Products Overview

An ion exchange resin is usually a polystyrene polymer that can exchange ions of opposite character from an aqueous medium. The beads are porous and has large surface areas with a large number of ionic sites which can be used to trap ions whilst exchanging them for other ions. Most of the resins are crosslinked with divinyl benzene which increases the strength of the beads but decreases the ion exchange capacity. Particle size also influence the exchange capacity as smaller beads have a higher surface area but this increases the overall head loss.

The resin itself is composed of organic polymers that form a network of hydrocarbons. Throughout the polymer matrix are ion exchange sites, where so-called “functional groups” of either positively-charged ions (cations) or negatively-charged ions (anions) are affixed to the polymer network. These functional groups readily attract ions of an opposing charge.

Ion exchange resin

 

The structure of the resin divides ion exchange resins into two major types- Gel resins with a pore size of approx. 1 angstrom and macroporous with pore size of 100-1000 angstroms. Gel resins are prepared with the bulk of the organic phase containing the monomers and catalysts whilst macroporous resins are made with either a solvent or a solid which are removed upon complete polymerization creating discrete holes inside the resin beads. Gel resins are generally used for water softening and demineralization whilst macroporous ones are used where strong regenerant is needed e.g. 22% nitric acid for ammonium nitrate recovery and for non-aqueous applications.

Purolite® is the leader in making small diameter beads of up to 35 microns.

Four main types of ion-exchange resins differ in their functional groups:
  • Strongly acidic, typically featuring sulfonic acid groups, e.g. sodium polystyrene sulfonate.
  • Strongly basic, typically featuring quaternary amino groups, for example, trimethylammonium groups.
  • Weakly acidic, typically featuring carboxylic acid groups.
  • Weakly basic, typically featuring primary, secondary, and/or tertiary amino groups, e.g. polyethylene amine

Categories of Purolite

  • Strong Acid Cation Ion Exchange Resins

    Strong acid cation resins are usually polystyrene based resins with sulfonic acid groups (-SO3H) as the functional group. Strong acid cation resins are available in two forms: the hydrogen form – RSO3H or sodium form RSO3Na.

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  • Weak Acid Cation Ion Exchange Resins
    These are usually acrylic base resins with a carboxylic group (-COOH) as the functional group.
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  • Strong Base Anion Ion Exchange Resins
    Anionic resins work during production cycle with the tertiary amine adsorbing the strong acid to free the electron pair of the amine...
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  • Weak Base Anion Ion Exchange Resins

    Purolite® manufactures two types of weak base anion ion exchange resins:

      • Weak base anion gel
      • Weak base anion macroporous...
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  • Adsorbent Resins
    Adsorbents are used to purify industrial products and concentrate the target molecules of interest. Purolite® products are available in a broad range of matrices and porosities, and our portfolio of adsorbent resins presents solutions for many industrial applications such as food and pharmaceutical processing, flavor and fragrance extraction and environmental applications...
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  • Chelating Resins
    Chelation is the bonding of ions and molecules to metal ions by the formation of two or more coordinate bonds between a multiple bonded ligand and a central atom...
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