Water adsorption in active carbon characterized by adsorption and immersion techniques

Abstract

The preadsorption of variable amounts of water, followed by the adsorption of nitrogen at 77 K or the immersion into water at 293 K has been examined for a set of well characterized active carbons. The results confirm the model proposed by Dubinin, suggesting that water forms clusters around primary centres, rather than filling the micropores by capillary condensation. The primary centres are occupied gradually, as adsorption proceeds. This is also suggested by immersion into benzene, which appears to displace completely the adsorbed water.

Surprising role of the BDC organic ligand in the adsorption of CO2 by MOF-5

“…Moreover, Ramsahye et al have explained that the step-like isotherms in MIL-53 family of MOFs is a consequence of the very large framework flexibility and breathing effect of these solids [9], rather than any Coulombic effect. Obviously, this explanation cannot be applied to the rigid framework of Prior to the studies in MOFs, similar sigmoidal isotherms were observed for the adsorption of water in porous carbons, which have been explained as arising from cluster-like adsorption of water molecules around ''anchored'' water molecules which adsorb first onto hydrophilic defects, typical in such materials [10,11]. However, the presence of such ''anchoring'' defects is unlikely in MOF-5, and are totally absent in the computer modeling studies so far reported, where perfect lattices are used.…”

Static Adsorption, by Activated Carbons, of Vapour Mixtures Corresponding to Immiscible Liquids

“…Pre-adsorption of n-nonane and n-undecane, followed either by immersion into water at 293 K or the determination of nitrogen adsorption isotherms at 77 K, was carried out as described in detail by Stoeckli et al (1991Stoeckli et al ( , 1992.…”

“…In the case of carbon UO-3, nitrogen isotherms were also measured at 77 K following the preadsorption of n-nonane (Stoeckli et al 1992), and analysed with equation (I) in the DR form (n =2). As shown in Table 3, Eodecreased from 17.2 kllmol to II kllmol as 8 increased from 0 to 0.77.…”

Modeling Molecular Recognition: Theory and Application

“…In particular, hydrogen bonding can be an important mechanism of adsorption when polar compounds in nonpolar phases adsorb onto polar surfaces (29,30,31). An example is the adsorption of oxygenated aromatic compounds (OAC) onto an acrylic ester resin.…”