How to Choose Chelating Resin?

About Chelating Resin

What Is Fine Mesh Resin?

Most chelating resins are polymers (more precisely copolymers) with reactive functional groups that chelate metal ions. Variation in chelating resins results from the nature of the chelating agent attached to the polymer backbone. The functional groups connected to the chelating resin include amino phosphonic acid, thiourea, 2-pyridinemethylamine, etc. There are many types of chelating resins, such as carboxylic acid type, thiol type, Schiff base type, and thiourea type. [1]

Chelating resins are commonly used for the preconcentration of metal ions in dilute solutions, as well as in the chlor-alkali industry for desalination of brine, boron removal in drinking water, and recovery of precious metals from solutions.

How Does Chelating Resin Adsorb Heavy Metals?

Chelating resin is different from other ion exchange resins. It contains O N, S, P, As, Se and other atoms that have not formed bonded lone pairs of electrons. They can coordinate with metal ions in water. This reaction and the functional groups are used to react with metal ions in water to form water-insoluble chelates. When it reaches a certain volume, the chelate is insoluble in water and precipitates under the action of gravity, thus achieving the removal effect.

What Are the Characteristics of Chelating Resin?

The difference between chelated ion exchangers and ordinary types of ion exchangers lies in three main characteristics:

  • High selectivity

The affinity of a particular metal ion for a certain chelated ion exchanger depends primarily on the chelating group and not on the size of the ion, its charge, or other physical properties that determine priority in the case of common ion exchangers.

  • Bond strength

In ordinary ion exchangers, the binding is electrostatic with a strength of 2-3 kcal/mole, while in the resin treated here, the binding energy is of the order 15-25 kcal/mole.

  • Kinetics

While in the ordinary type of exchanger the exchange process is faster and controlled only by diffusion, which is itself a function of the mobility and concentration gradient of the entering and leaving ions, the exchange process in the chelating exchanger is much slower and controlled by particle diffusion mechanisms or secondary chemical reactions.

Chelating Resin Selection Guide

Depending on different application requirements or characteristics such as functional groups, you can find the most suitable chelating resin from the table below. The adsorption selectivity and adsorption capacity are two important indicators for evaluating the performance of chelating resin. Among them, the adsorption capacity depends on the specific surface area of the adsorption material and the density of surface functional groups, which is a key factor affecting water treatment efficiency.

Chelating Resin Selection List

Catalog SelectivityFunctional GroupMass CapacityApplicationPrice
ACMA00033698Alkaline earth metalAminophosphonic>1.7meq/mlRemove the hardness in saturated brine
Removal of divalent metals such as copper and nickel from wastewater and various process streams
ACMA00033699AntimonyHybridRemoval of trace amounts of antimony
Removal of silica in process water
ACMA00033701ArsenicHybridRemoval of arsenic from drinking water
Removal of uranium and other trace pollutants
ACMA00033703ArsenicSecondary Amine≥0.9meq/mlRemoval of arsenicINQUIRY
ACMA00033707BoronMethylglucamine≥5meq/mlRemoval of boronINQUIRY
ACMA00033708BoronMethylglucamineRemoval of boron from drinking water, ultrapure water and concentrated brineINQUIRY
ACMA00033710BoronMethylglucamine≥0.9meq/mlAdsorption of BoronINQUIRY
ACMA00033711BoronN-methylglucamine group≥ 2.7meq/mlBoron removalINQUIRY
ACMA00033714Brine purificationTertiary AmineSecondary brine refining in the ion-exchange membrane caustic soda industry
Tungsten and Molybdenum Separation
ACMA00033715Brine purificationSecondary amino groupSecondary brine refining in the ion-exchange membrane caustic soda industry
Heavy metal industrial wastewater treatment
ACMA00033697ChromiumMixed amines>2.1meq/mlAll chromate removalINQUIRY
ACMA00033718Divalent transition metalsTrimethylamine> 1.5meq/mlRemoval of uranium
Removal of chromate and arsenate
ACMA00033719Divalent transition metalsBis-Picolylamine≥35meq/mlCobalt/Nickel Separation in nickel plant
Purification of Trivalent Chromium Plating Bath.
ACMA00033720Divalent transition metalsIminodiacetic>1.4meq/mlRemove heavy metalsINQUIRY
ACMA00033727GoldFerrous oxide≥0.6meq/mlPure water preparation
Adsorption of gold cyanide complex anions
ACMA00033731MercuryThiouronium>1.5meq/mlMercury removal
Removal/recycling of various precious metals
ACMA00033732MercuryThiolMercury removal
Removal/recycling of various precious metals
ACMA00033734MercuryThioureido≥0.8meq/mlRemoval of various forms of mercury in wastewaterINQUIRY
ACMA00033735MercuryThiol≥200meq/mlRemove mercury
Recover precious metals from industrial wastewater
ACMA00033736MercurySulfhydryl≥3.8meq/mlVarious mercury removalINQUIRY
ACMA00033739Polyvalent metal ionIminodiacetic Acid≥0.8meq/mlAdsorption of polyvalent metal ions
Separation and purification of various metals
ACMA00033740Polyvalent metal ionAminophosphonic≥0.9meq/mlAdsorption of polyvalent metal ions
Separation and purification of various metals
ACMA00033742Polyvalent metal ionThioureidoSeparation and purification of precious metal ionsINQUIRY
ACMA00033744Polyvalent metal ionImine diacetoxyl≥2.0meq/mlSeparation and purification of high-valent metal ions and transition elementsINQUIRY
ACMA00033748Polyvalent metal ionAzylphosphonateSeparation and purification of high-valent metal ions and transition elementsINQUIRY
ACMA00033749RadiumHybridRemoval of radium in drinking waterINQUIRY
ACMA00033750RadiumSulfonic Acid> 1.8meq/mlRadium removalINQUIRY
ACMA00033751UraniumPicolylamine>0.8 meq/mlMetal surface treatment
Highly acidic three-color electroplating bath

What Are the Precautions for Using Chelating Resin?

  • Chelating resin is easily oxidized, so direct treatment with brine solutions containing free chlorine should be avoided. Some measures should be taken, such as preliminary reaction with sulfur dioxide, sulfite or pretreatment with activated carbon. The chlorate concentration of the brine solution is usually very high, so the displacement rinse before regeneration must be effective to prevent the chlorate in the brine solution from contacting the regeneration acid to form free chlorine.
  • Wasted chelating resin cannot be discarded directly because chelating resin cannot leach complexed heavy metal ions through organic matter, which will cause secondary pollution to the environment.


  1. Chu S, et al. Industrial & Engineering Chemistry Research, 2022, 61(31), 11309-11328.
  2. Schmuckler G. Talanta, 1965, 12(3), 281-290.

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