Metal (Hydr)oxides for the removal of Cr(VI) from drinking water: a XAFS study

16th International Conference on X-ray Absorption Fine Structure

Pinakidou, F.^1 ; Kaprara, E.^1 ; Katsikini, M.^2 ; Paloura, E.C.^2 ; Simeonidis, K.^2 ; Mitrakas, M.^1

Aristotle University of Thessaloniki, School of Chemical Engineering, Analytical Chemistry Laboratory, Thessaloniki

54124, Greece^1

Aristotle University of Thessaloniki, School of Physics, Department of Solid State Physics, Thessaloniki

54124, Greece^2

关键词: Adsorption behaviour;    Cr complexes;    Exafs analysis;    Inner spheres;    Octahedral sites;    Reduction mechanisms;    Surface coverages;    XANES spectra;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/712/1/012082/pdf
DOI  :  10.1088/1742-6596/712/1/012082

来源: IOP

【 摘 要 】

The reduction mechanism and adsorption behaviour of Cr(VI) onto Tin(II) oxy- hydroxides are investigated using Cr-K edge X-ray absorption fine structure (XAFS) spectroscopies. The synthesis of the Sn oxy-hydroxide proceeds via hydrolysis of SnSO4. The successful reduction of Cr(VI) was identified by the analysis of the Cr-K edge XANES spectra where only Cr(III) species in octahedral sites are detected. According to the Cr-K edge EXAFS analysis results, Cr(III) forms bidentate inner sphere (binuclear (2C) and mononuclear (2E)) complexes. However, the surface coverage of Cr affects the type of Cr(III)-complexes formed: as the Cr-loading increases, Cr(III)-oxy-anions preferentially sorb in a "combined"2C and1V configuration, at the expense of the existing2E sorption geometry.