A liquid-process feed stream F contains 99 mol-% of species 1 and 1 mol-% of impurity, species 2. The impurity level is to be reduced to 0.1 mol-% by contacting the feed stream with a stream S of pure liquid solvent, species 3, in a mixer/settler. Species 1 and 3 are essentially immiscible. Owing to "good chemistry," it is expected that species 2 will selectively concentrate in the solvent phase.
(a) With the equations given below, determins the required solvent-to-feed ratio nS/nF
(b) What is mole fraction X2 of impurity in the solvent phase leaving the mixer/settler?
(c) What is "good" about the chemistry here? With respect to liquid-phase non-idealities, what would be "bad" chemistry for the proposed operation?
Given: GE12/RT = 1.5 x1x2
GE23/RT = - 0.8x2x3