Efficiency of Magnetic Halloysite Nanotube/ Graphene Oxide Nanocomposite (M-HNT/GO) for Removal of Zinc Ions from Aqueous Solutions

Industrial and municipal wastewater often contains metal ions that once they are in excess of permitted limit they can be harmful to humans and aquatic animals’ health. Zinc is one of the pollutants which damages the aquatic environment and endangers the health of humans, animals and plants. In this study, graphene oxide (GO) with high surface area along with natural halloysite nanotubes (HNTs) and iron oxide nanoparticles are used as M-HNT /GO magnetic nanocomposite for the removal of zinc ions from aqueous solutions. In this study, magnetic halloysite nanotube/ graphene oxide nanocomposite (M- HNT/GO) was synthesized and then used as a nano-adsorbent for zinc removal from aqueous solutions. The M-HNT/GO nanocomposite was investigated and identified by using FT-IR, XRD and SEM methods. Vibrating sample magnetometer technique (VSM) was used to measure magnetic properties. The effect of different parameters such as pH, initial concentration of metal, temperature, stirring speed, adsorbent dosage and contact time on zinc removal by M- HNT/GO were investigated and optimum values were determined. Then, efficiency of fabricated nano-adsorbent was studied for removal of zinc ions from real sample. Optimal conditions for zinc ions removal were found at pH 6, the contact time of 90 minutes, the ion concentration of 2ppm, the GO to HNT and Fe3O4 ratio of 1: 1: 10 respectively, the buckling speed 250 rpm, the amount of adsorbent 005 g and the temperature of 25 ° C. The study of adsorption isotherms indicated the best fitting of experimental data with Fredlichl isotherm model. To describe kinetic data, pseudo first order and pseudo second order kinetic models were used. Dynamic data for zinc metal was adapted to pseudo second order kinetics model. The results showed that synthesized nano-adsorbents could be used with 95.2% ± 0.41% for zinc removal from wastewater contaminants. Furthermore, the M- HNT/GO nano-adsorbents can be recycled and reused frequently.