Metal-organic frameworks derived magnetic carbon-αFe/Fe3C composites as a highly effective adsorbent for tetracycline removal from aqueous solution

Efficient removal of tetracycline (TCN) from aqueous solution is important for water environment security. Herein, magnetic carbon-αFe/Fe3C derived from metal-organic frameworks (MOFs) were synthesized by a carbonization method and used for TCN adsorption. The magnetic carbon-αFe/Fe3C adsorbent was characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), thermal gravimetric analyzer (TGA), X-ray photoelectron spectrum (XPS) and vibrating sample magnetometer (VSM). The resultant magnetic carbon-αFe/Fe3C exhibited outstanding TCN adsorption capacity (511.06 mg g−1) from aqueous solution due to its large specific surface area (171.72 m2 g−1) and pore volume (0.31 cm3 g−1), and abundant active adsorption sites. The main adsorption mechanisms were physisorption and chemisorption, including pore filling effect and electrostatic adsorption. Moreover, magnetic carbon-αFe/Fe3C could remove TCN at low concentrations (<5 mg L−1) in aqueous solution to a relatively low level, which was very significant for the actual application. The high absorbability and good reusability in real water samples insured the magnetic carbon-αFe/Fe3C with great potential in practical application.