Nanostructure Iron(III)-Zirconium(IV) Binary Mixed Oxide: Synthesis, Characterization, and Physicochemical Aspects of Arsenic(III) Sorption from the Aqueous Solution

Characterization of synthetic Fe(III)-Zr(IV) mixed oxide (NHIZO) by the X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) analyses confirmed the material as agglomerated nanocrystallite particles (16-21 nm) which was used for As(III) sorption from water. The optimum pH and equilibrium time (As(III) concentrations (mgL(-1)), 5.0 and 10.0; NHIZO dose, 2 g.L-1; temperature, 303 K) were 7.0 +/- 0.2 and 2.0 h, respectively. The kinetic and equilibrium data described, respectively, the pseudo-second-order equation and the Langmuir as well as the Redlich-Peterson isotherm models very well. The Langmuir capacity was 65.5 +/- 1.0 mg.g(-1) at 303 K, which increased with increasing temperature. The positive enthalpy (Delta H degrees) and negative free energy (Delta G degrees) changes indicated the endothermic and spontaneous nature of the reaction, respectively. The sorption energy (4.64-5.20 kJ.mol(-1)) and Fourier transform infrared (FTIR) analyses suggested physissorption of As(III) by NHIZO. The sorbed arsenic could be desorbed (similar to 80%) by 2.0 M alkali. The toxicity leaching characteristic procedure test marked As(III)-NHIZO as nonhazardous waste.