A study in analytical chemistry of adsorption of heavy metal ions using chitosan/graphene nanocomposites

In this work, chitosan/graphene nanocomposite granules with weight percentages of 0.5%, 1%, 2% and 5% were prepared using a solution method. At first, graphene was oxidized with sulfuric and nitric acid then triethylenetetramine was grafted on graphene surface. Functionalized graphene was characterized by Fourier-transform infrared spectroscopy (FT-IR), Therapeutic Goods Administration (TGA), X-ray energy diffraction spectroscopy (EDX) and Scanning electron microscope (SEM). Results showed functionalization of graphene was successfully accomplished. The thermogravimetric analysis curves showed the pristine, oxidized and functionalized graphenes are stable up to 400, 250, and 300, respectively. The pristine graphenes are more stable than oxidized graphenes and the oxidized graphenes are more stable than functionalized graphenes. The observed stabilized temperature is known to be strongly influenced by the step of the functionalization. The morphology of nanocomposite was monitored by Scanning electron microscope (SEM). The SEM images showed that the porosity was reduced due to presence of nano graphenes. Results showed that the nanocomposite samples have higher potential for ion metals adsorption than that of neat chitosan. The adsorption of nano samples for cadmium was increased around 20% in comparison to neat chitosan. Atomic adsorption spectrometry showed that the optimal adsorption rate of cadmium ion occurs in a solution of 50 ppm with a pH = 7 and a contact time of 2 hours and an adsorbent of 25 mg