甲基橙分子印迹聚合物的制备及性能研究

Preparation and property study of molecularly imprinted polymers for methyl orange

以甲基橙(MO)为模板分子、丙烯酰胺(AM)为功能单体、乙二醇二甲基丙烯酸酯(EDMA)为交联剂、偶氮二异丁腈(AIBN)为引发剂、邻苯二甲酸二丁酯(DBP)为溶胀剂、聚苯乙烯微球为种球,通过种子溶胀法,探讨了不同溶剂制备的甲基橙分子印迹聚合物(MO-MIPs)的红外谱图及其对模板分子的吸附能力;使用最佳溶剂进行溶剂用量探讨。当溶剂用量为10 m L时,所制备的M O-M IPs对M O吸附效果最好;选取最优条件下制备的M O-M IPs,进行了最佳p H确定、斯卡查德曲线分析、热力学模型曲线拟合以及循环使用次数测试,结果最佳吸附p H为6;吸附过程中存在两类结合位点,其中高亲和力位点平衡解离常数为3.59 mg/L,最大吸附量为1.87 mg/g;低亲和力位点平衡解离常数为33.43 mg/L,最大吸附量为5.47 mg/g;热力学模型更符合弗伦德里希模型;经过8次循环利用,吸附量并没有明显的下降趋势。

Methyl orangemolecularly imprinted polymers（ MO-MIPs） were prepared by swelling and polymerization method using different solvents and methyl orange（ MO） as template,acrylamide（ AM） as functional monomer, ethylene glycol dimethyl acrylate（ EDMA） as crosslinking agent,azodiisobutyronitrile（ AIBN） as initiator,dibutyl phthalate（ DBP） as the sweller,and polystyrene microspheres as the seed. Corresponding infrared spectra and its adsorption capacity on the template molecules were studied. The best solvent was used for the determination of optimal dosage,and the results show thatthe MO-MIPs has the best adsorption capacity for MO at the dosage of 10 m L. MO-MIPs prepared under the optimal conditions were chosen for the determination of best p H,scatchard curve analysis,curve fittingfor thermodynamic model and recycling time test. The study showed that the optimal p H was 6,and there were two classes of binding sites in the process of adsorption. Among them,the equilibrium dissociation constant and maximum adsorption amount ofhigh-affinity binding sites were calculated to be 3. 59 mg/L and 1. 87 mg/g,respectively,while the values for low-affinity binding siteswere33. 43 mg/L and 5. 47 mg/g,respectively. Thermodynamic model was more consistent with the Freundlich model. There was no significant decline trend ofthe adsorption amount after eight times of recycle.