An XAS study of zinc speciation in aqueous acetate solutions at 25-200 degrees C

作者：Borg Stacey J^*; Liu Weihua

来源：Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment , 2010, 619(1-3): 276-279.

DOI：10.1016/j.nima.2009.10.170

• Zinc
• Acetate
• XAS
• EXAFS
• Hydrothermal solutions
• Thermodynamics

Solutions of zinc(II) acetate in acetic acid/sodium acetate buffer solutions of varying concentration were examined by X-ray absorption spectroscopy (XAS) at temperatures between 25 and 200 degrees C. The influence on speciation by increasing the ratio of available acetate to Zn concentration was marked, and followed a similar trend to that observed with increasing temperature. End-member X-ray absorption spectra were observed at both the low and high temperature/acetate concentration regimes. Fitting of the EXAFS spectra gave Zn-O bonding distances in the range 1.95-2.05 angstrom, which are comparable to available crystallographic data. Thermodynamic modelling of the XANES data shows ZnAc(+) is important at lower acetate concentration, while ZnAc(2)(aq) predominates solutions with acetate concentrations above 1.5 m at 25 degrees C, and the evolution of the XANES spectra shows that ZnAc(2)(aq) becomes more important with increasing temperature. Therefore acetate has been shown to be a valid Zn transport ligand under hydrothermal conditions.

• 出版日期2010-7-1
• 单位CSIRO