Application areas of ion exchange resins, introduction to ion exchange resins

1) Water treatment.

Ion exchange resins are in high demand in the water treatment field, accounting for about 90% of the production of ion exchange resins, which are used for the removal of various anions and cations in water. At present, the largest consumption of ion exchange resins is used in the pure water treatment of thermal power plants, followed by atomic energy, semiconductors, electronics industry, etc.

2) Food industry.

Ion exchange resins can be used in industrial equipment such as sugar production, monosodium glutamate, wine refining, and biological products. For example, the manufacture of high fructose syrup is made by extracting starch from corn, and then hydrolysis reaction to produce glucose and fructose, and then through ion exchange treatment, high fructose syrup can be generated.

Ion exchange resins are second only to water treatment in the food industry.

3) Pharmaceutical industry.

Ion exchange resins in the pharmaceutical industry play an important role in the development of a new generation of antimicrobials and the quality improvement of the original antimicrobials. The successful development of streptomycin is a striking example. In recent years, there has also been research on the commission of traditional Chinese medicine.

4) Synthetic chemistry and petrochemical industry.

In organic synthesis, acids and alkalis are commonly used as catalysts for esterification, hydrolysis, transesterification, hydration and other reactions. Ion exchange resins can be used instead of inorganic acids and alkalis to carry out the above reactions, and there are many advantages. For example, the resin can be used repeatedly, the product is easy to separate, the reactor will not be corroded, the environment will not be polluted, and the reaction is easy to control.

The preparation of methyl tert-butyl ether (MTBE) is made by using macroporous ion exchange resin as a catalyst, which is made by reacting isobutylene with methanol to replace the original tetraethyl lead, which can cause serious pollution to the environment.

5) Environmental protection.

Ion exchange resins have been used in many environmental protection issues of great concern. At present, many aqueous or non-aqueous solutions contain toxic or non-ionic substances, which can be used with resins. Such as the removal of metal ions in the electroplating waste liquid, the useful substances in the film production waste liquid, etc.

6) Hydrometallurgy and others.

Ion exchange resins can separate, enrich, purify uranium and extract rare earth elements from depleted uranium ore.

1 Pinyin 2 Definition.

3 History of discovery.

4 Classification of ion exchange resins.

5 Uses of ion exchange resins.

lí zǐ jiāo huàn shù zhī

Ion exchange resins are a class of polymers with ionizable groups on their structure.

The phenomenon of ion exchange was discovered by Thompson as early as the mid-18th century. It was not until 1935 that Aclams and Holmes researched and synthesized polymer materials with ion exchange function, that is, the first batch of ion exchange resins, polyphenolic strong acid cation exchange resins and polyaniline weak anion exchange resins. The great development of ion exchange resins was mainly after the Second World War.

At that time, some companies in the United States and the United Kingdom successfully synthesized polystyrene-based cation exchange resins, and on this basis, other polystyrene-based ionic resins with high exchange capacity and good physical and chemical stability were successively developed, and polyacrylic acid-based cationic resins were developed one after another.

Ion exchange resins are a class of polymer materials with ion exchange functions. In solution, it can exchange its own ions with the same number of ions in the solution. According to the different properties of exchange groups, ion exchange resins can be divided into two categories: cation exchange resins and anion exchange resins.

Most cation exchange resins contain acidic groups such as sulfonic acid groups (—SO3H), carboxyl groups (—COOH) or phenol groups (—C6H4OH), in which hydrogen ions can be exchanged with metal ions or other cations in solution. For example, the polymer of styrene and divinylbenzene is sulfonated to obtain a strong acid cation exchange resin, and its structural formula can be simply expressed as R—SO3H, where R represents the resin matrix, and its exchange principle is.

2r—so3h＋ca2＋ （r—so3）2ca＋2h

This is also the principle of hard water softening.

Anion-exchange resins contain pristine groups such as quaternary amine groups [N(CH3)3OH], amine groups (—NH2), or imino groups (—NR H). They can generate OH ions in water, which can be exchanged with various anions, and its exchange principle is as follows.

r—n（ch3）3oh＋cl r—n（ch3）3cl＋oh

Since the ion exchange effect is reversible, the used ion exchange resin is generally washed with an appropriate concentration of inorganic acid or pyridine, which can be restored to the original state and reused, a process called regeneration. The cation exchange resin can be washed with dilute hydrochloric acid, dilute sulfuric acid and other solutions; Anion-exchange resins can be treated with solutions such as sodium hydroxide for regeneration.

The principle of ion exchange resin is the process by which the ion exchange tree separates the salts from the solution

In the aqueous solution in the ion exchange resin environment, the metal cations (Na+, Ca2+, K+, Mg2+, Fe3+, etc.) contained in the ion exchange resin are exchanged with H+ on the cation exchange resin (containing sulfonic acid groups (—SO3H), carboxyl groups (—COOH) or phenol groups (—C6H4OH) and other acidic groups, which are easy to generate H+ ions in water), so that the cations in the solution are transferred to the resin, and the H+ on the resin is exchanged into water. (i.e., the cation exchange resin principle).

The anions (Cl-, HCO3-, etc.) in the aqueous solution are exchanged with the OH- on the anion exchange resin (containing basic groups such as quaternary amine group [-N(CH3)3OH], amine group (-NH2) or imino group (-NH2), which is easy to generate OH- ions in water), and the anions in the water are transferred to the resin, and the OH- on the resin is exchanged into the water, (that is, the principle of anion exchange resin). H+ is combined with OH- to produce water, which achieves the purpose of desalination.

Ion exchange resin is a water treatment product that has been very popular in recent years. Its core technology is mainly to replace the anion and cation ions in the water quality through anion and cation exchange resins, which are mainly used in the preparation of ultrapure water and high-purity water, and are widely used in the food industry, pharmaceutical industry and other water treatment industries.

Ion exchange resins are non-toxic. However, it is flammable in case of open flame and high heat, so ion exchange resin should be stored in a cool, ventilated warehouse, and away from fire and heat sources, and the storage temperature should not exceed 30. If the ion exchange resin needs to be regenerated after failure, the regenerant is generally hydrochloric acid and sodium hydroxide, if the regenerator is of good quality, rinse thoroughly after regeneration, the effluent is harmless, but if the regenerant contains substances harmful to the human body, and the rinsing is not thorough, it will be harmful to the human body.

What are ion exchange resins?

Ion exchange is a reversible chemical reaction in which dissolved ions are removed from a solution and replaced with other ions of the same or similar charge. Ion exchange resins themselves are not chemical reactants, but physical mediums that facilitate ion exchange reactions. The resin itself is made up of organic polymers that form a network of hydrocarbons.

The entire polymer matrix is an ion exchange site in which so-called "functional groups" of positively charged ions (cations) or negatively charged ions (anions) are immobilized on the polymer network. These functional groups tend to attract oppositely charged ions.

Ion exchange resin matrices are formed by cross-linking hydrocarbon chains with each other in a process called polymerization. Cross-linking gives the resin polymer a stronger, more resilient structure and greater capacity (by volume). While the chemical composition of most IX resins is polystyrene, some types are manufactured from acrylic acid (acrylonitrile or methyl acrylate).

The resin polymer then undergoes one or more chemical treatments to bind the functional groups to ion exchange sites located throughout the matrix. These functional groups give ion exchange resins their ability to separate, and can vary greatly from one resin to the next. The most common ingredients include:

1.Strong acid cation exchange resins

Consists of a polystyrene matrix and a sulfonate (SO3-) functional group with sodium ions (Na2+) for softening applications, or hydrogen ions (H+) for demineralization.

2.Weak acid cation exchange resin

The resin consists of an acrylic polymer that has been hydrolyzed with sulfuric acid or caustic soda to produce carboxylic acid functional groups. Due to their high affinity for hydrogen ions (H+), weak acid cation exchange resins are often used to selectively remove cations related to alkalinity.

3.Strong alkali anion exchange resin

It typically consists of a polystyrene matrix that has undergone chloromethylation and amination to immobilize anions to the exchange site. Type 1 strong alkali anion exchange resins are produced by the application of trimethylamine, which produces chloride ions (Cl-), while type 2 strong alkali anion exchange resins are produced by the application of dimethylethanolamine, which produces hydroxide ions (OH-).

4.Weak base anion exchange resin

It typically consists of a polystyrene matrix that has been chloromethylated and then dimethylaminated. Weak base anion exchange resin

The uniqueness is that they do not possess exchangeable ions and are therefore used as acid absorbers to remove anions associated with strong inorganic acids.

5.Chelating resin

Chelating resins are the most common type of specialty resin used to selectively remove certain metals and other substances. In most cases, the resin matrix consists of polystyrene, although a variety of substances are used for functional groups, including mercaptans, triethylammonium, and aminophosphine, among others.

What are ion exchange resins? 1.Ion exchange resin is a solid polymer compound with a network three-dimensional structure that is insoluble in acids, alkalis and organic solvents.

The unit structure of an ion exchange resin consists of two parts. One part is a network skeleton that is immovable and has a three-dimensional structure, and the other part is a movable active ion.

2.Ion exchange resin is a kind of polymer material with ion exchange function, which can exchange its own ions with the same number of ions in the solution in the solution. If the resin releases active cations, it can exchange with the cations in the solution, called cation exchange resinIf it releases active anions, it can exchange anions in the solution, called anion exchange resin.

What is the principle of ion exchange resins? In the ion exchange process, cations in water (such as Na+, Cat, KT, Mg2+, Fe3+, etc.) are exchanged with H+ on the cation exchange resin, and the cations in the water are transferred to the resin, and the H+ on the resin is exchanged into the water. Anions in water (e.g., C1-, HCO, etc.) are exchanged with O on the anion exchange resin, the anions in the water are transferred to the resin, and the OH- on the resin is exchanged into the water.

H+ is combined with 0H- to produce water, which is used for filtration.

Potassium and chloride ions are electrically similar and can promote the movement between ions.