Tutorial Ion Exchange [PDF]

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Tutorial Ion Exchange Separation Process 2 May 2018



1. An ion-exchange column containing 99.3 g of amberlite ionexchange resin was used to remove Cu2+ from a solution where c0 = 0.18 M CuSO4. The tower height = 30.5 cm and the diameter = 2.95 cm. The flow rate was 1.37 cm3 solution/s to the tower. The breakthrough data are shown below: t (s)



420



480



510



540



600



660



720



780



810



870



900



c (g mol Cu/L)



0



0.0033



0.0075



0.0157



0.0527



0.1063



0.1433



0.1634



0.1722



0.1763



0.180



The concentration desired at the break point is c/c0 = 0.010. Determine the break-point time, fraction of total capacity used up to the break point, length of the unused bed, and the saturation loading capacity of the solid.



c/c0



t



2. Use the conditions of Example 12.4-1 for ion exchange of Cu2+ with H+. However, determine the effect of total concentration in the solution on the loading of Cu2+ on the resin. Do this for a total concentration C of 0.010 N in the solution at equilibrium instead of 0.10 N. also, the concentration of Cu2+ in the solution is 0.002 M (0.004 N) instead of 0.02 M.



3. For the case where the cation NH4+ (A) replaces H+ (B) in a polystyrene resin with 8% DVB, calculate the equilibrium constant KA,B. The total resin capacity Q = 2.0 equiv/L wet bed volume. The total concentration C = 0.20 N in the solution. Calculate at equilibrium the equivalents of NH4+ in the resin when the concentration of NH4+ in solution is 0.04 N.



Table 12.4-1 Strong-Base Anion Exchange (Relative to Cl- as 1.0)



ClINO3CH3COOSO42OH-



1.0 8.7 3.8 0.2 0.15 0.05 – 0.07



Strong-Acid Cation Exchanger (Relative to Li+ as 1.0)



Li+ H+ Na+ NH4+ K+ Mg2+ Cu2+ Ca2+



1.0 1.27 1.98 2.55 2.90 3.29 3.85 5.16