Dynamic properties of water in silicalite-1 powder

Andrey Filippov, Sergey V. Dvinskikh, Aidar Khakimov, Mattias Grahn, Han Zhou, Istvan Furo, Oleg N. Antzutkin, Jonas Hedlund

Результат исследований: Научные публикации в периодических изданияхстатья

12 Цитирования (Scopus)

Аннотация

Self-diffusion of D2O in partially filled silicalite-1 crystals was studied at 25°C by 2H nuclear magnetic resonance (NMR) with bipolar field gradient pulses and longitudinal Eddy-current-delay. For the first time, reliable experimental diffusion data for this system were obtained. Analysis of NMR diffusion decays revealed the presence of a continuous distribution of apparent self-diffusion coefficients (SDCs) of water, ranging from 10-7 to ~10-10 m2/s, which include values much higher and lower than that of bulk water (~10-9 m2/s) in liquid phase. The observed distribution of SDC changes with variation of the diffusion time in the range of 10-200 ms. A two-site Kärger exchange model was successfully fitted to the data. Finally, the water distribution and exchange in silicalite-1 pores were described by taking into account (a) a gas-like phase in the zeolite pores, a gas-like phase in mesopores and an intercrystalline gas-like phase and (b) intercrystalline liquid droplets with intermediate exchange rate with the other phases. The other phases experience fast exchange on the NMR diffusion time scale. Diffusion coefficients and mean residence times of water in some of these states were estimated.

Язык оригиналаанглийский
Страницы (с-по)1022-1031
Число страниц10
ЖурналMagnetic Resonance Imaging
Том30
Номер выпуска7
DOI
СостояниеОпубликовано - 1 сен 2012

Предметные области Scopus

  • Биофизика
  • Биомедицинская техника
  • Радиология, радиационная медицина и радионуклидная визуализация

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