1. The meaning of chelating resin
Chelate Synthetic resinUsually refers to a cross-linked polymer as the backbone with special functional groups, and can form bonds with metal ions through ionic bonds or coordination bonds Physical functional resin. In most cases, it is a cyclic compound formed by more than two functional groups and metal ions. This functional resin usually has a hydrophobic skeleton and hydrophilic functional groups. Through the formation of electrostatic field, steric hindrance, synergy of functional groups, dilution or concentration and other polymer effects, a certain metal ion can be highly selectively complexed and adsorbed from a solution containing a variety of metal ions. The resin is insoluble and non-explosive, and can be recycled and used for enrichment, separation, analysis, recovery, etc. of metal ions.
Due to the separation properties of polymer chelating agents, they are widely used in hydrometallurgy, inorganic chemicals, analytical chemistry, and radiochemistry. Applications in , marine chemistry, and environmental chemistry have been rapidly developed, such as treating industrial sewage and extracting certain metals from the ocean to make up for resource shortages.
2. Classification of polymer chelating agents
(1) Classification by polymer chelating agentsource span>
This classification method can be roughly divided into natural polymer chelating agents and synthetic polymer chelating agents. The latter is obtained by synthetic methods according to people’s intentions, with large quantities and many varieties. There are also many natural polymer chelating agents in nature. Because there are many organic natural polymers in plants, animals, human bodies and other living organisms, such as cellulose, protein, peptides, alginic acid, chitin, etc. These natural polymers have various functional groups containing oxygen, nitrogen, sulfur, phosphorus, etc., such as hydroxyl, carboxyl, amine, amide, phosphate, etc. They can easily form coordination bonds with metal ions and generate natural Polymer metal chelates. For example, heme complexed with iron atoms is the basic substance for the blood to transport oxygen in the human body; the blood of shrimp, which also has the function of transporting oxygen, is blue because its heme is complexed with copper atoms. It is an example of natural polymer chelating agents with similar structures complexing different metal atoms.
(2) Classification according to the structure of polymer chelating agents
can be divided into two major categories: one type has the chelating group on the main chain, and the other type has the chelating group on the side chain.
(3) According to the classification of ligand atoms or groups of polymer chelating agents, they can be divided into categories as shown in Table 3 and 6 of several categories.
As can be seen from Table 3-6, the coordinating atoms are mainly O , P, N, S, As, Se, etc., and the more common ones are O, N, S and other coordination atoms in organic groups, and the functional groups are nothing more than alcohols composed of O, N, S, Ether, aldehyde, ketone, acid, ester group or amine, imine, hydroxylamine, oxygen-containing acid, etc. In many cases, instead of using one coordination atom or group, two or more coordination atoms may be used. Atoms and ligands are one of the reasons why there are so many types of polymer chelating agents. As long as the number and distribution of functional groups in the polymer structure are controlled, and the relationship between the structure and function of high molecules is continuously studied, polymer chelating agents for various purposes can be obtained.
