adsorbant non polaire

OBS: Les zéolithes sont des alumino-silicates cristallisés microporeux de formule globale (AlO[indice 2]M,nSiO[indice 2]) où M représente le plus souvent un métal alcalin ou alcalino-terreux et n [est plus grand que ou égal à] 1. Il existe plus de 100 espèces de zéolithes, différant par la valeur de n et la structure cristallographique. La présence de cations dans les micropores génère des champs électriques de l'ordre de 10[exposant 10] V.m[exposant -1], ce qui fait de ces corps de puissants adsorbants polaires. [...] Les alumines activées sont des adsorbants amorphes, moyennement polaires et hydrophiles.
OBS: [...] la cyclohexanone se désorbe très mal et [...] la désorption des éthers de glycol nécessite des essais préalables associant souvent des solvants de désorption polaires et non polaires.

CONT: Common adsorbents are either polar or hydrophilic types, or nonpolar, hydrophobic types. ... Nonpolar adsorbents, such as coal-derived carbons and activated carbons, are generally used to remove less polar contaminants from polar bulk streams ...
CONT: [A] significant adsorptive characteristic is possessed not alone by carbons, charcoal and chars, but also by such materials as zeolite, silica, alumina, mica and some other. All these differ widely in the number and kinds of substances they adsorb, as well as in the amount of sorbed substances they will retain. In general, the silicaneous, metallic oxides and active earth types of adsorbents are electrically polar - that is, their molecular structure contains an unsymmetrical electron distribution. Since polar substances have strong attraction for one another and since water is highly polar, the polar adsorbents mentioned above retain water in preference to most other fluids and are, therefore, incapable of adsorbing non-aqueous gases efficiently from a humid atmosphere. For use in air conservation, however, which requires a sorbent to extract very small quantities of a very numerous variety of gases and vapors from either dry or humid air during a very brief interval of contact, non-polar adsorbents such as specially processed carbon of high activity, dense structure and extreme relative hardness have been found to be adequate. Activated carbon, being non-polar and hence electronically symmetrical in structure, has no particular affinity for moisture and preferentially adsorbs organic gases and vapors.