ADSORPTION OF AROMATIC HYDROCARBON VAPORS AT THE GAS- SOLID AND GAS-WATER INTERFACE

摘要

It is apparent that there is a lack of experimental data on the adsorption of polycyclic aromatic hydrocarbons at the gas-water environmental interface such as fog droplets that offers a high surface area for potential accumulation of these hydrophobic organic compounds. An inverse gas chromatography (IGC) technique using Chromosorb P NAW as the packing support to obtain the thermodynamic properties of adsorption for three aromatic compounds (benzene, naphthalene and phenanthrene) at gas/water and gas/solid interfaces. The partition constant and free energy at different temperatures were measured and used to compute the enthalpy and entropy of adsorption using the Gibbs-Duhem equation. The enthalpy of adsorption at the gas/water interface for all three compounds was larger than the enthalpy of liquefaction and enthalpy of aqueous solvation. This supports the prevailing "critical cluster" model for the dynamics of the transfer of compounds to the gas/water interface. The thermodynamics of adsorption at the gas/solid interface was more favorable than the gas/water interface.