Effective adsorption of Congo red by a MOF-based magnetic material

Abstract

Metal–organic frameworks (MOFs) are an exciting class of porous crystallized materials, which have attracted great interest in sustainable energy and environmental remediation. Magnetite (Fe₃O₄) is one of the best-known magnetic materials and has been extensively studied with respect to properties involving high saturation magnetization, biocompatibility and low toxicity. The combination of MOFs and Fe₃O₄ has shown its potential applications in drug delivery, catalysis and wastewater treatment. However, only classical porous MOFs are used to encapsulate magnetic nanoparticles, such as MIL-100(Fe), ZIF-8, UiO-66 and so on. Herein, we firstly synthesized a new MOF ZTB-1 and surveyed its applications in magnetic materials. As a result, a highly water-stable MOF-based magnetic material Fe₃O₄@ZTB-1 has been obtained, and it was for the first time used as an excellent adsorbent for the fast adsorption of Congo red (CR) from aqueous solutions, exhibiting an adsorption capacity of 458 mg CR per gram. The electrostatic interactions and hydrogen bond are responsible for binding of CR with Fe₃O₄@ZTB-1. The magnetic material Fe₃O₄@ZTB-1 shows a potential application in dyeing wastewater treatment.