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采用水热合成法制备了疏水性介孔二氧化硅材料(MCM-41-dry)并经煅烧制得亲水性介孔二氧化硅材料(MCM-41-cal)。试验探讨了pH值、吸附时间、投加量以及U(Ⅵ)初始浓度等因素对MCM-41材料煅烧前后吸附U(Ⅵ)效果的影响,利用SEM、EDS、BET和FTIR分析其吸附机理。试验结果表明,MCM-41-dry材料因具有有机模板剂,其吸附效果远高于MCM-41-cal的吸附效果;当pH值为5,吸附时间为180 min,温度为30℃,MCM-41-dry投加量为0.2 g/L,U(Ⅵ)初始浓度为10 mg/L时,其对U(Ⅵ)的吸附率可达99.2%;Langmuir吸附等温模型和准二级动力学方程能较好的拟合其吸附过程,当T=303 K时,理论饱和吸附量为241.935 mg/g,吸附为单分子层吸附,以化学吸附为主。通过BET、FTIR表征则说明MCM-41-dry具有六方形介孔结构能吸附U(Ⅵ),官能团羟基和氨基发挥了很大的作用。
Hydrophobic mesoporous silica (MCM-41-dry) was prepared by hydrothermal synthesis and then calcined to obtain hydrophilic mesoporous silica (MCM-41-cal). The effects of pH value, adsorption time, dosage and initial U (Ⅵ) concentration on the adsorption of U (Ⅵ) on MCM-41 were studied. The adsorption mechanism was analyzed by SEM, EDS, BET and FTIR. The experimental results show that the adsorption effect of MCM-41-dry material is much higher than that of MCM-41-cal because of its organic templating agent. When the pH value is 5, the adsorption time is 180 min and the temperature is 30 ℃, The adsorption rate of U (Ⅵ) to the U (Ⅵ) was 99.2% when the initial concentration of 41-dry was 0.2 g / L and the initial concentration of U (Ⅵ) was 10 mg / L. Langmuir adsorption isotherm model and quasi-second order kinetic equation It can fit the adsorption process well. At T = 303 K, the theoretical saturated adsorption capacity is 241.935 mg / g. The adsorption is monolayer adsorption, mainly by chemical adsorption. Characterization by BET and FTIR indicated that hexagonal mesoporous structure of MCM-41-dry could adsorb U (Ⅵ), and the hydroxyl and amino groups of functional groups played a significant role.