Ion exchange resins are used to demineralize water and to separate mixtures of ions. One important characteristic of ion exchange resin is its capacity, expressed in terms of milliequivalents of exchangeable ion per gram of resin.
Technically, resin capacity is a measurement of total capacity, as determined by a test performed in the lab by a titration methodology. A measured quantity of cation resin, for example, is fully converted to the hydrogen (H) form with an excess of strong acidand then well rinsed. A measured quantity of caustic (NaOH) is then passed through the resin so as to totally exhaust the resin. The effluent is captured. The NaOH that passed through the column represents the sodium (Na) ions that were not captured by the resin. This solution is then titrated with acid to neutralize it and the amount of acid required is expressed in equivalents. The difference between the total equivalents of NaOH passed through the column and the NaOH exiting the column represents the total equivalents of Na captured by the resin. The capacity of the resinis then determined. Similarly, anion resin would be fully regenerated with NaOH and exhausted with acid to make the capacity measurement.
Different resins intended for different needs will have different definitions for capacity. The total capacity for a resin is a representation of the total number of exchange sites built into the resin. In the real world, you will never achieve the total capacity because it represents a 100-percent regenerated resin being run to complete exhaustion.
Our product Lanlang ® TC012FG is food grade high cross linkage gel type strong acid cation exchange resin used for softening potable water and water for foods and beverages. We also get it certified by WQA. It's total exchange capacity is higer or equals to 2.2eq/L. If you would like to find a high capacity dark water softening resin, welcome to contact us!