SYNTHESIS OF Fe-CTAB-BENTONITE COMPLEXES FROM CO DINH BENTONITE BY ION EXCHANGE AND HYDROTHERMAL ASSISTING ION EXCHANGE METHODS
Abstract
In this study, CTAB–Fe–bentonite complexes were synthesised by pre-modifying Co Dinh – Thanh Hoa bentonite using cetyltrimetyl ammonium bromide (CTAB), then pillaring the organoclay with poly-hydroxy-Fe or polyoxo-Fe cations. The resultant inorganic–organic bentonite complexes were characterized by X-ray diffraction (XRD), thermal analysis (TG - DTA), Infrared Spectroscopy (IR) and nitrogen adsorption/deadsorption isotherms. After introduction of CTAB into bentonite by ion exchange, the d001 basal spacing increased from 14.4 for parent bentonite to 19.3 Å. The basal spacings of the CTAB-Fe-bentonite complexes depended on the ratio of Fe pillaring solution. During pillaring poly-hydroxy-Fe or polyoxo-Fe cations into clay interlayer space, part of the intercalated surfactants was removed, resulting in a decrease of d001 values and an increase of specific surface area compared with those of organoclay. Hydrothermal assisting ion exchange significantly enhanced the intercalation of poly-hydroxy-Fe or polyoxo-Fe cations into layers of montmorillonite, but montmorillonite structure was rather delaminated.
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