Ion exchange resin, also known as ion exchange polymer, is a functional polymer material containing ion exchange groups in the structure of cross-linked polymer microspheres. Ion exchange resin consists of three parts, including cross-linked polymer matrix, functional groups attached to the matrix, and the exchangeable ions of oppositely charged carried by the functional groups. Most resins are based on the typical polymer matrix of polystyrene-divinylbenzene. In addition, there are polyacrylic acid or polymethacrylic acid resins.