Hostname: page-component-7479d7b7d-jwnkl Total loading time: 0 Render date: 2024-07-11T11:55:25.806Z Has data issue: false hasContentIssue false
  • English
  • Français

Mechanisms of Palygorskite and Sepiolite Alteration as Deduced from Solid-State 27Al and 29Si Nuclear Magnetic Resonance Spectroscopy

Published online by Cambridge University Press:  02 April 2024

Sridhar Komarneni
Sridhar Komarneni*
Affiliation:
Materials Research Laboratory and Department of Agronomy, The Pennsylvania State University, University Park, Pennsylvania 16802
Get access Rights & Permissions [Opens in a new window]

Abstract

The mechanisms of palygorskite and sepiolite alteration to smectite under mild hydrothermal conditions were investigated by solid-state 27Al and 29Si magic-angle spinning-nuclear magnetic resonance (MAS-NMR) spectroscopy, X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). Palygorskite altered to smectite in the presence of NaOH at 150°C. 27Al MAS-NMR spectroscopy showed that the Al coordination changed from chiefly octahedral in palygorskite to chiefly tetrahedral in the smectite product. 29Si MAS-NMR spectroscopy showed that the nearest neighbor environment of Si also changed when palygorskite altered to smectite. The XRD data showed that the synthetic smectite is trioctahedral in nature with tetrahedral charge. The TEM results revealed that the needle-like morphology of palygorskite was preserved in the product smectite. The MAS-NMR results in conjunction with the above XRD and TEM studies suggest that the mechanism of palygorskite alteration was a dissolution and recrystallization process rather than a solid-state reorganization to form 2:1 layer silicate units from the preexisting chain structure. Sepiolite altered to smectite in the presence of 2 N salt solutions at 300°C. The trioctahedral nature of the product smectite as detected by XRD and the foil-like morphology of product smectite as shown by TEM suggest that the mechanism of sepiolite transformation to smectite was also a dissolution and recrystallization process. The tetrahedral Al coordination detected by 27Al MAS-NMR in the smectite altered from sepiolite corroborated the XRD and TEM results.

Keywords

Al coordinationHydrothermal transformationNuclear magnetic resonancePalygorskiteSepioliteSmectiteX-ray powder diffraction
Type
Research Article
Information
Clays and Clay Minerals , Volume 37 , Issue 5 , October 1989 , pp. 469 - 473
Copyright
Copyright © 1989, The Clay Minerals Society

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Bethke, C. M. and Altaner, S. P., 1986 Layer-by-layer mechanism of smectite illitization and application to a new rate law Clays & Clay Minerals 34 136 – 145.CrossRefGoogle Scholar
Brindley, G. W. and Brown, G., 1980 Crystal Structures of Clay Minerals and their X-ray Identification London Mineralogical Society.CrossRefGoogle Scholar
DeJong, B H W S Schramm, C. M. and Parziale, V. E., 1983 Polymerization of silicate and aluminate tetrahedra in glasses, melts, and aqueous solutions–IV. Aluminum coordination in glasses and aqueous solutions and comments on the aluminum avoidance principle Geochim. Cosmochim. Acta 47 1223 – 1236.CrossRefGoogle Scholar
Eberl, D., Whitney, G. and Khoury, H., 1978 Hydrothermal reactivity of smectite Amer. Mineral 63 401 – 409.Google Scholar
Fyfe, C. A., Gobbi, G. C., Hartman, J., Lenkinski, R., O’Brien, J., Beange, E. R. and Smith, M. A. R., 1982 High resolution solid state MAS spectra of Si-29, A1-27, B-11 and other nuclei in inorganic systems using a narrow-bore 400 MHz high resolution NMR spectrometer J. Mag. Reson 47 168 – 173.Google Scholar
Golden, D. C., Dixon, J. B., Shadfan, H. and Kippenberger, L. A., 1985 Palygorskite and sepiolite alteration to smectite under alkaline conditions Clays & Clay Minerals 33 44 – 50.CrossRefGoogle Scholar
Greene-Kelley, R., 1955 Dehydration of montmorillonite minerals Mineral. Mag 30 604 – 615.Google Scholar
Giiven, N. and Carney, L. L., 1979 The hydrothermal transformation of sepiolite to stevensite and the effect of added chlorides and hydroxides Clays & Clay Minerals 27 253 – 260.CrossRefGoogle Scholar
Hofmann, V. U. and Kiemen, R., 1950 Verlust der Austauschfahigkeit von Lithiumionen an Bentonit durch Erhitzung Z. Anorgan. Chemie 262 95 – 99.CrossRefGoogle Scholar
Howard, J. J., 1981 Lithium and potassium saturation of illite/smectite clays from interlaminated shales and sandstones Clays & Clay Minerals 29 136 – 142.CrossRefGoogle Scholar
Komaraeni, S. and Breval, E., 1985 Characterization of smectites synthesized from zeolites and mechanism of smectite synthesis Clay Miner 20 181 – 188.CrossRefGoogle Scholar
Komarneni, S., Freeborn, W. P. and Smith, C. A., 1979 Simple cold-weld sealing of noble metal tubes Amer. Mineral 64 650 – 651.Google Scholar
Komarneni, S., Fyfe, C. A. and Kennedy, G. J., 1986 Detection of nonequivalent Si sites in sepiolite and palygorskite by solid-state 29Si magic-angle spinning-nuclear magnetic resonance Clays & Clay Minerals 34 99 – 102.CrossRefGoogle Scholar
Lippmaa, E., Magi, M., Samoson, A., Engelhardt, G. and Grimmer, A. R., 1980 Structural studies of silicates by solid-state high-resolution Si-29 NMR J. Amer. Chem. Soc 102 4889 – 4893.CrossRefGoogle Scholar
Magi, M., Lippmaa, E., Samoson, A., Engelhardt, G. and Grimmer, A. R., 1984 Solid-state high-resolution silicon-29 chemical shifts in silicates J. Phys. Chem 88 1518 – 1522.CrossRefGoogle Scholar
Muller, D., Gessner, W., Behrends, H. J. and Scheler, G., 1981 Determination of the aluminum coordination in aluminum-oxygen compounds by solid-state high-resolution 27Al NMR Chemical Physics Letters 79 59 – 62.CrossRefGoogle Scholar
Mumpton, F. A. and Roy, R., 1956 New data on sepiolite and attapulgite Clays & Clay Minerals 566 136 – 143.Google Scholar
Roberson, H. E. and Lahann, R. W., 1981 Smectite to illite conversion rates, effect of solution chemistry Clays & Clay Minerals 29 129 – 135.CrossRefGoogle Scholar
Schultz, L. G., 1969 Lithium and potassium absorption, dehydroxylation temperature and structural water content of aluminous smectites Clays & Clay Minerals 17 115 – 149.CrossRefGoogle Scholar
Whitney, G. and Northrup, H. R., 1987 Experimental investigation of the smectite to illite reaction: Dual reaction mechanisms and oxygen-isotope systematics Amer. Mineral 73 77 – 90.Google Scholar