Removal of Cetyldimethylbenzylammonium Chloride Surfactant from Aqueous Solution by Adsorption onto Mesoporous Silica

In this work, batch adsorption experiments were carried out for the removal of Cetyldimethylbenzylammonium chloride (BAC) as a pollute surfactant from aqueous solutions on mesoporous silica as adsorbents. This silica was prepared from sodium silicate as a precursor and cetyltrimethylammonium bromide (CTAB) as template using sol-gel method. The effects of major variables governing the efficiency of the process such as dosage of mesoporous silica (0.05-0.1, 0.2 and 0.3g) and temperature (298-328 K) were investigated. Equilibrium data were fitted to the Langmuir, Freundlich and Temkin isotherm models and isotherm constants were determined. The equilibrium data were best represented by the Freundlich isotherm model. The adsorption kinetic data were analyzed using pseudo-first-order, pseudo-second-order and intra particles diffusion models. The results matched well with Pseudo-second-order and the intraparticle diffusion model suggests that the adsorption process proceeds by surface sorption and intra-particle diffusion. Thermodynamic parameters such as changes in the free energy of adsorption (G), enthalpy (H) and entropy (S) were calculated and the results obtained indicate that these systems were spontaneous and exothermic in nature.