Tracing The Influence Of Extra-Framework Cations On N-2 And O-2 Adsorption Characteristics Under Plateau Environment By Gcmc Simulations

Pressure swing adsorption (PSA) coupling with molecular sieves, especially the Li low silica X (Li-LSX) zeolite, adsorption technology is widely used in O-2 generator instrument under plateau environment. However, the studies of N-2 and O-2 adsorption and separation properties on zeolite under plateau environment are still obscure to date. In this work, the influence of N-2 and O-2 adsorptions on the LSX zeolites in harsh plateau environment (3000 - 5000 m) was investigated by Grand Canonical Monte Carlo (GCMC) simulations. Three kinds of LSX zeolites including Li-LSX, Ag-LSX and LiCa-LSX were taken into consideration. The simulation results indicate that the adsorption amount and affinity of both N-2 and O-2 elevate with the increasing altitude and following the order of Ag-LSX > Li-LSX > LiCa-LSX. The N-2 adsorption was dominated over all three LSX zeolites, leaving O-2 much easier to permeate through the LSX zeolites. The isosteric adsorption heat and adsorption density results further proved that N-2 and O-2 have extremely different adsorption strategies. Moreover, the selectivity and separation coefficients based on ideal adsorption solution theory (IAST) were calculated from GCMC simulations, and the results indicate Ag-LSX has the highest diffusion selectivity and the steadiest diffusion coefficient among the three LSX zeolites. These findings may contribute to the N-2/O-2 separation molecular sieves for plateau applications by tailoring the LSX zeolite with different extra-framework cations.