Resumo

BARROS, M. A. S. D. et al. Multicomponent ion exchange isotherms in NaX zeolite. Lat. Am. appl. res. [online]. 2003, vol.33, n.3, pp.339-344. ISSN 0327-0793.

In this work the ion exchange isotherms of Cr³⁺, Mg²⁺, Ca²⁺ and K⁺ in single solutions and in binary mixtures (Cr/K, Cr/Ca, Cr/Mg) using NaX zeolite at 30^oC, 45^oC and 60^oC were reported. NaX isotherms were very favorable for all metal cations studied. The respective isotherms had some differences in shape, a consequence of competition for the exchange sites. The Kielland plots of all systems were non linear, which is a characteristic of sites of different energies involved in the exchange process. Temperature influenced the ion exchange as it could alter the hydration sphere of the in-going ions. Consequently, differences in thermodynamic properties and also in the selectivity were seen. It was concluded that NaX did not have a pronounced selectivity towards chromium.

Palavras-chave : Ion Exchange; Isotherm; Zeolite.

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