SEPARATION OF CITRIC AND LACTIC ACIDS IN AQUEOUS-SOLUTIONS BY SOLVENT-EXTRACTION AND LIQUID MEMBRANE PROCESSES

The use of solvent extraction (SX) and supported liquid membrane (SLM) for the separation of citric and lactic acids in aqueous solutions we re studied. Experiments were carried out as a function of the total ac id concentration, the concentration ratio of the acids, and the concen tration of extractant tri-n-octylamine (TOA). In SLM systems, the effe cts of temperature and strip-phase composition were also examined. It was shown that the equilibrium distribution of SX of each acid was gre atly affected in the presence of the other. In addition, the competiti ve transport of the acids in SLM was explained from the kinetics of SX . Separation factors based on SX distribution and SLM transport were d efined and used to optimize conditions for effective separation.