Question

M4. Water Softening Using Ion Exchange Method It is desired to remove Ca ions from water using ion exchange technique. For this purpose, water, initially containing 700 mg Ca2+/L, is passed through a column filled with sulphonated styrene-based cation exchange resin. The breakthrough curve of this ion exchange process is given in Figure 1. 141 a) Show the breakthrough point and also the point, where the exchange capacity of the resin is exhausted, on the same graph. [3] b) How can you calculate breakthrough ion exchange capacity of the resin? Show it on the graph. [3] c) How can you calculate total ion exchange capacity of the resin? Show it on the graph. [10] d) Which parameters change the position of the breakthrough point and how? Give at least four examples. 700 600 500 Ca2Concentration in Effluent, (ppm) 400 300 200 100 0 250 500 750 1000 1250 1500 1750 2000 2250 2500 2750 3000 Volume of Effluent, [ml] Figure 1. Breakthrough curve

Answer 1

E 10 Exhausion point CDBO area groglifo n corporeanos no Breakthrough V capacity CD ABO & Total capacity O 1500 m2 Breakthrough capacity yo ③ Breakpoint Effluent volume v7 (1) In the given graph break through point (1500, 100) lie volume of effluenta cat conanlatan in effluent = lnopom estawhere exchange capacity of resin is each enbarted is (2250, 675 ppm) Cice valunce cart conventealien = 2250 R m2 of effluent in efflicent (6) The brak through ion exchange recapacity 675 ppm) is this care will be = area under the auta EDB o in the graph point (700ppm Ca2+, Oml efflent) point P ( 1500, 700) C! → point B (1500, 100) poent o Co.o)