Ion exchange resins play an important role in the modern sugar industry. Many sugar factories in the world make refined sugar and high-grade edible syrups, and most of them use ion exchange resins to decolor and purify the sugar liquid. In the past, sugar refineries that traditionally used bone charcoal also gradually turned to ion exchange resins.
Ion exchange technology has a long history. Certain natural substances such as zeolite and sulfonated coal made by sulfonation of coal can be used as ion exchangers. However, with the rapid development of modern organic synthesis industrial technology, many kinds of ion exchange resins with excellent performance have been researched and produced, and a variety of new application methods have been developed. Ion exchange technology has developed rapidly, in many industries, especially high-tech industries. And widely used in scientific research. In recent years, hundreds of resin varieties have been produced at home and abroad, with an annual output of hundreds of thousands of tons.
In industrial applications, the advantages of ion exchange resins are mainly large processing capacity, wide decolorization range, high decolorization capacity, can remove various ions, can be reused repeatedly, have long working life, and low operating costs (although the cost of one-time input Larger). A variety of new technologies based on ion exchange resins, such as chromatographic separation, ion exclusion, and electrodialysis, each have unique functions and can perform various special tasks, which are difficult to achieve by other methods. The development and application of ion exchange technology is still developing rapidly.
The application of ion exchange resins has been a key research topic in the sugar industry at home and abroad in recent years, and is an important symbol of the modernization of the sugar industry. The application of membrane separation technology in the sugar industry has also been extensively studied.
ion exchange resins are all made by organic synthesis. Commonly used raw materials are styrene or acrylic acid (ester), which is made by polymerization to generate a skeleton with a three-dimensional network structure, and then introduce different types of chemically active groups (usually acidic or basic groups) into the skeleton. .
Ion exchange resin is insoluble in water and general solvents. Most are made into granules, and some are made into fibers or powder. The size of the resin particles is generally in the range of 0.3 to 1.2 mm, most of which are between 0.4 to 0.6 mm. They have high mechanical strength (fastness), chemical properties are also very stable, and have a long service life under normal conditions.
The ion exchange resin contains one (or several) chemically active groups, which are exchange functional groups, which can dissociate certain cations (such as h or na) or anions (such as oh- or cl-) in aqueous solution. Other cations or anions originally present in the adsorption solution. That is, the ions in the resin and the ions in the solution exchange each other to separate the ions in the solution.
The type of chemically active groups in the resin determines the main properties and types of the resin. Firstly, it can be divided into two categories: cationic resin and anionic resin, which can perform ion exchange with the cation and anion in the solution. Cationic resins are further divided into two types, strong acid and weak acid. Anionic resins are further divided into two types, strong alkaline and weak alkaline (or medium strong acid and medium strong alkaline).
Ion exchange resins are classified into styrene resins and acrylic resins according to the type of matrix, and into gel type and macroporous type according to the physical structure of the resin.
There are many varieties of ion exchange resins, which have different functions and characteristics due to different chemical compositions and structures, and are suitable for different purposes. Appropriate types and varieties of resins should be selected according to process requirements and material properties.