Metal recovery, separation and/or pre-concentration

Abstract

Metals are essential for the existence of life. Due to their chemical, physical, electrical and mechanical properties, they found a large number of applications, their use being intrinsically associated with the development of society. Besides their natural occurrence in the ecosystem, the application of metallic compounds in several industrial and agricultural sectors gives an inevitable rise to their release and dispersion into the environment. Accordingly, metallic ions must be separated from water and industrial water or effluents prior to final discharge whenever toxic or radioactive, or recovered in the case of valuable and precious species. In this chapter, the ion exchange of metallic ions solutions with the aim to recover, separate or pre-concentrate them is reviewed and discussed. After a general introduction on the topic, the discussion is divided into several sections according to the nature of the ionic species: precious, radioactive, priority pollutants and other metals. The main parameters of the sorption process are generally analysed, such as the influence of pH, temperature and initial concentration on the equilibrium and kinetic performance, as well as sorbent regeneration details and modelling.