Liquid phase adsorption of each isomer of xylene and toluene with iso-octane as diluent was investigated over KY-and NaY-zeolites for the whole range of isomer concentration at 0℃, 30℃ and 50℃.
The inversion of selectivity on the two zeolites was found from the adsorption isotherms; i.e. p-xylene is adsorbed more selectively on the KY-zeolite but m-xylene on the NaY-zeolite. It is proposed that effects of temperature and concentration on the sorption selectivity can be explained by the dependence on the activity coefficient and the immersion free energy.
The rate of counterdiffusion of xylene isomer into the Y-zeolites preadsorbed with toluene was measured and the initial effective diffusion coefficient was estimated to be in the range of $10^{-12}-10^{-13}㎠/sec$. The effects of other preadsorbed materials on the counterdiffusion rate were measured and discussed.
