Froth-frothate concentration relations in foam fractionation

Concentration relations between foams and their residual liquids (frothates) have been examined. Clean air streams of 88, 91, and 96% water saturation were bubbled into aqueous solutions of isobutyl alcohol. The concentration of the alcohol in the collected and collapsed foam was plotted against its concentration in the bulk liquid. Varying the saturation of the air stream resulted in both positive and negative enrichment of the foam with the surface‐active alcohol. This suggests that where froth‐frothate‐concentration relations are unfavorable, a change in operating conditions may advantageously affect these relations and allow the mixture to be foam separated.