Adsorption of phenol from aqueous solutions by organomontmorillonite Original Research Article

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 (FTIR) 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.