金属有机框架UiO-66-(COOH)_(2)吸附亚甲基蓝的作用机制

Mechanism of Adsorption of Methylene Blue by Metal-Organic Framework UiO-66-(COOH)_(2)

为减少染料废水的排放造成的环境污染,分别采用溶剂热法和机械搅拌法制备了金属有机骨架材料UiO-66和羧基改性材料UiO-66-(COOH)_(2),研究了两种吸附剂对有机染料亚甲基蓝(MB)的吸附性能,并探讨了相应的吸附机理。结果表明:UiO-66和UiO-66-(COOH)_(2)对MB均具有较好的吸附能力,UiO-66-(COOH)_(2)对MB的平衡吸附量达416.95 mg/g,比UiO-66材料提高了38.6%。UiO-66-(COOH)_(2)对MB的高效吸附是静电相互作用、π-π相互作用和氢键作用等多重机制共同作用的结果。吸附过程符合拟二级动力学模型,吸附平衡符合Freundlich吸附模型。

To reduce the environmental pollution caused by the discharge of dye wastewater,the metal-organic framework materials UiO-66 and carboxyl modified material UiO-66-(COOH)_(2) were prepared by solvothermal and mechanical stirring methods,respectively.The adsorption properties of the two adsorbents for the organic dye methylene blue(MB)were investigated,and their adsorption mechanisms were studied.The results show that both UiO-66 and UiO-66-(COOH)_(2) have good adsorption capacity for MB,and the equilibrium adsorption capacity of UiO-66-(COOH)_(2) for MB reaches 416.95 mg/g,which is 38.6%higher than that of UiO-66.The highly-efficient adsorption of MB by UiO-66-(COOH)_(2) is because of multiple interactions such as electrostatic interaction,π-πinteraction and hydrogen bonding.The adsorption processes conform to the pseudo-second-order kinetic model,and the adsorption equilibrium is described by the Freundlich adsorption model.