B.Sc (H) Chemistry, Semester -VI Paper DSE
Description: B.Sc (H) Chemistry, Semester -VI Paper DSE Industrial Chemicals and Environment Air Pollution (Sulphur Oxides and Particulate Matter) BY RITU MALIK Assistant Professor Rajdhani College University of Delhi AIR POLLUTION Air Pollution is the
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slide1. B.Sc (H) Chemistry, Semester -VI Paper DSE Industrial Chemicals and Environment Air Pollution (Sulphur Oxides and Particulate Matter) BY
RITU MALIK
Assistant Professor
Rajdhani College
University of Delhi<br>
slide2. AIR POLLUTION Air Pollution is the contamination of the indoor or outdoor environment by any chemical, physical or biological agent that modifies the natural characteristics of the atmosphere.
It may cause diseases, allergies and even death in humans and harm other living organisms such as animals and food crops and damage the natural or built environment.
Air pollution is generated due to both natural and human activity.
Factors affecting Air Pollution:
1. Meteorology
2. Topography
3.Physical and chemical properties of the pollutants<br>
slide3. TYPES OF AIR POLLUTANTS Primary Air Pollutants: These air pollutants are emitted directly from the source into the atmosphere. Examples: Sulfur dioxide, Carbon monoxide, Nitrogen oxides and Particulate Matter.
Secondary Air Pollutants: These pollutants are not emitted as such but, when other pollutants (primary pollutants themselves or primary pollutant and atmospheric components) react in the atmosphere. Examples are photochemical oxidants (acids, Nitrogen dioxide, Sulfur dioxide and ozone); and Secondary particulate matter.<br>
slide4. Types of Air Pollutants as recognized by EPA Carbon monoxide
Sulphur dioxide
Nitrogen Oxides
Ozone
Particulate Matter
Lead<br>
slide6. Burning of fossil fuels (coal, petroleum and petroleum products)
Petroleum refinery processes
Smelting of sulfide ores ( Copper and Zinc ores)
Manufacture of Sulfuric acid
Manufacture of paper
Burning of domestic refuse<br>
slide8. Continued<br>
slide9. Continued…<br>
slide10. Continued<br>
slide11. Effects of Sulphur Oxides Vegetation: Sulphur oxides interfere chlorophyll synthesis and destroy the plant cells. Leaf blotching and low crop yield is observed.
Non-living materials
Stone leprosy (erosion of carbonate stones)
Metal corrosion
Retardation of drying of paints
Discoloration and embrittlement of paper
Discoloration and weathering of leather and fabric.
Deterioration of electrical instruments.
Reduced visibility due to sulphate aerosols.
Acid Rain<br>
slide12. Estimation of Sulphur Oxides<br>
slide13. Continued…<br>
slide14. Continued…. 2. Conductimetry: Sulphur dioxide is put in a solution of hydrogen peroxide which oxidizes it into sulphuric acid. The resulting increase in electrical conductance due to sulphuric acid is measured.
3. Ion Chromatography (IC): Passing Sulphur dioxide through hydrogen peroxide to form sulphate ions, and further analysis of sulphate ions is done by IC.
4. Flame Photometry: The Sulphur gases are burned in hydrogen flame and Sulphur emission line at 394 nm is observed.
5. Mass direct spectrophotometric methods - Non-dispersive IR absorption, Fourier Transform infrared FTIR analysis, UV absorption, molecular resonance fluorescence and second derivative spectrophotometry; are also used for Sulphur dioxide estimation.<br>
slide15. Control Procedures of Sulphur Dioxide<br>
slide16. Continued<br>
slide17. Flue-Gas Desulfurization Techniques<br>
slide18. Continued…<br>
slide19. Sources of Particulate Matter Natural Sources:
Meteorites
Volcanic Eruptions
Vegetation [ spores, pollens, terpenes – (∝-pinene discharged from forest trees)]. These cause blue haze in atmosphere due to dispersion of light
Storms: Turbulence introduced due to dust storms and sand storms suspend the particulates in the atmosphere for a longer period of time.<br>
slide20. Continued…. Forest Fires: Forest fires release polynuclear aromatic hydrocarbons and salts of calcium, iron, zinc and magnesium and these suspend in the atmosphere.
Sea Salt Sprays: Salt laden water droplets are introduced into atmosphere by the ocean waves. When water evaporates, salts are left as suspended particles.
Anthropogenic Sources:
Vehicular Exhaust: The vehicular exhaust (soot, lead compounds, crankcase oil and hydrocarbons) interact with other air pollutants to produce secondary particulates which produce photochemical smog.<br>
slide21. Continued….<br>
slide22. Particulate Matter and its types Particulate matter also known as particle pollution or PM is a complex mixture of extremely small particle and liquid droplets. It is made up of number of components including acids (such as nitrates and sulphates), organic chemicals metals and soil or dust particles.
Particulate Types
On the basis of size and origin, particular matter is classified into 2 types:
Primary particulates are directly injected into the atmosphere by physical or chemical methods. They are generally 1 to 20 micrometer in diameter (maybe as large as 100 micrometer). Examples from natural sources: pollen, volcanic debries, soil dust and sea salt spray; from Anthropogenic sources: coal, fly ash, cement dust and milled flour.
Secondary particulates are formed either due to gas phase reactions or due to reactions between pollutant gases and primary particulates. Examples from natural sources include volcanoes, decaying organic matter and vapours from trees; and from anthropogenic sources include vehicular emissions, industrial operations and combustion processes. Secondary particulates are of three types based on the types of functional groups present:
Sulphate particulates
Hydrocarbon particulates
Nitrate particulates<br>
slide23. Continued<br>
slide24. Continued<br>
slide25. Continued ….<br>
slide26. Continued<br>
slide27. Particulate categorization according to EPA The size of Particulate matter is directly related to their probability to cause health problems. EPA studies about the particles that are 10 micrometers in diameter or smaller as these particles usually pass through air passage. Once inhaled, these particles damage the heart and lungs and cause ill-effects on health. EPA categorized particulates into two categories :
"Inhalable coarse particles," found near roadways and dusty industries, are larger than 2.5 micrometers and smaller than 10 micrometers in diameter.
"Fine particles," found in smoke and haze, are 2.5 micrometers in diameter and smaller. These particles can be directly emitted from sources such as forest fires, or they can form when gases emitted from power plants, industries and automobiles react in the air.<br>
slide28. Control of particulates Many systems are employed to control the particulate matter. These include Gravitational settling chamber, inertial collectors (cyclonic separators), fabric filter collectors (bag houses), wet scrubbers and electrostatic precipitators.
Gravitational settling chamber: It is employed to separate particles >50 micrometer. The polluted gas enters the chamber at < 0.3 m/s and particles are allowed to settle due to gravity high density and are separated.
Cyclone separator: The polluted gas enters the cyclone separator tangentially from the top and rotates, generating the centrifugal force that throw the particles to the cyclone walls as the gas spirals upwards inside the cone. The particulates slide down the walls of the cone and collected at bottom outlet.<br>
slide29. Continued… Fabric Filter: It separates particulates ≥ 0.5 micrometer. The pollutant gas is passed through a fabric bag that filters out the particulates and allow the clean gas to move out. The particular dust Mat is collected inside the bag and must be cleaned from time to time.
Wet collectors: It separates the particulates from polluted gas stream as liquid droplets. Common wet scrubbers are spray tower, venturi scrubber and cyclone scrubber.<br>
slide30. Continued Electrostatic precipitator: The carbon other dust particles released in the atmosphere from industries are removed by electrostatic precipitator. In this method, two electrodes are fitted against the inside walls of the smokestack. When high voltage is applied and electric discharge takes place across the stack and as a result air in the stack is ionised. The ionizes air consists of ions and free electrons. The free electrons attached to the gaseous particles moving up the stack. The particles get negatively charged and are attracted to the positive electrode, located on the inner wall of the stack and settle down there. These can be dislodged from the electrodes by vibration of the electrodes and are collected in a reservoir. In this way, about 99% of the particulate matter gets removed from the fuel gases by this process.<br>
slide31. Electrostatic Precipitator This Photo by Unknown Author is licensed under CC BY<br>
slide32. REFRENCES Stanley E. Manahan: Environmental Chemistry
S.M Khopkar, Environmental Pollution Analysis
J.A. Kent: Handbook of Industrial Chemistry
G.S Sodhi: Environmental Chemistry<br>
slide33. THANK YOU Ritu Malik Assistant Professor Rajdhani College University of Delhi<br>
RITU MALIK
Assistant Professor
Rajdhani College
University of Delhi<br>
slide2. AIR POLLUTION Air Pollution is the contamination of the indoor or outdoor environment by any chemical, physical or biological agent that modifies the natural characteristics of the atmosphere.
It may cause diseases, allergies and even death in humans and harm other living organisms such as animals and food crops and damage the natural or built environment.
Air pollution is generated due to both natural and human activity.
Factors affecting Air Pollution:
1. Meteorology
2. Topography
3.Physical and chemical properties of the pollutants<br>
slide3. TYPES OF AIR POLLUTANTS Primary Air Pollutants: These air pollutants are emitted directly from the source into the atmosphere. Examples: Sulfur dioxide, Carbon monoxide, Nitrogen oxides and Particulate Matter.
Secondary Air Pollutants: These pollutants are not emitted as such but, when other pollutants (primary pollutants themselves or primary pollutant and atmospheric components) react in the atmosphere. Examples are photochemical oxidants (acids, Nitrogen dioxide, Sulfur dioxide and ozone); and Secondary particulate matter.<br>
slide4. Types of Air Pollutants as recognized by EPA Carbon monoxide
Sulphur dioxide
Nitrogen Oxides
Ozone
Particulate Matter
Lead<br>
slide6. Burning of fossil fuels (coal, petroleum and petroleum products)
Petroleum refinery processes
Smelting of sulfide ores ( Copper and Zinc ores)
Manufacture of Sulfuric acid
Manufacture of paper
Burning of domestic refuse<br>
slide8. Continued<br>
slide9. Continued…<br>
slide10. Continued<br>
slide11. Effects of Sulphur Oxides Vegetation: Sulphur oxides interfere chlorophyll synthesis and destroy the plant cells. Leaf blotching and low crop yield is observed.
Non-living materials
Stone leprosy (erosion of carbonate stones)
Metal corrosion
Retardation of drying of paints
Discoloration and embrittlement of paper
Discoloration and weathering of leather and fabric.
Deterioration of electrical instruments.
Reduced visibility due to sulphate aerosols.
Acid Rain<br>
slide12. Estimation of Sulphur Oxides<br>
slide13. Continued…<br>
slide14. Continued…. 2. Conductimetry: Sulphur dioxide is put in a solution of hydrogen peroxide which oxidizes it into sulphuric acid. The resulting increase in electrical conductance due to sulphuric acid is measured.
3. Ion Chromatography (IC): Passing Sulphur dioxide through hydrogen peroxide to form sulphate ions, and further analysis of sulphate ions is done by IC.
4. Flame Photometry: The Sulphur gases are burned in hydrogen flame and Sulphur emission line at 394 nm is observed.
5. Mass direct spectrophotometric methods - Non-dispersive IR absorption, Fourier Transform infrared FTIR analysis, UV absorption, molecular resonance fluorescence and second derivative spectrophotometry; are also used for Sulphur dioxide estimation.<br>
slide15. Control Procedures of Sulphur Dioxide<br>
slide16. Continued<br>
slide17. Flue-Gas Desulfurization Techniques<br>
slide18. Continued…<br>
slide19. Sources of Particulate Matter Natural Sources:
Meteorites
Volcanic Eruptions
Vegetation [ spores, pollens, terpenes – (∝-pinene discharged from forest trees)]. These cause blue haze in atmosphere due to dispersion of light
Storms: Turbulence introduced due to dust storms and sand storms suspend the particulates in the atmosphere for a longer period of time.<br>
slide20. Continued…. Forest Fires: Forest fires release polynuclear aromatic hydrocarbons and salts of calcium, iron, zinc and magnesium and these suspend in the atmosphere.
Sea Salt Sprays: Salt laden water droplets are introduced into atmosphere by the ocean waves. When water evaporates, salts are left as suspended particles.
Anthropogenic Sources:
Vehicular Exhaust: The vehicular exhaust (soot, lead compounds, crankcase oil and hydrocarbons) interact with other air pollutants to produce secondary particulates which produce photochemical smog.<br>
slide21. Continued….<br>
slide22. Particulate Matter and its types Particulate matter also known as particle pollution or PM is a complex mixture of extremely small particle and liquid droplets. It is made up of number of components including acids (such as nitrates and sulphates), organic chemicals metals and soil or dust particles.
Particulate Types
On the basis of size and origin, particular matter is classified into 2 types:
Primary particulates are directly injected into the atmosphere by physical or chemical methods. They are generally 1 to 20 micrometer in diameter (maybe as large as 100 micrometer). Examples from natural sources: pollen, volcanic debries, soil dust and sea salt spray; from Anthropogenic sources: coal, fly ash, cement dust and milled flour.
Secondary particulates are formed either due to gas phase reactions or due to reactions between pollutant gases and primary particulates. Examples from natural sources include volcanoes, decaying organic matter and vapours from trees; and from anthropogenic sources include vehicular emissions, industrial operations and combustion processes. Secondary particulates are of three types based on the types of functional groups present:
Sulphate particulates
Hydrocarbon particulates
Nitrate particulates<br>
slide23. Continued<br>
slide24. Continued<br>
slide25. Continued ….<br>
slide26. Continued<br>
slide27. Particulate categorization according to EPA The size of Particulate matter is directly related to their probability to cause health problems. EPA studies about the particles that are 10 micrometers in diameter or smaller as these particles usually pass through air passage. Once inhaled, these particles damage the heart and lungs and cause ill-effects on health. EPA categorized particulates into two categories :
"Inhalable coarse particles," found near roadways and dusty industries, are larger than 2.5 micrometers and smaller than 10 micrometers in diameter.
"Fine particles," found in smoke and haze, are 2.5 micrometers in diameter and smaller. These particles can be directly emitted from sources such as forest fires, or they can form when gases emitted from power plants, industries and automobiles react in the air.<br>
slide28. Control of particulates Many systems are employed to control the particulate matter. These include Gravitational settling chamber, inertial collectors (cyclonic separators), fabric filter collectors (bag houses), wet scrubbers and electrostatic precipitators.
Gravitational settling chamber: It is employed to separate particles >50 micrometer. The polluted gas enters the chamber at < 0.3 m/s and particles are allowed to settle due to gravity high density and are separated.
Cyclone separator: The polluted gas enters the cyclone separator tangentially from the top and rotates, generating the centrifugal force that throw the particles to the cyclone walls as the gas spirals upwards inside the cone. The particulates slide down the walls of the cone and collected at bottom outlet.<br>
slide29. Continued… Fabric Filter: It separates particulates ≥ 0.5 micrometer. The pollutant gas is passed through a fabric bag that filters out the particulates and allow the clean gas to move out. The particular dust Mat is collected inside the bag and must be cleaned from time to time.
Wet collectors: It separates the particulates from polluted gas stream as liquid droplets. Common wet scrubbers are spray tower, venturi scrubber and cyclone scrubber.<br>
slide30. Continued Electrostatic precipitator: The carbon other dust particles released in the atmosphere from industries are removed by electrostatic precipitator. In this method, two electrodes are fitted against the inside walls of the smokestack. When high voltage is applied and electric discharge takes place across the stack and as a result air in the stack is ionised. The ionizes air consists of ions and free electrons. The free electrons attached to the gaseous particles moving up the stack. The particles get negatively charged and are attracted to the positive electrode, located on the inner wall of the stack and settle down there. These can be dislodged from the electrodes by vibration of the electrodes and are collected in a reservoir. In this way, about 99% of the particulate matter gets removed from the fuel gases by this process.<br>
slide31. Electrostatic Precipitator This Photo by Unknown Author is licensed under CC BY<br>
slide32. REFRENCES Stanley E. Manahan: Environmental Chemistry
S.M Khopkar, Environmental Pollution Analysis
J.A. Kent: Handbook of Industrial Chemistry
G.S Sodhi: Environmental Chemistry<br>
slide33. THANK YOU Ritu Malik Assistant Professor Rajdhani College University of Delhi<br>