Fysisorptioon

Fysisorptioon, a term derived from physics and adsorption, refers to a type of adsorption where the forces binding the adsorbate to the adsorbent are weak, primarily van der Waals forces. This is in contrast to chemisorption, which involves stronger chemical bonds. Fysisorptioon is a reversible process, meaning the adsorbate can be easily desorbed from the surface of the adsorbent, often by increasing temperature or decreasing pressure. The enthalpy of adsorption for fysisorptioon is typically low, ranging from 20 to 40 kJ/mol.

This type of adsorption occurs readily at low temperatures and high pressures. The adsorbate molecules do not undergo any chemical transformation and retain their original molecular identity. Fysisorptioon is not limited to specific chemical interactions between the adsorbate and adsorbent; it can occur between any gas and any solid. A key characteristic is that it often involves the formation of multiple layers of adsorbate on the adsorbent surface, as described by the Brunauer-Emmett-Teller (BET) theory. Applications of fysisorptioon include gas separation, purification, and the storage of gases.