gasadsorptieanalyse

Gas adsorptieanalyse, often referred to as gas adsorption analysis, is a technique used to characterize porous materials by measuring the amount of gas that adsorbs onto their surface as a function of pressure. This method provides valuable information about the physical properties of a material's porous structure, including its surface area, pore volume, and pore size distribution.

The fundamental principle behind gas adsorption analysis relies on the physical interaction between gas molecules and the solid surface of the material. At low pressures, gas molecules adsorb onto the surface of the porous material. As the pressure increases, more gas molecules are adsorbed, eventually leading to multilayer adsorption. When the pressure is then decreased, the gas desorbs from the surface, and the amount of gas desorbed at different pressures is recorded.

The resulting data is typically plotted as an adsorption-desorption isotherm, which shows the volume of gas adsorbed as a function of relative pressure. Different shapes of isotherms correspond to different types of porous structures, as classified by the International Union of Pure and Applied Chemistry (IUPAC). By analyzing these isotherms using specific theoretical models, such as the Brunauer-Emmett-Teller (BET) theory for surface area determination and the Barret-Joyner-Halenda (BJH) method for pore size distribution, detailed insights into the material's porosity can be obtained. Common adsorbates include nitrogen, argon, and carbon dioxide, chosen for their inertness and well-defined adsorption properties. Gas adsorptieanalyse is widely applied in fields such as materials science, catalysis, pharmaceuticals, and environmental science for understanding and optimizing materials with porous structures.