AN ANALYTICAL SOLUTION FOR COMPETITIVE FACILITATED MEMBRANE-TRANSPORT

Facilitated transport with a "competitive binding" reaction mechanism occurs when two or more solutes (gas or liquid) are transported by competing with each other to reversibly react with the carrier molecule. In this study, competitive facilitated transport was analyzed with a different approach. The free (uncomplexed) carrier concentration, C(H)+ was assumed to be constant. The resulting expression for C(B)+ shows how the equilibrium constant for each reaction affects the transport of each solute. Model equations containing diffusion and reaction terms were solved analytically for the facilitation factor, F, of the solutes. This analytical expression for F was tested with experimental and modeling results from the literature. The trends in the data agreed well. This expression is an improvement over previous analytical results in that it can be used over the entire range of operating conditions from diffusion-limited to reaction-limited regimes to identify trends in the facilitation factor, although there are better ways, such as numerical methods, to predict the exact value of F.