铯离子表面印迹聚合物的制备及其吸附性能研究

摘要

A Cs(Ⅰ) ion-imprinted polymer was prepared using cesium ion as the template, chitosan (CTS) as functional monomer, and modifying the surface of mesoporous silica SBA-15 by amino, glutaraldehyde via surface imprinting.The prepared polymer was characterized through Fourier-transform infrared, energy dispersive spectrometry, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and N2 adsorption-desorption.The results showed the synthesized polymer possessed a highly ordered mesoporous structure.The adsorption capacity of the imprinted polymer for cesium ion was tested in batch experiments.The results showed that at pH=5-6, the adsorption equilibrium could be reached in 1 hour and the maximum static adsorption capacities of the imprinted polymer was 36.19mg/g higher than the non-imprinted polymer (NIP) at 25 ℃.The adsorption behavior of Cs(Ⅰ) onto Cs(Ⅰ)-IIP belonged to the pseudo-second-order kinetic model.The Langmuir model was well fitted with the data.The selectivity coefficients of the polymer for Cs(Ⅰ)/Li(Ⅰ), Cs(Ⅰ)/Na(I), Cs(Ⅰ)/K(Ⅰ), Cs(Ⅰ)/Rb(Ⅰ), and Cs(Ⅰ)/Sr(Ⅱ) were 1.50, 2.00, 2.22, 1.32, 4.00, respectively.And the adsorption capacity did not significantly decrease after five adsorption-desorption cycle.Therefore, the polymer is stable and reusable.%采用表面印迹技术,以Cs(Ⅰ)为模板,壳聚糖为功能单体,在介孔材料SBA-15表面进行氨基化、醛基化修饰,并以HCl 为洗脱液,成功制备了铯离子表面印迹聚合物[Cs(Ⅰ)-IIP].产物进行了FT-IR、EDS、XRD、SEM、TEM和N2吸附-脱附等表征.结果表明,Cs(Ⅰ)被成功引入材料中,且Cs(Ⅰ)-IIP仍保持着有序介孔结构.研究了Cs(Ⅰ)-IIP对溶液中Cs(Ⅰ)的吸附性能,在25 ℃,pH值=5~6,吸附平衡时间为1 h,最大吸附量为36.19 mg/g,高于非印迹聚合物(NIP).吸附动力学较好的符合准二级动力学模型,吸附等温符合Langmuir模型.Cs(Ⅰ)-IIP对Cs(Ⅰ)/Li(Ⅰ)、Cs(Ⅰ)/Na(Ⅰ)、Cs(Ⅰ)/K(Ⅰ)、Cs(Ⅰ)/Rb(Ⅰ)、Cs(Ⅰ)/Sr(Ⅱ)的选择性系数分别为1.50,2.00,2.22,1.32,4.00,表明合成的Cs(Ⅰ)-IIP具有良好的吸附选择性.此外,经5次吸附-解吸实验后,Cs(Ⅰ)-IIP的吸附量没有明显的下降,表明该材料具有一定的循环利用性能.