How To Choose Ion Exchange Resin

The general principle of selecting ion exchange resins is to select resins with large exchange capacity, easy recycling, and durability.

To be specific:
(1) Exchange capacity is an important indicator of the performance of ion exchange resin, the greater the ease of mutual exchange, the more ions can be adsorbed by the same volume of resin, and the greater the amount of water produced in a mutual exchange cycle. Generally, the exchange capacity of weak acid or weak basic resin is larger than that of strong acid or strong basic resin. In addition, in the same type of resin, due to the different crosslinking degree of resin, the exchange capacity is also different. Generally, the exchange capacity of resin with low crosslinking degree is large. The exchange capacity of resin with high crosslinking degree is small. Therefore, pay attention to the selection of resin.
(2) The resin should be selected according to the nature of the ions that need to be removed in the raw water. If you only need to remove the ions that are weakly adsorbent in the water, you must choose a strong acid or a strong basic resin.
(3) To choose the resin according to the effluent water quality requirements. If only a partial desalting system is needed, strong acidic positive resin and weak alkaline negative resin can be used together. For pure water or high purity water systems that must be completely desalted, it is necessary to select strong acidic cation exchange resins with strong adsorption and basic anionic exchange resins to use each other to remove ions that are difficult to adsorb.
(4) To choose the resin according to the composition of impurities in the raw water. If there is more organic matter in the raw water, or when the radius of ion removal is large, a resin with a larger cross-linking hole diameter should be selected. Choose high strength porous resins whenever possible.
(5) The resins used for mixing beds are more the combination of strong acid-strong alkaline resins. However, it is necessary to consider that the layering of mixed bed resin is easy to be reused, so the difference between the wet true density of the two resins should be larger, usually not less than 15% to 20%. In addition, it is also necessary to consider that the mutual exchange flow rate is relatively large when the mixing bed is running, and the resin wear is more serious, so the resin with wear resistance should be selected.
(6) The resin should be selected according to the requirements of the brine process. For example, the double chamber bed, the use of strong and weak resins with each other, because the weak resin is easy to be recycled, the quality requirements of the regenerant are also relatively low, you can use the regeneration liquid after the regeneration of the strong resin to regenerate the weak resin, so that the consumption of the regenerant is low, and the cost of water production is low.