Application of Green Nanocomposite to Adsorb Cadmium ion in Wastewater

Under to the development of the industrialization, people have polluted the water source with chemicals and wastes from factories and enterprises. These chemicals are not treated and discharged directly to the natural environment, especially heavy metals. Cadmium and its compounds are released to the environment from different sources of waste, such as metal, alloy and metal plating, and Cd-Ni batteries, which clearly showed a danger to the human health. In this work, silicon oxide nanoparticles (SiO2) functionalized with polyaniline (PANI) polymer, then C2H5OH-SiO2/PANI (CSP) was synthesized by dispersion process in ultrasound sonication by ethanol solution. CSP were successfully synthesized and determined by several characterizations such as FTIR, SEM, TEM and BET. Based on the practical data, the Cd(II) adsorption was followed by Langmuir adsorption isotherms, and the pseudo-second order adsorption kinetic. CSP has obtained the Cd maximum adsorption capacity of 301.23 mg g-1, which is higher than the previous reported adsorbents. Cd(II) adsorption by CSP is desired at pH 6, reaction time of 150 min, initial concentration at 300 mg L-1, and weight of 0.6 g. Adsorption data show that pH is one of the most important factor in Cd(II) adsorption due to the formation of surface complexes between Cd2+ and the functional groups of CSP such as hydroxyl group (OH-), silanol (Si-OH), amine (–NH2), quinoid imine [C=N–] and benzenoid amine [–NH–].