Characterization of arsenate adsorption on amorphous Al gels with Keggin structure by Fourier transformed infrared spectroscopy and MAS ^(27)Al NMR  

Characterization of arsenate adsorption on amorphous Al gels with Keggin structure by Fourier transformed infrared spectroscopy and MAS ^(27) NMR

作　　者：ZHAO Fenghua 

机构地区：[1]Department of Resource and Earth Science, China University of Mining and Technology, Beijing 100083, China

出　　处：《Chinese Journal Of Geochemistry》2009年第1期61-69,共9页中国地球化学学报

基　　金：supported by the specialized research funds for the doctoral program of Higher Education of China (Grant No. 2006029009);the Program for New Century Excellent Talents in Universities and Colleges (Grant No. NCET-07-0801)

摘　　要：Fourier transformed infrared spectrometry (FTIR) and 27Al Magic Angle spinning (MAS) nuclear magnetic resonance spectroscopy were employed to characterize arsenate adsorption on amorphous Al gels with Keggin structure at pH =4–10. These studies have proven that: the surface complex species of arsenate show significant differences under acidic and alkaline conditions, which was deduced based on the As-O stretching vibration bands located respectively at 774 and 870 cm-1; poorly crystalline Al13 (or Al)-arsenate precipitation could be easily formed under acid medium condition and high loading level, which was supported by comparing the As-O vibration (at ≈732 cm-1) of precipitation to adsorbed Al gels; arsenate (AsO43-) adsorption has no effect on the Keggin structure of Al gels with basicity (R) =2.6 and 3.0, even at high loading level, as evidenced by the signal at ≈63×10-6 of magic angle spinning (MAS)-27Al NMR. The adsorption envelope was determined by conventional batch experiments.Fourier transformed infrared spectrometry （FFIR） and ^27Al Magic Angle spinning （MAS） nuclear magnetic resonance spectroscopy were employed to characterize arsenate adsorption on amorphous AI gels with Keggin structure at pH =4-10. These studies have proven that： the surface complex species of arsenate show significant differences under acidic and alkaline conditions, which was deduced based on the As-O stretching vibration bands located respectively at 774 and 870 cm^-1; poorly crystalline Al13 （or Al）-arsenate precipitation could be easily formed under acid medium condition and high loading level, which was supported by comparing the As-O vibration （at =732 cm^-1） of precipitation to adsorbed Al gels; arsenate （AsO4^3-） adsorption has no effect on the Keggin structure of AI gels with basicity （R） =2.6 and 3.0, even at high loading level, as evidenced by the signal at ≈63×10^-6 of magic angle spinning （MAS）-27Al NMR. The adsorption envelope was determined by conventional batch experiments.

关 键 词：RTIR 稳定性 地球化学 元素 

分 类 号：P595[天文地球—地球化学]