Mass transfer in pressure-driven membrane separation processes, Part I

An introduction to new theoretical approaches to describe the mass transfer in pressure-driven membrane separation processes is presented. This theory consists of two novel analytical models, namely the Analytical Solution-Diffusion Pore-Flow (ASDPF) model, presented in Part I, and the Molecular Trap (MT) model described in Part II from this work. These two models incorporate the membrane micro-structural parameters, the solute molecular properties, with the feed solution physical properties as well as the operational conditions into one rigorous mathematical description. The ASDPF model is proposed to explain the effects of the operational condition, namely the hydraulic pressure and the temperature, on membrane microstructure and the pure solvent physical properties, from which the permeability coefficient is obtained. The MT model further develops that by considering the molecular properties of the solute when introduced to the solvent in order to obtain the final system permeability. The new approaches are applied for several calculation examples, which are found to be qualitatively in agreement with the experimental findings.