Ion exchange resin and application of the principle

Ion exchange resin is a polymer with appropriate functional groups. In general, conventional sodium ion exchange resin with a large number of sodium ions. When the water content of high calcium and magnesium ions, ion exchange resins can release sodium ions, functional groups and the combination of calcium and magnesium, calcium and magnesium ions so the water content decreased, the hardness of the water drop. Hard water into soft water on, this is the working process of softening equipment.
When the resin on a large number of functional groups combined with calcium and magnesium ions, reduced capacity softening resin can flow through the resin with a sodium chloride solution, then the solution of the sodium ion content, functional groups will release calcium and magnesium with the sodium ion binding, so the exchange capacity of resin was restored, the process called "regeneration."
As the actual work, soft water equipment, standard operating procedures include: work (sometimes called production water, the same below), anti-washing, absorption of salt (renewable) and the slow rinse (replacement), fast wash five processes. All the processes of different softening equipment is very close, only because the actual process or control the needs of different, there may be some additional process. Any sodium ion exchange softening equipment based on the five processes are developed based on the past (including, automatic soft water equipment will increase the salt water re-injection procedure).

Backwash: work after a period of time the equipment will be in the upper resin block dirt brought a lot of raw water, after the removal of these contaminants, ion exchange resins to be fully exposed out of the effect of regeneration can be guaranteed. Anti-wash process is the bottom of the wash water from the resin into, out from the top, so you can block off the top of the dirt washed away. This process usually takes 5-15 minutes.

Absorption of salt (renewable): Coming into the resin tank in the process of salt, the traditional devices are injected with salt brine pump, automatic equipment is built by private jet to saline inhalation (as long as the water pressure can be certain ). In practice the process, salt water flows through a slower regeneration of the resin is better than simply the effect of resin with a brine well, so slow softening equipment are based on the brine flow through the regeneration of the resin method, a process that normally takes 30 minutes, actual time is good enough for the impact of salt.

Slow rinse (replacement): After the resin in the salt water off with the raw water to flow slowly to the same resin in the salt water to clean all the washing process is called slow, due to the washing process is still a large number of functional groups on the calcium and magnesium ions are sodium ion exchange, based on actual experience, this process is the main process of regeneration, so many people this process is called replacement. This process is generally the same as with the absorption of salt, which is 30 minutes.

Fast Rinse: In order to thoroughly rinse the salt residues to working close with the actual flow rate, with the raw water to wash the resin, the process should be the final effluent compliance of soft water. In general, faster process for 5-15 minutes, rinse.
Application
1) Water Treatment
Water treatment ion exchange resins in great demand, accounting for ion exchange resins yield of 90%, for the various ions in water removal. Currently, the maximum consumption of ion exchange resin is used in the power plant's water treatment, followed by atomic energy, semiconductors, electronics industries.

2) Food Industry
Ion exchange resins can be used for sugar, MSG, refined wine, biological products and other industrial devices. For example: the manufacture of high fructose syrup extracted from corn starch, and then by hydrolysis to produce glucose and fructose, and then by ion exchange treatment, can produce high fructose syrup. Ion exchange resins in the food industry is second only to water consumption.

3) pharmaceutical industry
Ion exchange resin pharmaceutical industry a new generation of antibiotics and the development of antibiotics on the original play an important role in improving the quality. Successful development of streptomycin is an obvious example. In recent years, so there is still medicine study commission.

4) Synthetic chemical and petrochemical industry
Commonly used in organic synthesis as catalyst for acid and alkaline esterification, hydrolysis, transesterification, hydration reaction. Ion exchange resin instead of inorganic acid, alkali, can be the same reaction, and the advantages more. Such as the resin can be used repeatedly, the product easy to separate the reactor will not be corrosion, no pollution, easy to control response.
Methyl tert-butyl ether (MTBE) in the preparation, is to use ion exchange resins macroporous catalyst made by the reaction of isobutylene and methanol, instead of the original may cause serious pollution to the environment of tetraethyl lead.

5) Environmental Protection
Ion exchange resin has been applied very popular in many environmental issues of concern. Currently, many non-aqueous solution containing the toxic ions or ionic substances, which can be recycled resin. Such as the removal of metal ions in electroplating waste, recycling waste in film production and other useful substances.

6) and other hydrometallurgical
Ion exchange resin can be separated from the depleted uranium mines, enrichment, purification, extraction of uranium and rare earth elements and precious metals.