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Conversion of Ferruginous Allophanes to Ferruginous Beidellites at 95 °C Under Alkaline Conditions With Alternating Oxidation and Reduction

Published online by Cambridge University Press:  28 February 2024

V. C. Farmer
V. C. Farmer*
Affiliation:
Division of Soils, Macaulay Land Use Research Institute, Craigiebuckler, Aberdeen AB15 8QH, United Kingdom
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Abstract

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Ferruginous beidellites with Al:Fe atomic ratios up to 2.36 were obtained when solutions containing Al, Fe2+ and H4SiO4 were adjusted to pH 8.5 with Ca(OH)2 and incubated at 95 °C in the presence of CaCO3 as a pH buffer. Incubation took place under cyclic reducing and oxidizing conditions achieved by adding 2 mM hydrazine at 14–15-d intervals over a period of 10–13 weeks. During the 14–15-d cycle, atmospheric oxygen slowly diffused through the high-density polyethylene bottles used, causing a slow oxidation of Fe(II) to Fe(III). The infrared (IR) spectra of the products approached that of natural beidellite, but indicated little change in octahedral Al:Fe ratio in the products for starting Al:Fe ratios from 2.5 up to 3.5, which was the highest Al:Fe ratio at which a well-crystallized product was obtained. Chemical analysis showed the presence of more Al+Fe in the products than could be incorporated into a dioctahedral formula. After the excess was assigned to a hydroxy-aluminium interlayer, the formula of the most Al-rich beidellite was calculated to be 0.575Ca(Si6.85A1.15)(Al2.47Fe1.53)O20(OH)4. This composition lay within the range recorded for the ferruginous beidellites that form in Vertisols.

Keywords

AllophaneBeidelliteInfrared SpectraNontroniteVertisolsX-ray Diffraction (XRD)
Type
Research Article
Information
Clays and Clay Minerals , Volume 45 , Issue 4 , August 1997 , pp. 591 - 597
Copyright
Copyright © 1997, The Clay Minerals Society

References

Barnhisel, R.I. Bertsch, P.M., Dixon, J.B. and Weed, S.B., 1989 Chlorites and hydroxy-in-terlayered vermiculite and smectite Minerals in soil environments 2nd ed Madison, WI Soil Sci Soc Am 729–788.Google Scholar
Ben-Dor, E. and Singer, A., 1987 Optical density of vertisol clay suspensions Clays Clay Miner 35 311–317 10.1346/CCMN.1987.0350409.CrossRefGoogle Scholar
Duchaufour, P. 1982. Pedology: Pedogenesis and classification. Paton, T.R., translator. London: George Allen and Unwin. 44. p.CrossRefGoogle Scholar
Farmer, V.C., 1974 The infrared spectra of minerals London Mineral Soc 10.1180/mono-4.CrossRefGoogle Scholar
Farmer, V.C. Fraser, A.R. and Tait, J.M., 1979 Characterisation of the chemical structures of natural and synthetic alumino-silicate gels and sols by infrared spectroscopy Geochim Cosmochim Acta 43 1417–1420 10.1016/0016-7037(79)90135-2.CrossRefGoogle Scholar
Farmer, V.C. Krishnamurti, G.S.R. and Huang, P.M., 1991 Synthetic-allophane and layer-silicate formation in SiO2-Al2OrFeO-Fe2O3-MgO-H2O systems at 23 °C and 89 °C in a calcareous environment Clays Clay Miner 39 561–570 10.1346/CCMN.1991.0390601.CrossRefGoogle Scholar
Farmer, V.C. McHardy, W.J. Elsass, F. and Robert, M., 1994 hk-Ordering in aluminous nontronite and saponite synthesized near 90 °C: Effects of synthesis conditions on nontronite composition and ordering Clays Clay Miner 42 180–186 10.1346/CCMN.1994.0420208.CrossRefGoogle Scholar
Farmer, V.C. Palmieri, F. Violante, A. and Violante, P., 1991 Amorphous hydroxyaluminium silicates formed under physiological saline conditions, and in CaCO3-buffered solutions. Stability and significance for Alzheimer plaque precipitates Clay Miner 26 281–287 10.1180/claymin.1991.026.2.11.CrossRefGoogle Scholar
Farmer, V.C. and Russell, J.D., 1964 The infrared spectra of layer silicates Spectrochim Acta 20 1149–1173 10.1016/0371-1951(64)80165-X.CrossRefGoogle Scholar
Farmer, V.C. Russell, J.D., Boodt, M.F. Hayes, M.H.B. and Herbillon, A., 1990 Structures and genesis of al-lophanes and imogolite, and their distribution in non-volcanic soils Soil colloids and their association in aggregates New York Plenum Pr 165–178 10.1007/978-1-4899-2611-1_8.CrossRefGoogle Scholar
Nadeau, P.H. Farmer, V.C. McHardy, W.J. and Bain, D.C., 1985 Compositional variations of the Unterrupsroth beidellite Am Mineral 70 1004–1010.Google Scholar
Paterson, E. Goodman, B.A. Farmer, V.C., Ulrich, B. and Sumner, M.E., 1991 The chemistry of aluminium, iron, and manganese oxides in acid soils Soil acidity Heidelberg Springer-Verlag 97–124 10.1007/978-3-642-74442-6_5.CrossRefGoogle Scholar
Velde, B., 1995 Origin and mineralogy of clays Berlin Springer-Verlag 10.1007/978-3-662-12648-6.CrossRefGoogle Scholar
Wada, K., Dixon, J.B. and Weed, S.B., 1989 Allophane and imogolite Minerals in soil environments 2nd ed Madison, WI Soil Sci Soc Am 603–638.Google Scholar
Weir, A.H. and Greene-Kelly, R., 1962 Beidellite Am Mineral 47 137–146.Google Scholar
Wilson, M.J., Schultz, L.G. van Olphen, H. and Mumpton, F.A., 1987 Soil smectites and related interstratified minerals: Recent developments Proc Int Clay Conf Denver. Bloomington, IN Clay Miner Soc 167–173.Google Scholar