ABSTRACT
Recent developments in separation techniques are a response to the growing demands imposed by extraction processes that cannot be carried out economically using conventional technologies. Typical examples are the treatment of wastewaters containing low concentrations of pollutants, such as heavy metals, and the downstream separation of biological products. In the case of wastewaters, environmental regulations impose discharge concentrations of the order of a few parts per million, or even per billion, for certain pollutants. Therefore, treatment using conventional solvent extraction would require large volumes of solvent and several extraction stages to achieve the target concentrations, even in systems with large metal distribution coefficients (see Chapter 4).
