Cd(II) removal and recovery enhancement by using acrylamide-titanium nanocomposite as an adsorbent

Acrylamide (AM) was in-situ doped into titanium during sal-gel reaction and used as an adsorbent for cadmium removal from aqueous solution. The resulting TiO2-AM nanocomposite was characterized by particle size distribution (PSD) and thermogravimetric analysis (TGA). After cadmium adsorption, the nanocomposite was also characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy/energy-dispersive X-ray (SEM/EDX) and X-ray photoelectron spectroscopy (XPS) analyses. The adsorption behavior of the nanocomposite was examined by kinetic and equilibrium studies in batch conditions. The maximum cadmium binding capacity of TiO2-AM was 322.58 mg g(-1) at an optimum pH of 8.0, compared to 86.95 mg g(-1) for nano-titanium. Cadmium sorption showed pseudo-second-order kinetics with a rate constant of 4.0 x 10(-4) and 9.4 x 10(-5) g mg(-1) min(-1) at an initial Cd(II) concentration of 100 and 500 mg L-1, respectively. Cd (II) adsorption interference of cations (Pb2+, Cu2+, Co2+ and Zn+2) and anions (CI-, SO42-, CO32-) at pH 8 was very nominal because of favorable complex formation of Cd(II) and amide. The Cd(II) adsorption of 27% that was achieved in the fifth cycle was regenerated with 0.05 N acidic solutions. (C) 2014 Elsevier B.V. All rights reserved.