Novel Membranes and Membrane Materials

Abstract

In this chapter, the state-of-the-art membrane materials used for forward osmosis (FO) and pressure-retarded osmosis (PRO) processes are presented. Conventional polymeric membranes, such as cellulose triacetate and thin-film composite membranes, are briefly introduced. Some of the major drawbacks for these conventional polymeric membranes include internal concentration polarization (ICP), low water flux, high reverse solute flux, and strong fouling tendency. At the same time, many novel membrane materials and structures have emerged in the recent membrane literature. Some notable examples include mixed matrix and nanocomposite structure for enhancing membrane permeability and reducing ICP and the use of aquaporins and carbon-based materials (e.g., carbon nanotubes and graphene oxides) to improve membrane separation properties. These techniques provide promising new dimensions for designing next generation FO/PRO membranes.