Adsorption of phenol with modified rectorite from aqueous solution

The natural rectorite (REC) was modified with surfactant of dodecyl benzyl dimethyl ammonium chloride, hexadecyl trimethyl ammonium bromide and octadecyl trimethyl ammonium bromide, respectively, to form three kinds of organic-modified rectorite (OREC), termed OREC1, OREC2 and OREC3. Three kinds of ORECs were used as adsorbents for phenol in aqueous solution. Through FTIR and XRD analysis, it confirmed the cation exchange reaction between REC and surfactant. The amount of surfactant exchanged in OREC1, OREC2 and OREC3 were determined as 0.27, 0.51 and 0.62 mmol/g, respectively, through incineration method. Through the research of phenol adsorption, it was found that the removal percentage (%) of phenol increased with the increase in adsorbents dose, whereas the adsorption amount qe (mg/g) decreased. The adsorption efficiency of OREC adsorbents was greatly affected by the initial phenol solution pH value. The thermodynamics study of adsorption process showed that the adsorption of phenol with three adsorbents was carried out spontaneously, and that the process was exothermic in nature. The adsorption kinetic data of phenol with OREC adsorbents were well fitted to the Lagergren rate equation. The Freundlich isotherm model was employed and well represented in the experimental data.