sorptionsisothermische

Sorptionsisotherme refers to a graphical representation that illustrates the relationship between the amount of a substance adsorbed onto a surface and the pressure or concentration of that substance at a constant temperature. The adsorbed substance is known as the adsorbate, and the material providing the surface is the adsorbent. The y-axis of a sorptionsisotherm typically represents the amount of adsorbate, often in units like mass per unit mass of adsorbent or moles per unit mass of adsorbent. The x-axis represents either the partial pressure of the adsorbate in a gas phase or the concentration of the adsorbate in a liquid phase. The key characteristic is that the temperature remains fixed throughout the measurement.

Several types of sorptionsisotherms exist, classified by the International Union of Pure and Applied Chemistry (IUPAC) into five main types: Type I, II, III, IV, and V. Type I isotherms are characteristic of monolayer adsorption, where the adsorbate forms a single layer on the adsorbent surface, often seen in chemisorption. Types II and III are associated with multilayer adsorption, where the adsorbate forms multiple layers. Type II typically shows a sharp increase in adsorption at higher pressures, while Type III exhibits a more gradual rise. Types IV and V are similar to II and III but include a hysteresis loop, indicating a difference in adsorption and desorption behavior, often related to capillary condensation in porous materials. Sorptionsisotherme are crucial in understanding gas storage, separation processes, catalysis, and the behavior of materials in contact with different substances.