with a selective adsorbent may be used to remove the non regenerable silicon compounds and prevent them from interfering with long term performance of the recirculating adsorbent for hydrocarbon feed service the adsorbent particles are in a preferred sense generally spherical in the original or new adsorbent with a narrow size range such as 16 u00d7 20 or 20 u00d7 24 tyler mesh liquid phase adsorption differs from gas phase adsorption in that diffusion is at least two orders of magnitude slower in the liquid phase than in the gas phase diffusion of components in a liquid phase requires additional residence time which is why adsorber vessel 108 is constructed in a series of adsorption stages 110 118 impurities adsorb on the solid adsorbent because the attraction of the adsorbent surface is stronger than the attractive force that keeps the impurities in the surrounding fluid liquid adsorption may be defined as a type of adhesion that in a thermodynamically preferred sense occurs at the surface of a solid having an adsorbable impurity in the liquid medium this preference results in a relatively increased concentration of adsorbable impurities entering the adsorbent particle pores solid porous particles can exhibit attraction for impurities for a number of reasons such as physisorption or chemisorption physisorption is due to physical attraction or van der waal 39 s forces chemisorption is that due to chemical or valence forces adsorption is accompanied by evolution of heat because the adsorbate molecules are stabilized on the adsorbent surface for limited quantities of impurities in the.