Adsorption

Adsorption is a surface-based process where a film of adsorbate is created on the surface of a solid material, known as the adsorbent. This process creates a surface phenomenon where particles, atoms or molecules of gas, liquid or dissolved solids adhere to a surface. Unlike absorption, where a fluid permeates or is dissolved by a liquid or solid, adsorption is a process that occurs on the surface of the material.

Mechanism of Adsorption

The mechanism of adsorption involves two main steps: the transport process and the attachment process. The transport process involves the movement of the adsorbate to the adsorbent surface, while the attachment process involves the interaction of the adsorbate with the surface of the adsorbent.

Types of Adsorption

There are two main types of adsorption: physical adsorption and chemical adsorption.

• Physical Adsorption: Also known as physisorption, physical adsorption involves weak van der Waals forces. The adsorbate adheres to the adsorbent's surface without any chemical bonding. It usually occurs at lower temperatures and can be easily reversed.

• Chemical Adsorption: Also known as chemisorption, chemical adsorption involves a stronger bond through chemical reactions between the adsorbate and the adsorbent. It usually occurs at higher temperatures and is not easily reversible.

Factors Affecting Adsorption

Several factors affect the process of adsorption, including the nature of the adsorbate and adsorbent, surface area of the adsorbent, temperature, and pressure.

Applications of Adsorption

Adsorption has a wide range of applications in various fields such as water purification, air conditioning, food storage, and in the medical field for drug delivery systems.

Illustration of the process of adsorption

See Also

• Desorption
• Sorption
• Catalysis
• Surface science