Small Size, Big Energy" - Ion Exchange Resin

Ion exchange and adsorption resins are widely used in chemical, metallurgy, water treatment, biomedicine, food, electronics and other fields because of their high adsorption efficiency, stable performance, long service life and high cost performance. According to research surveys, the global ion exchange and adsorption resin market has been expanding thanks to the growth in demand from end-use industries. Globally, the Asia-Pacific region is the largest ion exchange and adsorption resin market, accounting for about 40% of the global market. In the Asia-Pacific region, China is the most important player. Next, let us briefly understand the basic classification of ion exchange resins!

  

Strong acid cation resin: This type of resin contains a large number of strong acid groups, such as sulfonic acid group -SO3H, which is easy to dissociate H+ in solution, so it is strongly acidic. After the resin dissociates, the negatively charged groups contained in the body, such as SO3-, can adsorb and bind other cations in the solution. These two reactions exchange H+ in the resin with cations in the solution. Strong acid resins have strong dissociation ability, and can dissociate and produce ion exchange in acidic or alkaline solutions. After the resin has been used for a period of time, it needs to be regenerated, that is, the ion exchange reaction is carried out in the opposite direction with chemicals, so that the functional groups of the resin can be restored to the original state for reuse. The above-mentioned cation resin is regenerated with strong acid. At this time, the resin releases the adsorbed cations, and then combines with H+ to restore the original composition.

Weak acid cation resin: This type of resin contains weak acid groups, such as carboxyl-COOH, which can dissociate H+ in water and become acidic. The remaining negatively charged groups after resin dissociation, such as R-COO- (R is a hydrocarbon group), can be adsorbed and combined with other cations in the solution, resulting in cation exchange. The acidity or dissociation of this resin is weak, and it is difficult to dissociate and perform ion exchange at low PH, and can only work in alkaline, neutral or slightly acidic solutions (such as PH 5-14). These resins are also regenerated with acid (easier to regenerate than strongly acidic resins).

Strong basic anion resin: This type of resin contains strong basic groups, such as quaternary amine group (also known as quaternary amine group)-NR3OH (R is a hydrocarbon group), which can dissociate OH- in water to form a strong base sex. The positively charged groups of this resin can adsorb and combine with anions in the solution, resulting in anion exchange. This resin is highly dissociative and works well at various PHs. It is regenerated with a strong base such as NaOH.

Weakly basic anion resins: These resins contain weakly basic groups, such as primary amine groups (also known as primary amine groups)-NH2, secondary amine groups (secondary amine groups)-NHR, or tertiary amine groups (tertiary amine groups) Amino group)-NR2, they can dissociate OH- in water and are weakly basic. The positively charged groups of this resin can adsorb and combine with anions in the solution, resulting in anion exchange. This resin in most cases adsorbs whole other acid molecules in solution.