Popular separation technique:

Solvent extraction is a popular separation technique because of its convenience, speed and a favourable economics. This versatile technique can be safely extended from micro levels to macro concentrations. Some of the important theoretical and practical aspects of the technique have been presented in Units 2 and 3. In Unit 2, the law governing the partitioning of chemical species, its limitations and the different terms used to explain distribution have been discussed. The focus of discussion was on the extraction of metal ions. A classification of different types of extractants used for metal ions has also been described. The characteristics, advantages and the problems faced in the use of different categories of extractants have been highlighted.

The role of diluents and modifiers in solvent extraction system mainly depends upon the composition of the aqueous and organic phases. Finally, the characteristics of diluents and modifiers have been explained.