Using a pressure difference of $55{10}^{5}Pa,$ the flux of seawater through a reverse osmosis membrane

at $25C$ was measured as $10{10}^{-3}k\frac{g}{m^2}.sec.$ The area of the membrane is $2{10}^{-3}{m}^2.$ The osmotic

pressure of seawater at $25C$ is $20{10}^5$ Pascal. The density of sea water can be approximated with the

density of pure water which is $1000k\frac{g}{m^3}.$ Calculate the minimum amount of energy required for

separating the salt from water.