CO[2] Sequestration by Natural Zeolite for Greenhouse Effect Control

Abstract

This paper describes the adsorption of CO[2] on pores in natural erionite exchanged with aqueous solutions of Na{+}, Mg{2+}, and Ca{2+} salts at different concentrations, variable time and temperature of treatment. Experimental data of CO[2] adsorption were treated by the Freundlich and Langmuir equations. Complementarily were evaluated standard adsorption energies and the degree of interaction of the gas with the zeolite; the evolution of isosteric heats of adsorption was analyzed. The exchange with Na{+} favors the creation of emergent pores thus causing an increase of the adsorption capacity for CO[2]. The presence of Na{+} at micropore entrances causes an increased adsorption into the nanocavities and on the external area of the ion-exchanged zeolites. The development of nanopores in erionite was evaluated through the Barrett-Joyner-Halenda and NLDFT methods. Depending on the conditions of the exchange treatment, Na{+} was found to be most favorable, well distributed, and accessible for N[2] adsorption.