pressureretarded
Pressure retarded osmosis (PRO) is a membrane-based process that uses a high-salinity draw solution separated from a low-salinity feed water by a semipermeable membrane. Water moves across the membrane from the feed to the draw solution due to osmotic pressure. An external hydraulic pressure is applied to the draw solution to oppose this flow, thereby retarding it. The resulting diluted draw solution can then be processed to recover fresh water, and energy can be harvested by expanding the draw solution through a turbine or energy-recovery devices as the draw solution is reconcentrated.
The operation relies on the osmotic pressure gradient between the two solutions. By applying pressure on the
Materials and design considerations include selecting membranes with low tendency for fouling and concentration polarization, and
Status and outlook: PRO has been studied since the mid-20th century, with renewed interest in the 2000s