The adsorption equilibria of C8 aromatics in diethyl benzene were studied by the dynamic method. The adsorption isotherms of paraxylene

orthoxylene

ethylbenzene at 170℃ were determined from the breakthrough curves. Theadsorption isotherms of para- and orthoxylene mixture were determined as well. It turned out that the isotherms follow Henrys law when the concentration is less than 3.0mol/l. The adsorption of two-solute solution can be predicted from the isotherms of the single-solute solution by Radke-Prausnitzs two-dimensional ideal dilute solution theory. The Polanyis adsorption potential theory was used to describe the adsorption equilibria of the paraxylene-diethylbenzene system. The calculated adsorption isotherm at 110℃ from the adsorption data at 170℃ agrees well with the experimental results.