硅胶表面苯并噻吩分子印迹聚合物的分子识别与吸附性能

选用γ-氨丙基三乙氧基硅烷和α-甲基丙烯酸修饰的硅胶作为载体,以甲基丙烯酸为功能单体,二甲基丙烯酸乙二醇酯为交联剂,苯并噻吩为模板分子,合成一种具有选择性识别苯并噻吩分子的印迹聚合物。采用红外光谱、元素分析及N2吸附对其结构进行了表征,以模拟汽油通过静态吸附对其吸附性能进行了研究。结果表明,在硅胶载体表面成功地嫁接了多孔的分子印迹聚合物薄层。印迹聚合物对苯并噻吩具有良好的识别性能,对苯并噻吩的吸附动力学满足Langergren准一级反应动力学方程,吸附过程属于单分子层吸附。符合Langmuir吸附模型印迹聚合物对苯并噻吩的平衡吸附容量达57.4×10-3,而非印迹聚合物的吸附容量为33.1×10-3。印迹聚合物在经过多次再生后其吸附容量基本不变,从而为在汽油深度脱硫中有效脱除噻吩类硫化物提供了一种新技术途径。

Molecular recognition and adsorption performance of benzothiophene imprinted polymer on silica gel surface

On the surface of silica gel chemically modified with γ-aminopropyltriethoxysilane and methacrylic acid, a molecularly imprinted polymer (MIP) for the selective benzothiophene recognition was prepared by using methacrylic acid as the functional monomer, ethylene glycol dimethacrylate as the crosslinker, and benzothiophene as the template molecule. The textural properties of MIP were characterized by FT-IR, elemental analysis and N₂ adsorption; its static adsorption performance for benzothiophene was tested with a model gasoline. The results showed that a porous thin layer of MIP was successfully grafted on the surface of silica gel carrier. The imprinted polymer exhibits good specific benzothiophene recognition; the adsorption of benzothiophene on it accords with Langergren quasi-one kinetic equation and Langmuir isotherm of monolayer adsorption. The adsorption capacity of MIP for benzothiophene reaches 57.4×10^-3, in comparison with 33.1×10^-3 of the non imprinted polymer; its adsorption capacity remains almost unchanged after regeneration for many times. This may provide a new approach for deep desulfurization of gasoline to remove sulfur-containing thiophenic compounds.