This document discusses adsorption, which is the process where molecules of gas or liquid adhere to a surface. It defines key terms like adsorbent, adsorbate, and sorption. It describes the mechanisms of physisorption and chemisorption. Finally, it outlines several factors that affect the extent of adsorption, such as the nature and surface area of the adsorbent, pressure and temperature of the system, and activation of the adsorbent.

1. Submitted By – NIDHI SANKET
M.Sc Chemistry Semester II
Department Of Chemistry
S.P.C. Govt. College, Ajmer
ADSORPTION

2. CONTENTS
• ADSORPTION
• ADSORPTION AND ABSORPTION
• SOME BASIC TERMS WHICH ARE USED IN ADSORPTION
• MECHANISM OF ADSORPTION
• CHARACTERISTICS OF ADSORPTION
• TYPES OF ADSORPTION -
 PHYSISORPTION
CHEMISORPTION
• FACTORS AFFECTING ADSORPTION
• APPLICATIONS OF ADSORPTION

5. SOME BASIC TERMS WHICH ARE USED IN
ADSORPTION
ADSORBENT - Surface of a substance on which adsorbate adsorbs
. For e.g., charcoal, silica gel etc
ADSORBATE - Substance that is adsorbed . For e,g., N2 , O2 , H2

6. SORPTION
• A process in which both
adsorption and absorption take
place simultaneously , it is called
sorption. E.g., when hydrogen is
taken up by the charcoal , it first
condenses on its surface . This is
adsorption . After sometime ,
hydrogen diffuses slowly into the
interior of the charcoal forming a
true solid solution . This is
absorption . So , the charcoal
has absorbed as well as
adsorbed hydrogen gas .
OCCLUSION
• The adsorption of a gas on the
surface of a metal is called
occlusion . According to Graham
who introduced the term occlusion
said that it has a significance
similar to sorption .
• E.g., Hydrogen is adsorbed on
the surface of nickel or palladium .

14. FACTORS AFFECTING ADSORPTION
• Nature of adsorbent (solid) and adsorbate(gas) – In
general,easily liqueliable gases e.g.,CO2 ,NH3 ,Cl2 and
SO2 etc . are adsorbed to a greater extent than the
permanent gases e.g.,H2,O2,N2 etc
Porous and finely powdered solid e.g.,charcoal adsorb
more as compared to hard non porous material .
• Surface area of adsorbent - More the surface
area ,greater is the extent of adsorption .

15. • ACTIVATION OF( SOLID) ADSORBENT
• Increasing adsorbing power of adsorbent - making
surface rough / increasing surface area (powder)
- removing already adsorbed gases .

16. • EFFECT OF PRESSURE
•An increase in the pressure of adsorbate gas increases the extent of adsorption .
•At low temperature , the extent of adsorption increases rapidly with pressure .
•Moderate Pressure , the extent of adsorption is found to be directly proportional
to the pressure .
•At higher pressure , after a certain pressure(closer to saturation pressure) there
is no increase in adsorption .

17. • EFFECT OF TEMPERATURE
• As adsorption is exothermic , so according to Le- Chatelier’s
principle, adsorption increases with decrease in temperature.
• A physisorption isobar shows decrease in extent of
adsorption as temperature rises .
• The isobar of chemisorption show an increase in beginning
and then decreases as temperature rises .

18. Reference
• Advance Physical Chemistry,22nd edition, Gurtu – Gurtu
• Keith J. Laidler, chemical Kinetics, Third edition, Pearson
Education, 2004
• Youtube