Determination of mass transfer rates in wetted and non-wetted microporous membranes

The mass transfer resistance of microporous membranes placed between a gas and a liquid phase was studied for both wetted and non-wetted membranes. It was found that the mass transfer coefficient can be described according to the film model in which the porosity of the membrane and the tortuosity of the pores is incorporated. For the non-wetted membranes (mean pore diameter of 0.1 um), the Knudsen and continuum diffusion must be taken into account. No difference was observed in the values of the liquid-phase mass transfer coefficients between systems with and without a membrance at the gas?liquid interface, despite the different hydrodynamic situation at the interface. The influence of a chemical equilibrium reaction on the mass transfer through a wetted membrane was analysed mathematically (two-film concept). With this model the tortuosity factor of the membrane was calculated from experimentally determined fluxes.

[1]  D. Cooney,et al.  GAS ABSORPTION IN A HOLLOW FIBER DEVICE , 1989 .

[2]  K. Kobe.  The properties of gases and liquids , 1959 .

[3]  W. Beek,et al.  Local mass transfer with chemical reaction , 1968 .

[4]  W. Whitman,et al.  The two film theory of gas absorption , 1962 .

[5]  K. Westerterp,et al.  Chemical reactor design and operation , 1983 .

[6]  J. A. Quinn,et al.  Separation of gases with synthetic membranes , 1983 .

[7]  R. Stokes.  An Improved Diaphragm-cell for Diffusion Studies, and Some Tests of the Method , 1950 .

[8]  E. A. Mason,et al.  Gas Transport in Porous Media: The Dusty-Gas Model , 1983 .

[9]  O. Maass,et al.  The Solubility of Hydrogen Sulphide in Water from the Vapor Pressures of the Solutions , 1932 .

[10]  H. Landeghem.  Multiphase reactors : mass transfer and modeling , 1980 .

[11]  Edward L Cussler,et al.  Microporous hollow fibers for gas absorption. I. Mass transfer in the liquid , 1985 .

[12]  K. Onda,et al.  SIMULTANEOUS DETERMINATION OF DIFFUSION COEFFICIENT AND SOLUBILITY OF GAS IN LIQUID BY A DIAPHRAGM CELL , 1975 .

[13]  Donald R. Olander,et al.  Simultaneous mass transfer and equilibrium chemical reaction , 1960 .

[14]  P. V. Danckwerts,et al.  The N2O analogy: The solubilities of CO2 and N2O in aqueous solutions of organic compounds , 1981 .

[15]  R. Higbie,et al.  The Rate of Absorption of a Pure Gas into a Still Liquid during Short Periods of Exposure , 1935 .

[16]  Geert Versteeg,et al.  A study on the reaction between CO2 and alkanolamines in aqueous solutions , 1983 .

[17]  A. Laurent,et al.  Aires interfaciales et coefficients de transfert de matière dans les divers types d'absorbeurs et de réacteurs gaz—liquide , 1974 .

[18]  K. Sirkar,et al.  Further studies on solvent extraction with immobilized interfaces in a microporous hydrophobic membrane , 1986 .

[19]  Edward L Cussler,et al.  Microporous hollow fibers for gas absorption : II. Mass transfer across the membrane , 1985 .

[20]  P. V. Danckwerts.  Significance of Liquid-Film Coefficients in Gas Absorption , 1951 .