This research is a comparative study of the surface chemistry and adsorptive characteristics of titanium dioxide nanoparticles on activated carbon (Ac/TiO2) and chitosan loaded on activated carbon (Ac/TiO2/Ch). For the first time, using three-fold composite of activated carbon prepared from Persian mesquite seeds, chitosan, and nanoparticles of titanium dioxide as an effective adsorbent for removing safranin o. X-ray Diffraction (XRD), scanning electron microscope (SEM), BET analysis, and thermogravimetric analysis (TGA) have been used to determine and confirm physicochemical variation during preparing and modifying activated carbon on both adsorbents. The results of XRD, SEM, and TGA are shown essential changes happened in porosity of the surface after the modification process. The Ac/TiO2 and Ac/TiO2/Ch adsorbents have been used to /remove safranin o as a cationic azo dye from an aqueous solution. The experimental data at different conditions were correlated by some famous kinetic and isotherm models. Extrapolated data displayed dye adsorption on the Ac/TiO2, and Ac/TiO2/Ch follows the pseudo-second-order kinetic model. High efficiency and sufficient adsorption capacity in safranin o removal suggested that Ac/TiO2/Ch could be successfully used as a good candidate in water filtration.
