Modeling Study of the Influence of Porosity on Membrane Absorption Process

Abstract

A theoretical model based on the advancing front model was developed to analyze the influence of porosity on membrane absorption process. Perturbation solutions were obtained and a nonlinear transformation was applied to increase the accuracy of the solutions. The concentration profile of the solute in the liquid side near the membrane surface was simulated for different operation conditions. The influencing factors on the diffusing rate of the solute concentration profile were analyzed qualitatively. In the case of the rapid mass transfer system, the time of reaction front to reach the midpoint of two proximate pores is relatively long, which means that the concentration layer of solute overcasts the whole surface of membrane slowly, there is a “dead” area for mass transfer, so the influence of porosity should be taken into account. In the case of slow mass transfer system, the time can be ignored compared with the overall experiment time, and the influence of porosity is negligible. The absorption rates were calculated based on the developed model and the calculated results agreed well with the literature results.