Desorb

Desorb refers to the process by which a substance is released from or through a surface. This term is commonly used in chemistry and physics to describe the removal of an adsorbate from a surface on which it is adsorbed. Desorption is the reverse of adsorption, which is the process by which atoms, ions, or molecules from a gas, liquid, or dissolved solid adhere to a surface.

Mechanism

Desorption can occur through various mechanisms, including:

• Thermal desorption: where increased temperature provides the energy needed for the adsorbate to overcome the binding energy and leave the surface.
• Pressure desorption: where a decrease in pressure reduces the concentration of the adsorbate in the surrounding phase, leading to desorption.
• Chemical desorption: where a chemical reaction changes the adsorbate into a form that is less strongly bound to the surface.

Applications

Desorption is a critical process in many industrial and scientific applications, including:

• Chromatography: where desorption is used to separate different components of a mixture.
• Catalysis: where desorption of reaction products from the catalyst surface is necessary for the catalyst to be reused.
• Environmental science: where desorption processes are studied to understand the release of pollutants from soils and sediments.

Factors Affecting Desorption

Several factors can influence the rate and extent of desorption, including:

• Temperature: Higher temperatures generally increase the rate of desorption.
• Pressure: Lower pressures can enhance desorption by reducing the concentration of the adsorbate in the surrounding phase.
• Surface properties: The nature of the surface, including its surface area, porosity, and chemical composition, can significantly affect desorption.

Related Concepts

• Adsorption
• Absorption
• Sorption
• Desorption isotherm
• Surface chemistry

See Also

• Adsorption
• Absorption
• Chromatography
• Catalysis
• Environmental science