Generalized Fick Jacobs Approach for describing Adsorption Desorption Kinetics in Irregular Pores under Non Equilibrium Conditions

摘要

We present a study exploring the range of applicability of a generalized FickJacobs equation in the case when diffusive mass transport of a fluid along apore includes chemical reactions in the bulk and pore surface. The studycontemplates nonequilibrium boundary conditions and makes emphasis on thecomparison between the predictions coming from the projected Fick Jacobsdescription and the corresponding predictions of the original two dimensionalmass balance equation, establishing a simple cuantitative criterion of validityof the projected description. For the adsorption desorption process, wedemonstrate that the length and the local curvature of the pore are therelevant geometric quantities for its description, allowing for giving veryprecise predictions of the mass concentration along the pore. Some schematiccases involving adsorption and chemical reaction are used to quantify withdetail the concentration profiles in transient and stationary states involvingequilibrium and nonequilibrium situations. Our approach provides novel andimportant insights in the study of diffusion and adsorption in confinedgeometries.