Modelling of protein mixture separation in a batch foam column

Abstract

Separation of proteins from their binary mixtures has been investigated using static foams. It is seen that for the two binary mixtures investigated (BSA–casein, BSA–lysozyme), adsorption is kinetically controlled and does not attain equilibrium. There is a strong interaction between the two proteins and the presence of one strongly influences the adsorption of the other. The concentration of a protein in the foam, depends not only on the amount adsorbed at the interface but also on the liquid associated with it. The latter changes with time due to drainage of foam. A phenomenological model is developed to predict the concentration of protein in foam. The model accounts for the interaction between the adsorption of the two proteins by associating a larger area to one of them because of its special surface morphology. The adsorption kinetics modified for the interaction along with the foam drainage, has been employed to predict the variation of protein concentration in foam as a function of time and other influencing parameters. The model is able to capture the various features of the phenomenon quantitatively.