Lignin-based Fe/Zn bimetallic Fenton-like catalysts for efficient degradation of tetracycline in water

To address the issues of metal-organic frameworks (MOFs) existing in powdered or solid particle form and their difficulty in recovery during repeated use, this study proposes an innovative preparation scheme: using Fe₃O₄ magnetic spheres as the core, MOFs as the shell, and lignin as the interfacial promoter to promote the in-situ growth of MOFs on the Fe₃O₄ magnetic spheres. Lignin based Fe/Zn bimetallic magnetic sphere catalyst prepared (Fe₃O₄@Lignin@ZIF-8) was used to degrade tetracycline (TC) and was easily separated from the solution. Various characterization methods were utilized to reveal the morphology and physicochemical properties of Fe₃O₄ @ Lignin @ ZIF-8. The effects of catalyst dosage, PDS concentration, pH, concentration and initial concentration on TC degradation were investigated by batch experiments. Furthermore, by using electron paramagnetic resonance spectroscopy and radical quenching studies, it was determined that the main oxidants produced in the “Fe₃O₄@Lignin@ZIF-8” system were OH, ¹O₂ and -O₂, respectively.