1. It is a surface phenomenon and refers to the uniform distribution of a substance through another at the surface e.g. solution of H2 in Pd.

2. It is the phenomenon in which a layer of ions, molecules or aggregates of molecules condense upon the surface with which they come in contact.

3. It is defined as the concentration of a substance at the interface or boundary between heterogeneous phases e.g. solid/ gas or two immiscible liquids

Adsorbate

It is the substance which is adsorbed at the surface of another substance

Examples are: gases, dyes, water vapors etc.

Adsorbent

It is the substance which adsorbs the other substance at its surface.

Examples are: activated charcoal, bone charcoal, alumina, silica gel, kaolin and filler’s earth.

Order Of Adsorption

I. Liquid/ Solid adsorptionII. Solid/ Gas adsorptionIII.Liquid/ Gas adsorptionIV.Liquid/ Liquid adsorption

Positive adsorption

Negative adsorption

Sorption

How adsorption occurs

Types of Adsorption

Vander walls or physical adsorption

Chemisorption

Factors effecting the adsorption

Solubility of adsorptionNature of AdsorbateNature of adsorbentConcentration of adsorbentPressureTemperaturepHAffinity between adsorbent and adsorbateStirring

Pharmaceutical Applications of adsorption

1. Activated charcoal2. Physiological Importance3. Purification4. Preparation of Vitamin B1

5. Gas masks6. Heterogeneous Catalysts7. Bacterial filtration8. Solid-liquid chromatography9. Emulsification10.Decolonization11.Adsorption of water vapors

Lecture by:

Dr. Muhammad Akbar