Hostname: page-component-78c5997874-ndw9j Total loading time: 0 Render date: 2024-11-03T08:41:20.271Z Has data issue: false hasContentIssue false
  • English
  • Français

Activation of a sepiolite with dilute solutions of HNO3 and subsequent heat treatments: III. Development of porosity

Published online by Cambridge University Press:  09 July 2018

F. Rodríguez-Reinoso ,
A. Ramírez-Sáenz ,
J. De D. López-González ,
C. Valenzuela-Calahorro  and
L. Zurita-Herrera
F. Rodríguez-Reinoso
Affiliation:
Department of Inorganic Chemistry, University of Granada, Granada, Spain
A. Ramírez-Sáenz
Affiliation:
Department of Inorganic Chemistry, University of Granada, Granada, Spain
J. De D. López-González
Affiliation:
Department of Inorganic Chemistry, University of Granada, Granada, Spain
C. Valenzuela-Calahorro
Affiliation:
Department of Inorganic Chemistry, University of Granada, Granada, Spain
L. Zurita-Herrera
Affiliation:
Department of Inorganic Chemistry, University of Granada, Granada, Spain
Get access Rights & Permissions [Opens in a new window]

Abstract

Porosity development in a sepiolite from Toledo, Spain, has been studied as a function of acid (0·25, 0·50, 0·75 and 1·0 m HNO3) and subsequent heat treatments (110–400°C). Adsorption isotherms of N2 at 77 K have been analysed by f-plot, t-plot, αs-plot and the Cranston & Inkley methods. Results are compared with those obtained on products heated without previous acid activation. Experimental conditions favouring porosity development are discussed.

Résumé

Résumé

On a étudié l'accroissement de la porosité d'une sépiolite de Tolède, Espagne, en fonction de traitements acides (HNO3 0·25, 0·50, 0·75 et 1·0 M) suivis de chauffage (110°–400°C). Les isothermes d'adsorption de N2 à 77 K ont été analysées selon les méthodes graphiques f, t, αs et par celle de Cranston et Inkley. On compare les résultats à ceux de produits chauffés n'ayant pas subi d'activation acide. On discute des conditions expérimentales qui favorisent l'accroissement de la porosité.

Kurzreferat

Kurzreferat

Untersucht wurde die Porositätsentwicklung eines Sepiolits aus Toledo, Spanien, in Abhängigkeit von Säure (0·25, 0·50, 0·75 und 1·0 m HNO3) und anschließender Hitzebehandlung (110–400°C). Mittels f-, t-, αs-Plot und der Cranston-u. Inkley-Methodik wurde die N2 Adsorptionskurve bei 77 K ermittelt. Diese Ergebnisse werden mit denen von erhitzten Proben ohne vorherige Säurebehandlung verglichen. Ferner werden jene experimentellen Bedingungen diskutiert, welche die Porositätsentwicklung fördern.

Resumen

Resumen

Se ha estudiado la evolución de la porosidad de una sepiolita de Toledo (España) producida por la activación con disoluciones de HNO3 (0·25, 0·50, 0·75 y 1·0 m), seguida de tratamientos térmicos en el intervalo 110–400°C. Para ello, las isotermas de adsorción de N2 a 77 K se han analizado utilizando los métodos f, t, αs y el de Cranston e Inkley. Los resultados se han comparado con los obtenidos para las muestras tratadas térmicamente alas mismas temperaturas pero sin activación ácida previa. Se discuten las condiciones experimentales más favorables para el desarrollo de la porosidad de la sepiolita.

Type
Research Article
Information
Clay Minerals , Volume 16 , Issue 4 , December 1981 , pp. 315 - 323
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1981

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

Bonilla, J.L., Lopez-Gonzalez, J. de D., Ramirez-Saenz, A., Rodriguez-Reinoso, F. & Valenzuela-Calahorro, C. (1981) Activation of ą sepiolite with dilute solutions of HNO3 and subsequent heat treatments: II. Determination of surface acid centres. Clay Miner. 16, 173–179.Google Scholar
Bye, G.C. & Sing, K.S.W. (1967) Nitrogen adsorption on systems containing both micro and transitional pores. Chem.Ind. 1139–1140.Google Scholar
Cranston, R.W. & Inkley, F.A. (1957) The determination of pore structures from nitrogen adsorption isotherms. Adv. Catal. 9, 143–154.Google Scholar
Fegnández-Alvarez, T. (1972) Etude de la structure de pore de divers solids par adsorption de l'azote. I.Sepiolite naturelle et ectivée par HCI. Proc. Int. Clay Conf., Madrid, 571–582.Google Scholar
Gregg, S.J. (1975) A simple method for comparing the shapes of closely related adsorption isotherms. J.C.S. Chem. Comm. 699–700.CrossRefGoogle Scholar
Gregg, S.J. & Langrord, J.F. (1977) Study of the effect of compaction on the surface area and porosity of six powders by measurement of nitrogen sorption isotherms. J.C.S. Faraday I, 73, 747-759.CrossRefGoogle Scholar
Gregg, S.J. & Sing, K.S.W. (1976) The adsorption of gases on porous solids. Pp. 231–359 in: Surface and Colloid Science 9 (Matijevic, E., editor).Google Scholar
Jimenez-Lopez, A., Lopez-Gonzalez, J. de D., Ramirez-Saenz, A., Rodriguez-Reinoso, F., Valenzuela-Calahorro, C. & Zurita-Herrera, L. (1978) Évolution of surface area in a sepiolite as a function of acid and heat treatments. Clay Miner. 13, 375–385.CrossRefGoogle Scholar
Lecloux, A. & Pirard, J.P. (1979) The importance of standard isotherms in the analysis of adsorption isotherms for determining the porous texture of solids. J. Colloid Interface Sci. 70, 265–281.CrossRefGoogle Scholar
Lippens, B.C. & De Boer, J.H. (1965) Studies on pore systems in catalysts. V. The t method. J. Catalysis, 4, 319–323.Google Scholar
Lopez-Gonzalez, J. de D., Ramirez-Saenz, A., Rodriguez-Reinoso, F., Valenzuela-Calahorro, C. & Zurita-Herrera, L. (1981) Activación de una sepiolita con disoluciones diluidas de NO3H y posteriores tratamientos térmicos. I. Estudio de la superficie específica. Clay Miner. 16, 103–113.Google Scholar
Pierce, C. (1968) The universal nitrogen isotherm. J. Phys. Chem. 72, 3673–3676.CrossRefGoogle Scholar
Rautureau, M. & Mifsud, A. (1977) Etude par microscope electronique des differents etats d'hydration de la sepiolite. Clay Miner. 12, 309–318.CrossRefGoogle Scholar
Sing, K.S.W. (1970) Utilization of adsorption data in the BET region. Pp. 25–34 in: Surface Area Determination (Everett, D. H. & Ottewill, R. H., editors). Butterworths, London.CrossRefGoogle Scholar