Sorption isotherm
Encyclopedia
A sorption isotherm describes the equilibrium of the sorption
of a material at a surface (more general at a surface boundary) at constant temperature
. It represents the amount of material bound at the surface (the sorbate) as a function of the material present in the gas phase and/or in the solution. Sorption isotherms are often used as empirical models, which do not make statements about the underlying mechanisms and measured variables. They are obtained from measured data by means of regression analysis
. The most frequently used isotherms are the linear isotherm, Freundlich isotherm, the Langmuir isotherm, and the BET model.
Sorption
Sorption refers to the action of absorption* Absorption is the incorporation of a substance in one state into another of a different state ....
of a material at a surface (more general at a surface boundary) at constant temperature
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
. It represents the amount of material bound at the surface (the sorbate) as a function of the material present in the gas phase and/or in the solution. Sorption isotherms are often used as empirical models, which do not make statements about the underlying mechanisms and measured variables. They are obtained from measured data by means of regression analysis
Regression analysis
In statistics, regression analysis includes many techniques for modeling and analyzing several variables, when the focus is on the relationship between a dependent variable and one or more independent variables...
. The most frequently used isotherms are the linear isotherm, Freundlich isotherm, the Langmuir isotherm, and the BET model.
See also
- AdsorptionAdsorptionAdsorption is the adhesion of atoms, ions, biomolecules or molecules of gas, liquid, or dissolved solids to a surface. This process creates a film of the adsorbate on the surface of the adsorbent. It differs from absorption, in which a fluid permeates or is dissolved by a liquid or solid...
- ChemisorptionChemisorptionChemisorption is a sub-class of adsorption, driven by a chemical reaction occurring at the exposed surface. A new chemical species is generated at the adsorbant surface...
- DesorptionDesorptionDesorption is a phenomenon whereby a substance is released from or through a surface. The process is the opposite of sorption . This occurs in a system being in the state of sorption equilibrium between bulk phase and an adsorbing surface...
- Gibbs isothermGibbs isothermThe Gibbs adsorption isotherm for multicomponent systems is an equation used to relate the changes in concentration of a component in contact with a surface with changes in the surface tension...
- Moisture sorption isothermMoisture sorption isothermAt equilibrium, the relationship between water content and equilibrium humidity of a material can be displayed graphically by a curve, the so called moisture sorption isotherm....