TY - JOUR
T1 - Dependence of the diffusion coefficients of methane in silicalite on diffusion distance as investigated by 1H PFG NMR
AU - Takaba, Hiromitsu
AU - Yamamoto, Atsushi
AU - Hayamizu, Kikuko
AU - Oumi, Yasunori
AU - Sano, Tsuneji
AU - Akiba, Etsuo
AU - Nakao, Shin Ichi
PY - 2004/7/21
Y1 - 2004/7/21
N2 - 1H PFG NMR was performed to measure the diffusion coefficient of methane in three MFI-type siliceous zeolite silicalite samples, which were synthesized under different hydrothermal conditions resulting in different crystal sizes or intracrystalline defects. Measured diffusivities of methane decreased at the diffusion distance around 7 μm for all samples. The distance almost corresponds with the distance between cracks in the intracrystalline. However, the well-calcined sample, which has no detectable cracks as observed by scanning electron microscope, also showed a drastic decrease in the diffusion coefficient. This result suggests the existence of an intracrystalline transport barrier in the single crystal, the size of which is below the SEM resolution.
AB - 1H PFG NMR was performed to measure the diffusion coefficient of methane in three MFI-type siliceous zeolite silicalite samples, which were synthesized under different hydrothermal conditions resulting in different crystal sizes or intracrystalline defects. Measured diffusivities of methane decreased at the diffusion distance around 7 μm for all samples. The distance almost corresponds with the distance between cracks in the intracrystalline. However, the well-calcined sample, which has no detectable cracks as observed by scanning electron microscope, also showed a drastic decrease in the diffusion coefficient. This result suggests the existence of an intracrystalline transport barrier in the single crystal, the size of which is below the SEM resolution.
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U2 - 10.1016/j.cplett.2004.05.086
DO - 10.1016/j.cplett.2004.05.086
M3 - Article
AN - SCOPUS:3142613173
VL - 393
SP - 87
EP - 91
JO - Chemical Physics Letters
JF - Chemical Physics Letters
SN - 0009-2614
IS - 1-3
ER -