Simulation of osmotic and reactive effects in membranes with resolved microstructure

Mathematical modeling and computer simulation are useful approaches, supporting membrane researchers and manufacturers in their work on designing better membranes and on selecting appropriate membranes for a particular application. In this work we examine two processes where the membrane morphology plays a crucial role, the first being osmosis (both forward and reverse), and the second micro/ultra/nano-filtration. We first discuss the mathematical modeling and simulation of solute transport through membranes used for forward and reverse osmosis. 3D simulations on virtual membranes generated using the software tool GeoDict based on SEM images, with two separate membrane morphology types, both finger-like and sponge-like membranes, are performed. By resolving the microstructure of the support layer, we investigate the influence of the support layer structure on the separation process. Numerical simulation also allows us to test the theoretical membrane performance under various operating conditions, such as varying flow rate and particulate concentration. Another process where the morphology of the membrane is highly influential is the micro/ultra/nano-filtration. The functionalization of these membranes is a recent approach enabling efficient removal of impurities, such as bacteria and viruses, using a lower pressure. This is achieved by using membranes with larger pores than in reverse osmosis, while the functionalization of the pore walls results in the increased adsorption of the selected contaminants. Computer simulation is performed at the pore-scale o n resolved membrane microstructures with absorptive walls and results are presented. Such numerical modeling will aid manufactures in designing efficient membranes requiring lower flow rates, thus reducing the operational energy requirements.