Ion exchange is an important part of adsorption along with seperation. In the process of ion exchange a solution or mixture is run over a bed or column of ion exchange resin (IER) beads. At the electically charged sites, ions from solution may attach. In the article "ION Exchange: A sphere of action" from the Chemical Engineerung journal it is pointed out that the size variation of the IER beads has a large effect on productivity.

The uniformity of the IER beads has a profound effect on the ion exchange capacity. The ability to exchange ions effectively is increased by 10-20% by using beads with less size and deviation. Furthermore, this reduction of size variation yields 10% less head loss. But, these advantages are not free of the 10-20% increase is effectiveness which corresponds to a 10-20% higher price.

Given this increase in uniformity, comes along an increase is selectivity. This increase is selectivity opens doors for new appliction. In particular, a biochemical engineer would be interested in its ability to seperate various antibiotics from fermentation broths. The use of IER gives higher yields and purities than solvent extraction or activated-carbon systems. IERs also have appliction in water purification. These resins have the ability to remove high selectivity heavy metals, nitrates and other trace metals from water. Furthermore, IERs will have an greater effect on food processing. An example given in the article is the concentration of a sugar mixture to attain high-fructose corn syrup. An IER chromographic column can retain fructose with greater selectivity giving a more efficient and effective process than current processes.

It is apparent that ion exchangers have growing applictions. The ability to efficiently produce high purity products cost effectively tells industry that other methods of seperation such as distillation, solvent extractation and crystallization things that need reconsideration.

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