Adsorption is the process in which molecules or particles adhere to the surface of a solid material. This phenomenon occurs when gases, liquids, or dissolved substances come into contact with a solid surface and adhere to it through van der Waals forces, electrostatic interactions, or chemical bonds. Adsorption is used in various industrial processes, such as water purification, gas separation, and catalysis. It is also widely studied in the field of materials science and chemistry to better understand the behavior of molecules on different surfaces and to develop new materials with specific adsorption properties.