原位生长UiO-66/海藻酸钠基气凝胶对双氯芬酸钠的吸附及分子模拟研究
- Adsorption and molecular simulation of diclofenac sodium by in-situ growth UiO-66/ sodium alginate aerogels
- 基金项目：国家自然科学基金(NO.42377060)；国家自然科学基金青年科学(NO.42207101)；长安大学中央高校基本科研业务费专项资金(NO.300102293208)
- 摘要：双氯芬酸钠(DCF)在水环境中广泛存在，如何有效去除水中DCF备受关注。气凝胶和金属有机框架(MOF)具备卓越的吸附性能，将其用于水中DCF去除具有广阔的应用前景。然而原始气凝胶和MOF材料分别存在孔隙结构差和粉末状难回收双重问题。本研究以海藻酸钠为前驱体、CaCl2为交联剂制备海藻酸钠基气凝胶，并原位生长锆基MOF(UiO-66)，构建出对DCF具有优异吸附性能的宏观材料。结果表明，通过将UiO-66原位生长在海藻酸钠气凝胶上不仅巧妙解决了MOF难回收的问题，而且使材料具有了高比表面积(276.7 m2?g-1)和丰富的孔结构，其对DCF的吸附量高达418.1 mg?g-1，并且具有一定的抗干扰能力和再生性能。通过模型拟合，说明其对DCF的吸附主要是以化学吸附为主的单层吸附过程。利用UiO-66的分子模拟，分析了该材料对DCF的吸附结合位点，结果表明，其吸附机理主要为羧酸氧以及氯原子与UiO-66中的Zr离子之间的配位作用，并伴随部分氢键作用以及金属(Zr)?π相互作用。研究成果为MOF基复合气凝胶宏观体的构建和吸附机理研究提供了参考。
- Abstract：Diclofenac sodium (DCF) exists widely in water environment, and how to effectively remove DCF from water has attracted much attention. Aerogels and metal-organic frameworks (MOF) have excellent adsorption properties, and they have broad application prospects in the removal of DCF from water. However, the original aerogel and MOF materials have double problems which include poor pore structure and difficult recovery of powder. In this study, sodium alginate-based aerogels are prepared by using sodium alginate as precursor and CaCl2 as cross-linking agent, and zirconium-based MOF(UiO-66) is grown in situ to construct a macro material with excellent adsorption performance for DCF. The results show that by growing UiO-66 on sodium alginate aerogel in situ, the problem that MOF is difficult to recover is skillfully solved.In addition, the material has high specific surface area (276.7 m2g-1) and rich pore structure and its adsorption capacity for DCF is as high as 418.1 mg·g-1. What’s more, this material has certain anti-interference ability and regeneration performance. Through the model fitting, it is shown that the adsorption of DCF is mainly a single-layer adsorption process dominated by chemical adsorption. The molecular simulation of UiO-66 is used to analyze the adsorption sites of DCF. The results show that the adsorption mechanism is mainly the coordination between carboxylate oxygen and chlorine atoms and Zr ions in UiO-66, accompanied by partial hydrogen bonding and metal (Zr)?π interaction. The research results provide reference for the construction and adsorption mechanism study of MOF-based composite aerogels.
