What ion exchange resins are used to remove heavy metal ions?

Heavy metal ions pose a threat to the environment and human health and therefore need to be effectively removed. Ion exchange technology is one of the commonly used methods to deal with heavy metal pollution, which can usually be removed using ion exchange resins, and the choice of the appropriate resin depends on the specific metal ions to be removed and the water quality conditions.
Common types of metal removal ion exchange resins and their uses:
1. Strong acid type ion exchange resin: Strong acid type ion exchange resin is usually used to remove polyvalent metal ions, such as copper, nickel, chromium, iron, zinc, etc. The sulfuric acid group (SO3H) on these resins can undergo ion exchange reactions with metal ions.
2. Strong alkali ion exchange resin: Strong alkali resin is usually used to remove cadmium, chromium (hexavalent) and other polyvalent metal ions, lead, etc. The hydroxide groups (OH-) on these resins can undergo ion exchange reactions with metal ions.
3. Chelating resin: Chelating resin has special functional groups that form coordination compounds with metal ions, thereby fixing metal ions to the resin. This resin is commonly used to remove specific metal ions, such as mercury, lead, zirconium, etc.
4. Selective resins: There are some ion exchange resins that are specifically designed to remove specific metal ions, such as copper selective resins, lead selective resins, etc. These resins are highly selective and can selectively remove the target metal in the presence of multiple metal ions.
5. Mixed bed resin: Mixed bed resin is a resin mixed with strong acid type and strong alkali type functional groups, which is usually used for the preparation of highly purified water to remove a variety of metal ions and other impurities.
How to choose demetallized ion exchange resin?
According to the research, the ionic radius, charge number and electron configuration of different heavy metal ions are different, so different ion exchange resins need to be used for different heavy metal ions.
For example, iron, cadmium, lead, and nickel plasma with divalent oxidation states can be removed using anion exchange resins. For trivalent chromium, aluminum, iron and antimony plasma, it is necessary to use a strong acid type cation exchange resin to remove. In addition, cadmium and copper chloride plasmas can be removed using a strong base type cation exchange resin, while ammonium chloride and barium chloride plasmas can be removed using a strong acid type cation exchange resin.
Overall, ion exchange resins are an important method for the treatment of heavy metal ions, but it should be noted that the types of ion exchange resins required for different heavy metal ions are different. Only by selecting the appropriate ion exchange resin according to the actual situation, can we ensure the good removal effect of heavy metal ions.