LAUSR

Abstract A novel multi amine-containing Gemini surfactant (including four positively charged N) modified organo-montmorillonite (GMt) was prepared and served as adsorbents of phenol, o-chlorophenol (2-CP) and 2,4,6-trichlorophenol (2,4,6-TCP). The structure and morphology of GMt were studied by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), N2 adsorption/desorption isotherms (BET) and thermo gravimetric analysis (TGA). A batch technique was applied to investigate the influence of various factors, and the results illustrated that the saturated intercalation concentration of the modifier was 0.8 times to the cation exchange capacity (CEC) of the original Na-Mt and the adsorption was pH dependent, the optimum adsorption occurred at pH = 10, 7, 5 for phenol, 2-CP and 2,4,6-TCP, respectively. At the same conditions, the adsorption capacities of original Na-Mt were only 8.29 mg/g, 26.20 mg/g and 39.13 mg/g for three phenolic pollutants, while the maximum equilibrium adsorption amounts were 81.68 mg/g, 336.59 mg/g and 535.49 mg/g for phenol, 2-CP and 2,4,6-TCP, respectively. The adsorption kinetics of all the three phenols was in good agreement with the pseudo-second order kinetics model. The adsorption isotherm of 2,4,6-TCP was abided by Langmuir and Freundlich isotherm, however, phenol and 2-CP were better modeled by Freundlich isotherm. The negative values of ∆G° and positive values of ∆H° got from thermodynamic study confirmed that the adsorption of 2-CP and 2,4,6-TCP on GMt was a physical, spontaneous and endothermic process. The adsorption process of phenol was an exothermic process. Both adsorption and partition contributed to the adsorption of these three phenols to organo-montmorillonite.