Calculate osmotic pressure from solute concentration and temperature.
Osmotic pressure is surprisingly large: physiological saline at 0.15 M generates about 7.6 atm, equivalent to a 78-metre column of water. That is why cells rupture in pure water. Reverse osmosis must apply pressure exceeding the osmotic pressure of the feed, which is why desalinating seawater needs 50 to 80 bar.
Osmotic Pressure
Π = i M R T, the van’t Hoff equation for osmotic pressure
Π = i M R T, the van’t Hoff equation for osmotic pressure Osmotic pressure is surprisingly large: physiological saline at 0.15 M generates about 7.6 atm, equivalent to a 78-metre column of water. That is why cells rupture in pure water.
Reverse osmosis must apply pressure exceeding the osmotic pressure of the feed, which is why desalinating seawater needs 50 to 80 bar.
This calculator takes 3 inputs: Molar concentration, Van’t Hoff factor, Temperature. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.