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 controlled by the kinetics. Phenomena affecting the rate of extraction are 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 upon their interfacial behaviour and the rate of extraction in classical and non classical extraction systems is considered. Appropriate kinetic models for interfacial and bulk volume reactions are presented. They suggest that the true mechanism of classical and non classical solvent extraction may include both of these pathways. Although important differences exist between classical extraction systems and micellar systems 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 structural effects of chelates upon the kinetics of metal extraction.