Electrostatic phenomena chemical properties

When a gas or vapor becomes in contact with a solid, some molecules attach to the surface of the solid. This phenomenon is termed adsorption . The solid that takes up the gas is called the adsorbent and the gas or vapor taken up on the surface is called the adsorbate. When adsorbed species detached from the surface of the solid and return into the gas phase, this phenomenon is called desorption . Physical adsorption is caused by van der Waals force and electrostatic forces between adsorbate molecules and the atoms which compose the adsorbent surface (Suzuki, 1990). Thus, adsorbents are conveniently characterized by surface properties such as surface area and polarity. In Chemical adsorption , the adsorbate molecules attach to the surface by forming a chemical (usually covalent) bond. 

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