Hostname: page-component-78c5997874-xbtfd Total loading time: 0 Render date: 2024-11-03T01:39:01.892Z Has data issue: false hasContentIssue false
  • English
  • Français

Ion Exchange Behavior of the Febex Bentonite. 1. Na/K, Na/Mg and Na/Ca Experimental Exchange Isotherms

Published online by Cambridge University Press:  21 March 2011

F.J. Huertas ,
P. Carretero ,
J. Delgado ,
J. Linares  and
J. Samper
F.J. Huertas
Affiliation:
Department of Earth Sciences and Environmental Chemistry, Estación Experimental del Zaidín, CSIC, Profesor Albareda 1, 18008 Granada, Spain
P. Carretero
Affiliation:
E.T.S. de Ingenieros de Caminos, Canales y Puertos, Universidade da Coruथa, Campus de Elviथa s/n, 15192 A Coruथa, Spain
J. Delgado
Affiliation:
E.T.S. de Ingenieros de Caminos, Canales y Puertos, Universidade da Coruथa, Campus de Elviथa s/n, 15192 A Coruथa, SpainEmail: [email protected]
J. Linares
Affiliation:
Department of Earth Sciences and Environmental Chemistry, Estación Experimental del Zaidín, CSIC, Profesor Albareda 1, 18008 Granada, Spain
J. Samper
Affiliation:
E.T.S. de Ingenieros de Caminos, Canales y Puertos, Universidade da Coruथa, Campus de Elviथa s/n, 15192 A Coruथa, Spain
Get access

Abstract

Na/K, Na/Mg, and Na/Ca exchange isotherms have been experimentally determined for the FEBEX bentonite. Na-homoionized FEBEXbentonite was reacted at room temperature with mixedsalt dissolution of NaCl/KCl, NaCl/MgCl2, or NaCl/CaCl2, while keeping a total cation normality of 0.5 eq L-1. Isotherm exchange experiments were performed using ten (duplicated)experimental points, which cover the complete range of the corresponding binary equivalent fractions. Results indicate that for the Na/K exchange reaction, Vanselow coefficients are larger than one, what is in agreement with the tendency of the smectite of having greater affinity for K than for Na. The exchange constant decreases as K progressively replaces Na in the smectite. This tendency ends when the equivalent fraction of potassium, EK, reaches a value of around 0.250.3. From this point to higher K contents, it remains nearly constant irrespective of EK but slightly decreasing again at values near one. The Vanselow selectivity coefficient for the Na/Mg isotherm indicates a preference for the divalent cation. It is nearly constant (Kv ≍ 5.6) for EMg < 0.6, but increases up to 10.2 for a nearly Mg-saturated smectite.

The Na/Ca exchange resembles that of Na/Mg, although the selectivity coefficients are larger (Kv ≍ 7.0 for ECa < 0.6). The comparison of the selectivity coefficients for the Na/Mg and Na/Ca exchange reactions indicates that the smectite has a slightly higher affinity for Ca than for Mg. This result is consistent with those observed for the Wyoming bentonite.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 663: Symposium – Scientific Basis for Nuclear Waste management XXIV , 2000 , 589
Copyright
Copyright © Materials Research Society 2001

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

REFERENCES

1. Linares, J., Huertas, F., Lachica, M., and Reyes, E., Proc. Intl. Clay Conf., 1, 351, (1972)Google Scholar
2. Caballero, E., Porto, M. Fernandes, Linares, J., Huertas, F., and Reyes, E., Est. Geol. 39, 121 (1983)Google Scholar
3. Leone, G., Reyes, E., Cortecci, G., Pochini, A., and Linares, J., Clay Miner. 18, 227 (1983)Google Scholar
4.J.M. Fernández Soler, PhD. Thesis, University of Granada, 1992 Google Scholar
5. Linares, J., Huertas, F., Reyes, E., Caballero, E., Barahona, E., Guardiola, J.L., Yáथez, J., Romero, E., and Delgado, A., ENRESA Technical Report 01/93, Madrid, 1993 Google Scholar
6.ENRESA, Technical Report 09/97, ENRESA, Madrid, 1997.Google Scholar
7. Shapiro, L., US Geol. Surv. Bull., 1401, 76 (1975)Google Scholar
8. Soil Conservation Service, Soil Survey Laboratory Methods and Procedure for Collecting Soil Samples, U.S.D.A., Washington DC, 1972 Google Scholar
9. Sposito, G., The Thermodynamics of Soil Solutions (Oxford University Press, New York), 1981 Google Scholar
10. Wolery, T.J., Report No. URCL-MA-110662 PT III, Lawrence Livermore National Laboratory, 1992 Google Scholar
11. Sposito, G., The Surface Chemistry of Soils (Oxford University Press, New York), 1984 Google Scholar
12. Bruggenwert, M.G.M., and Kamphorst, A., in Soil Chemistry. 5-B. Physico-chemical Models, edited by Bolt, G.H. (Elsevier, Amsterdam), p. 141, 1983 Google Scholar
13. Fletcher, P., Sposito, G., and LeVesque, C.S., Soil Sci. Soc. Am. J. 48, 1016 (1984)Google Scholar
14. Huertas, F.J., Cuadros, J., and Linares, J., Appl. Geochem. 10, 347 (1995)Google Scholar
15. Shainberg, I., and Kaiserman, A., Soil Sci. Soc. Am. J. 33, 547 (1969)Google Scholar
16. Verburg, K. and Baveye, P., Clays Clays Miner. 42, 207 (1994)Google Scholar
17. Suarez, D.L., and Zahow, M.F., Soil Sci. Soc. Am. J. 53, 52 (1989)Google Scholar
18. Vanselow, A.P., Soil Sci. 33, 95 (1932)Google Scholar
19. Gapon, E.N., J. Gen. Chem. 3, 144 (1933)Google Scholar
20. Gaines, G.L., and Thomas, H.C., J. Chem. Phys. 21, 714 (1953)Google Scholar
21. Appelo, C.A.J., and Postma, D., , D., Geochemistry, Groundwater and Pollution (Ed. Balkema, Rotterdam), 1993 Google Scholar
22. Fletcher, P., Chemical Thermodynamics for Earth Scientists (Longman Eds., Burt Mill), 1993 Google Scholar
23. Delgado, J., Carretero, P., Juncosa, R., Samper, J., Huertas, F.J., Cisneros, C. Jiménez de, Caballero, E., Huertas, F., Linares, J., in this volume Google Scholar