Mesoporous silicas have a very attractive ability of sorption and enrichment of metal ions due to their huge surface area and facile functionalization by organic ligands. In this work, phosphonate-amino hifunctionaliz...Mesoporous silicas have a very attractive ability of sorption and enrichment of metal ions due to their huge surface area and facile functionalization by organic ligands. In this work, phosphonate-amino hifunctionalized mesoporous silica SBA-15 （PA-SBA-15） as U（VI） sorbent was fabricated through post-grafting method. The obtained mesoporous silica was character- ized by SEM, XRD, NMR and nitrogen sorption/desorption experiments, which revealed the existence of ordered mesoporous structure with uniform pore diameter and large surface area. The adsorptivity of PA-SBA-15 for U（VI） from aqueous solution was investigated using batch sorption technique under different experimental conditions. The preliminary results show that the U（VI） sorption by PA-SBA-15 is very quick with equilibrium time of less than 1 h, and the U（VI） uptake is as large as 373 mg/g at pH 5.5 under 95℃. The sorption isotherm has been successfully modeled by the Langmuir isotherm, suggesting a monolayer homogeneous sorption of U（VI） in PA-SBA-15. The sorption is pH-dependent due to the pH-dependent charge of sorbent in the aqueous solution. The thermodynamics research shows that the sorption is a feasible and endothermic process. Based on these results, PA-SBA-15 could be a promising solid phase sorbent for highly-efficient removal of U（VI） ions from waste water and enrichment of U（VI） from a solution at a very low level.展开更多
基金supported by the National Natural Science Foundation of China (91026007)the "Strategic Priority Research program" of the Chinese Academy of Sciences (XDA03010401,XDA03010403)
文摘Mesoporous silicas have a very attractive ability of sorption and enrichment of metal ions due to their huge surface area and facile functionalization by organic ligands. In this work, phosphonate-amino hifunctionalized mesoporous silica SBA-15 （PA-SBA-15） as U（VI） sorbent was fabricated through post-grafting method. The obtained mesoporous silica was character- ized by SEM, XRD, NMR and nitrogen sorption/desorption experiments, which revealed the existence of ordered mesoporous structure with uniform pore diameter and large surface area. The adsorptivity of PA-SBA-15 for U（VI） from aqueous solution was investigated using batch sorption technique under different experimental conditions. The preliminary results show that the U（VI） sorption by PA-SBA-15 is very quick with equilibrium time of less than 1 h, and the U（VI） uptake is as large as 373 mg/g at pH 5.5 under 95℃. The sorption isotherm has been successfully modeled by the Langmuir isotherm, suggesting a monolayer homogeneous sorption of U（VI） in PA-SBA-15. The sorption is pH-dependent due to the pH-dependent charge of sorbent in the aqueous solution. The thermodynamics research shows that the sorption is a feasible and endothermic process. Based on these results, PA-SBA-15 could be a promising solid phase sorbent for highly-efficient removal of U（VI） ions from waste water and enrichment of U（VI） from a solution at a very low level.
