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Thermal transformations of synthetic allophane and imogolite as revealed by nuclear magnetic resonance

Published online by Cambridge University Press:  09 July 2018

M. A. Wilson ,
K. Wada ,
S. I. Wada  and
Y. Kakuto
M. A. Wilson
Affiliation:
CSIRO Division of Coal Technology, PO Box 136, North Ryde, NSW 2113, Australia
K. Wada
Affiliation:
Faculty of Agriculture, Kyushu University 46, Fukuoka 812, Japan
S. I. Wada
Affiliation:
Faculty of Agriculture, Kyushu University 46, Fukuoka 812, Japan
Y. Kakuto
Affiliation:
Faculty of Agriculture, Kyushu University 46, Fukuoka 812, Japan
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Abstract

Imogolite, protoimogolite and two synthetic allophanes (A and B) with very different Si/Al ratios have been pyrolysed over a range of temperatures, and the reactions followed by high-resolution solid-state 27AI and 29Si nuclear magnetic resonance (NMR) spectroscopy. The Si(OAloct)3OH groups of protoimogolite are destroyed at relatively low (∼ 200°C temperatures, whereas the same structures in imogolite are stable to ∼ 300°C. During pyrolysis of both materials there is little change in the observed coordination of AI at temperatures of < 500°C but at 500°C or higher, ∼25% of the NMR-visible Al is converted to tetrahedral coordination. The mechanism of decomposition of both protoimogolite and imogolite is shown to involve the formation of highly branched Si-O-Si chains. As far as can be discerned by 27Al and 29Si NMR, allophanes A and B both appear to produce products similar to protoimogolite on pyrolysis.

Type
Research Article
Information
Clay Minerals , Volume 23 , Issue 2 , June 1988 , pp. 175 - 190
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1988

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References

Barron, P.F., Wilson, M.A., Campbell, A.S. & Frost, R.L. (1982) Detection of imogolite in soils using solid state 29Si NMR. Nature 299, 616–618.Google Scholar
Cradwick, P.D.G., Farmer, V.C., Russell, J.D., Masson, C.R., Wada, K. & Yoshinaga, N. (1972) Imogolite, a hydrated aluminium silicate of tubular structure. Nature 240, 187–189.Google Scholar
Farmer, V.C., Fraser, A.R., Russell, J.D. & Yoshinaga, N. (1977a) Recognition of imogolite structures in allophanic clays by infra-red spectroscopy. Clay Miner. 12, 55–57.CrossRefGoogle Scholar
Farmer, V.C., Fraser, A.R. & Tait, J.M. (1977b) Synthesis of imogolite. A tubular aluminium silicate polymer. Chem. Commun. 462-463.Google Scholar
Farmer, V.C., Fraser, A.R. & Tait, J.M. (1979) Characterization of the chemical structures of natural and synthetic aluminosilicate gels and sols by infra-red spectroscopy. Geochim. Cosmochim. Acta 43, 1417–1420.Google Scholar
Farmer, V.C., Russell, J.D. & Berrow, M.L. (1980) Imogolite and proto-imogolite allophane in spodic horizons: evidence for a mobile aluminium silicate complex in podzol formation. J. Soil Sci. 31, 673–684.Google Scholar
Farmer, V.C., Adams, M J., Fraser, A.R. & Palmieri, F. (1983) Synthetic imogolite: properties, synthesis and possible applications. Clay Miner. 18, 459–472.CrossRefGoogle Scholar
Goodman, B.A., Russell, J.D., Montez, B., Oldfield, E. & Kirkpatrick, R.J. (1985) Structural studies of imogolite and allophanes by Al-27 and Si-29 N.M.R. spectroscopy. Phys. Chem. Miner. 12, 342–346.CrossRefGoogle Scholar
Lippmaa, E., Magi, M., Samoson, A., Engelhardt, B. & Grimmer, A.R. (1980) Structural studies of silicates by solid state high resolution 29Si n.m.r. J. Am. Chem. Soc. 102, 4889–4893.CrossRefGoogle Scholar
Parfitt, R.L. & Henmi, T. (1980) Structure of some allophanes from New Zealand. Clays Clay Miner. 28, 285294.CrossRefGoogle Scholar
Parfitt, R., Furkert, R.J. & Henmi, T., (1980) Identification and structure of two types of allophane from volcanic ash soils and tephra. Clay Miner. 28, 328–334.Google Scholar
Russell, J.D., McHardy, W.J. & Fraser, A.R. (1969) Imogolite: A unique aluminosilicate. Clay Miner. 8 CrossRefGoogle Scholar
Van Der Gaast, S.J., Wada, K., Wada, S.I. & Kakuto, Y. (1985) Small angle X-ray powder diffraction, morphology and structure of allophane and imogolite. Clays Clay Miner. 33, 237–243.CrossRefGoogle Scholar
Wada, S-I. & Wada, K. (1977) Density and structure of allophane. Clay Miner. 12, 289–298.Google Scholar
Wada, S-I., Eto, A. & Wada, K. (1979) Synthetic allophane and imogolite. J. Soil Sci. 30, 347–355.CrossRefGoogle Scholar
Wilson, M.A. (1987) NMR Techniques and Applications in Geochemistry and Soil Chemistry. Pergamon Press, Oxford.Google Scholar
Wilson, M.A. & McCarthy, S. A. (1985) Long range effects of the aluminium avoidance principle. Anal Chem. 57, 2733–2735.Google Scholar
Wilson, M.A. McCarthy, S.A., & Fredericks, P.M. (1986), Structure of poorly-order aluminosilictaes. Clay Miner. 21, 879–897.Google Scholar
Wilson, M.A., Barron, P.F. & Campbell, A.S. (1984) Detection of aluminium co-ordination in soils and clay fractions using 27A1 magic angle spinning n.m.r. J. Soil Sci. 35, 201–207,Google Scholar
Yoshinaga, N. & Aominb, S. (1962) Imogolite in some andosols. Soil Sci. Pi. Nutr. 8, 22–29.Google Scholar