Enhanced hydrogen solubility ethanol and n-hexane confined in a silica aerogel matrix

Internationa

Sursolubilité de l'hydrogčne dans des liquides mésoconfinés

National @ INGENIERIE+SCLInternational audienceNon

Enhanced hydrogen solubility in nanosized ethanol and n-hexane in silicate aerogel and carbon matrices

Nationa

Gas Uptake in Solvents Confined in Mesopores: Adsorption versus Enhanced Solubility

International audienceThree molecular mechanisms for gas uptake in a solvent confined in mesopores are identified. On the one hand, CO2 uptake is an adsorption-driven phenomenon that arises from the strong interaction between the gas molecules and the pore surface. On the other hand, H-2 uptake is a confinement-induced enhanced solubility in which solubility is favored in the regions of low solvent density formed by the layering of the solvent. In partially filled pores, adsorption at the gas/liquid solvent interface is a third mechanism that leads to large gas uptakes. This study, which sheds light on previously reported yet unclear oversolubility in pores, provides a guide to design hybrid porous catalysts consisting of a solvent confined in a porous soli

Enhanced H2 uptake of n-alkanes confined in mesoporous materials

The hydrogen uptake in hybrid sorbents consisting of n-alkane solvents confined in mesoporous silica aerogel is measured at different temperatures from 273 to 313 K and pressures up to 40 bar. An apparent “oversolubility” effect is observed as the H2 uptake in the hybrid sorbents is much larger than that in bulk solvents. The H2 uptake in the hybrid sorbents is found to increase with increasing temperature, which suggests that the flexibility and conformation of n-alkane molecules confined in the aerogel play a crucial role; high-entropy (disordered) alkane configurations lead to the creation of numerous cavities which make it possible to solubilize a larger number of H2 molecules. This departs from adsorption-driven solubility effects for which the number of solubilized molecules decreases with increasing temperature. For a given temperature and pressure, it is found that the number of solubilized H2 molecules per unit volume increases with decreasing alkane chain length. Such an effect, which is observed for both the bulk alkanes and the alkanes confined in the silica aerogel, can be rationalized by considering the number density of CHx (x = 2 or 3) groups; for a given temperature, the latter number density decreases with decreasing alkane chain length so that the free volume available to solubilize H2 molecules increases

Nanocomposite zeolite-alumina hollow-fibre membrane: generalization of a method.

internationalInternational audienc

Enhanced H₂ Uptake of <i>n-</i>Alkanes Confined in Mesoporous Materials

The hydrogen uptake in hybrid sorbents consisting of <i>n-</i>alkane solvents confined in mesoporous silica aerogel is measured at different temperatures from 273 to 313 K and pressures up to 40 bar. An apparent “oversolubility” effect is observed as the H₂ uptake in the hybrid sorbents is much larger than that in bulk solvents. The H₂ uptake in the hybrid sorbents is found to increase with increasing temperature, which suggests that the flexibility and conformation of <i>n-</i>alkane molecules confined in the aerogel play a crucial role; high-entropy (disordered) alkane configurations lead to the creation of numerous cavities which make it possible to solubilize a larger number of H₂ molecules. This departs from adsorption-driven solubility effects for which the number of solubilized molecules decreases with increasing temperature. For a given temperature and pressure, it is found that the number of solubilized H₂ molecules per unit volume increases with decreasing alkane chain length. Such an effect, which is observed for both the bulk alkanes and the alkanes confined in the silica aerogel, can be rationalized by considering the number density of CH_<i>x</i> (<i><i>x</i> = </i>2 or 3) groups; for a given temperature, the latter number density decreases with decreasing alkane chain length so that the free volume available to solubilize H₂ molecules increases

Enhanced H 2

INGENIERIE+SCL:LHO:MPE:DFAThe hydrogen uptake in hybrid sorbents consisting of n-alkane solvents confined in mesoporous silica aerogel is measured at different temperatures from 273 to 313 K and pressures up to 40 bar. An apparent oversolubility" effect is observed as the H-2 uptake in the hybrid sorbents is much larger than that in bulk solvents. The H-2 uptake in the hybrid sorbents is found to increase with increasing temperature, which suggests that the flexibility and conformation of n-alkane molecules confined in the aerogel play a crucial role; high-entropy (disordered) alkane configurations lead to the creation of numerous cavities which make it possible to solubilize a larger number of H-2 molecules. This departs from adsorption-driven solubility effects for which the number of solubilized molecules decreases with increasing temperature. For a given temperature and pressure, it is found that the number of solubilized H-2 molecules per unit volume increases with decreasing alkane chain length. Such an effect, which is observed for both the bulk alkanes and the alkanes confined in the silica aerogel, can be rationalized by considering the number density of CHx (x = 2 or 3) groups; for a given temperature, the latter number density decreases with decreasing alkane chain length so that the free volume available to solubilize H-2 molecules increases