Theoretical modification of the surface force-pore flow model for reverse osmosis transport

One relatively new and popular model used to describe and predict the performance of reverse osmosis type membranes, the surface force-pore flow (SF-PF) model, has been modified and extended. The two most serious problems with the SF-PF model are that an incorrect form of material balance is used and that the potential function in the pore is inconsistent with the cylindrical pore geometry. A modified model, the MD-SF-PF model, which is based on the same physical precepts is derived. Equations describing the concentration profile for both models have been derived and compared. It has been shown that the SF-PF model can predict physically unacceptable results. Simulation results for the MD-SF-PF model are consistent with what is expected for reverse osmosis type membranes.