Chitosan-Titanium Dioxide Nanoadsorbent for Cd(II), Cu(II), Ni(II) and Pb(II) Ions: Adsorption Isotherm and Characterization Studies

Abstract The application of nanotechnology in water treatment is predicted to continue to grow in coming years, worldwide. Environmental scientists are currently focusing on development of cost-effective and eco-friendly nanoadsorbents, nanomembranes, nanofilters and nanophotocatalysts to treat contaminated water. In this research work, chitosan-titanium dioxide (Cs-TiO 2 ) nanocomposite was prepared using a simple one-step method. The physicochemical properties of nanocomposite were studied using spectroscopy and microscopy techniques. The consequences of experimental parameters on adsorption performance of Cs-TiO 2 for Cd(II), Cu(II), Ni(II) and Pb(II) metal ions were studied in details. The Langmuir model fitted the adsorption isotherm very well with correlation coefficient values of R 2 > 0.99. The separation factor ( R L ) values were in the range of 0-1.0 for all metal ions studied, suggesting the adsorption activity was favorable. The maximum adsorption capacities ( Q max ) of Cs-TiO 2 for Cd(II), Cu(II), Ni(II) and Pb(II) metal ions were determined as 133.33, 416.67, 151.51 and 277.78 mg/g, respectively. From Fourier Transform Infrared (FTIR) spectra, the appearance and wavenumber of absorption bands for functional groups of Cs-TiO 2 changed and shifted after adsorption of metal ions. The X-ray Diffraction (XRD) spectroscopy and Scanning Electron Microscopy (SEM) analyses revealed the change in crystallinity and surface morphology after interaction of Cs-TiO 2 with metal ions studied. Overall, findings obtained from this research work highlight the feasibility of Cs-TiO 2 as a nanoadsorbent for the treatment of water contaminated by toxic Cd(II), Cu(II), Ni(II) and Pb(II).