Na-montmorillonite was modified via an ion-exchange reaction with octadecyl dihydroxy ethyl methylammonium bromide (ODEM). The modified material (Na-Mt) was characterized by X-ray diffraction (XRD), Fourier transform infrared (FUR) spectroscopy. and Scanning electron microscopy (SEM). The basal spacing of the modified Na-Mt was 2.47 nm and the IR spectra of modified Na-Mt showed CH2 vibrations. The adsorption of phenol by modified Na-Mt from aqueous solution was indicative of a pseudo-second-order model which was used to calculate the corresponding rate constants (2.07 g/mg min(-1) at 308 K), and the Langmuir isotherms fitted the adsorption best, giving the highest adsorption capacity (384.61 mg/g at 308 K). The calculated thermodynamic parameters suggested that the adsorption of phenol onto modified Na-Mt was physisorptive, spontaneous and exothermic in nature. (C) 2010 Elsevier B.V. All rights reserved.