Demineralisation process

Water Technology-Hardness removing-Softening process

1. 1
DEMINERALISATION PROCESS
Presented By
Dr.M.Kumaresan,
Professor and Head,
Department of Chemistry,
Erode Sengunthar Engineering College (Autonomous),
Thudupathi, Erode,
Tamilnadu, India
Email: [email protected]
Dr.M.Kumaresan
Professor and Head,
Department of Chemistry,
Erode Sengunthar Engineering
College, Erode, Tamilnadu,
India
WATER
CHEMISTRY
19BS103
ENGINEERING
CHEMISTRY

2. 2
Dr.M.Kumaresan
Professor and Head,
Department of Chemistry,
Erode Sengunthar Engineering
College, Erode, Tamilnadu,
India
WATER
CHEMISTRY
19BS103
ENGINEERING
CHEMISTRY
Ionexchangeordemineralisation
processremovesalmostalltheions
(bothanionsandcations)presentin
thehardwater.

3. 3
Dr.M.Kumaresan
Professor and Head,
Department of Chemistry,
Erode Sengunthar Engineering
College, Erode, Tamilnadu,
India
WATER
CHEMISTRY
19BS103
ENGINEERING
CHEMISTRY
Thisprocessiscarriedoutby
usingionexchangeresins,whichare
longchain,crosslinked,insoluble
organicpolymerswithamicro
processstructure.
Thefunctionalgroupsattachedto
thechainsareresponsiblefortheion
exchangingproperties.

4. 4
Dr.M.Kumaresan
Professor and Head,
Department of Chemistry,
Erode Sengunthar Engineering
College, Erode, Tamilnadu,
India
WATER
CHEMISTRY
19BS103
ENGINEERING
CHEMISTRY
Cation exchanger
Resinscontainingacidicfunctionalgroups
(–COOH,–SO3H)arecapableofexchanging
theirH+ionswithothercationsofhardwater.
Cation exchange resin is represented as RH2.
Examples:
Sulphonatedcoals
Sulphonatedpolystyrene
R–SO3H; R–COOH ≡ RH2

5. 5
Dr.M.Kumaresan
Professor and Head,
Department of Chemistry,
Erode Sengunthar Engineering
College, Erode, Tamilnadu,
India
WATER
CHEMISTRY
19BS103
ENGINEERING
CHEMISTRY
Anion Exchanger
Resinscontainingbasicfunctionalgroups
(–NH2,–OH)arecapableofexchangingtheir
anionswithotheranionsofhardwater.
Anion exchange resin is represented as R (OH)
2.
Examples:
Urea-formaldehyde resin.
R–NH
2≡ R (OH)
2

6. 6
Dr.M.Kumaresan
Professor and Head,
Department of Chemistry,
Erode Sengunthar Engineering
College, Erode, Tamilnadu,
India
WATER
CHEMISTRY
19BS103
ENGINEERING
CHEMISTRY
Ion-Exchange Process

7. 7
Dr.M.Kumaresan
Professor and Head,
Department of Chemistry,
Erode Sengunthar Engineering
College, Erode, Tamilnadu,
India
WATER
CHEMISTRY
19BS103
ENGINEERING
CHEMISTRY
PROCESS : CATION EXCHANGER
Thehardwaterfirstpassedthrougha
cationexchangewhichabsorbsallthe
cationslikeCa
2+
,Mg
2+
Na
+,
K
+
,etc.
presentinthehardwater.
RH
2+ CaCl
2→ RCa + 2HCl
RH
2 + MgSO
4→ RMg + H
2SO
4

8. 8
Dr.M.Kumaresan
Professor and Head,
Department of Chemistry,
Erode Sengunthar Engineering
College, Erode, Tamilnadu,
India
WATER
CHEMISTRY
19BS103
ENGINEERING
CHEMISTRY
PROCESS:ANION EXCHANGER
Thecationfreewateristhenpassed
throughaanionexchangecolumn,
whichabsorbsalltheanionslikeCl
–
,
SO
4
2-
,HCO
3
–
,etc.,presentinthewater.
R' (OH)
2+ 2HCl→ R'Cl
2+ 2H
2O
R'(OH)
2+ H
2SO
4→ R'SO
4+ 2H
2O

9. 9
Dr.M.Kumaresan
Professor and Head,
Department of Chemistry,
Erode Sengunthar Engineering
College, Erode, Tamilnadu,
India
WATER
CHEMISTRY
19BS103
ENGINEERING
CHEMISTRY
Demineralisedwater
Thewatercomingoutoftheanion
exchangercompletelyfreefromcations
andanions.
Thiswaterisknownasdemineralised
waterordeionisedwater.

10. 10
Dr.M.Kumaresan
Professor and Head,
Department of Chemistry,
Erode Sengunthar Engineering
College, Erode, Tamilnadu,
India
WATER
CHEMISTRY
19BS103
ENGINEERING
CHEMISTRY
Regeneration: Cation exchanger
Whenthecationexchangeresinisexhausted,
itcanberegeneratedbypassingasolutionof
dil.HClordil.H
2SO
4.
RCa + 2HCl → RH
2+ CaCl
2

11. 11
Dr.M.Kumaresan
Professor and Head,
Department of Chemistry,
Erode Sengunthar Engineering
College, Erode, Tamilnadu,
India
WATER
CHEMISTRY
19BS103
ENGINEERING
CHEMISTRY
Regeneration: Anion exchanger
Whentheanionexchangeresinisexhausted,it
canberegeneratedbypassingasolutionof
dil.NaOH.
R'Cl
2+ 2 NaOH → R'(OH)
2+ 2 NaCl

12. 12
Dr.M.Kumaresan
Professor and Head,
Department of Chemistry,
Erode Sengunthar Engineering
College, Erode, Tamilnadu,
India
WATER
CHEMISTRY
19BS103
ENGINEERING
CHEMISTRY
ADVANTAGES
The water is obtained by this process will
have very low hardness.
Highly acidic or alkaline water can be
treated by this process.

13. 13
Dr.M.Kumaresan
Professor and Head,
Department of Chemistry,
Erode Sengunthar Engineering
College, Erode, Tamilnadu,
India
WATER
CHEMISTRY
19BS103
ENGINEERING
CHEMISTRY
DISADVANTAGES
The equipment is costly.
More explosive chemicals are needed for
this process

14. 14
Dr.M.Kumaresan
Professor and Head,
Department of Chemistry,
Erode Sengunthar Engineering
College, Erode, Tamilnadu,
India
WATER
CHEMISTRY
19BS103
ENGINEERING
CHEMISTRY
THANK YOU