| The inorganic gels were prepared by adding NaOH into solution that mainly contains Al13 tridecameric polycation, X-ray differaction (XRD), Fourier transformed infrared spectrometry (FT-IR) and 27 Al Magic Angle Spinning nuclear magnetic resonance spectroscopy (MAS NMR) and other techniques were employed to characterize structure of fresh gels, structural varation during aging time and mineralogical transformation, firstly provide the mechanism that inorganic Al13 gel changes into gibbsite and nordstranite by Keggin structure; macroscopic adsorption of arsenate (AsO43-) on fresh gels was investigated, the result shows that the arsenate adsorbed on gels has diffetent surface complexes during acid and alkali conditions, surface precipition occurs with adsorption process. The organic Al13-Oxalate gel was prepared by adding oxalate into solution that mainly contains Al13 tridecameric polycation, BET, SEM, XRD, FT-IR and 27Al MAS NMR techniques were adopted to characterize its physical and chemical property, which shows that the gel obviously is different from the common Al gels and their oxalate precipitations, this provides new evidence for newly surveying universality of Al13 existing in natural environment. The chemical formula of gel was determined to be AIO4Al12(OH)24(H2O)12(C2O4)7/2 using ion chromatography and spectrophotometry. Single and competing adsorption behavior of arsenate and phosphate on organic Al13 gel was studies detailedly, thermodynamic parameters of adsorption reactions were calculated; adopted FT-IR and XPS to carry out molecular level study on adsorption, and prelimentarily probe adsorption species, electron transfer during adsorption and each atomic core level shift. |
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