溶胶-凝胶法制备的罗丹明B/二氧化钛分子印迹聚合物的结构与吸附性能

Structure and adsorption performance of Rhodamine B/titanium dioxide molecularly imprinted polymers prepared by sol-gel method

以罗丹明B为模板分子,以钛酸丁酯为交联剂,采用溶胶-凝胶法在酸性条件下制备了罗丹明B二氧化钛溶胶-凝胶分子印迹聚合物;利用傅立叶变换红外光谱和透射电镜分析了分子印迹聚合物的结构,使用热重分析测定了其热稳定性,采用静态吸附和动态吸附方法考察了其吸附性能,并与非印迹聚合物进行了对比.结果表明,与非印迹聚合物相比,印迹聚合物具有网络状多孔隙凝胶微结构及对模板分子的特异性识别结合位点,因而对模板分子具有更好的吸附性能和特异选择性.其原因可能在于,模板分子上的羰基与钛酸丁酯水解产生的羟基产生氢键作用,使钛酸围绕于模板分子周围,并通过缩聚形成凝胶;当模板分子洗脱后,孔隙得到保留并形成网络状凝胶,从而能够吸附更多的模板分子.

Rhodamine B/titanium dioxide molecularly imprinted polymers were prepared under acidic conditions by sol-gel method with Rhodamine B as the template molecule and butyl titan-ate as the cross-linking agent.The structure of as-synthesized molecularly imprinted polymers were analyzed by Fourier transform infrared spectrometry and transmission electron microsco-py,their thermal stability was evaluated based on thermogravimetric analysis,and their ad-sorption properties were determined and compared with those of non-imprinted polymers by static and dynamic adsorption experiments.Results show that,as compared with non-imprin-ted polymers,as-synthesized molecularly imprinted polymers exhibit better adsorption capacity and specific selectivity to template molecule,because they have reticular porous gel microstruc-ture network and binding sites with specific recognition to template molecules.The reason might lie in that the hydrogen bonding interaction between the carbonyl of the template mole-cule and the hydroxyl generated via the hydrolysis of butyl titanate allows titanic acid to sur-round the template molecule and form gel via condensation.After elution,the pores that could accommodate the template molecules are maintained to form network-like gel so that more template molecules could be adsorbed.