Abstract: The acid modified kaolinite and Mo supported on acid modified kaolinite were used as the adsorbents for VO-OEP in cyclohexane. The adsorption behavior as well as adsorption mechanism were investigated thermodynamically. The results show that the adsorption process follows the Langmuir′s isotherms, indicating a monolayer VO-OEP adsorbed on the modified kaolinite. The adsorption of VO-OEP on the modified kaolinite is exothermic in nature with the adsorption heat exceeding 40kJ/mol, which illustrates that chemical bonds are formed between VO-OEP and the modified kaolinite by adsorption.