功能化炭基磁性介孔材料的制备及其对铀的吸附性能

以介孔氧化硅SBA-15为模板,通过纳米浇筑法在模板孔道中引入不同质量的铁源和炭源作为前驱物,经过原位聚合反应,再使用[3-(三甲氧基硅烷)丙基]脲(UPTS)和氨丙基三乙氧基硅烷(APS)有机试剂对其表面进行后嫁接改性,得到介孔结构规整有序的功能化炭基磁性介孔材料(FCMMC)。并通过红外光谱(FT-IR)、N2吸附-脱附分别表征了FCMMC的结构。考察了溶液pH值、铀初始浓度、吸附剂用量和吸附时间等因素对FCMMC吸附铀的影响。结果表明:炭基和铁基均被负载在介孔氧化硅基体上,FCMMC具有较高的比表面积和较窄的孔径分布。FCMMC吸附铀的最佳条件为:pH=6.0、铀初始浓度25mg/L、FCMMC用量40mg、吸附时间1.0h。对吸附动力学模型和吸附等温模型进行了分析,FCMMC对铀的吸附动力学过程符合准二级动力学模型,吸附等温线符合Langmuir等温线模型,最大理论吸附量为128.69mg/g。同时,使用3种不同的解吸剂对FCMMC解吸再生8次后,其对铀的吸附率均在80%以上,说明FCMMC具有良好的再生性能。

Preparation of Functionalized Carbonaceous Magnetic Mesoporous Composite and Its Adsorption Property to Uranium

The macroporous silica SBA-15 as the hard template, a novel functionalized carbonaceous magnetic mesoporous composite (FCMMC) with highly ordered mesoporous structure was obtained using ferric nitrate and glucose as the precursors via one-step nanocasting followed by in-situ polymerization reaction, and using organic reagents UPTS and APS after grafting modification on its surface. FT-IR and N₂ adsorption-stripping experiment were used to characterize FCMMC, and the factors impacting the adsorption of uranium on FCMMC were investigated including pH value, initial concentration of uranium ions, FCMMC dosage and adsorption time. The results show that the carbon and iron resource are successfully loaded on the mesoporous silica substrate, respectively. And FCMMC has high specific surface area and narrow pore size distribution. The optimal adsorption conditions are as following: The pH of the solution is 6.0, initial concentration of uranium ions is 25 mg/L, the FCMMC dosage is 40 mg and the adsorption time is 1.0 h. The kinetic model can be described by the pseudo-second-order model well, and its correlation coefficient is above 0.99. The isotherm model is fitted to Langmuir adsorption model, and the maximal theoretical adsorption capacity is 128.69 mg/g. At the same time, the adsorption rate is over 80% after FCMMC regenerated 8 times using three different desorption agents. This shows that FCMMC has good regeneration performance.