kinetics and thermodynamics of air pollutants

1. Kinetics and Thermodynamics of
Air pollutants
Ravi Kumar GARRE

2. Introduction
• The commonly available techniques of control of
gaseous emissions into atmosphere are:
absorption, adsorption and combustion.
• These processes may undergo heat release (or)
heat absorption. Some of the processes may take
place only in the presence of catalysts.
• So, the selection of method to employ, for the
purification of gaseous emissions, the knowledge
of kinetics and thermodynamics of air pollutants
is required.

3. Kinetics of Air pollutants
• The air pollution kinetics deals with the rates
of reactions of pollutant gases with the
substances which are used to control the
gaseous emission.
• The aim of kinetics is to determine the rate of
reaction.

4. Thermodynamics of Air pollutants
• Thermodynamics deals with the quantitative
relation between heat energy and the rate of
reaction.
• The heat produced during the conversion of
pollutants into other substance is the primary
concern in thermodynamics of air pollution.
• The aim of thermodynamics is to determine
the amount of heat exchange/ heat difference
between the reactants and products.

5. Rate of reaction
• The rate of reaction can be taken as “ the formation of
products per time (or) the rate of consumption of reactant per
time”.
• If the reaction is homogeneous, the rate or reaction depends
upon concentration of gas.
• It’s unit is: mg/l/sec.

6. Enthalpy
• It is the sum of internal energy added and the
product of pressure and volume of the system.
• It reflects the capacity of react and capacity to
release heat.
H = U+PV
• For a chemical reaction enthalpy of reaction is
the difference in enthalpy between products
and reactants.
• Units: KJ/moles

7. Significance of Kinetics and Thermodynamics
• The proper knowledge of kinetics and thermo
dynamics of air pollution will helps in the selection of
application of control of gaseous emissions.
• It includes the knowledge related to:
 The rate at which molecules interact under
certain conditions
 The manner in which molecules would react
when the conditions change
 Mechanism through which reactant molecules
are transformed into products
 The factors which control the rate of reaction

8. Factors influencing rate of chemical reaction/
kinetics & thermodynamics/ selection of
technique to control gaseous pollutants
1. Strength of bonds
2. Temperature
3. Concentration
4. Surface area/ contact area
5. Catalysts
6. Radiations

9. Thank you