Drift spectroscopy of nitrogen diffusion, codiffusion and counterdiffusion from N2−O2 mixtures in zeolites

Abstract

Abstract A novel DRIFTS method is described to study sorption kinetics of nitrogen, N 2 , and other gases on microporous sorbents, specifically zeolites. It utilizes the time evolution of IR-stretching bands of symmetrical molecules due to perturbation by interaction with sorption sites. Sorption uptake is explored for N 2 , both as single and mixture component with oxygen, O 2 , on zeolites NaLSX, NaZSM-5 and NaA. Lower limits to transport diffusivity of N 2 in theses sorbents are assessed at ambient temperature. Mixture experiments enable to conclude that N 2 -sorption rate from O 2 -rich mixtures is controlled by codiffusion of N 2 and O 2 within the intercrystalline void volume of zeolite samples. They also show a strong influence of O 2 on N 2 sorption by NaLSX from N 2 −O 2 mixtures.