1. 1st SEM Applied Chemistry
SRM University
1st SEM Applied Chemistry

2. Technology Of Water Water:
Water is a chemical substance with the chemical formula H2O.
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 or transpiration (evapotranspiration),

3. Evotranspiration Process

4. Evapotranspiration (ET) is a term used to describe the sum of evaporation and plant transpiration from the Earth's land surface to atmosphere.
Evaporation :-
The movement of water to the air from sources such as the soil, canopy interception, and water bodies.
Transpiration :-
The movement of water within a plant and the subsequent loss of water as vapor through stomata in its leaves.
An element (such as a tree) that contributes to evapotranspiration can be called an evapotranspirator.

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

7. Types Of Impurities 1. Dissolved Impurities: a) Inorganic salts e
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

8. 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.

9. 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 Leather Formation.
due to presence of:- salts like bicarbonates, sulphates,
chlorides of mg and other metals
Units of Hardness:
1) ppm ) mg/l ) ̊Cl ) ̊Fr
Relation - 1ppm = 1mg/l = ̊Cl = 0.1 ̊Fr

10. Hardness Table Water Classification Hardness, mg/L
Hardness. Grains/Gal
Sodium Added  mg/L
Soft
0 to 49
0 to 2.9
0 to 22.5
Medium Hard
50 to 149
2.9 to 8.7
23 to 68.5
Hard
150 to 249
8.7 to 14.6
69 to 115
Very Hard
250 to 299
14.6 to 173
115 to 138
Extremely Hard
300 and up
17.5 and up
138 and up
mg/L = milligrams/Liter

11. 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 ↑
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

12. Disadvantages of Hard Water
(A) Domestic Uses:
Washing Bathing Drinking 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- destroy resin of soap
3. Sugar industries: Sulphates and Alkaline carbonates- Deliquescent
4. Dyeing Industries: should not contain iron and hardness
5. Laundries: should be soft

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

14. For Temporary Hardness:
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:
50ml sample water in conical flask
2-3 drops of methyl orange indicator
Titrated against N/50 HCl
Change colour from yellow to orange
Take 100 ml of same sample of water
Boil until 1/5th volume
Make them again 100 ml Distilled water
Take 50ml and perform again the above steps

15. 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:
50 ml hard water + 50 ml Na2CO3 solution
Boiled and Evaporated to dryness.
Chlorides of Ca and Mg ppt. as carbonates of Ca and Mg.
Extract residue with distilled water
Add few drops of methyl orange as indicator
Titrate against N/50 HCl
End point changes colour from yellow to orange.

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

17. 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

18. 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

19. Disadvantages of Scale Formation
1. Wastage of fuel Decreases in Efficiency
3. Lowering of boiler safety Danger of Explosion
5. Corrosion
Removal of Scales
By scrapping 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
Chocking of pipes
Low supply of heat
Wastage of fuel
Get entrapped in scales

20. Prevention of Sludge Formation
Blow down Process: Withdrawing portion of sludge containing water and replacing with fresh water
Softening of water
Method of Preventing Scale Formation
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

21. 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:
Addition of sodium sulphate or sodium phosphate. Which will block hair-cracks.
Addition of tannin and lignin- blocks the cracks.
Excess of Na2SO4 is avoided else it will form CaSO4

22. Priming:- Carry over of varying amounts of water in the steam e.g.
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:-
Presence of suspended impurities and dissolved salts
High steam velocity and sudden boiling
High water levels
Faulty boiler design
Preventions:
Good boiler design
Avoid rapid changes in temp.
Maintaining low water level
Fitting mechanical steam purifier
Normal Bubble
Carry Over

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

24. Internal Treatment Method
Treatment Methods of Water
A. Internal Treatment
B. External Treatment
Internal Treatment Method
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
Used in low pressure boilers

25. 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

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

27. 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:

28. 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
MgCl 2 + Na2Ze → MgZe + 2NaCl
Mg (NO3)2 + Na2Ze → MgZe + 2NaNO3
Exchange of Na ions continues until Na ions are exhausted
Regeneration:
CaZe + 2NaCl → Na2Ze + CaCl 2
MgZe + 2NaCl → Na2Ze + MgCl 2
CaCl 2 and MgCl 2 led to drain and Na2Ze can be reused.

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

30. B. 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.

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

32. 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

33. Desalination
Processes that remove some amount of 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:
Electrodialysis
Reverse Osmosis

34. 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 Semi permeable membrane

35. 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

36. 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:
to µm
Advantages:
Removes both ionic and non ionic and colloidal matters
Maintenance cost is low
Membrane replacement can be done with in few minutes.

37. Domestic Treatment of Water
Removal of Suspended Impurities
Removal of Micro organisms
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.

38. 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.

39. B. Removal of Micro Organisms
Boiling
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

40. 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 ppm Cl is sufficient.
Lower pH is favourable (5-6.5)
Advantages:
Effective and Economical
Stable and does not deteriorate on storage
No impurities such as salts are introduced.
Can be used at high as well as low temp.

41. Disadvantages
Excess chlorination produces unpleasant taste. ( ppm only)
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 which disinfect Water.
Advantages
Oxidizes organic compounds, reducing substances and ammonia.
Removes colour and taste.
Kill germs.
- Excess of Declorination can be done by
Filtering through bed of molecular carbon
Addition of SO2 and Na2SO3
SO2 + Cl2 + 2H 2O → H 2SO4+ 2HCl
Na2SO3 + Cl2 + H 2O → Na2SO4 + 2HCl

42. 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
3O → 2O3 (Highly Unstable)
O → 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

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