Membrane contactor (membrane absorption) and membrane adsorption

In a membrane contactor, gas is transported through the dry pores from the pore entrance to the pore exit where it is absorbed by liquid. Unlike membrane distillation, the temperature difference between the two sides of the pore is not the driving force, therefore only mass transfer is considered in its transport model. Both the membrane and liquid phase contribute to the mass transfer resistance and the Wilson plot can be applied to calculate the contribution of the liquid phase to the overall resistance. In membrane adsorption, adsorption sites are at the surface and the pore wall of the membrane, and the adsorbates are selectively adsorbed to these adsorption sites. Thus, membrane adsorption effectively combines the filtration and adsorption performance of the membrane. After a long period of operation, adsorption sites are saturated and the solutes are removed only by filtration. Hence, a breakthrough curve is obtained when the permeate solute concentration is plotted versus time.