Tutorial: Reverse Osmosis Membrane Technologies for Purifying Water

Today’s membranes for reverse osmosis are primarily thin film composite constructions or porous asymmetric films that are rolled into modules for incorporation into water purification plants. The composite membranes are comprised of non-porous thin surface layers coated onto porous mechanical polymeric supports that are all mounted on a fabric backing. They efficiently transport water under pressure and reject salts and other contaminants. Unfortunately, cleaning and durability are challenging because the polyamide separating layers are not chemically stable against the strong oxidants that are required for such operations. The discussion will include the polymers that have been used in the development of such membranes, and challenges and opportunities for advancing the field.