Several processes can be used to attract soluble ions from the liquid phase to the solid phase and among these is ion exchange, which is arguably the most widely used in the water treatment industry for this purpose (1-4). Ion exchange (IX) provides a means for transferring one or more ionic species from one liquid phase to another via intermediate solid resins. To achieve this, a group of ion species (the target ions) present in a solution is exchanged with another group of ion species belonging to a solid phase (IX resin or IXR). The target ions, which may be toxic, precious, or contaminants affecting water purity, are therefore concentrated on the resin, while nontoxic, precious or contaminating ions are released from the resin to replace them in the solution. The use of a regenerant on the IXR could, subsequently, release the target ions into solution again (i.e., the regenerant) and allow recovery of the IXR's exchange capacity so that it may be applied again on more of the original solution. [ABSTRACT FROM AUTHOR]
