Physisorption

Chemisorption

1) It happens due to Van der

Waals forces.

2) It is reversible.

3) It is not specific in nature.

4) Low enthalpy of adsorption

(20-40 KJ mol^-1)

5) Low temperature is favourable.

It decreases with increase in temperature.

6) Very less activation energy is needed.

7) It results in the multimolecular layer.

1) It is caused by Chemical bond formation.

2) It is irreversible.

3) It is very specific in nature.

4) High enthalpy of adsorption

(80-240 KJ mol^-1)

5) The high temperature is favourable.

It Increases with an increase in temperature.

6) High activation energy is needed.

7) It results in the unimolecular layer.