Diffusion of Volatile Organic Chemicals in Porous Media.1.Alcohol/Natural Zeolite Systems

摘要

The aim of the present paper was to measure the diffusion coefficients,mode of transport,and activation energies of some alcohols into the porous structure of a Turkish natural zeolite.Diffusion coefficients,modes of transport,and activation energies of methanol,ethanol,n-propanol,2-propanol,and n-butanol into the porous structure of the Turkish Manisa Gordes natural zeolite were measured at 24-28 deg C.The diffusion coefficients of alcohols were calculated from the slope of graphs of M_t/M_infinity versus t~(1/2).As the molecular weight of the alcohols increased,diffusion coefficients decreased,the activation energy for diffusion increased,and the time necessary to reach equilibrium was increased.The diffusion constants increased linearly with an increase in the temperature.The diffusion of alcohols in the zeolite obeyed the anomalous transport mechanism.Diffusion rate constants remained unchanged as the temperature was increased.With increasing molecular weight of the volatile alcohols,the activation energies also increased.The calculated activation energies of diffusion were 18.3,46.4,79.7,57.3,and 90.1 kJ/mol for methanol,ethanol,n-propanol,i-propanol,and n-butanol,respectively.