Adsorption equilibrium, isotherm, kinetics, and thermodynamic of modified bentonite for removing Rhodamine B

Abstract

Anionic and cationic surfactant modified sodium bentonite (Na-Bt) has been prepared by the cationic surfactant cetyltrimethyl ammonium bromide (CTAB) and the anionic surfactant sodium dodecyl benzene sulfonate (SDBS) to sodium bentonite, respectively. The properties of the modified samples are characterized by XRD, SEM, BET and FT-IR. The results of characterization shown that the cationic surfactant had changed the structure and properties of natural sodium bentonite, which proved that surfactants had been successfully implanted into sodium bentonite. But anionic surfactant had no change, this manifested SDBS didn’t insert the layers of bentonite. In addition, adsorption experiments of Rhodamine B (RhB) proved that the modified sodium bentonite adsorption performance is greatly improved. The adsorption experiments also indicated that CTAB-bentonite had the largest adsorption capacity compared with SDBS-bentonite due to the formation of a highly effective partition medium by cationic surfactant micelle. The adsorption data of RhB is analyzed with the isothermal model, thermodynamics and kinetics. Overall, this study provided high-efficiency method for the removal RhB by the surfactant modified bentonite.