AN EXPERIMENTAL STUDY OF THE STATE OF HEXANE IN A CONFINED GEOMETRY

摘要

Literature data about hysteresis closure points of sorption isotherms has been summarized and it was shown that these points are located in one half of the (1-T/Tc, P/P°) plan. Below the limiting straight line, no hysteresis can be found. A study of the transition between the reversible and the irreversible (hysteretic) regime for n-hexane adsorbed on MCM-41 or similar mesoporous materials has been carried out. The dependence on pressure, temperature and pore size has been investigated and confirmed the literature data. Enthalpies of adsorption have also been derived from the isotherms using the isosteric method. The enthalpies showed a dependence on pore size: when the pore size decreases, the adsorptive is stabilised and the enthalpy of adsorption becomes more negative.