EXTRACTION KINETICS,SYNERGISTIC EFFECTS AND INTERFACIAL CHEMISTRY FOR D_2 EHPA MPA-Fe~(3+) MIXED EXTRACTION SYSTEM

The thermodynamics of micella formation,interfacial characteristics,synergistic effectsand interfacial kinetics for synergistic extraction system D_2 EHPA-MPA-Fe~(3+) have beenstudied.It was found that D_2EHPA in the mixed system strongly exhibits the effect onthe micella formation thermodynamics and interracial characteristics of MPA.Some ther-modynamic parameters for constants of micelles formation(K_m).free energies of micellesformation(ΔG_m)and critical micella concentrations(CMC)were obtained.The inter-facial adsorption behaviour of D_2EHPA is opposite to that of MPA.The emulsificationfor single MPA and the mixed system was discussed.The synergistic effects were foundin this mixed extraction system.It is proved that the process of the Fe~(3+) extractionfor non-mixed extraction system is controlled by chemical reaction and the controllingreaction occurs at the interface.