Comparative Study of Adsorption of Safranin o by TiO2/Activated Carbon and Chitosan/TiO2/Activated Carbon Adsorbents

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, a three-fold composite of activated carbon was prepared from Persian mesquite seeds, chitosan, and nanoparticles of titanium dioxide as an effective adsorbent for removal of safranin o. X-ray Diffraction (XRD), scanning electron microscope (SEM), BET analysis and thermogravimetric analysis (TGA) have been used to determine and confirm the physicochemical variations during the preparation and modification of activated carbon on both adsorbents. The results of XRD, SEM and TGA showed that the 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 the safranin o, a cationic azo dye, from an aqueous solution. The experimental data at different conditions were correlated with some famous kinetic and isotherm models. Extrapolated data showed that the dye adsorption on the Ac/TiO2 and Ac/TiO2/Ch follows the pseudo-second-order kinetic model. High efficiency and sufficient adsorption capacity of Ac/TiO2/Ch for safranin o removal makes it a good candidate for water filtration.