Building Model for Simulating the Effect of Main Factors on the PVDF Membrane Formation Process

Abstract

Membrane separation technology has been widely studied as an effective means of treating wastewater. The method of mathematical modeling has been widely used in existing studies. In this study, we describe mathematically the conservation of mass, momentum and energy in a simple ternary membrane system, and construct basic control equations to simulate the main influencing factors. The system pressure P and system temperature T during the molding process were simulated in total, as well as the effects of the initial concentration of solvent in the polymer solution, the addition of non-solvent and the initial concentration of polymer on the evolution of the membrane structure. The results show that the concentration difference between the components, as the driving force of diffusion, jointly affects the diffusion ability of the PVDF; the system pressure P and the system temperature T change the rate of phase separation during the membrane formation process, which in turn changes the membrane structure. The influence of the initial concentration of each component on the membrane formation process is in the following order: polymer concentration > non-solvent concentration > solvent concentration, and the initial concentration of the polymer dominates the membrane formation process and its final morphology.