MIL-126(Fe) shows great potential for aqueous phase drug adsorption due to its permanent porosity and easy modification. Herein, we utilized the ligand installation method to introduce two ligands, 2-amino terephthalic acid (NH 2 -BDC) and 2-nitro terephthalic acid (NO 2 -BDC), into MIL-126(Fe) to prepare MIL-126(Fe)-NH 2 and MIL-126(Fe)-NO 2 , respectively. Various analytical tools were used to confirm the successful installation of the 1, 4-phthalic acid (BDC) series of ligands, as well as the successful introduction of amino (-NH 2 ) and nitro (-NO 2 ) groups. The presence of both -NH 2 and -NO 2 groups improved the adsorption of TC by the adsorbent material, with -NH 2 groups having a stronger influence on the enhancement. The experimental results indicated that MIL-126(Fe)-NH 2 had the highest adsorption performance at the optimal pH of 7, achieving a static adsorption capacity of 326.5 mg/g, which was about twice the adsorption capacity of the original MIL-126(Fe). X-ray photoelectron spectroscopy (XPS) determined that the adsorption of TC by MIL-126(Fe)-NH 2 relies mainly on π-π interaction and Fe-N coordination bonds. Furthermore, the higher adsorption capacity of MIL-126(Fe)-NH 2 can be attributed to the O-H⋯N hydrogen bonds interaction between -NH 2 and the phenolic hydroxyl group (Ph-OH) in the TC molecule.
The development of efficient technology for natural gas separation in industrial processes has become imperative. In this regard, the exploration of novel and effective adsorbents has gained significant attention. One promising approach is the metal regulation of metal–organic frameworks (MOFs), particularly heterometallic MOFs, which offer greater potential for gas separation due to their diverse composition. This study presents the synthesis of a series of iron- and vanadium-based heterometallic MOFs (MIL-126), featuring interpenetrated structures, and investigates their adsorption performance for methane (CH4), ethane (C2H6), and propane (C3H8). Experimental results reveal that the choice of metal combinations within the MOF framework significantly influences the adsorption performance of MIL-126. Notably, heterometallic MIL-126(Fe/Ni) exhibits a stronger binding affinity for C3H8, with an impressive uptake of 177 cm3/g. The C3H8/CH4 ideal adsorbed solution theory selectivity of MIL-126(Fe/Ni) surpasses that of MIL-126(Fe) by a factor of 7, reaching a value of 853, second only to the highest reported value. Furthermore, MIL-126(Fe/Ni) exhibits remarkable potential for the recovery of pure CH4 from the equimolar C3H8/CH4 mixture, with the amount of pure CH4 approaching the maximum reported value for MOFs. Insights from isosteric heat at zero loading and Henry’s coefficients indicate that the transformation of metal types leads to a change in the interaction energy between C3H8 and the framework. Furthermore, breakthrough experiments validate the effective separation capability of MIL-126(Fe/Ni) for CH4/C2H6/C3H8 mixtures. These findings underscore the remarkable potential of heterometallic MOFs in constructing a wide range of new MOFs with tailorable properties, thereby enhancing their gas separation performance.
危险品化学品经营许可证（带存储）