基于三角芳香配体的金属有机框架对染料木素的吸附性能与机理

Genistein adsorption performance and mechanism by metal-organic frameworks based on triangular aromatic ligands

目的:提高染料木素的吸附率。方法:采用水热法合成2种含不同尺寸三角芳香配体的MOFs(MOF-808和PCN-777),通过系列表征确定MOFs的合成,比较其与线性二元羧酸配体构筑的MOF(UiO-66)对染料木素的吸附效果;考察孔隙特征、疏水性变化等对吸附性能的影响,利用X射线光电子能谱探究其吸附机理。结果:与线性配体构筑的UiO-66相比,三角芳香配体构筑的MOFs(MOF-808和PCN-777)的孔径分别从0.65 nm增大到1.81,3.55 nm,水接触角分别从47.91°增大到110.68°,128.23°。线性配体构筑的UiO-66对染料木素的吸附量为40.08 mg/g,吸附率为39.98%;而三角芳香配体构筑的MOFs(MOF-808和PCN-777)对染料木素的吸附量分别为61.80,81.75 mg/g,吸附率分别为61.63%,81.52%。结论:金属有机框架可用于染料木素的吸附富集,相较于线性配体,引入不同尺寸的三角芳香配体改变了MOFs孔径及疏水性,加强了MOFs的内部可及性并提供了更多吸附位点,从而提高了对染料木素的吸附效果。PCN-777对染料木素的吸附机理为金属螯合作用、π-π相互作用和疏水相互作用的协同。

Objective:To improve the adsorption of genistein by zirconium-based metal-organic frameworks(MOFs)with triangle aromatic ligands.Methods:Two MOFs(MOF-808 and PCN-777)containing different sizes of triangle aromatic ligands were synthesized by hydrothermal method for adsorption of genistein.The synthesis of MOFs was determined by a series of characterization methods,and the adsorption performance was compared with that of a linear binary carboxylic acid ligand-constructed MOF(UiO-66),to evaluate the effects of pore characteristics,hydrophobicity changes,and other factors on the adsorption performance,and to explore the adsorption mechanism by XPS analysis.Results:Compared with linear ligand-constructed UiO-66,the pore sizes of triangular aromatic ligand-constructed MOFs(MOF-808,and PCN-777)increased from 0.65 nm to 1.81 nm and 3.55 nm,respectively,and the water contact angles increased from 47.91°to 110.68°and 128.23°,respectively.The adsorption capacity and adsorption efficiency of genistein in linear ligand-constructed UiO-66 was 40.08 mg/g and 39.98%,respectively,while the adsorption capacity and adsorption efficiency of genistein in MOFs constructed by triangular aromatic ligand(MOF-808,PCN-777)was increased to 61.80 mg/g,81.75 mg/g and 61.63%,81.52%respectively.Conclusion:Metal-organic frameworks(MOFs)can be used for the adsorption and enrichment of genistein.Compared with linear ligands,the introduction of triangular aromatic ligands with different sizes changes the pore size and hydrophobicity of MOFs,enhances the internal accessibility of MOFs,and provides more adsorption sites,which improves the adsorption effect of genistein.The adsorption mechanism of genistein in PCN-777 is based on the synergistic combination of metal-chelating interactions,π-πinteractions,and hydrophobic interactions.