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Surface acidity of imogolite and allophane

Published online by Cambridge University Press:  09 July 2018

T. Henmi  and
K. Wada
T. Henmi
Affiliation:
Faculty of Agriculture, Kyushu University, Fukuoka, Japan
K. Wada
Affiliation:
Faculty of Agriculture, Kyushu University, Fukuoka, Japan
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Abstract

The acid strength and the number of acid sites on various clays were determined by observing the colouration of Hammett indicators adsorbed on them and by titrating benzene suspensions of them with n-butylamine, respectively. H(Al)-saturated allophane behaves as a strong acid (Ho; −5·6 ∼ 1·5) in a relatively dry environment (relative humidity 10-55%), but its acid strength is very much reduced either by increasing its water content or by saturating it with alkali or alkali earth metal cations. Imogolite shows only a very weak acidity (Ho; 4·6 ∼ 6·8) under medium dry to moist conditions (relative humidity; 30-100%). Both allophane and imogolite show a marked enhancement of acidity (Ho; −8·2 ∼ 1·5) when they have been dried over P2O5 or heated to result in dehydroxylation. H(Al)-saturated montmorillonite, kaolinite and halloysite show stronger acidities (Ho; −5·6 ∼ 1·5) than allophane (Ho; 1·5 ∼ 6·8) in a relatively moist environment (relative humidity; >60%). The n-butylamine titre and CEC show a good agreement for montmorillonite, but a poor agreement for allophane. The latter discrepancy which is larger for allophane when it has been heated at 150 and 300°C, is also found for imogolite when similarly heated. In these titrations, excess butylamine is found in supernatants at end-points. Therefore, the n-butylamine titre as such can not be used for the estimation of the number of acid sites on imogolite and allophane. The origin, structure and transformation of the acid sites on these clays is discussed.

Type
Research Article
Information
Clay Minerals , Volume 10 , Issue 4 , December 1974 , pp. 231 - 245
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1974

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References

Aomine, S. & Higashi, T. (1955) Miner. J. Japan, 1, 278.CrossRefGoogle Scholar
Aomine, S. & Wada, K. (1962) Am. Miner. 47, 1024.Google Scholar
Aomine, S. & Yoshinaga, N. (1955) Soil Sci. 79, 349.CrossRefGoogle Scholar
Benesi, H.A. (1956) J. Am. Chem. Soc. 78, 5490.CrossRefGoogle Scholar
Benesi, H.A. (1957) J. Phys. Chem. 61, 970.CrossRefGoogle Scholar
Birrell, K.S. & Gradwell, M. (1956) J. Soil Sci. 7, 130.CrossRefGoogle Scholar
Brindley, G.W. & Nakahira, M. (1959) J. Am. Ceram. Soc. 42, 311.CrossRefGoogle Scholar
Cradwick, P.D.G., Farmer, V.C., Masson, C.R., Russell, J.D., Wada, K. & Yoshinaga, N. (1972) Nature phys. Sci. 240, 187.CrossRefGoogle Scholar
Fieldes, M. & Schofield, R.K. (1960) N.Z. Jl. Sci. 3, 563.Google Scholar
Harada, Y. & Wada, K. (1974) Trans. 10th Int. Congr. Soil Sci. 2, 248.Google Scholar
Harada, Y. & Wada, K. (1973) Soil Sci. PL Nutr., Tokyo, 19, 73.CrossRefGoogle Scholar
Iimura, K. (1966) Bull. Nat. Inst. Agric. Sci. B17, 101.Google Scholar
Mehra, O.P. & Jackson, M.L. (1960) Clays Clay Miner. 7, 317.CrossRefGoogle Scholar
Miyauchi, N. & Aomine, S. (1966) Soil Sci. PI. Nutr. Tokyo, 12, 187.Google Scholar
Mortland, M.M. (1970) Advan. Agron. 22, 75.CrossRefGoogle Scholar
Solomon, D.H. & Murray, H.H. (1972) Clays Clay Miner. 20, 135.CrossRefGoogle Scholar
Tsuzuki, Y. (1961) J. Earth Sci. Nagoya Univ. 9, 305.Google Scholar
Wada, K. & Ataka, H. (1958) Soil PI. Food, Tokyo, 4, 12.CrossRefGoogle Scholar
Wada, K. & Harada, Y. (1969) Proc. Int. Clay Conf. Tokyo, 1, 561.Google Scholar
Wada, K. & Yoshinaga, N. (1969) Am. Miner. 54, 50.Google Scholar
Walling, C. (1950) X Am. Chem. Soc. 72, 1164.CrossRefGoogle Scholar
Yamamoto, D. (1960) Clay Sci. 1, 32.Google Scholar
Yoshida, M. (1970) J. Sci. Soil Manure, Japan, 41, 483.Google Scholar
Yoshida, M. (1971) J. Sci. Soil Manure, Japan, 42, 329.Google Scholar