Forward Osmosis- Membracon, UK

Forward osmosis (FO) is an osmotic membrane process that uses the natural driving force of osmotic pressure to separate water from a solution. FO uses a semipermeable membrane to separate two solutions with different concentrations: a feed solution and a draw solution. The draw solution has a higher concentration of solutes than the feed solution, which creates an osmotic pressure gradient. The water in the feed solution moves across the membrane to the draw solution, driven by the osmotic pressure difference.

How does Forward Osmosis work?

As water is drawn from the feed solution into the draw solution across the semi-permeable membrane, two things occur; the feed becomes concentrated, and the draw solution becomes diluted. The result of this is a reduction in the osmotic gradient between solutions and in turn a reduction in the flow rate across the semi-permeable membrane known as flux rate. For forward osmosis to operate continuously, water drawn across the membrane into the draw solution must be removed continuously so that a maximum draw concentration can be maintained and a maximum concentration gradient achieved.