Types of cation exchange resins 阳离子交换树脂种类性能

   Ion exchange resins play an important role in the modern sugar industry. Many sugar factories in the world manufacture refined sugar and high-grade edible syrup, and most of them use ion exchange resins to decolorize and purify sugar liquids. In the past, the traditional sugar refineries that used bone charcoal also gradually turned to ion exchange resins.

Ion exchange technology has a long history, and some natural substances such as zeolite and sulfonated coal obtained 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 made, and a variety of new application methods have been developed. 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, removal of various ions, repeated regeneration, long working life, and low operating costs (although one-time investment costs larger). A variety of new technologies based on ion exchange resins, such as chromatographic separation, ion exclusion, electrodialysis, etc., each have unique functions and can perform various special tasks that are difficult to achieve by other methods. The development and application of ion exchange technology is still developing rapidly.

The application of ion exchange resin is a key research topic in the sugar industry at home and abroad in recent years, and it is an important symbol of the modernization of the sugar industry. The application of membrane separation technology in the sugar industry has also been widely studied.

Ion exchange resins are made by organic synthesis methods. The commonly used raw materials are styrene or acrylic acid (ester), which is produced by polymerization to generate a skeleton with a three-dimensional spatial network structure, and then introduce different types of chemically active groups (usually acidic or basic groups) into the skeleton. .

Ion exchange resins are insoluble in water and general solvents. Most are in granular form, and some are in fibrous or powdered form. The size of the resin particles is generally in the range of 0.3 to 1.2 mm, and most of them are between 0.4 and 0.6 mm. They have high mechanical strength (fastness), are chemically 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 some cations (such as h or na) or anions (such as oh- or cl-) in aqueous solution, and at the same time Adsorb other cations or anions originally present in the solution. That is, the ions in the resin are exchanged with the ions in the solution, thereby separating the ions in the solution.

The type of chemically active groups in the resin determines the main properties and types of the resin. First of all, it is divided into two categories: cation resin and anion resin, which can be ion-exchanged with cation and anion in solution, respectively. Cationic resins are divided into strong acid and weak acid, and anion resins are divided into strong base and weak base (or divided into medium-strong acid and medium-strong base).

Ion exchange resins are classified into styrene resins and acrylic resins according to the type of their substrates, and 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 properties due to different chemical compositions and structures, and are suitable for different purposes. Appropriate types and varieties of application resins should be selected according to process requirements and material properties.