Adsorption of supercritical N-2 and O-2 on pore-controlled carbon aerogels

Carbon aerogels (CA), having well-defined pore structure and different surf ace chemistry natures, were used to study the adsorption of supercritical N -2 and O-2 at 303 K. alpha (s), Langmuir, and DR methods were applied for i nterpretation of the experimental adsorption data. The surface chemistries were analyzed by XPS, The effect of the pore width and the surface chemistr y on the supercritical gas adsorption is discussed. Ce, Zr-doped CA adsorbs more supercritical N-2 and O-2 than CA. This effect is unlikely to be due to the pore structure, since Ce, Zr-doped CA has wider micropores. The larg er contribution of specific interactions between substrate sites and the ad sorbate at ambient temperature appears to play a very significant role. (C) 2001 Academic Press.