Chapter 5 - Water Adsorption by Carbons. Hydrophobicity and Hydrophilicity

Abstract

In spite of their intrinsically hydrophobic character, nanoporous carbon materials are able to adsorb a large amount of water, which can compromise their adsorption performance in gas-phase separation applications. The intention of this chapter is to show the importance of surface hydrophobicity and hydrophilicity in the adsorption of water by carbons. A variety of experimental approaches has revealed the key role of polar groups, which act as nucleation centers at the different stages of cluster formation and pore filling, whether in low-resolution experiments such as gas adsorption techniques, in higher-resolution scattering observations such as SAXS or SANS, or again in local methods such as NMR. The conclusions drawn for porous carbons, however, do not necessarily extend to CNTs. Several outstanding questions in water adsorption still remain incompletely understood, or even open. Understanding of these questions may be improved by the synergism between experimental and computational efforts.