配体改性对锆系金属-有机骨架吸附分离芳烃混合物的影响：计算化学研究

he adsorption and separation properties of benzene and toluene on the zirconium-based frameworks UiO-66, -67, -68 and their functional analogues UiO-Phe and UiO-Me2 were studied using grand canonical Monte Carlo (GCMC) simulations, density functional theory (DFT) and ideal adsorbed solution theory (IAST). Remarkable higher adsorption uptakes of benzene and toluene at low pressures on UiO-Phe and -Me2 were found compared to their parent framework UiO-67. It can ascribed to the presence of functional groups (aromatic rings and methyl groups) that significantly intensified the adsorption, majorly by reducing the effective pore size and increasing the interaction strength with the adsorbates. While pore volumes and accessible surfaces of the frameworks turned to be the dominant factors governing the adsorption at high pressures. In the case of toluene/benzene separation, toluene selectivities on UiOs showed a two-stage separation behavior at the measured pressure range, resulting from the greater interaction affinities of toluene at low pressures and steric hindrance effects at high pressures. Additionally, the enhanced π delocalization and suitable pore size of UiO-Phe corporately gave rise to the highest toluene selectivity, suggesting the ligand functionalization strategy could reach both high adsorption capacity and separation selectivity from aromatic mixtures at low concentrations.