Facile Route to Synthesize Pore Expanded Platelet SBA-15 for Enhanced Amidoxime-Functionalization and Efficient Extraction of U(Ⅵ) from Aqueous Solution

Short channel platelet SBA-15 mesoporous material is one of the effective adsorbent for the recovery of U(Ⅵ) from aqueous solution. Nevertheless, the defect is that the mesoporous size limits the total stripping of attached U(Ⅵ) in recycling use and the increasing densities of organic groups after functionalization. Thus, a simple and controllable method was adopted to prepare SBA-15-type material with expanded pore channel by adding trimethylbenzene in synthesis procedure. The structure, morphology and functional groups were characterized by scanning electron microscope, powder X-ray diffraction, thermogravimetric analysis, transmission electron microscope, FTIR and N_2 adsorption-desorption isotherm analysis. Furthermore, the adsorption behavior of obtained product was test under various factors such as initial concentration, pH, elution rate and contact time. The pore expanded platelet SBA-15 exhibited higher U(Ⅵ) adsorption capacity, higher elution rate, and more bearing of amidoxime groups. Due to the higher amidoxime groups, the adsorption capacity of U(Ⅵ) on the amidoxime functionalized pore-expanded SBA-15 was 674 mg-Ug^-1. The results show that the simple and controllable pore-expanded method is an effective strategy to enhance the elution effect and increase grafting amount of organic groups on the mesoporous materials.