Adsorption

Adsorption

ADSORPTION (from the Latin words "ad" which means "at" and "sorbeo" which means "devour" * EN: adsorption; DE: Adsorption, Adsorbieren, Adsorbierung; FR: adsorption; ES: adsorcion; RU: адсорбция) is the intake of the individual components of the gaseous (steamy) or liquid mixtures at the surface of the solid body (or at the volume of its micropores) or liquid. They usually understand the adsorption in the technology as the intake at the surface of the solid body (adsorbent).

Adsorption is the foundation of the technological processes of the fine cleaning of the gaseous and other streams with the low initial content in them of the target component (see the Adsorptive cleaning of the gas). They distinguish between the (physisorption) physical adsorption and the chemisorption.

The (physisorption) physical adsorption is caused by the van der Waals (electrostatic) forces of the attraction of the particles of the substance, which is adsorbed, to the particles of the adsorbent. During the chemisorption, the molecules of the intaken substance chemically react with the molecules of the adsorbent. The adsorption is selective and reversible. The reverse process of the release of the absorbed component from the solid phase is called the desorption, or the regeneration of the adsorbent. There are used as the adsorbent the solid substances, which have the large specific (that is per the unit of the weight or volume) surface, namely the activated carbon, alumina, silica gel, zeolites, etc.

The adsorption is performed in the column apparatuses, which are filled with the adsorbent. The process is cyclic: the bed (layer) of the adsorbent is saturated with the target component in the adsorption cycle, after which they regenerate the adsorbent. The adsorption is performed periodically or continuously in one or several apparatuses. The selectivity of the adsorption for the mineral particles determines the effectiveness of the flotation, which is achieved by the introduction of the special reagents, which are called the regulators, by the choice of the pH of the medium, of the density of the pulp, by the physical impact on the pulp (the ultrasonic and electrochemical processing, heating, steaming, etc.). During the benefication of the asbestos, the high adsorptive properties of the material are causing the increased dustiness of the product.