Magnetically separable Zn2FeOx@CN microcubes derived from metal-organic frameworks for efficient tetracycline removal

Abstract

Removing tetracycline (TC) from water is vital for protecting both human health and aquatic life. One promising solution involves using magnetic carbon adsorbents derived from metal-organic frameworks (MOFs). In this study, we created a bimetallic MOF precursor, Zn2[Fe(CN)6]·3H2O (Zn/Fe-MOF), and applied a one-step pyrolysis process to produce Zn2FeOx@CN composite oxides with magnetic properties. This approach combines efficiency with practicality, offering a powerful tool for tackling water contamination challenges. The version of this adsorbent created at 500 °C, called Zn2FeOx@CN-500, demonstrated a strong ability to capture TC, with a capacity of 769 mg g-1, reaching equilibrium within just an hour at 298 K. This adsorbent remains stable across a wide pH range (3-11) and can work in various water conditions. Our analysis showed that the adsorption process is endothermic and involves a multilayer chemical adsorption, mainly driven by surface complexation, π-π stacking interactions, hydrogen bonding, and electrostatic attraction between Zn2FeOx@CN-500 and TC molecules. Moreover, Zn2FeOx@CN-500 can be easily separated magnetically and shows strong reusability, making it a practical choice for real-world water treatment applications.Accepted versionRP 1/22 EA