Boosting tetracycline degradation by integrating MIL-88A (Fe) with CoFe2O4 persulfate activators

Abstract

Iron-based metal organic framework MIL-88A (Fe)/CoFe2O4 nanocomposites were successfully prepared by hydrothermal synthesis for catalytic degradation of tetracycline (TC) via persulfate (PS) activation process. A comprehensive characterization of the produced materials was conducted to elucidate their surface textures, element composition, and structural features. This comprehensive assessment employed various investigative techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Fourier-transform infrared spectroscopy (FT-IR), and Brunauer-Emmett-Teller (BET) analysis. The results showed that pristine MIL-88A (Fe), CoFe2O4, and the MIL-88A (Fe)/CoFe2O4 nanocomposites were successfully synthesized with high purity. MIL-88A (Fe)/CoFe2O4 catalyst significantly boosted the TC degradation efficiency with a typical rate exceeding twice that of unique CoFe2O4. The catalytic performance was influenced by several factors, including pH, initial TC concentration, catalyst amount, and persulfate (PS) concentration. The optimal conditions for TC degradation were as follows: pH 6.8, 10 mg/L initial TC concentration, 1.0 mg/L PS concentration, and 250 mg/L MIL-88A (Fe)/CoFe2O4 catalyst. The MIL-88A (Fe)/CoFe2O4-PS system could degrade 90% of 10 mg/L TC at room temperature for 1 h reaction time. The pseudo-second order kinetics described the best the TC degradation process (r2=0.9466 for optimal conditions), corresponding to a rate constant of 0.0117 L/min.mg. The successful degradation of TC catalyzed by the MIL-88A (Fe)/CoFe2O4-PS was a collaborative effort, with SO4•- radicals leading the charge and HO• radicals contributing a significant role. The impressive ability of MIL-88A (Fe)/CoFe2O4 to degrade TC persisted beyond three cycles, with its efficiency staying above 82%, revealing its robustness and potential for practical applications.