National Cheng Kung University. Department of Earth Sciences)
Hong, Hanlie (China University of Geosciences. Faculty of Earth Sciences)

Fecha:	2010
Resumen:	Due to swelling, smectite minerals are capable of intercalating many organic molecules in their interlayer space. Tetracycline (TC) is a group of antibiotics used extensively in human and veterinary medicine. The great aqueous solubility and long environmental half life of TC mean that the study of interactions between swelling clay minerals and TC are of great importance in TC transport and retention in subsurface soils. In the present study, the intercalation of TC molecules at different levels into smectites was investigated using Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The shift of the FTIR bands of amide I and II in comparison to crystalline TC suggested a strong interaction between the amide groups and the clay surfaces. The band at 1455 cm remained the same after TC intercalation into SAz-1, SWy-2, and SYn-1, suggesting that complexation was not a dominant mechanism of TC uptake by these minerals. With cation exchange as the major mechanism of TC intercalation into these minerals, simultaneous removal of H from solution protonated the TC molecules and provided a positive charge to interact with negatively charged mineral surfaces even in neutral to slightly alkaline conditions. The increase in interlayer distance after intercalation by TC, as revealed by XRD, suggested a tilted orientation of the intercalated TC molecules in both twisted conformation in acidic condition and extended conformation in alkaline condition.
Derechos:	Tots els drets reservats.
Lengua:	Anglès
Documento:	Article ; recerca ; Versió publicada
Materia:	Cation Exchange ; Complexation ; Deuterated Tetracycline ; Ph ; Swelling Clay ; Surface Adsorption
Publicado en:	Clays and Clay Minerals, Vol. 58, Núm. 4 (2010) , p. 462-474, ISSN 1552-8367

DOI: 10.1346/CCMN.2010.0580402

13 p, 1.4 MB  Acceso restringido a la UAB

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