Separation Mechanism and Membrane Properties

This chapter explores the fundamental separation mechanisms and key membrane properties that govern performance in water treatment and purification processes. Typical mechanisms include size exclusion, charge repulsion, and adsorption-diffusion. In size exclusion, or sieving, separation is based on pore size, allowing only smaller solutes to pass through, ideal for removing particles and macromolecules. Charge-based separation utilizes electrostatic interactions between the membrane surface and charged solutes, effectively rejecting ions and enhancing selectivity. Adsorption-diffusion involves the interaction and transport of molecules through the membrane matrix, influenced by chemical affinity and solubility. These mechanisms are directly linked to the membrane's physical and chemical attributes, such as pore size, surface charge, hydrophilicity, and functional groups. Innovations in membrane materials and design are improving efficiency in desalination and wastewater treatment, offering sustainable solutions to global water scarcity. A thorough understanding of these mechanisms is essential for optimizing membrane systems and advancing their environmental and industrial applications.