Ion exchange resin
Ion exchange resins are used to remove dissolved particles from liquids. Therefore, functional groups are bonded to the polymer beads.
These functionalized polymers adsorb particular anions or cations from the liquid and discharge others.
Water treatment is the best-known and biggest field of application for ion exchange resins.
In household, such applications are used among others to soften water.
An ion-exchange resin or ion-exchange polymer is an insoluble matrix (or support structure) normally in the form of small (0.5-1 mm diameter) beads, usually white or yellowish, fabricated from an organic polymer substrate.
Types of resins
ion-exchange resins are based on crosslinked polystyrene.
The actual ion exchanging sites are introduced after polymerisation. Additionally, in the case of polystyrene, crosslinking is introduced via copolymerisation of styrene and a few percent of divinylbenzene .
Types of ion exchange resins
Strongly acidic, typically featuring sulfonic acid groups.
Strongly basic, typically featuring quaternary amino groups.
Weakly acidic, typically featuring carboxylic acid groups.
Weakly basic, typically featuring primary, secondary, and/or tertiary amino groups.
Cation Exchange Resin
Formula: R-H
Reaction :
2(R)-H + CaCl2 = Ca(R2) + 2HCl
Anion Exchange Resin:
Formula : N(R)4-OH
Reaction
N(R)4-OH + HCl = N(R)4Cl + H2O
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