Resumo

HERNANDEZ, Miguel Ángel et al. EVALUACIÓN DE LA POROSIDAD DE ZEOLITAS NATURALES POR MEDIO DE CURVAS DIFERENCIALES DE ADSORCIÓN. Rev. Int. Contam. Ambient [online]. 2005, vol.21, n.2, pp.71-81. ISSN 0188-4999.

Differential curves of adsorption (DCA) were determined from experimental data of N2 adsorption at 76 K on natural zeolites. The variations in the adsorbed volume V with respect to the thickness of the adsorbed layer t, represented by the derivative dV/ dt , are indicative of the processes that take place in pores of molecular dimensions (micropores). The shapes of the differential curves of adsorption provide very valuable information about the distributions of pore sizes existing in the studied zeolites. The differential curves of adsorption of dealuminated clinoptilolite zeolites showed the presence of both micropores and micropores. Sharp peaks were due to the microporous structure and wider signals were caused by the mesoporous contribution, which was attributed to the presence of irregular mesopores. It was confirmed that the position of the peaks is related to the size of the pores that are present in these zeolites. The method of evaluation of pore sizes presented herein is not related to any specific adsorption mechanism.

Palavras-chave : adsorption; natural zeolites; micropores; mesopores; differential curves of adsorption; pore size distribution.