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以3-氨丙基三甲氧基硅烷为改性剂,利用后嫁接方法,制备出氨基修饰SBA-15(记为N-SBA-15)。利用X射线衍射仪、傅立叶红外光谱仪、N2吸附-脱附对样品进行表征,并探讨了吸附动力学与吸附等温特性。结果表明,改性后的SBA-15吸附水中Pb2+时在120 min内可以达到吸附平衡,吸附过程符合拟2级动力学模型。Langmuir模型及Dubinin-Radushkevich模型很好地描述了Pb2+在氨基修饰SBA-15上的吸附行为,其中基于D-R模型计算得出的318 K时最大吸附量为1.172 mmol/g,平均吸附自由能在318 K时为-24.88 kJ/mol,表明吸附可能属于表面络合作用,可以归为化学过程,且该过程是自发和吸热的。
Amino-modified SBA-15 (denoted as N-SBA-15) was prepared by post-grafting using 3-aminopropyltrimethoxysilane as a modifier. The samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy and N2 adsorption-desorption. The adsorption kinetics and adsorption isotherms were discussed. The results showed that adsorption of Pb2 + on the modified SBA-15 could reach adsorption equilibrium within 120 min, and the adsorption process accorded with the pseudo-second-order kinetic model. Langmuir model and Dubinin-Radushkevich model describe the adsorption behavior of Pb2 + on amino-modified SBA-15 well. The maximum adsorption capacity of 318 Pb at the concentration of 1.172 mmol / g based on DR model is 318 K -24.88 kJ / mol, indicating that the adsorption may belong to the surface complexation can be classified as chemical processes, and the process is spontaneous and endothermic.