INVESTIGATION OF THERMAL AND STRUCTURAL PROPERTIES OF NATURAL AND ION-EXCHANGED ANALCIME
Abstract
In this study, the thermal and structural properties of natural analcime zeolite obtained from the Çanakkale-Küçükkuyu-Ayvacık region and its cationic forms (HA, FeA, AgA and CuA) were characterized using a range of methods. These included X-ray fluorescence (XRF), X-ray diffraction (XRD), thermogravimetric analysis (TG), differential thermogravimetric analysis (DTG), differential thermal analysis (DTA) and specific surface area measurement techniques. Cationic forms were prepared by using 1 M HCl, 1 M Fe(NO3)3.9H2O, 1 M AgNO3 and 1 M Cu(NO3)2.3H2O solutions. Quantitative XRD analysis showed that the natural zeolite was mainly composed of analcime accompanied by quartz, feldspar, montmorillonite and amorphous substances. AgA and HA samples showed different thermal and structural behaviors due to their rearranged crystal structure and chemical composition. Adsorption properties of samples were determined by using adsorption isotherms and specific surface areas obtained by the Brunauer-Emmet-Teller (BET) method. The specific surface areas of the ion-exchanged analcime zeolites were found to be higher in comparison to natural analcime. Among all the modified forms, it was found that the H-form of the analcime sample has the largest surface area HA (41.88 m2/g).
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References
- [1] Shaobin W, Yuelian P. Natural zeolites as effective adsorbents in water and wastewater treatment. Chem Eng J 2010; 156: 11-24.
- [2] Taylor W.H. The structure of analcite (NaAlSi2O6.H2O). Z Kristallogr 1930; 74: 1-19.
- [3] Hurlbut CS, Klein C. Manual of Mineralogy, 20th ed. New York, NY, USA: Wiley, 1985.
- [4] Calleri M, Ferraris G. Struttura dellíanalcime: NaAlSi2O6•H2O. Atti Accad Sci Tolrino 1964; 98: 821- 846.
- [5] Knowles CR, Rinaldi FF, Smith JV. Refinement of the crystal structure of analcime. Indian Mineral 1965; 6: 127–140.
- [6] Ferraris G, Jones DW, Yerkess J. A neutron-diffraction study of the crystal structure of analcime, NaAlSi206.H20. Z Kristallogr 1972; 135: 240–252.
- [7] Pechar F. Crystal-chemistry of analcime. Acta Univ Carol Geol 1989; 4: 469-487.
- [8] Mazzi F, Galli E. Is each analcime different? Am Mineral 1978; 63: 448–460.
- [9] Armbruster T, Gunter, ME. Crystal structures of natural zeoltes, Natural Zeolites: Occurrence, Properties, Applications. In: Bish DL, Ming DW, editors. Mineralogical Society of America Reviews in Mineralogy and Geochemistry, Washington, DC USA, 2001, pp. 1-57.
- [10] Hovis GL, Roux J, Rodrigues E. Thermodynamic and structural behavior of analcime - leucite analogue systems. Am Mineral 2002; 87: 523-532.