Characteristics And Differences Between Gel Type And Macroporous Type Of Ion Exchange Resin Structure

There are basically two types of water treatment resins: ion exchange resin and chelating resin. The resin structure of ion exchange resin is usually divided into two types: macroporous type and gel type. The two different structural types also have some differences in adsorption and performance. The following is a detailed introduction to the characteristics and differences between the gel type and macroporous type of ion exchange resin.

Ionic resins are often divided into two types: gel type and macroporous type:
The polymer skeleton of gel-type resin has no pores inside when dry. It swells when it absorbs water, forming very fine pores between macromolecule links, often called micropores. The average pore diameter of wet resin is 2~4nm (2×10-6~4×10-6mm).
This type of resin is more suitable for adsorbing inorganic ions, and their diameter is small, generally 0.3~0.6nm. This type of resin cannot adsorb macromolecular organic substances because the latter are larger in size. For example, protein molecules have a diameter of 5 to 20 nm and cannot enter the microscopic pores of this type of resin.

Macroporous resin is made by adding a porogen during the polymerization reaction to form a porous sponge-like structure with a large number of permanent micropores inside, and then introducing exchange groups. It has both micropores and macro-pores, and the pore diameter of the wetted resin is 100 to 500nm. Its size and number can be controlled during manufacturing. The surface area of the channels can be increased to over 1000m2/g. Blue film water treatment and finishing not only provides good contact conditions for ion exchange, shortens the ion diffusion distance, but also adds many chain link active centers, which generates molecular adsorption through van der Waals force between molecules, and can act like activated carbon. In this way, it can absorb various non-ionic substances and expand its function. Some macroporous resins without exchange functional groups can also adsorb and separate a variety of substances, such as phenols in chemical plant wastewater.

The internal pores of macroporous resin are many and large, the surface area is large, there are many active centers, the ion diffusion speed is fast, and the ion exchange speed is also much faster, about ten times faster than gel-type resin. It is fast and efficient when used, and the required processing time is shortened. Macroporous resin also has many advantages: resistance to swelling, not easy to break, resistance to oxidation, wear resistance, heat resistance and temperature change resistance, and easier adsorption and exchange of organic macromolecules, so it has strong resistance to pollution and is relatively Easy to regenerate.