Diffusion of carbon dioxide in 5A zeolites (laboratory-synthesized and commercial powders, pressed and manufactured pellets) was investigated (figure 1) using the frequency-response method. Intra- and intercrystalline diffusion processes could be distinguished and determined from the response spectra generated. Effects of mass and heat transfer resistances on the response spectra were observed, but could be eliminated by dispersing a small amount of sample in a plug of glass-wool and carrying out measurements at relatively high temperatures.

Frequency-Response Studies of CO2 Diffusion in Commercial 5A Powders and Pellets. G.Onyestyák, D.Shen, L.V.C.Rees: Microporous Materials, 1996, 5[5], 279–88

Figure 1

Diffusivity of CO2 at 1Torr in 5A Zeolite

(a: Ca-ZK4, b: synthesized Ca-A, c: Lancaster 5A)