Magnetic Nitrogen-Rich UiO-66 Metal–Organic Framework: An Efficient Adsorbent for Water Treatment
Farhad Ahmadijokani, Salman Ahmadipouya, Mahdi Heidarian Haris, Mashallah Rezakazemi, Awais Bokhari, Hossein Molavi, Mohsen Ahmadipour, Swee‐Yong Pung, Jiří Jaromír Klemeš, Tejraj M. Aminabhavi, Mohammad Arjmand
Abstract
The postsynthetic modification of metal–organic frameworks (MOFs) has opened up a promising area to widen their water treatment application. However, their polycrystalline powdery state still restricts their widespread industrial-scale applications. Herein, the magnetization of UiO-66-NH 2 is reported as a promising approach to facilitate the separation of the used MOFs after water treatment. A two-step postmodification procedure employing 2,4,6-trichloro-1,3,5-triazine (TCT) and 5-phenyl-1 H -tetrazole (PTZ) agents was introduced to level up the adsorption performance of the magnetic nanocomposite. Despite a decrement in porosity and specific surface area of the designed MOFs (m-UiO-66-TCT) compared to neat UiO-66-NH 2, it outweighs in adsorption capacity. It was observed that m-UiO-66-TCT has an adsorption capacity of ≈298 mg/g for methyl orange (MO) with facile MOF separation using an external magnet. Pseudo-second-order kinetic model and Freundlich isotherm models suitably interpret the experimental data. Thermodynamic studies showed that MO removal using m-UiO-66-TCT is spontaneous and thermodynamically favorable at higher temperatures. The m-UiO-66-TCT composite exhibited easy separation, high adsorption capacity, and good recyclability, rendering it an attractive candidate for the adsorptive removal of MO dye from aqueous environments.