Prediction of Equilibria and Mass Transfer Rates in Continuous Foam Fractionation of Phosphate

Abstract

An experimental investigation of the effect of the operating variables on the removal of phosphate in continuous foam fractionation using ethylhexadecyl dimethylammonium bromide as surfactant was performed. The removal of phosphate is described in terms of surface concentration of phosphage, and the operating variables are bubble residence time, concentration of phosphate, and pH of the bulk solution. Experimental equilibrium residence times agree well with those calculated from the Poisson equation of surface potential. The preferential adsorption ratio of divalent to monovalent phosphate is derived from the Gibbs equation, and is found to be six, based on a statistical correlation using the Langmuir adsorption isotherm.