DFT and local reactivity descriptor studies on the nitrogen sorption selectivity from air by sodium and calcium exchanged zeolite-A

In the present paper, we have attempted to explain the sorption behavior of nitrogen and oxygen molecule in the sodium and calcium ion exchanged zeolite-A. We have specified the essential role of different cations in making the interaction of the molecules strongly with the cations present at the different reactive sites. All the studies are carried out through local density approximation (LDA). We have also used the recently developed density based global and local reactivity descriptors (GRD and LRD) to study the site reactivity and the energetic patterns of the nitrogen and oxygen molecule with all possible cationic sites. It is found that the calculated interaction energy from our reactivity descriptor model is in agreement with the experimental values. Our methodology can be considered as one of the important tools to investigate the effect of zeolite framework, charge and size of the cations on determining the sorption properties