Membrane filtration (RO, NF, UF, MFT) - Theoretical aspects: permeability and selectivity

The aim of this dossier is to theoretically analyze the efficiency of reverse osmosis RO, nanofiltration NF, ultrafiltration UF and microfiltration MFT membrane filtration processes through their permeability and selectivity. The effect of operating conditions on these operating conditions is detailed, and orders of magnitude of the phenomena involved are given. Some elements concerning process coupling and qualitative comparisons between membrane processes and other unit operations are provided.

The aim is to provide explanations and solutions to operating problems, and to provide the tools and know-how needed to design and optimize membrane filtration systems. It is based on the [J 2 789] file for theoretical considerations and transfer mechanisms, from which the theoretical analysis of processes is developed. In simplified terms, the [J 2 789] file presents the cause of the phenomena (the transfer mechanisms involved), whereas this file presents the consequences of these phenomena on the efficiency of the process, including the consequences of polarization and clogging phenomena on the permeability of the process, and the role of membrane transfers on the selectivity of the process.