Self-diffusion of D2O in partially filled silicalite-1 crystals was studied at 25C using 2H nuclear magnetic resonance with bipolar field gradient pulses and longitudinal eddy-current delay. For the first time, reliable experimental diffusion data were obtained for this system. Analysis of NMR diffusion decays revealed the presence of a continuous distribution of apparent self-diffusion coefficients of water, ranging from 10−7 to about 10−10m2/s; including values which were much higher and lower than that of bulk water (about 10−9m2/s) in the liquid phase. The observed distribution of self-diffusion coefficients changed upon varying the diffusion time from 10 to 200ms. A two-site Kärger exchange model was successfully fitted to the data.

Dynamic Properties of Water in Silicalite-1 Powder. A.Filippov, S.V.Dvinskikh, A.Khakimov, M.Grahn, H.Zhou, I.Furo, O.N.Antzutkin, J.Hedlund: Magnetic Resonance Imaging, 2012, 30[7], 1022–31