Article ID Journal Published Year Pages File Type
639100 Journal of Membrane Science 2006 8 Pages PDF
Abstract
The permeation of initially pure methanol into >95% relative humidity air has been demonstrated with three membranes, supported poly(1-trimethylsilyl-1-propyne) (PTMSP), supported poly(dimethylsiloxane) (PDMS), and a 125-μm polysilicone film. Although fundamentally similar to pervaporation, the arrangement entailed small scale (∼1 cm2) membrane dispensing of methanol with water counterdiffusion. Volumetric readings over time, final concentration measurements, and subsequent parameter fitting to a derived first-order mathematical model revealed high selectivities - 8.4, 10.3, and 8.3 for the respective membranes - for delivery of methanol versus uptake of water. These selectivities represented factors of 1.5, 1.9, and 1.5 beyond the relative saturation vapor pressures of methanol and water, perhaps, as a result of a favorable inhibition of water counterdiffusion by methanol permeation. Initial methanol permeation rates of 380, 730, and 260 g/h m2 were also estimated. A transport mechanism adjustment is suspected with PTMSP because of a slightly more rapid permeation rate decrease than indicated by the model. The experimental arrangement and mathematical model provide a new general framework for evaluation of membranes and designs for potential dispensing applications.
Related Topics
Physical Sciences and Engineering Chemical Engineering Filtration and Separation
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