Amino-Functionalized Chromium-Based Metal-Organic Framework NH2-MIL-101(Cr) for the Removal of Nanoplastics from Water

纳米塑料颗粒(NPs)作为一类新型污染物，其纳米级尺寸特性对水生生态系统具有显著危害。开发高效吸附材料是应对水环境中NPs污染的重要途径。本研究制备了胺基功能化铬基金属有机框架材料NH2-MIL-101(Cr)作为高效吸附剂用于水体NPs治理，并系统探究了环境因子对吸附行为的影响机制。通过引入经3-氨基丙基三甲氧基硅烷(APTMS)修饰的MIL-101(Cr)，该材料展现出对NPs吸附的选择性及强化吸附能力。研究明确了影响吸附效率的最佳条件，最终实现对聚苯乙烯纳米塑料(PS NPs)高达97.5%的去除率。等温吸附实验表明最大吸附容量可达508.39 mg/g，PS NPs主要通过表面吸附作用固定。值得注意的是，在酸性、中性和碱性条件下，NH2-MIL-101(Cr)表面始终带正电荷，而PS NPs在其所处环境中呈负电性。Nanoplastics (NPs), plastic particles at the nanometer scale, constitute an emerging class of pollutants with significant adverse effects on aquatic ecosystems. Developing efficient adsorbent materials is an important approach to addressing the issue of NPs pollution in water environments. In this research, we prepare the amino-functionalized chromium metal-organic framework, NH2-MIL-101(Cr), as effective adsorber to abating of NPs in water. Furthermore, the study also investigates how various environmental factors affect adsorption behavior and mechanism. By incorporating 3-aminopropyltrimethoxysilane (APTMS) modified MIL-101(Cr), the material demonstrates selectivity against NPs adsorption and the ability to enhance adsorption. The study identifies the optimal conditions that affect the efficiency of adsorption. By the end of the study, a remarkable 97.5% removal of PS NPs is achieved using NH2-MIL-101(Cr). Notably, the maximal adsorptive ability is determined by isothermal analysis to be 508.39 mg/g, with PS NPs sorbed to the surface. Under acidic, neutral, and alkaline conditions, NH2-MIL-101(Cr) consistently displays a positive charge, while PS NPs exhibit a negative charge within their environment.