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Three new, quick CEC methods for determining the amounts of exchangeable calcium cations in calcareous clays

Published online by Cambridge University Press:  01 January 2024

R. Dohrmann  and
S. Kaufhold
R. Dohrmann*
Affiliation:
BGR/LBEG, Stilleweg 2, D-30655 Hannover, Germany
S. Kaufhold
Affiliation:
BGR/LBEG, Stilleweg 2, D-30655 Hannover, Germany
*
* E-mail address of corresponding author: [email protected]
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Abstract

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The cation exchange capacity (CEC) is one of the most important properties of clays in terms of their performance in both natural and technical processes. For decades, common methods for determining exchangeable cations have failed when calcareous clays or soils were examined, because calcite is at least partly dissolved throughout the exchange experiment which in turn increases measureable Ca2+ concentrations. As a result, exchangeable Ca2+ and the sum of exchangeable cations by far exceed the amount of negative charges. In the past, the silver-thiourea method (AgTU) has been modified to overcome this problem (AgTUcalcite), but is unsatisfactory as the method is laborious. In the present study three new methods based on two alternative metal complexes, cobalt(III) hexamine (CoHex) and copper(II) triethylenetetramine (Cu-trien), are proposed. The optimum solid/liquid ratios of these methods and the optimum complex concentration of Cu-trien are reported, depending on the mineralogical composition of the samples. The key development is that the exchange solutions are saturated with respect to calcite prior to the experiment. Approximately 70–90% of the dissolution of calcite present as an admixture in a clay sample is suppressed in the subsequent cation exchange experiment, but not all. The Ca2+ exchange is not suppressed and there is no evidence for any precipitation of this Ca2+. Three possibilities for how to handle this problem are discussed, one of which is to perform no further correction. The resulting error arises from the remaining calcite solubility of the different solutions after pre-treatment with calcite. This corresponds to errors of 0.2–1.3 (CoHexcalcite)and 0.7–8.4 (Cu-triencalcite) meq/100 gCa2+ for samples with small and large CEC values, respectively. As a consequence of the poor performance of Cu-triencalcite for samples with large CEC, a more concentrated Cu-trien5 × calcite solution was developed which performed much better: 0.1–0.8 meq/100 g(Cu-trien5 × calcite). For Cu-trien5 × calcite and CoHexcalcite at least, the errors are in the range of the non-systematic scattering for exchangeable Ca2+ determination. Therefore, the methods suggested provide ‘operationally correct’ Ca2+ values without additional effort. Moreover, owing to the high selectivity of the index cations applied in the present study, only one exchange step is required, providing a significant advantage over the AgTUcalcite method.

Keywords

AgTUcalcite MethodBentonitesCalcareous ClaysCECCoHexcalcite MethodCu-trien5 × calcite MethodCu-triencalcite MethodExchangeable Calcium
Type
Article
Information
Clays and Clay Minerals , Volume 57 , Issue 3 , June 2009 , pp. 338 - 352
Copyright
Copyright © The Clay Minerals Society 2009

References

Bracke, G. Satir, M. and Krauss, P., 1995 The Cryptand [222] for exchanging cations of micas Clays and Clay Minerals 43 732–737 10.1346/CCMN.1995.0430609.CrossRefGoogle Scholar
Buhmann, D. and Dreybrodt, W., 1987 Calcite dissolution in the system H2O-CO2-CaCO3 with participation of foreign ions Chemical Geology 64 89–102 10.1016/0009-2541(87)90154-9.CrossRefGoogle Scholar
Ciesielski, H. and Sterckeman, T., 1997 Determination of cation exchange capacity and exchangeable cations in soils by means of cobalt hexamine trichloride. Effects of experimental conditions Agronomie 17 1–7 10.1051/agro:19970101.CrossRefGoogle Scholar
Ciesielski, H. and Sterckeman, T., 1997 A comparison between three methods for the determination of cation exchange capacity and exchangeable cations in soils Agronomie 17 9–15 10.1051/agro:19970102.CrossRefGoogle Scholar
Dohrmann, R., 1997 Kationenaustauschkapazität von Tonen-Bewertungbisheriger Analysenverfahren und Vorstellung einer neuen und exakten Silber-Thioharnstoff-Methode Aachen, Germany RWTH Aachen 237 pp.Google Scholar
Dohrmann, R., 2006 Cation Exchange Capacity Methodology II: proposal for a modified silver-thiourea method Applied Clay Science 34 38–46 10.1016/j.clay.2006.02.009.CrossRefGoogle Scholar
Dohrmann, R., 2006 Cation exchange capacity methodology III: Correct exchangeable calcium determination of calcareous clays using a new silver-thiourea method Applied Clay Science 34 47–57 10.1016/j.clay.2006.02.010.CrossRefGoogle Scholar
Dohrmann, R., 2006 Cation Exchange Capacity Methodology I: An efficient model for the detection of incorrect cation exchange capacity and exchangeable cation results Applied Clay Science 34 31–37 10.1016/j.clay.2005.12.006.CrossRefGoogle Scholar
Dohrmann, R., 2006 Problems in CEC determination of calcareous clayey sediments using the ammonium acetate method Journal of Plant Nutrition and Soil Science 169 330–334 10.1002/jpln.200621975.CrossRefGoogle Scholar
Hissink, D.J., 1923 Method for estimating adsorbed bases in soils and the importance of these bases in soil economy Soil Science 15 269 10.1097/00010694-192304000-00005.CrossRefGoogle Scholar
Kaufhold, S. and Dohrmann, R., 2008 Detachment of colloids from bentonites in water Applied Clay Science 39 50–59 10.1016/j.clay.2007.04.008.CrossRefGoogle Scholar
Kaufhold, S. Dohrmann, R. Koch, D. and Houben, G., 2008 The pH of aqueous bentonite suspensions Clays and Clay Minerals 56 338–343 10.1346/CCMN.2008.0560304.CrossRefGoogle Scholar
Koppelman, M.H. and Dillard, J.G., 1978 An X-ray photo-electron spectroscopic (XPS) study of cobalt adsorbed on the clay mineral chlorite Journal of Colloid and Interface Science 66 345–351 10.1016/0021-9797(78)90313-2.CrossRefGoogle Scholar
McBride, M.B., 1979 An interpretation of cation selectivity variations in M+-M+ exchange on clays Clays and Clay Minerals 27 417–422 10.1346/CCMN.1979.0270604.CrossRefGoogle Scholar
Mehlich, A., 1948 Determination of cation- and anion-exchange properties of soils Soil Science 66 429–445 10.1097/00010694-194812000-00004.CrossRefGoogle Scholar
Meier, L.P. and Kahr, G., 1999 Determination of the Cation Exchange Capacity (CEC) of clay minerals using the complexes of copper (II) ion with triethylenetetramine and tetraethylenepentamine Clays and Clay Minerals 47 386–388 10.1346/CCMN.1999.0470315.CrossRefGoogle Scholar
Morel, R., 1958 Observations sur la capacité d'échange et les phénomènes d'échange dans les argiles Bulletin du Groupe français des argiles 10 5 3–8 10.3406/argil.1958.942.CrossRefGoogle Scholar
Pearson, F.J., Arcos, D., Bath, A., Boisson, J.Y., Fernández, A.M., Gäbler, H.E., Gaucher, E., Gautschi, A., Griffault, L., Hernán, P., and Waber, H.N. (2003) Mont Terri Project — Geochemistry of Water in the Opalinus Clay Formation at the Mont Terri Rock Laboratory. Reports of the Federal Office for Water and Geology (FOWG), Geology Series No. 5, 319 pp.Google Scholar
Pleysier, J. and Cremers, A., 1975 Stability of silver—thiourea complexes in montmorillonite clay Journal of the Chemical Society, Faraday Transactions I 71 256–264 10.1039/f19757100256.CrossRefGoogle Scholar
Schoonheydt, R.A., Vaughan, D.J. and Pattrick, R.A.D., 1995 Clay mineral surfaces. Chapter 9 Mineral Surfaces London Chapman & Hall.Google Scholar
Środoń, J. and McCarty, D.K., 2008 Surface area and layer charge of smectite from CEC and EGME/H2O-retention measurements Clays and Clay Minerals 56 155–174 10.1346/CCMN.2008.0560203.CrossRefGoogle Scholar
Sterckeman, T. (2006) Results of the inter-laboratory comparison for the validation of ISO DIS 23470 “Soil Quality — Determination of effective cation exchange capacity (CEC) and exchangeable cations using a cobaltihexamine trichloride solution”. Unpublished report.Google Scholar
Thomas, G.W., 1977 Historical developments in soil chemistry: Ion exchange Soil Science Society of America Journal 41 230–238 10.2136/sssaj1977.03615995004100020015x.CrossRefGoogle Scholar
Thompson, H.S., 1850 On the adsorbent power of soils Journal of the Royal Agricultural Society of England 11 68–74.Google Scholar
Tucker, B.M., 1954 The determination of exchangeable calcium and magnesium in carbonate soils Australian Journal of Agricultural Research 5 706–715 10.1071/AR9540706.CrossRefGoogle Scholar
Ufer, K. Stanjek, H. Roth, G. Dohrmann, R. Kleeberg, R. and Kaufhold, S., 2008 Quantitative phase analysis of bentonites with the Rietveld method Clays and Clay Minerals 56 272–282 10.1346/CCMN.2008.0560210.CrossRefGoogle Scholar
Way, J.T., 1852 On the power of soils to adsorb manure Journal of the Royal Agricultural Society of England 13 123–143.Google Scholar