The behavior of methane in LTA-type zeolites was deduced from molecular dynamics simulations. Upon taking account of the polarization interaction of exchangeable cations with methane molecules, the self-diffusion coefficients in NaCaA zeolite were found to decrease by an order of magnitude when compared with the cation-free analogue, ZK4. The order of magnitude of the calculated values was in agreement with nuclear magnetic resonance data.
Influence of Exchangeable Cations on the Diffusion of Neutral Diffusants in Zeolites of Type LTA. An MD Study. S.Fritzsche, R.Haberlandt, J.Karger, H.Pfeifer, K.Heinzinger, M.Wolfsberg: Chemical Physics Letters, 1995, 242[3], 361-6
Table 8
Diffusion of Cs in Type-A Synthetic Zeolite
Temperature (C) | Process | D(cm2/s) |
0 | slow | 2.2 x 10-12 |
0 | fast | 8.0 x 10-11 |
14 | slow | 4.1 x 10-12 |
14 | fast | 1.4 x 10-10 |
22 | slow | 5.4 x 10-12 |
22 | fast | 1.9 x 10-10 |
30 | slow | 6.8 x 10-12 |
30 | fast | 2.6 x 10-10 |