金属有机骨架(MOFs)作为先进的纳米多孔材料正在兴起,以去除苯基砷酸,对-阿桑酸(p-ASA),和罗沙松(ROX)在水溶液中,虽然MOFs通常以粉末状态存在,并且在吸附后的恢复中遇到困难,这极大地限制了它们在水性环境中的实际应用。在这里,MIL-101(Fe),典型的MOF,采用三维(3D)打印技术,与海藻酸钠和明胶混合制备MIL-101@CAGE,然后将其用作可分离的吸附剂以除去水溶液中的苯基砷酸。首先通过X射线衍射(XRD)对3D打印的MIL-101@CAGE的结构进行了表征,扫描电子显微镜(SEM),傅里叶变换红外(FTIR),以及热重法和差示热重法(TG-DTG)。发现MIL-101(Fe)的八面体形态在3D打印过程中没有变化。然后,通过吸附动力学系统研究了MIL-101@CAGE在苯基砷酸类上的吸附过程,吸附等温线,吸附热力学,条件实验,和循环再生实验。最后,进一步研究了MIL-101@CAGE与苯基砷酸的吸附机理。结果表明,朗缪尔,Freundlich,Temkin等温线很合适,根据Langmuir拟合结果,MIL-101@CAGE在25℃p-ASA和ROX上的最大吸附量分别为106.98和120.28mg/g,分别。MIL-101@CAGE对p-ASA和ROX的去除在宽pH范围内以及在各种共存离子的存在下保持稳定。再生实验表明,3D打印的MIL-101@CAGE在5次循环后仍能保持90%以上的去除率。该体系的吸附机理可能包括苯基砷酸上的苯环与MIL-101@CAGE中的有机配体之间的π-π堆积相互作用,氢键,和配体键合相互作用(Fe-O-As)。本研究为基于MOF材料的可分离、可循环吸附剂的规模化制备提供了新思路,用于高效去除水溶液中的苯基砷酸。
Metal-organic frameworks (MOFs) are emerging as advanced nanoporous materials to remove phenylarsenic acid, p-arsanilic acid (p-ASA), and roxarsone (ROX) in the aqueous solution, while MOFs are often present as powder state and encounter difficulties in recovery after adsorption, which greatly limit their practical application in the aqueous environments. Herein, MIL-101 (Fe), a typical MOF, was mixed with sodium alginate and gelatin to prepare MIL-101@CAGE by three-dimensional (3D) printing technology, which was then used as a separatable adsorbent to remove phenylarsenic acid in the aqueous solution. The structure of 3D-printed MIL-101@CAGE was first characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and thermogravimetry and differential thermogravimetry (TG-DTG). The octahedral morphology of MIL-101 (Fe) was found unchanged during the 3D printing process. Then, the adsorption process of MIL-101@CAGE on phenylarsenic acids was systematically investigated by adsorption kinetics, adsorption isotherms, adsorption thermodynamics, condition experiments, and cyclic regeneration experiments. Finally, the adsorption mechanism between MIL-101@CAGE and phenylarsenic acid was further investigated. The results showed that the Langmuir, Freundlich, and Temkin isotherms were well fit, and according to the Langmuir fitting results, the maximum adsorption amounts of MIL-101@CAGE on p-ASA and ROX at 25 °C were 106.98 and 120.28 mg/g, respectively. The removal of p-ASA and ROX by MIL-101@CAGE remained stable over a wide pH range and in the presence of various coexisting ions. The regeneration experiments showed that the 3D-printed MIL-101@CAGE could still maintain a more than 90% removal rate after five cycles. The adsorption mechanism of this system might include π-π stacking interactions between the benzene ring on the phenylarsenic acids and the organic ligands in MIL-101@CAGE, hydrogen-bonding, and ligand-bonding interactions (Fe-O-As). This study provides a new idea for the scale preparation of a separatable and recyclable adsorbent based on MOF material for the efficient removal of phenylarsenic acid in the aqueous solution.