The proposal is concerned with the synthesis and characterization of new gas adsorbents to be used especially with the pressure swing adsorption process, and with the modeling of hysteresis in the PSA process. Four kinds of adsorbents will be studied: pillared clays, ion-exchanged zeolites, polymeric adsorbents and modified carbon molecular sieves. With regard to the synthesis of new pillared clays, and PI has already synthesized and studied ZrO2 and AL2O3 PILC's, and these studies indicated that the equilibrium separation of N2/CH4 and O2/N2 are feasible with AL-PILC. The PI suggests new experiments in which pillared clays already synthesized for catalytic purposes will be modified to improve their sorbent characteristics. The zeolites which will be studied are ion-exchanged A and X type and clinoptilolites. The PI gives some preliminary data which indicates that the clinoptilolites are promising sorbents for kinetic separation of N2 and CH4. Polymeric adsorbents will focus on unfunctionalized polystyrenic sorbents, whose preliminary data indicates that the SO2 and NOx adsorption amounts are significant, to particularly functionalized adsorbents. With regard to the modelling of hysterisis in the PSA process, single particle cyclic scanning curves will be measured using a TGA, and these results will be used in modeling the PSA process.