1. SCSVMV University
B.Muthukumaran
M.Phil
Unit-I Advanced Applied Chemistry

2. Technology Of Water
Water:
• Existance on Earth
1. Solid state-ice,
2. Gaseous state (water vapor or steam)
3. Liquid
• Water is not only universal solvent but also an essential material
for engineering applications.
• Prime factor in development
• Water on Earth moves continually through a cycle of evaporation

3. Sources of Water
• The source of water are listed under two categories
1. Surface Water
2. Underground Water
A. Surface Waters:
1. Rain Water
2. River Water
3. Lake Water
4. Sea water
B. Underground Water:
1. Spring
2. Well water

4. Types of Impurities
1. Dissolved Impurities:
a) Inorganic salts e.g
sulphates and chlorides of calcium, Magnesium, Iron
b) gases like carbon dioxide, nitrogen , oxygen, hydrogen
sulphides
c) organic salts
2. Suspended Impurities:
a) Clay
b) mud
c) Vegetable and animal matters

5. 3. Colloidal Impurities:
a) fine size like silica and alumina, organic wastes etc.
- These are soluble materials, other than gases
- cannot be removed by conventional filters
- referred as TDS which stands for total dissolved solids.
4. Bacterial Impurities:
a) Bacteria, Germs, Pathogens, Microbes, Viruses, Parasites
- include
- algae, beneficial bacteria that decompose wastes
- harmful bacteria such as those that cause cholera.

6. Effects of Impurities:
a) colour of surface water- dissolved organic matters
b) Taste and Odour- formation of compounds
c) Turbidity- suspended Impurities
d) Pathogenicity- micro organisms
Hardness of Water
• Characteristics of water which prevent the Lather Formation.
• due to presence of:- salts like bicarbonates, sulphates,
chlorides of mg and other metals
Units of Hardness:
1) ppm 2) mg/l 3) ̊Cl 4) ̊Fr
• Relation - 1ppm = 1mg/l = 0.07 ̊Cl = 0.1 ̊Fr

7. Hardness Table
Water Classification Hardness, mg/L
Soft 0 to 49
Medium Hard 50 to 149
Hard 150 to 249
Very Hard 250 to 299
Extremely Hard 300 and up
mg/L = milligrams/Liter

8. Types of Hardness
1) Temporary:- 0r Carbonate Hardness
Water that contains bicarbonate of calcium and
magnesium or of both
• removed by boiling
Ca(HCO3)2 → CaCO3 ↓ + CO2 ↑+ H2O
Mg(HCO3)2 → Mg (OH)2 ↓ + 2CO2 ↑
2) Permanent :- or Non- Carbonate Hardness
Contains chlorides or sulphates of calcium or
magnesium or of both
• Can not be removed by boiling
CaCl2 → Ca+2
+ 2Cl-1
MgSO4 → Mg+2
+ SO4
-2

9. Disadvantages of Hard Water
(A) Domestic Uses:
1. Washing 2. Bathing 3. Drinking 4. Cooking
C17 H35 COO Na + H2O→ C17 H35 COOH + NaOH
C17 H35 COOH + C17 H35 COO Na → Lather
C17 H35 COO Na + CaSO4 → (C17 H35 COO)2 Ca ↓ + Na2SO2
(in water) (White Scum)
(B) Industrial Uses:
1. Boiler Feed: should not contain nitrates- scale and sludges
2. Paper Mill: should not contain iron and lime- color and quality will
be changed
3. Sugar industries: Sulphates and Alkaline carbonates- affects the
crystallization ,Deliquescent
4. Dyeing Industries: should not contain iron and hardness
5. Laundries: should be soft

10. Estimation Of Hardness
1. EDTA Method 2. O.Herner’s Method
1. EDTA Method:
Ethylene Diamine Tetra Acetic Acid
-OOOCH2 CH2COO-
NCH2.CH2N
-OOOCH2 CH2COO-
• Estimation is by titration method at pH 10
• Using Indicator Eriochrome Black-T
Method:
1. Take 50 ml water in coinical flask
2. Add buffer and few drops of EBT-T
3. Titrate against EDTA
4. Red colour change to steel blue/violet

11. O.Herner’s Method (0r) Alkali Titration Method
• Bicarbonates of Ca and Mg makes water alkaline and can react with
HCl
Ca(HCO3)2 + 2HCl → CaCl2 + 2CO2 ↑+ 2H2O
Mg(HCO3)2 + 2HCl → MgCl2 + 2CO2 ↑+ 2H2O
• Ca(HCO3)2 and Mg(HCO3)2 decomposes into insoluble carbonates on
boiling the water.
For Temporary Hardness:
1) 50ml sample water in conical flask
2) 2-3 drops of methyl orange indicator
3) Titrated against N/50 HCl
4) Change colour from yellow to orange
5) Take 100 ml of same sample of water
6) Boil until 1/5th
volume
7) Make them again 100 ml Distilled water
8) Take 50ml and perform again the above steps

12. For Permanent Hardness
• Caused by Chlorides and Sulphates of Calcium and Magnesium
• Can be determined by using Na2CO3 and HCl.
CaCl2+Na2CO3→CaCO3 ↓+ 2NaCl
CaSO4+Na2CO3→CaCO3 ↓+ 2NaSO4
Method:
1. 50 ml hard water + 50 ml Na2CO3 solution
2. Boiled and Evaporated to dryness.
3. Chlorides of Ca and Mg ppt. as carbonates of Ca and Mg.
4. Extract residue with distilled water
5. Add few drops of methyl orange as indicator
6. Titrate against N/50 HCl
7. End point changes colour from yellow to orange.

13. Determination of Alkalinity in water
• It is due to 1) OH-
and CO3
-2
2) HCO3
-
• Titrate against phenolphthalein and methyl orange
Method
1. 100 ml sample water in conical flask
2. Add 2-3 drops of phenolphthalein indicator
3. Titrate against N/50 H2SO4
4. Continue till pink colour disappear
5. To the same solution add 2-3 drops of methyl orange
6. Titrate till yellow colour changes to red
Reaction Involved:
OH-
+H+
→ H2O (using phenolphthalein)
CO3
-2
+ H+
→ HCO3
-
(using phenolphthalein)
HCO3
-
+H+
→ H2O+ CO2 (using methyl orange)

14. Scale and Sludge
• Troubles met in boiler which are used in steam production.
Scale:
When water is evaporated in boilers to produce steam continuously
the concentration of the slats present in the water increases
progressely
As the concentration reaches a saturation point the salts are thrown
over the inner surface of the boiler.
Sludge:
During boiling salts form precipitate of loose slimy form.
Magnesium Chloride
Decomposes to form hydroxide and hydrochloric acids. The former will
produce hard scale and the later lowers the pH.
MgCl2 + 2H2O → 2HCl + Mg(OH)2
Magnesium Sulphate
Forms a hard scale on the heating surfaces

15. Calcium Sulphate
Forms a hard scale on the heating surfaces
Calcium Bi-carbonate
Decomposes at a low temperature when CO2 is liberated. Remaining
Calcium carbonate deposits on the heating surface as a soft scale.
Ca(HCO3)2 → CaCO3 + CO2 + H2O

16. Disadvantages of Scale Formation
1. Wastage of fuel 2. Decreases in Efficiency
3. Lowering of boiler safety 4. Danger of Explosion
5. Corrosion
Removal of Scales
1. By scrapping 2. Giving thermal shocks
3. Dissolving by using chemicals e.g CaCO3 by 5-10% HCl
4. Adding complexing agents e.g CaSO4 by EDTA
5. Blow down Process
Disadvantages of Sludge Formation
1. Chocking of pipes
2. Low supply of heat
3. Wastage of fuel
4. Get entrapped in scales

17. Prevention of Sludge Formation
1. Blow down Process: Withdrawing portion of sludge containing water
and replacing with fresh water
2. Softening of water
Method of Preventing Scale Formation
1. External Treatment:
Treatment of water before entering into boiler
- Removal of Ca, Mg and Silica
2. Internal Treatment:
Addition of chemicals directly to water in boiler.
- Scale forming substances produces loose precipitate
- Blow down process
- Adding complexing agents: to form soluble complex

18. Caustic embrittlement :
It is the phenomenon in which the material of
a boiler becomes brittle due to the accumulation of caustic substances.
• Sodium carbonate is used in softening of water by lime soda process,
due to this some sodium carbonate maybe left behind in the water.
Na2CO3 + H2O → 2NaOH + CO2
• As Conc. of NaOH increases, water flows into minute hair cracks.
• Water get evaporated and NaOH increases further and react with
iron of boiler, hence cause Embrittlement.
Prevention:
1. Addition of sodium sulphate or sodium phosphate. Which will block
hair-cracks.
2. Addition of tannin and lignin- blocks the cracks.
3. Excess of Na2SO4 is avoided else it will form CaSO4

19. Priming and Foaming
Priming:- Carry over of varying amounts of water in the steam e.g.
(Foam, mist)
- Leads to deposits of salt crystals
- Lowers the energy efficiency
Causes:-
a) Presence of suspended impurities and dissolved salts
b) High steam velocity and sudden boiling
c) High water levels
d) Faulty boiler design
Preventions:
a) Good boiler design
b) Avoid rapid changes in temp.
c) Maintaining low water level
d) Fitting mechanical steam purifier
Normal Bubble
Carry Over

20. Foaming: Formation of small bubbles and froth on the surface of water
- Caused by high conc. of any solids in water
Causes:
a) Difference b/w conc. of solute and suspended matters.
b) Surface tension lowering substances
c) Oil and grease
Prevention:
a) Adding antifoaming agents e.g. castor oil
b) Removing oily particles using silicic acid and sodium aluminate.
Boiler Corrosion: Decay of material by chemically or electrochemically
Causes:
a) Presence of dissolved gases e.g. O2 , CO2
b) Caustic Embrittlement
c) Acid formation due to Hydrolysis
d) Presence of free acids.

21. Treatment Methods of Water
A. Internal Treatment
B. External Treatment
Internal Treatment Method
1. Phosphate Conditioning:
- Small amount of phosphate ions are added to precipitate Ca ions.
- Chosen depending on the pH conditions of boiler.
2. Colloidal Conditioning:
- Using kerosine, tannin, starch etc
- Get coated over the scale forming particles
- Removed by Blow down Process
3. Carbonate conditioning:
- Na2CO3 is added to precipitate Ca salts as CaCO3
- Removed by Blow down Process
- Used in low pressure boilers

22. • Calgon Conditioning:
- Scale forming salts are converted into soluble complexes.
- E.g. Sodium Hexameta Phosphate (Na2PO3)6 is added…reacts with Ca
and forms Calcium Hexameta Phosphate (Ca2PO3)6
- Prevents Scale formation
• Radioactive conditioning:
- Adding radioactive tablets
- Emits radiation energy which prevents Scale formation
• Electrical Conditioning:
- Mercury bulbs placed in boiler
- Emits electrical discharge
- Prevents Scale formation

23. External Treatment Method (or) Water softening Method
• Removal of hardness causing substances from water
Methods:
1. Zeolite process
2. Ion Exchange Process
3. Mixed Bed deionization
Zeolite (or Permutit) Process: are Hydrated sodium alumino Silicate
Na2O. Al2O3 X SiO2 Y H2O (X= 2-10, Y= 2-6 )
Natural Zeolites:
1. Natrolite - Na2O. Al2O3 4SiO2 .2H2O
2. Laumontite - CaO. Al2O3 4SiO2 .4H2O
3. Harmotome - (BaO.K2O). Al2O3 5SiO2 .5H2O
- Capable of exchanging its Na ions.

24. A. Natural Zeolite:-
Derived from green sand by washing, Heating, treating
with NaOH.
• Non porous in nature.
B. Synthetic Zeolite: -
Prepared from solution of Sodium Silicate and AlOH
• Higher exchange capacity and porous in Nature.
Process:

25. • Consist of Steel Tank
• Having Thick Layer of Zeolite
• When water pass through it hardness causing ions (Ca, Mg) are
retained by Zeolite.
Chemical Reaction:
Ca(HCO3)2 + Na2 Ze → CaZe + 2 NaHCO3
CaSO4 + Na2Ze → CaZe + Na2SO4
MgCl2 + Na2Ze → MgZe + 2NaCl
Mg (NO3)2 + Na2Ze → MgZe + 2NaNO3
• Exchange of Na ions continues until Na ions are exhausted
Regeneration:
CaZe + 2NaCl → Na2Ze + CaCl2
MgZe + 2NaCl → Na2Ze + MgCl2
• CaCl2 and MgCl2 led to drain and Na2Ze can be reused.

26. Advantages
1. Hardness can be completely removed
2. Process can be made automatically
3. Easy operation. No experts required
4. Less time and sludge
5. Small area requires
Disadvantages
1. Only Ca+
and Mg+
ions can be removed
2. Large amount of Na ions present in treated water.
3. Leaves other acids which causes corrosion
4. Fe2+
and Mn2+
containing water can not be treated because Fe and Mn
Zeolite can not be regenerated
5. Water should be free from suspended impurities to prevent clogging
on Zeolite beds.
6. Treated water contains more dissolved solids.

27. 2. Ion Exchange (or) Demineralization (or) Deionization Process.
• mineral ions are removed
• physical process which uses specially-manufactured ion exchange
resins which bind to and filter out the mineral salts from water.

28. Advantage:
1. Produces soft water
2. Can treat highly acidic or alkaline water
3. Regeneration of ion resins are possible
4. Maintenance cost is low
Disadvantage:
1. Cost of equipment is high
2. Highly turbid water can not be treated
3. Expensive chemicals are required.

29. 3. Mixed Bed Deionization
• This equipment consist of single column which contain mixture of
cation and anion exchangers.
• When water pass through bed, it comes in contact several times with
both exchangers
• Resultant water contain lesser amount of salt.
Regeneration: by back wash
a) anions with dil. NaOH
b) cations with dil. H2SO4
Advantages:
• More convenient and more effective
Disadvantages:
• Regeneration cost is more
• Equipment cost is high

30. Desalination
• Processes that remove salt and other minerals from Water.
• Brackish Water: contain 3.5 % salts & salty taste. Unfit for drinking
• Separation of salts from water by evaporation followed by
condensation.
• Freezing method can also be employed
• Commonly used methods:
1. Electrodialysis
2. Reverse Osmosis

31. A. Electrodialysis:
• Method of separation of ions from salt water by passing electric
current.
• Semi permeable membranes are placed
• Consist of three compartments containing
1. Sea Water 2. Pair of electrodes 3. Semi permeable membrane

32. • As current applied Na ions moves towards cathode and Cl moves
towards anode
• As result brine concentration decreases in the middle compartment.
• Pure water is removed from the central compartment.
• Conc. Brines are replaced by fresh brine water.
• Much more effective separation Ion selective membranes are used

33. Reverse Osmosis (or) Super Filtration (or) Hyper Filtration
• Movement of solvent molecule from concentrated side to diluted
side.
• If only pressure higher than that of osmotic pressure
Membranes:
Cellulose Acetate, Polymide,
Polymethylmethaacrylate
Thickness:
0.0005 to 0.0000002 µm
• Advantages:
1. Removes both ionic and non ionic and colloidal matters
2. Maintenance cost is low
3. Membrane replacement can be done with in few minutes.

34. Domestic Treatment of Water
A. Removal of Suspended Impurities
B. Removal of Micro organisms
Removal of Suspended Impurities
1. Screening:
Floating matters are removed by passing through screens.
2. Sedimentation:
- Big tanks are used
- Left undisturbed
- Water settle down due to gravity.
- Supernatent water is drawn with the help of pump
- Takes 2-6 hours
3. Filtration:
Sand Filters are used.

35. 4. Sedimentation with Coagulation:
- Addition of Chemicals (Coagulants) to water. E.g. Alum (Potash Alum
or Ferric Alum), Sodium Aluminate (NaAlO2) ,Ferrous Sulphate (FeSO4)
- On addition they form an insoluble gelatinous, flocculent precipitate
which absorbs very fine particles and form bigger flocs.
- Due to this tiny particles which have no charge also come closers.

36. B. Removal of Micro Organisms
1. Boiling
2. Adding Bleaching Powder:
- 1 kg for 1000 KL
- Mixed and Allowed to stand several hours
CaOCl2 + H2O → Ca (OH)2 + Cl2
Cl2 + HO → HOCl (Hypochlorous Acid) + HCl
HOCl + Germs → Germs Killed
HOCl → HCl+ [O] (Nascent Oxygen)
[O] + Germs → Germs Killed
Disadvantages:
- Excess addition give bad odour and taste.
- Introduces Ca into water and makes it hard
- Disintegrates on storing

37. 3. By Chlorination:
- Chlorine produces Hypochlorous Acid.
- Hypochlorous acid is strong Germicide.
Cl2 + HO → HOCl (Hypochlorous Acid) + HCl
HOCl + Germs → Germs Killed
- Cl may be used in Gaseous or Concentrated Form.
- Filtered water with 0.3-0.5 ppm Cl is sufficient.
- Lower pH is favourable (5-6.5)
Advantages:
1. Effective and Economical
2. Stable and does not deteriorate on storage
3. No impurities such as salts are introduced.
4. Can be used at high as well as low temp.

38. Disadvantages
1. Excess chlorination produces unpleasant taste. (0.1-0.2 ppm only)
2. More effective at low pH.
Breakpoint Chlorination:
- The addition of chlorine in such amount that it Oxidizes the organic
matter, reducing matters and free ammonia in raw water. And leaves
free residual Cl.
Advantages
1. Oxidizes organic compounds, reducing substances and ammonia.
2. Removes colour and taste.
3. Kill germs.
- Excess of Declorination can be done by
1. Filtering through bed of molecular carbon
2. Addition of SO2 and Na2SO3
SO2 + Cl2 + 2H2O → H2SO4+ 2HCl

39. 4. By chloramine:
- Using 2 : 3 ratio of Cl3 and NH3
ClNH2+ H2O → HOCl + NH3
HOCl + Germs → Germs Killed
5. By Ozonization:
- Ozone and raw water are allowed to come in contact with each other
- 10 – 15 min. in 2-8 ppm
3O2 → 2O3 (Highly Unstable)
O3 → O2 + [O]
[O] + Germs → Germs Killed
Advantage: 1. Leaves no residue. Because of unstability
2. Removes odour, colour, Taste.
Disadvantage: Very Expensive
6. By Ultraviolet Radiation:
- Using Electric mercury vapour lamp

40. International Standards for water
- Depends on purpose
- Standards Set By:
1. WHO- World Health Organization
2. USPHD- United States Health Service
3. ICMR- Indian Council of Medical Research
Water should be free from
1. Turbidity, Colour
2. Taste, Odour
3. Microbes
4. Toxicity (Organic and Inorganic Metals)