Influence of continuous aqueous phase on the preparation and stability of colloidal liquid aphrons

Abstract

Colloidal Liquid Aphrons (CLAs) were prepared from various solvents such as nonpolar hydrocarbons, alcohols, and amines. The influence of surfactant type and concentration on CLA preparation were studied and maximum phase volume ratio (PVR: volume ratio of the dispersed solvent phase to the water phase) was also investigated. The CLA preparation from nonpolar hydrocarbons or alcohols was possible with a high PVR regardless of surfactant type. However, stable CLA preparation was possible using cationic or nonionic water-soluble surfactant in case of a basic solvent. Since solvent recovery is as important as selection of solvent in CLA-based process design, the stability of CLAs in a given dispersion was quantified from released solvent volume when CLAs broke up. The effect of surfactant types, concentrations, and solvent types were investigated under various continuous phase conditions. Equation of pseudo-first-order-reaction kinetics was found well to fit the data only when the CLA was made from kerosene or ionic strength of continuous phase was very low.