Hostname: page-component-586b7cd67f-g8jcs Total loading time: 0 Render date: 2024-11-22T14:58:46.373Z Has data issue: false hasContentIssue false
  • English
  • Français

Acid Hydrolysis of Octahedral Mg2+ Sites in 2:1 Layered Silicates: An Assessment of Edge Attack and Gallery Access Mechanisms

Published online by Cambridge University Press:  28 February 2024

Hemamali Kaviratna  and
Thomas J. Pinnavaia
Hemamali Kaviratna
Affiliation:
Department of Chemistry and Center for Fundamental Materials Research, Michigan State University, East Lansing, Michigan 48824
Thomas J. Pinnavaia
Affiliation:
Department of Chemistry and Center for Fundamental Materials Research, Michigan State University, East Lansing, Michigan 48824
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

The acid hydrolysis products of trioctahedral fluorohectorite and phlogopite have been investigated by XRD, MAS NMR spectroscopy and nitrogen BET surface area analysis in an effort to assess the relative importance of edge attack and gallery access mechanisms. A dramatic loss of X-ray crystallinity and the formation of Q3 and Q4 SiO4 sites accompanied the depletion of Mg2+ from the octahedral sheet of both 2:1 layered structures. Depending on the extent of hydrolysis, the products derived from fluorohectorite exhibited surface areas up to 208 m2/g, whereas phlogopite hydrolysis products gave values <20 m2/g. The dramatic differences in surface areas were not related to differences in hydrolysis mechanisms. 19F MAS NMR studies indicated that the hydrolysis of fluorohectorite occurred primarily by an edge attack mechanism equivalent to the hydrolysis pathway for phlogopite. A gallery access mechanism contributed to the hydrolysis of fluorohectorite only at the later stages of octahedral Mg2+ depletion. Solvation effects appeared to be important in determining the surface areas of the reaction products derived from the swelling (fluorohectorite) and non-swelling (phlogopite) precursors.

Keywords

Acid hydrolysisFluorohectoriteMechanismPhlogopite
Type
Research Article
Information
Clays and Clay Minerals , Volume 42 , Issue 6 , December 1994 , pp. 717 - 723
Copyright
Copyright © 1994, Clay Minerals Society

References

Acosta, J. L., Rocha, C. M., and Ojeda, M. C.. 1984 . The effect of several modified sepiolites on the transition temperatures and crystallinity of filled propylene. D. Angew Makro mol. Chemie. 126: 51–57.CrossRefGoogle Scholar
Butruille, J-R., Michot, L. J., Barres, O., and Pinnavaia, T. J.. 1993 . Fluorine-mediated acidity of alumina-pillared fluorohectorite. J. Catal. 139: 664–678.CrossRefGoogle Scholar
Cetisli, H., and Gedikbey, T.. 1990 . Dissolution kinetics of sepiolite from Eskisehir (Turkey) in hydrochloric and nitric acids. Clay Miner. 25: 207–215.CrossRefGoogle Scholar
Corma, A., Perez-Pariente, J., Fornes, V., and Mifsud, A.. 1984 . Catalytic activity of modified silicates: I Dehydration of ethanol catalysed by acidic sepiolite. Clays & Clay Miner. 19: 673–676.CrossRefGoogle Scholar
Corma, A., Mifsud, A., and Perez, J.. 1986 . Etude cinetique de l'attaque acide de la sepiolite: Modifications des proprietes texturales. Clay Miner. 21: 69–84.CrossRefGoogle Scholar
Corma, A., and Perez-Pariente, J.. 1987 . Surface acidity and activity of a modified sepiolite. Clay Miner. 22: 423–433.CrossRefGoogle Scholar
Corma, A., Mifsud, A., and Sanz, E.. 1987 . Influence of the chemical composition and textural characteristics of palygorskite on the acid leaching of octahedral cations. Clay Miner. 22: 225–232.CrossRefGoogle Scholar
Corma, A., Mifsud, A., and Sanz, E.. 1990 . Kinetics of the acid leaching of palygoskite: Influence of the octahedral sheet composition. Clay Miner. 25: 197–205.CrossRefGoogle Scholar
Dandy, A. J., and Nadiye-Tabbiruka, M. S.. 1982 . Surface properties of sepiolite from Amboseli, Tanzania, and its catalytic activity for ethonol decomposition. Clays & Clay Miner. 30: 347–352.CrossRefGoogle Scholar
Gonzalez, L., Ibarra, R. L., and Rodriguez, D. A.. 1982 . Preparation of silica by acid dissolution of sepiolite and study of its reinforcing effect in elastomers. D. Angew Makromol. Chemie. 103: 51–60.Google Scholar
Gonzalez, L., Ibarra, R. L., Rodriguez, D. A., Moya, J. S., and Valle, F. J.. 1984 . Fibrous silica gel obtained from sepiolite by HCl attack. Clay Miner. 19: 93–98.CrossRefGoogle Scholar
Gonzalez, F., Pesquera, C., Bennito, I., Mendioroz, S., and Parares, J. A.. 1989 . Structural and textural evolution of Aland Mg-rich palygoskites, I. under acid treatment. Appl. Clay Sci. 4: 373–388.CrossRefGoogle Scholar
Harkonen, M. A., and Keiski, R. L.. 1984 . Porosity and surface area of acid leached phlogophite: The effect of leaching conditions and thermal treatment. Colloids and Surfaces 11: 323–339.CrossRefGoogle Scholar
Huve, L., Delomotte, L., Martin, P., Dred, R. Le, Baron, J., and Saehr, T.. 1992 . 19F MAS-NMR study of structural fluorine in some natural and synthetic 2: 1 layer silicates. Clays & Clay Miner. 40: 186–191.CrossRefGoogle Scholar
Johnson, D. W., Peters, F. A., and Kirby, R. C.. 1964 . Methods for producing alumina from clay. Bur. Mines Rep. Invest. 27 6431: 1–25.Google Scholar
Luce, R. W., Bartlett, R. W., and Parks, G. A.. 1972 . Dissolution kinetics of magnesium silicates. Geochimica et Cosmochimica Acta 36: 35–50.CrossRefGoogle Scholar
Mendioroz, S., Pajares, J. A., Benito, I., Pesquera, C., Gonzalez, F., and Blanco, C.. 1987 . Texture evolution of montmorillonite under progressive acid treatment: Change from H3 to H2 type of hysteresis. Langmuir 3: 676–681.CrossRefGoogle Scholar
Rice, N. M., and Strong, L. W.. 1974 . The leaching of lateritic nickel ores in hydrochloric acid. Canadian Metallurgical Quarterly b13: 485–493.CrossRefGoogle Scholar
Rhodes, C. N., and Brown, D. R.. 1992 . Structural characterisation and optimisation of acid-treated montmorillonite and high-porosity silica supports for ZnCl2 alkylation catalysts. J. Chem. Faraday Trans. 88(15): 2269–2274.CrossRefGoogle Scholar
Rodriguez-Reinoso, F., Ramirez-Sanz, A., Lopez-Gonzalez, J. De D., Valenzuela-Calahorro, C., and Zurita-Herrera, L.. 1981 . Activation of a sepiolite with dilute solutions of HNO3 and subsequent heat treatment. Clay Miner. 16: 315–385.CrossRefGoogle Scholar
Sanz, J., and Serratosa, J. M.. 1984 . 29Si and 27Al high-resolution MAS-NMR spectra of phyllosilicates. J. Am. Chem. Soc. 106: 4790–4793.CrossRefGoogle Scholar
Srasra, E., Bergaya, F., Vandamme, H., and Ariauib, N. K.. 1989 . Surface properties of an activated bentonite-decoloration of Rape-seed oil. Appl. Clay Sci. 4: 411–421.CrossRefGoogle Scholar
Suquet, H., Chevalier, S., Marcilly, C., and Barthomeuf, D.. 1991 . Preparation of porous materials by chemical activation of the Llano vermiculite. Clay Miner. 26: 49–60.CrossRefGoogle Scholar