Please answer all the above questions correctly providing necessary formulae, equations, expressions, diagrams, charts, graphs, plots and tables.

a) Explain the mechanism of 'Reverse Osmosis' process in light of "Solution-Diffusion" model for membrane transport. b) How the ultra filtration membranes are characterized based on their MWCO? c) A membrane is to be used to separate a gaseous mixture of A and B whose feed flow rate is 1104cm3 (at STP)/s and feed composition of A is 0.5 mole fractions. The desired composition of the reject is 0.25 mole fraction. The membrane thickness is 2.54103cm, the pressure on feed side is 80cmHg and pressure on permeate side is 20cmHg. The permeabilities are: (PM)A=501010cm3(STP)cm/scm2cmHg(PM)B=51010cm3(STP)cm/scm2cmHg Assume complete mixing model, derive the expression for permeate composition \& reject concentration and calculate the values of permeate composition, fraction permeated and membrane area. a) How the 'maximum capacity' and 'molar selectivity coefficient' is determined for an ionexchange resin? b) Design an RO module for production of pure water by rejection of salt in terms of fractional rejection of salts and fractional recovery of water. Design a RO module for 1500m3/ day potable water containing not more than 250ppm salt from sea water containing 34g salt per litre. A proprietary asymmetric cellulose acetate membrane with an inherent salt rejection ability of 98% is to be used. The water permeation coefficient is 0.043m3/m2.day.atm. The recovery of feed water should be 35% and an operating pressure of 70 atm gauge is suggested. The permeate side is at essentially atmospheric condition. If spiral wound modules of 5m2 effective membrane area each is used, how many modules in parallel are required? What fraction of the input power can be recovered from the retentate if a turbine of 70% efficiency is used for energy recovery? The osmotic pressure of 5% brine (linear in salt concentration) is 39.5atm. [2] c) At complete rejection condition, show that concentration polarization modulus, (Cm/Cb)= exp(Jw/k1), where; Cm= solute conc. at membrane Cb= solute conc. in bulk solution Jw= volumetric solvent flux kl= liquid phase mass transfer coefficient 6+(8+7)+4