füüsikadsorptsioon

Füüsikadsorptsioon, often shortened to physisorption, is a type of adsorption where the adsorbate (the substance being adsorbed) is held to the adsorbent's surface by weak van der Waals forces. This is in contrast to chemisorption, where chemical bonds are formed. Physisorption is a reversible process, meaning the adsorbate can easily detach from the surface and return to the gas or liquid phase. The strength of the van der Waals forces depends on factors such as the distance between the adsorbate and adsorbent molecules, and the polarizability of these molecules.

This type of adsorption typically occurs at low temperatures, as higher temperatures provide enough kinetic energy for the adsorbate molecules to overcome the weak attractive forces and desorb. The amount of substance adsorbed in physisorption is generally higher than in chemisorption, and it can form multiple layers on the adsorbent surface. Physisorption is crucial in various scientific and industrial applications, including gas storage, separation processes, and chromatography. For example, activated carbon readily physisorbs gases due to its large surface area and porous structure. The identification and quantification of physisorption are often carried out using techniques like gas adsorption isotherms.