Conventional purification and isolation

Adsorption, chromatography-based techniques, nanofiltration (NF), and electrodialysis (ED) are con- solidated operations that could be applied in the fourth stage of the Universal Recovery Process (Chap- ter 3). Since engineering aspects of such conventional techniques are well known, they could be applied with a large range of raw materials, depending on the chemical/physical compositions of such matri- ces. Recovery yields generally depend on the concentration of target molecules and on their relative amounts with respect to those compounds having similar features (size, charge, chemical structure, etc.). The latter compounds compete with the former ones within the recovery processes. This chapter is dedicated to briefly describing the main features of the above-mentioned technologies and proposes practical suggestions for the development of processes aimed at the selective recovery of chemicals from wastes. Furthermore, a number of case studies and recent works are presented.