Chitin-Assisted Fabrication of an Fe3O4/BiOCl Composite for Visible-Light Photocatalytic Degradation of Ciprofloxacin

A novel recyclable composite, Fe₃O₄/chitin/BiOCl, was synthesized via a solvothermal approach using cetyltrimethylammonium bromide (CTAB), bismuth nitrate pentahydrate (Bi(NO₃)₃·5H₂O), chitin, and Fe₃O₄ as precursors. The composite was systematically characterized via X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) analysis, ultraviolet-visible (UV-vis) spectroscopy, and vibrating sample magnetometry (VSM). Characterization results indicated that the incorporation of chitin significantly improved the porosity and specific surface area of the catalyst. Furthermore, the synergistic effects between chitin and Fe₃O₄ effectively reduced the recombination rate of photogenerated electron-hole pairs. The photocatalytic activity of the composite was evaluated by degrading ciprofloxacin (CIP) under visible-light irradiation. When the contents of Fe₃O₄ and chitin were 5% and 2% (by weight), respectively, the catalyst exhibited excellent photocatalytic performance with a degradation rate of 89.54%, and the rate constant was 5.1 times higher than that of pure BiOCl. Additionally, the catalyst exhibited excellent magnetic recoverability and photocatalytic stability.