Redox-Assisted Arsenic(III) Adsorption for Removal from Aqueous Solution by Cerium(IV)-Incorporated Zirconium Oxide Nanocomposites

摘要

Ceria-incorporated zirconia nanocomposites (CIZNCs) are prepared and characterized by some latest analytical tools. The efficiency of this material is evaluated toward arsenic(III) immobilization for removal via adsorption from its aqueous phases. The physicochemical aspects of this immobilization reaction have been reported at optimized pH 5.0. The kinetics of this reaction is of pseudo-second order type. The equilibrium data fit very well with the Langmuir isotherm with a monolayer adsorption capacity of 17.07 mg-g(-1) (226 mmol.kg(-1)) at 303 K. Analysis of reaction kinetics parameters shows that the fraction of molecules bearing the threshold energy of reaction (Delta(N)/N-av) is 0.99 at our working conditions. Thermodynamic analysis of equilibrium data reveals the exothermic and spontaneous nature of arsenic(III) adsorption over CIZNCs. X-ray photoelectron spectroscopy and cyclic voltammetric examinations have confirmed the oxidation of arsenic(III) to arsenic(V) over the CIZNC surface.