ABSTRACT
Among the unit processes utilized for recovering valuable products from waste, removing trace toxic metals, recycling of water, and other elements in pollution control, the ion exchange process is one of the most versatile. Due to the polluting aspects of some ion-exchange processes, their use may be limited in areas where water sources are limited or brackish. A variety of processes have been developed to reduce the quantity of regenerant or eluting solution with the aim of attaining stoichiometry for the reaction. Two industrial processes are operating in which water is used as an eluant involving ions to transform an ionic complex to a normal salt. The industrial processes are: removal of iron in concentrated HC1 and zinc recovery from pickle liquor. The anion exchanger is treated with water for recovering the zinc as zinc chloride. An ion exchanger can be considered to be concentrated ionic solution with fixed charge on the matrix of the polymer and a free counter-ion.
