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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 (FTIR) and 27 Al 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 in acidic and alkaline conditions, which was deduced based on the As-O stretching vibration bands located at 774 and 870 cm-1; poorly crystalline Al13 (or Al) -arsenate precipitation could be formed in acid medium condition and high loading level, which was supported by comparing the As-O vibration (at ≈732 cm -1) of precipitation to adsorbed Algels; arsenate (AsO43-) adsorption has no effect on the Keggin structure of Algels with basicity (R ) = 2.6 and 3.0, even at high loading level, as evidenced by the signal at ≈ 63x10-6 of magic angle spinning (MAS) -27Al NMR. The adsorption envelope was determined by conventional batch exper iments.