Surfactant-Aided Extraction of Volatile Organic Acids from Aqueous Solution

The phase equilibrium data for ternary systems containing volatile organic acids (i.e. acetic, propionic, and butyric acids), water and a surfactant (Novel 23-Ethoxylate 2 (N23-E2)) were established at 35°C. The phase equlibrium data were obtained to evaluate the possibility of using the N23-E2 as solvent for the extraction of volatile organic acids from aqueous solutions. The data were fitted to local composition activity coefficient models (i.e. NRTL and UNIQUAC) to identify the more suitable model for establishing the phase diagrams of the ternary systems considered. Results showed that the extractability of volatile organic acids from aqueous solution using N23-E2 increases with the number of carbon in the acid, indicating that this surfactant could be used to selectively extract butyric acid from an aqueous solution containing both acetic and and butyric acids.