The adsorption of volatile organic compounds (VOCs) on the activated carbon, silica gel, and type-13X synthetic zeolite were investigated by a gravimetric adsorption method. The sorbates (VOCs) include benzene, toluene, o-xylene, p-xylene, and m-xylene. The equilibrium isotherm data obtained from this study were fitted by the Freundlich equation. The standard deviations for the predicted adsorption isotherms in the activated carbon bed were from 0.44 to 0.92, and the standard deviations were from 0.25 to 4.79 in the silica gel bed and were from 0.12 to 0.87 in the 13X zeolite bed.