2. A thin rectangular channel of length 5 m and equivalent diameter of 2 mm is used for the treatment of brackish water containing 16 kg/m of salt in a RO plant. The operating pressure is at 4000 kPa. A commercial grade RO membrane of permeability 1.8 x 10-12 mPa.s is used. Velocity of the solution through the channel is 1 m/s and the real retention of the membrane is 0.975. Assuming film theory to be valid, find the permeate flux and considering that the osmotic pressure of salt is II(Pa)= 85400C. Salt diffusivity is 1.7 x 10 m/s. (10 marks) m