In Situ EXAFS Study of Sr Adsorption on TiO2(110) under High Ionic Strength Wastewater Conditions
In Situ EXAFS Study of Sr Adsorption on TiO2(110) under High Ionic Strength Wastewater Conditions
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DOI：
10.3390/min11121386
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发表时间：
2021-12
期刊：
影响因子：
2.5
通讯作者：
A. van Veelen;P. Francisco;N. Edwards;J. Mosselmans;Tsutomu Sato;R. Wogelius
中科院分区：
文献类型：
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作者：
A. van Veelen;P. Francisco;N. Edwards;J. Mosselmans;Tsutomu Sato;R. Wogelius
为了提供关于Sr的吸附反应的重要细节，在粉末状TiO 2和金红石（110）上完成了分批反应和一组非原位和原位掠入射X射线吸收精细结构（GIXAFS）吸附实验，两者都与SrCl 2或SrCO 3溶液反应。TiO2对锶（Sr）的吸附容量范围分别为550 ppm（SrCl2溶液，二级动力学）至1400 ppm（SrCO3溶液，一级动力学），并且是快速的。锶吸附下降的氯离子浓度的函数，但显着增加碳酸盐浓度的增加。在碳酸盐存在下，由于SrCO3薄膜的快速外延表面沉淀，TiO 2从溶液中去除Sr的能力增加了约4倍，SrCO3薄膜在金红石（110）表面上记录为类锶石相（d间距为2.8 μ m）。扩展的X射线吸收精细结构（EXAFS）的结果表明，最初的附着是通过四齿内层锶吸附。此外，从浓SrCl2溶液中的吸附物含有碳酸盐和羟基物种，这导致在内部和外部球吸附物，并解释了减少Sr吸附在这些系统中。这些结果不仅提供了新的见解锶动力学和吸附在二氧化钛，但也提供了有价值的信息，有关潜在的改进废水处理模型，并在核电厂内的金红石涂层结构材料的处理方法的发展是相关的。
In order to provide important details concerning the adsorption reactions of Sr, batch reactions and a set of both ex situ and in situ Grazing Incidence X-ray Absorption Fine Structure (GIXAFS) adsorption experiments were completed on powdered TiO2 and on rutile(110), both reacted with either SrCl2 or SrCO3 solutions. TiO2 sorption capacity for strontium (Sr) ranges from 550 ppm (SrCl2 solutions, second order kinetics) to 1400 ppm (SrCO3 solutions, first order kinetics), respectively, and is rapid. Sr adsorption decreased as a function of chloride concentration but significantly increased as carbonate concentrations increased. In the presence of carbonate, the ability of TiO2 to remove Sr from the solution increases by a factor of ~4 due to rapid epitaxial surface precipitation of an SrCO3 thin film, which registers itself on the rutile(110) surface as a strontianite-like phase (d-spacing 2.8 Å). Extended X-ray Absorption Fine Structure (EXAFS) results suggest the initial attachment is via tetradental inner-sphere Sr adsorption. Moreover, adsorbates from concentrated SrCl2 solutions contain carbonate and hydroxyl species, which results in both inner- and outer-sphere adsorbates and explains the reduced Sr adsorption in these systems. These results not only provide new insights into Sr kinetics and adsorption on TiO2 but also provide valuable information concerning potential improvements in effluent water treatment models and are pertinent in developing treatment methods for rutile-coated structural materials within nuclear power plants.