The adsorption characteristics of o-chlorophenol by treated Jordanian natural zeolite were investigated. The treatment was done using urea and thiourea. Column experiments were performed to evaluate the effects of various experimental parameters on the removal of o-chlorophenol, such as: calcined of zeolite, contact time, the pH and the initial concentration. The rate of removal of o-chlorophenol from aqueous solution by the modified zeolite was studied in batch conditions at different temperatures. Different kinetic models were used to evaluate the obtained results such as pseudo-second-order, intra-particle diffusion and Elovich models. The R 2 values showed that the pseudo-second-order equation was the most appropriate model for the description of o-chlorophenol transport. The activation energy of sorption was calculated using pseudo-second-order rate constant, Desorption was achieved using methanol solution (30%, v/v). The treated natural zeolite was found to be Suitable for reuse without noticeable loss of adsorption capacity. (C) 2009 Published by Elsevier B.V.