Functionalized Mesoporous Silica For The Sorption Of U(â…¥)

Two kinds of different organic groups modified SBA-15 have been synthesized by a post-grafting method using dihydroxy bezladely derivatives and amidoxime derivatives which are SBA-15-3,4-dihydroxy benzaldehyde(SBA-15-OHBA), SBA-15-2,4-dihydroxy benzaldehyde(MHBA), S BA-15-2,4-dihydroxy acetophenone(SBA-15-RATP) and SBA-15-amidoxime(SBA-15-AO), S BA-15- two amidoxime(S BA-15-2AO). These silica mater ials were characterized by XRD, 13 C NMR, TEM, elemental analysis, FT-IR and nitrogen adsorption/desorption experiments and so on. The results suggested that we had synthesis functionalized SBA-15 successfully which remained original well-ordered pore.In the different experimental conditions, batch experiments have been conducted to study the effects of adsorbent dosage, shaking time, initial concentration of metal ion, temperature, ionic strength, pH and coexisting ions on U( VI) sorption behaviors of pure and functional S BA-15 by static adsorption method. At the same time, we used typical thermodynamic sorption model(Langmuir and Freundlich) and sorption kinetics pseudo second-order models to determined sorption process and related parameters were calculated. The test results indicated that the sorption ability of organic modified s ilica was better than pure silica. The sorption process for all mater ials was found to follow pseudo-second-order type sorption kinetics and the adsorption dosage increased obviously with the increasing of pH value. All adsorbents was influenced little by ionic strength, so inner-sphere complexation may be the main sorption mechanism of U(VI). What’s more, the temperatures effects turned out that the sorption process was exothermic for all sorbents. At last, modified SBA-15 have a better ability of selectivity for U(VI) over a number of coexisting competing metal ions.