Ion exchange process

Ion exchange process

• 1.
  ION EXCHANGE PROCESS orDemineralization or Deionzation • Hardness causing ions are exchanged with ions of resins • Water obtained- free from minerals and hardness causing ions (Known as deionized or demineralized water) ION-EXCHANGE RESINS • Cross linked, high mol weight organic polymers • functional groups attached to the polymeric chains are responsible for ion-exchange properties • Natural Resins comes from plants Ion exchange resin beads 1
• 2.
  TYPES OF IONEXCHANGE RESINS Cation exchange resin Anion exchange resin • Cation exchange resin • Anion exchange resin −CH=CH2 2 Styrene divinyl benzene copolymers
• 3.
  • Cation exchangeresin Styrene divinyl benzene copolymers, Have acidic functional groups like –COOH or -SO3H which can exchange the cations of hard water (Ca2+, Mg2+) by their H+ ions Styrene divinyl benzene copolymers on sulphonation become capable of exchanging their H+ ions with the cations of solution 2 RH + Ca2+ → R2Ca + 2H+ Resin Hard Water 2 RH + Mg2+ → R2Mg + 2H+ Resin Hard WateR 3
• 4.
  • Anion exchangeresin Styrene divinyl benzene copolymers having basic functional groups like –NH2 or –NH4 + These resins after treatment with NaOH become capable of exchanging their OH- ions with the anions of water Cl- , SO4 2- R’OH + Cl- → R' Cl + OH- Resin Hard Water 2 R’OH + SO4 2- → R2'SO4 + 2OH- Resin Hard Water 4
• 5.
  PROCESS Ca2+, Mg2+ Cl-, SO4 2- 5 H- + OH- → H2O
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• 7.
  7 The exhausted cationexchange resin can be regenerated by passing a solution of dil HCl and H2SO4. The exhausted anion exchange resin can be regenerated by passing a solution of dil NaOH