Desorption

Desorption is a phenomenon whereby a substance is released from or through a surface. This is the opposite of absorption, wherein a substance diffuses into a material. The process is used in many scientific, environmental and industrial applications.

Process

Desorption may occur in two situations. If an atom or molecule is adhered to a solid surface, it may be removed by providing enough energy to overcome the chemical bond holding it there. Alternatively, if the substance is dissolved in a liquid or gas, it may be removed by altering the conditions to reduce the solubility so that the dissolved substance precipitates out.

Types of Desorption

There are several types of desorption processes, including:

• Thermal desorption - This is a remediation method used to clean contaminated soil or other material by heating it to a high temperature. The contaminants are vaporized and can then be collected and treated.

• Electron-stimulated desorption - This process involves the use of a beam of electrons to remove adsorbed atoms or molecules from a surface.

• Photon-stimulated desorption - This is a process where photons are used to remove adsorbed atoms or molecules from a surface.

• Desorption electrospray ionization - This is a method used in mass spectrometry to produce ions from a sample without the need for any preliminary treatment.

Applications

Desorption techniques are used in a variety of applications, including environmental remediation, food processing, and scientific research. For example, thermal desorption is often used to remove organic contaminants from soil, while desorption electrospray ionization is used in mass spectrometry to analyze the chemical composition of a sample.

See also

• Adsorption
• Sorption
• Chemisorption
• Physisorption

References

Desorption Resources
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