Study on Solvent Extraction of Citric Acid from Fermentation Broth

Abstract

Extraction of citric acid from aqueous solutions with tertiary amine, dissolved in mixtures of kerosene and phase modifier have been studied as a function of exaction yield at different phase modifier volume fraction, temperatures, stirring speed and exaction time. The optimal experimental conditions of extraction were obtained: reaction temperature 303K, reaction time 3 min, the kerosene volume fraction 20%, and 45% 1−octanol as phase modifier, stirring speed 450rpm/min. Under these conditions, the extraction yield could reach 75%. The complex of citric acid and tertiary amine was a surfactant that makes surface tension decrease. The composition of the citric acid complex is (R3N) · (H3A). The formation of complex was exothermic reaction that the standard enthalpy change and standard entropy change are obtained: ΔHθ=-10.17kJ/mol, ΔSθ=-11.86J/(mol·K).