H. Kreulen et al., DETERMINATION OF MASS-TRANSFER RATES IN WETTED AND NON-WETTED MICROPOROUS MEMBRANES, Chemical Engineering Science, 48(11), 1993, pp. 2093-2102
The mass transfer resistance of microporous membranes placed between a
gas and a liquid phase was studied for both wetted and non-wetted mem
branes. It was found that the mass transfer coefficient can be describ
ed according to the film model in which the porosity of the membrane a
nd the tortuosity of the pores is incorporated. For the non-wetted mem
branes (mean pore diameter of 0.1 mum), the Knudsen and continuum diff
usion must be taken into account. No difference was observed in the va
lues of the liquid-phase mass transfer coefficients between systems wi
th and without a membrane at the gas-liquid interface, despite the dif
ferent hydrodynamic situation at the interface. The influence of a che
mical equilibrium reaction on the mass transfer through a wetted membr
ane was analysed mathematically (two-film concept). With this model th
e tortuosity factor of the membrane was calculated from experimentally
determined fluxes.