Topics - Adsorption
is a process whereby material (contained in a contacting fluid) interacts by physical forces (dispersive, polar or ionic) with a surface, thereby, causing a layer (or layers) of the material to adhere to that surface. The surface in most cases will be a solid (e.g. silica gel., alumina, charcoal etc,) or sometime a liquid (e.g. surfactants on water surfaces). The contacting fluid may be a liquid or a gas. The surface layer(s) may be single, double or multiple. The relationship between the concentration of the adsorbed material on the surface and the concentration of the material in the contacting fluid is called the adsorption isotherm. Two of the well established adsorption isotherms, are the Langmuir isotherm and the Freundlich isotherm. The adsorption process is used industrially for extraction, isolation and purification and as a gas/solid or liquid/solid distribution system in chromatography.