KINETICS AND INTERFACIAL PHENOMENA IN CLASSICAL AND MICELLAR EXTRACTION SYSTEMS

Kinetic and interfacial phenomena in classical extraction systems and in micellar media are discussed. The work is limited to the process co ntrolled by the kinetics. Phenomena affecting the rate of extraction a re examined and appropriate examples of acceleration or inhibition of metal extraction with hydrophobic chelating extractants are given. The effects of surfactants on the rate of extraction and complexation in micellar media are reviewed. The effect of extractant hydrophobicity u pon their interfacial behaviour and the rate of extraction in classica l and non classical extraction systems is considered. Appropriate kine tic models for interfacial and bulk volume reactions are presented. Th ey suggest that the true mechanism of classical and non classical solv ent extraction may include both of these pathways. Although important differences exist between classical extraction systems and micellar sy stems their kinetic behaviour indicates serious similarities. It seems that further studies of the micellar systems with the use of a broad range of extractants may deliver useful information to predict the str uctural effects of chelates upon the kinetics of metal extraction.