A new and effective nanobiocomposite for sequestration of Cd(II) ions: Nanoscale zerovalent iron supported on sineguelas seed waste

In this study, the synthesis and characterization of a new adsorbent containing nanoscale zerovalent iron particles (NZVI) supported on sineguelas waste (S-Na0H-NZVI) from agriculture biomass was developed as a new nanobioadsorbent for the adsorption of inorganic pollution such as Cd(II) ions. The combination of ZVI particles on surface of sineguelas waste can help to overcome the disadvantage of ultra-fine powders which may have strong tendency to agglomerate into larger particles, resulting in an adverse effect on both effective surface area and catalyst performance. The synthesized materials were characterized with different methods such as CHN elemental analysis, inductively coupled plasma/atomic emission spectroscopy (ICP-OES), Fourier transform-infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray (EDX) and the point of zero charge (pHpzc). Good dispersion of NZVI particles (ca. 10-70 nm) on the sineguelas waste was observed. The effects of various parameters, such as contact time, pH, concentration, adsorbent dosage and temperature were studied. The adsorption of Cd(II) ions has been studied in terms of pseudo-firstand -second-order kinetics, and the Freundlich, Langmuir and Langmuir-Freundlich isotherms models have also been used to the equilibrium adsorption data. The adsorption kinetics followed the mechanism of the pseudo-secondorder equation. The thermodynamic parameters (Delta G, Delta H and Delta S) indicated that the adsorption of Cd(II) ions were feasible, spontaneous and endothermic at 25-80 degrees C. EDX analysis indicated the presence of Cd(II) on the S-NaOH-NZVI surface. The study suggests that the sineguelas waste associated with NZVI particles can be designed at low cost and the materials are environmentally benign for the removal of Cd(II) ions, and likely many other heavy metal ions, from water. (C) 2014 The Institution of Chemical Engineers. Published by Elsevier &V. All rights reserved.