DISTRIBUTION EQUILIBRIUM OF CITRIC-ACID BETWEEN AQUEOUS-SOLUTIONS ANDTRI-N-OCTYLAMINE-IMPREGNATED MACROPOROUS RESINS

In this paper, experiments were conducted on equilibrium distribution of citric acid between aqueous solutions and tri-n-octylamine (TOA)-im pregnated resins in the 288-318 K temperature range. Analysis of the r esults showed that the sorption of citric acid could be explained by t he formation of acid-TOA complexes in the resin phase with the general composition (H3A)p(TOA)qBAR. Mole fraction of the complexes formed in the resin phase as a function of citric acid concentration in the aqu eous solution was obtained. The effect of temperature on equilibrium d istribution was also studied, and the apparent thermodynamic data for sorption reactions were determined. Finally, the distribution of citri c acid between aqueous solutions and the resins impregnating with a mi xture of TOA and bis(2-ethylhexyl)phosphoric acid was examined.