Application of EXAFS with a bent crystal analyzer to study the pH dependent microstructure of Eu(III) onto birnessite

作者：Dong, Lijia; Liao, Qing; Linghu, Wensheng; Huang, Yuying; Shen, Runpu^*; Alsaedi, Ahmed; Wang, Jin^*; Hayat, Tasawar; Sheng, Guodong^*

来源：Journal of Environmental Chemical Engineering, 2018, 6(1): 842-848.

DOI：10.1016/j.jece.2018.01.015

• Eu(III)
• Interaction mechanism
• Microstructure
• delta-MnO2

Herein, Eu(III) retention mechanism and microstructure on delta-MnO2 as a function of solution pH were studied using both the conditional macroscopic method and molecular-level high resolution EXAFS technique with a bent crystal analyzer. The results suggested that the sorption Eu(III) onto delta-MnO2 was strongly dependent on pH but not on ionic strength, implying the formation of inner-sphere surface complexation for Eu(III) on delta-MnO2 surface. Molecular-level results from EXAFS methods showed that Eu was surrounded by similar to 80 atoms in first coordination shell at REu-O approximate to 2.42 angstrom, and second shell of Mn atoms at REu-Mn approximate to 3.91 angstrom was found in four sorption samples from different solution pH. All this results reflected the formation of a bidentate surface complex with Eu(III) bonding by corner sharing to MnO6-octahedron on delta-MnO2 surface. Both the macroscopic findings and microstructure of Eu(III) at the delta-MnO2-water interface enhance our understanding for the reaction dynamics and states of Eu(III) and related radionuclides in natural environment.

• 出版日期2018-2
• 单位绍兴文理学院; 中国科学院; 中国科学院上海应用物理研究所; 广州大学