Cross-Linked Smectites. I. Synthesis and Properties of Hydroxy-Aluminum-Montmorillonite
Tóm tắt
A stable porous system consisting of montmorillonite cross-linked by Al-hydroxide oligomers was synthesized by reacting at room temperature an aqueous solution of such oligomers with a unit-layer dispersion of montmorillonite. The resulting cross-linked montmorillonite (Al-CLM) is a nonswelling material, showing basal spacings of 14.4 to 18.8 Å after air drying and between 14.2 to 18.0 Å after treatment at 110°C. The basal spacing is found to depend on the age and OH/Al ratio of the Al-hydroxide solution, as well as on the relative amounts of the two reactants. A specific surface area of 160 m2/g and a diffraction pattern with a dominant basal spacing of 17.5 Å is obtained by using Al-hydroxide with OH/Al = 1.85, aged for at least 5 days, and by applying an Al/montmorillonite ratio greater than 1.5 in the cross-linking process. The basal spacing of Al-CLM remains essentially unchanged after heating at 220°C, while the specific surface area is not affected by heat treatment up to 480°C.
Two possible configurations of Al-hydroxide oligomers, homogeneously distributed between parallel montmorillonite unit-layers, were considered in order to account for the basal spacing of 17.5–18.8 Å, viz. (a) stacking of two oligomeric ring units in parallel orientation relative to the clay lamellae and (b) perpendicular orientation of individual oligomeric units.
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Tài liệu tham khảo
Hem, J. D. and Roberson, C. E. (1967) Form and stability of aluminum hydroxide complexes in dilute solution: U.S. Geol. Surv. Water-Supply Pap. 1827-A. 55 pp.
Smith, R. W. and Hem, J. D. (1972) Effect of aging on aluminum hydroxide complexes in dilute aqueous solutions: U.S. Geol. Surv. Water-Supply Pap. 1827-D. 51 pp.
Greenland, 1968, Iron hydroxides and clay surfaces, 9th Int. Congr. Soil Sci. Trans., 1, 657
Somasiri, 1972, Effect of hydrolysis of aluminum on competitive adsorption of potassium and aluminum by expansible phyllosilicates, Int. Clay Conf., 2, 53
Slaughter, 1960, The formation of chlorite-like structure from montmorillonite, Clays and Clay Minerals, 7, 114
Meyers, 1972, Correlation of X-ray IR, DTA, DTGA and CEC observations on Al-hydroxy interlayers, Int. Clay Conf., 2, 243
Brydon, 1966, The nature of aluminum hydroxide montmorillonite complexes, Am. Mineral., 51, 875
Hsu, 1964a, Formation of X-ray amorphous and crystalline aluminum hydroxide, Mineral. Mag., 33, 749
Caillere, 1949, Experimental formation of chlorite from montmorillonite, Mineral. Mag., 28, 612
Anderson, 1966, Umiat bentonite: an unusual montmorillonite from Umiat, Alaska, Am. Mineral., 51, 1443
Bailey, 1962, Chlorite polytypism: I. Regular and semi-random one-layer structures, Am. Mineral., 47, 819
Van Olphen, H. (1963) Clay Colloid Chemistry: Interscience Publ., New York, 301 pp.
Weiss, 1963, Über die Lafe der austauschbaren Kationen bei Kaolinit, Proc. Int. Clay Conf., 1, 203
Schoen, 1970, Structures of aluminum hydroxide and geochemical implications, Am. Mineral., 55, 43
Grim, 1954, Clay mineral investigation of sediments in the northern Gulf of Mexico, Clays and Clay Minerals. N.A.S.-N.R.C., Publ., 327, 81
Davey, 1968, Clay-water interaction as affected by hydrous aluminum oxide films, 9th Int. Congr. Soil Sci., 1, 607
Shabtai, 1976, Synthesis and catalytic properties of a 1,4-DIAZABICYCLO (2,2,2) octane-Montmorillonite system—A novel type of molecular sieve, Proc. 6th Int. Congr. Catal., B5, 1
Thiessen, 1942, Wecheselseitige Adsorption von Kolloiden, Z. Elektrochem., 48, 675
Kruyt, 1952, Colloid Science
Herrera, 1972, Effects of anions on the formation and stability of montmorillonite-Fe (III) complexes, Int. Clay Conf., 2, 255
Gupta, 1969b, Fixation of hydroxy-aluminum by montmorillonite, Am. Mineral., 34, 1625
Jackson, 1963a, Interlayering of expansible layer silicates in soils by chemical weathering, Clays and Clay Minerals, 11, 29