Title: Creating nanoporosity in Na, Ca and Mg exchanged erionite zeolite

Authors: Miguel A. Hernández; Fernando Rojas; Roberto Portillo; Martha A. Salgado; Efraín Rubio; Sinuhé Ruíz

Addresses: Departamento de Investigación en Zeolitas, and Posgrado de Agroecosistemas, Instituto de Ciencias, Benemérita, Universidad Autónoma de Puebla, México, Edificio 103-O, Complejo de Ciencias, Ciudad Universitaria, C.P. 72570, Puebla, Pue. México ' Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, Apartado Postal 55-534, México 09340, D.F. ' Facultad de Ciencias Químicas, Universidad Autónoma de Puebla, México, 14 Sur, San Manuel, Ciudad Universitaria, C.P. 72570, Puebla, Pue. México ' Facultad de Ciencias Químicas, Universidad Autónoma de Puebla, México, 14 Sur, San Manuel, Ciudad Universitaria, C.P. 72570, Puebla, Pue. México ' Centro Universitario de Vinculación y Transferencia de Tecnología, Prolongación de la 24 Sur, Edif 104, Complejo de Ciencias, Ciudad Universitaria, C.P. 72570, Puebla, Pue. México ' Facultad de Ingeniería Química, Universidad Autónoma de Puebla, México, 18 Sur y San Claudio, Ciudad Universitaria, CP 72570, Puebla, Pue. México

Abstract: This paper deals with the emergence of pores in natural erionite zeolite during ion-exchange treatment with aqueous Na⁺, Mg²⁺ and Ca²⁺ solutions of different concentrations. The exchange took place at variable time and temperature of exposure. The effect of this cationic exchange upon the zeolite micropores is analysed by scanning electron microscopy, energy dispersive X-ray spectroscopy and N₂ adsorption at 76 K. The characterisation results suggest the presence of Na⁺ at the pores' mouth that causes an increased adsorption inside nanocavities as well as on the external area of the exchanged zeolites. The generation of pores emerging in erionite zeolites after ion exchange was evaluated through Dubinin-Astakhov and classical Barrett-Joyner-Halenda methods. Depending on the exchanging conditions, Na⁺ was found to be well distributed and accessible for N₂ adsorption. The results indicate that the tested exchange treatments with Na⁺ favour creation of emerging pores, as an increase of the adsorption capacity occurs.

Keywords: nanoporosity; erionite zeolite; ion exchange treatment; adsorption capacity; Dubinin-Astakhov; Barrett-Joyner-Halenda; BJH; sodium; calcium; magnesium; pores; nanotechnology; zeolite micropores; nanocavities.

DOI: 10.1504/IJNT.2016.074521

International Journal of Nanotechnology, 2016 Vol.13 No.1/2/3, pp.28 - 43

Published online: 04 Feb 2016 *

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