The Interstratified Structure And Interlayer Nature Of Hydrobiotite In Weili

Tseganbrark vermiculite deposit in Weili, Xinjiang, is mainly composed of hydrobiotite, a vermiculite-phlogopite interstratified mineral. Following the previous studies on hydrobiotite in Weili, the characteristics of interstratified structure, the variation of structure to different thermal treatment, ion-exchange, preparation and properties of organic-hydrobiotite and the potential of organic polutants disposal are discussed in this paper.The main IR bands of Weili hydrobiotite has been classified in this paper. The structure and nature of heated hydrobiotite at different temperatures have been studied. At 500℃~600℃, hydrobiotite loses its rehydration property, and the interlayer cations become unexchangeable. The hydroxyls banded to octahedral Fe and Mg dehydrate at 800℃ -900℃ and 900℃ ~ 1000℃ respectively. Hydrobiotite is destroyed to forsterite at 1100℃. According to volume expansion times, IR and SEM study, the most suitable condition in which hydrobiotite expands is sudden thermal treatment at about 800 ℃.The segregated phases of vermiculite and phlogopite have been found in Weili hydrobiotite. The characteristics of XRD pattern of Weili hydrobiotite is similar to that found in other countries. However, the coefficient of variation of basal spacing, the breadths at half-maximum intensity and peak intensities differentiate Weili hydrobiotite from strictly ordered hydrobiotite. The graphical technique, first used for the interstratified structure of vermiculite and mica in this paper, indicates the presence of random mixing of strictly ordered hydrobiotite layer and vermiculite or mica layer. The Fourier transform demonstrates the efficiency of the graphical technique proposed.The inorganic and organic ion-exchange have been studied. The Na+ and Ca2+ in the vermiculite interlayer is exchangeable, and K+ in the phlogopite interlayer is unexchangeable. The effects of interlayer cation on the nature of interlayer water have been studied. With the increase of ionic potential, the dehydrated temperature and the bending vibration frequency of interlayer water increase, and strength vibration frequency decreases. Owing to the hydrolysis in the hydrobiotite interlayer, Al3* doesn't abide by the above rule.The organic-hydrobiotite has been obtained by the treatment of hexatrimethylammonium (HDTMA). The basic characteristics of organic-hydrobiotite have been studied in this paper. Alkylammonium ions form paraffin-type structure in the hydrobiotite interlayer. The interaction of HDTMA with hydrobiotite includes ion-exchange and molecular uptake. As a result of contact arrangement of HDTMA in the interlayer, the BET Specific Surface Area of organic-hydrobiotite doesn't increase although hydrobiotite is expanded by HDTMA.Hydrobiotite has no adsorption to non-ionic organic contaminants such as phenol and chlorobenzene. However, the HDTMA-modified hydrobiotite has great adsorption to phenol and chlorobenzene. The adsorption depends on the content of organic carbon and the type of surfactant. The adsorption of phenol and chlorobenzene by organic-hydrobiotite is a partitionmechanism between water phase and organic phase in organic-hydrobiotite, and the adsorption isotherm is a linear type. The adsorptive ability of organic-hydrobiotite has been strengthened, not weakened, by the competitive uptake of phenol and chlorobenzene. This property has the practical value when organic-hydrobiotite is used in removal of more than one contaminants from waste water.