Novel magnetic metal-organic framework derivative: An adsorbent for efficient removal of fluorine-containing wastewater in mines

Abstract

The long-term drinking of high-concentration fluorine-containing wastewater by residents in the mining area will cause fluorosis of varying severities. In order to avoid fluorosis, this paper used Fe3O4 as the core and MOF-Co as the shell to synthesize Fe3O4@MOF-Co through the layer-by-layer assembly method, and then employed cellulose nano-fibers to modify its surface. Finally, the magnetic metal-organic framework derivative (Fe3O4@MOF-Co@CNF) with core-shell structure was obtained. The adsorbent was characterized by Fourier transform infrared spectrometer (FTIR), diffraction of x-rays (XRD), scanning electron microscopy (SEM), nitrogen adsorption and desorption (BET), and thermogravimetry (TG). The effects of pH, adsorption time, temperature, initial concentration, adsorbent dosage, coexisting ions and regeneration conditions on the adsorption properties were investigated. At the same time, in order to explain the adsorption mechanism of the adsorbent, the changes of FTIR, SEM and XPS microscopic characterization before and after the adsorption were compared and analyzed. In addition, the molecular dynamic simulation technology was employed to calculate the adsorption energy and simulate the distributions of electrostatic potential and concentration for the purpose of further clarifying the adsorption mechanism. The results suggest that the interaction of ligand exchange and hydrogen bond adsorption is the key factor to promote the adsorption for F-. This paper provides a new idea for the application of adsorbent materials in wastewater treatment.