Puissant synergistic effect between g-C3N4 and MIL-100(Fe) for highly stable enhanced activation of H2O2 to degrade antibiotic tetracycline hydrochloride

Abstract

The release of antibiotics in the environment has raised concerns about ecological damage and human health. As a promising technology, Fenton-like processes have been extensively studied to degrade pollutants in water and achieve rapid and efficient removal. Composites of metal-organic frameworks (MOFs) and graphitic carbon nitride (g-C3N4) have shown excellent performance in Fenton-like processes as a potent combination. However, there is a lack of similar studies to confirm their outstanding catalytic performance and stability in catalyzing the H2O2 process. Therefore, to complete the research in this field and to explore the efficient removal of antibiotics, composites of g-C3N4 and MIL-100(Fe) (CNMIL-x) were fabricated by post-synthesis for highly efficient H2O2 activation to remove tetracycline hydrochloride (TC-HCl). Scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) show that the characteristic morphology and peaks of g-C3N4 and MIL-100(Fe) varied according to the mass ratio between them. According to X-ray photoelectron spectroscopy (XPS), Fe is primarily in the Fe(Ⅲ) state. Besides, CNMIL-1.5 shows a SBET value of 598.46 m2·g−1, a Vpore of 0.42 cm3·g−1, and a pore size of 7.31 nm, which are significantly enhanced compared with g-C3N4. During TC-HCl degradation, the degradation rate of CNMIL-1.5 (0.02772 min−1) is 9.1 and 1.8 times faster compared to that of g-C3N4 and MIL-100(Fe), respectively. Furthermore, the excellent stability of CNMIL-1.5 are demonstrated by the quintuple cyclic experiments and characterization. A possible degradation mechanism dominated by •OH as well as a relative pathway of TC-HCl removal are proposed.