Reverse osmosis systems are most commonly known for their use in drinking water purification from water, 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”. Reverse osmosis applies an external pressure to reverse the natural flow of pure solvent.
Industrial Reverse Osmosis System Schematic Diagram