金属有机骨架-分子印迹复合材料的制备、表征及其对吗啉的吸附性能

Preparation,characterization and adsorption property for a metal organic frames(MOFs)-molecularly imprinted polymer(MIPs)composite material

以金属有机骨架为载体,通过表面化学修饰后再接枝分子印迹聚合物制备了一种对吗啉具备高选择性能的新型复合材料,用红外光谱、扫描电镜分别探测了所获材料的表面化学基团分布及形貌特征。研究了金属有机骨架-分子印迹(MOFs-MIPs)复合材料对吗啉分子的吸附动力学及选择性,测试了材料表面的结合位点分布特征,并考察了复合材料对水果粗提物溶液中吗啉的固相萃取效能。印迹材料可在150 min内达到吸附平衡,其对吗啉的静态吸附量为183.3 mg/g。Scatchard分析表明分子印迹聚合物表面主要存在两类吸附位点,高亲和位点的平衡离解常数K和最大表观吸附量Qmax分别为0.5679 g/L和326.5 mg/g,而低亲和位点的K和Qmax值分别为2.493 g/L和562.9 mg/g。印迹材料对吗啉的选择因子相对于甲基吗啉、乙基吗啉和甲基吗啉氧化物分别为2.47、2.48和2.24。MOFs-MIPs复合材料用于固相萃取时,在优化条件下单步洗脱中吗啉回收率达82.44%,显示了较高的富集效能,且这种材料可多次重复使用。

In present work,metal organic frames(MOFs)-molecularly imprinted polymer(MIPs)composite material was synthesized by a surface-imprinting technique based on a chemically modified metal organic frame as the support matrix.FTIR spectroscopy was utilized to study on chemical groups and SEM was to observe superficial morphology and structure in the MIPs.Adsorption dynamics and selectivity for this MIP toward morpholine molecules were explored and sites distribution on the surface of the MOFs-MIPs composite material was tested.In addition,the capability for this material in solid phase extraction(SPE)of morpholine in fruits crude extract was explored.When this MIP was used as a sobent,adsorption equilibrium could be reached within 150 min,indicating a rapid adsorption dynamics,with an adsorption capacity of 183.3 mg/g.Scatchard analysis indicated that there were two types of binding sites,with a dissociation constant(K)of 0.579 g/L and a maximum apparent adsorption capacity(Qmax)of 326.5 mg/g for the high affinity sites and a K value of 2.493 g/L and a Qmax value of 562.9 mg/g for the low affinity sites,respectively.Selectivity factors for this MIP toward morpholine relative to methylmorpholine,ethylmorpholine and 4-methylmorpholine-N-oxide were 2.47,2.48 and 2.24,respectively.Under the optimized conditions,the recovery of morpholine obtained by a single step through the MIP solid phase extraction of morpholine in fruits crude extract was 82.44%,showing a high capability in the enrichment of this compound.This material was also shown with a higher reusability.