Self-diffusion of water-ethanol mixtures in polyacrylic acid-polysulfone composite membranes obtained by pulsed-field gradient nuclear magnetic resonance spectroscopy
1995; Elsevier BV; Volume: 100; Issue: 3 Linguagem: Inglês
10.1016/0376-7388(94)00267-3
ISSN1873-3123
AutoresV. I. Volkov, Svetlana A. Korotchkova, Haruhiko Ohya, Qunhui Guo,
Tópico(s)Advanced MRI Techniques and Applications
ResumoThe self-diffusion of water, ethanol and water-ethanol mixtures in polyacrylic acid (PAA) and PAA-polysulfone (PSF) composite membranes was measured with pulsed-field gradient (PFG)-nuclear magnetic resonance (NMR) spectroscopy. The partial solubilities and self-diffusion coefficients were obtained. An attempt was made to explain the transport properties of water and ethanol through the PAA layer and PAA-PSF composite membranes. It was concluded that there are two types of channels for diffusate transfer in PAA: an ionogenic hydrophilic channel which is selective for water and a hydrophobic channel which contains a predominance of ethanol molecules. The existence of aluminum nitrate in PAA influences the morphology of the latter channel. There is a good agreement between of the separation factors estimated from PFG-NMR data and those obtained by pervaporation testing.
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