BETporositeitsanalyse

BETporositeitsanalyse, also known as BET analysis, is a technique used to determine the specific surface area and pore size distribution of a material. The method is based on the adsorption of a gas, typically nitrogen, onto the surface of the material. The adsorption process follows the Brunauer-Emmett-Teller (BET) theory, which describes the multilayer adsorption of gases on solid surfaces.

The BET analysis involves several steps. First, the material is degassed to remove any adsorbed gases and to ensure a clean surface. Then, the material is exposed to the adsorbate gas (nitrogen) at various pressures. The amount of gas adsorbed is measured at each pressure, and a plot of the adsorption data is generated. The specific surface area is calculated from the linear portion of the BET plot, which corresponds to the monolayer adsorption of the gas.

The pore size distribution is determined by analyzing the desorption branch of the adsorption-desorption isotherm. The desorption data is used to calculate the pore volume and the pore size distribution using models such as the Barrett-Joyner-Halenda (BJH) method or the Density Functional Theory (DFT).

BET analysis is widely used in various fields, including materials science, catalysis, and environmental science. It provides valuable information about the surface properties of materials, which can influence their performance in various applications. The technique is relatively simple and cost-effective, making it a popular choice for characterizing porous materials. However, the accuracy of the results depends on the quality of the sample and the experimental conditions.