Reverse osmosis is most commonly known for its use in drinking
water purification from
seawater, removing the
salt and other substances from the water molecules. This is the reverse of the normal
osmosis process, in which the solvent naturally moves from an area of low solute concentration, through a membrane, to an area of high solute concentration. The movement of a pure solvent to equalize solute concentrations on each side of a membrane generates a pressure and this is the "osmotic pressure." Applying an external pressure to reverse the natural flow of pure solvent, thus, is reverse osmosis.
