SYNTHESIS AND CHARACTRISATION OF Fe3O4/PANI /CHITOSAN NANOCOMPOSITE AS ELECTROCHEMICAL SENSOR FOR THE DETERMINATION OF Cd( II) AND Pb(II) IONS

Abstract

Magnetite (Fe3O4) was produced using co-precipitation method while polyaniline (PANI) and Fe3O4/PANI nanocomposite were synthesized using in-situ polymerization of aniline in aqueous solution of Fe3O4 in the presence of oleic acid and sodium dodecayl sulphate (SDS). The ternary system (Fe3O4/PANI/Chitosan) composite was formed by blending the binary nanocomposite with chitosan. Structural and morphological properties of the as produced material were characterized using X-ray diffraction (XRD), Scanning electron microscope (SEM/EDX), Fourier transformed infrared and Uv-vis spectroscopy. The XRD pattern indicated semi crystalline structure of PANI, amorphous structure of magnetite but Fe3O4/PANI and Fe3O4/PANI/Chitosan have crystalline structures. Moreover, electrochemical behaviors of glassy carbon (GC) electrode modified by the as prepared nanomaterials was characterized using cyclic voltammetry in the presence of K3Fe(CN)6, in 1 M H2SO4 and 0.2 M phosphate buffer (PBS)/ 0.1 M KCl. The result depicted that Fe3O4 modified GCE is more electroactive compare to other modified electrodes. Besides, all modified electrodes in 1 M H2SO4 showed a reversible process whereas in buffer solution (pH 7) an irreversible electrochemical behavior was observed. Before utilizing GCE/Fe3O4/ PANI/Chitosan as a sensor for toxic heavy metals experimental parameters such as pH and deposition time were optimized. GCE/PANI, GCE/Fe3O4/PANI and GCE/Fe3O4/PANI/Chitosan were used as a sensor for the determination of Cd(II) and Pb(II) ions in standard solution with the concentration range from 10 to 50 ppm at optimum pH 7 and deposition time of 3min in 0.2 M PBS/0.1 M KCl using differential pulse anodic stripping voltammetry . The GCE/Fe3O4/PANI/Chitosan sensor exhibited a linear range of 10 to 50 ppm, 20 to 50 ppm, sensitivity 0.068 µA/ppm, 0.027 µA/ppm and detection limit 4.3 ppm, 4.3 ppm for Cd(II) and Pb(II) ions, respectively. The sensor was also used to determine the amount of Cd(II) and Pb(II) ions in water collected from Haramaya university waste water disposal and the concentration of Cd(II) and Pb(II) ions was 39.93 ppm and 17.14 ppm, respectively. Therefore, GCE/Fe3O4/PANI/Chitosan sensor can be a good alternative for the determination of toxic heavy metals in waste water samples