Enhanced catalytic degradation of ciprofloxacin over Ce-doped OMS-2 microspheres

• Published in: Applied catalysis. B, Environmental Vol. 181; pp. 561 - 569
• Main Authors: Zhang, Lili, Tu, Jinjun, Lyu, Lai, Hu, Chun
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-02-2016
• Subjects: Catalysis; Catalytic oxidation; Ce-OMS-2; Ciprofloxacin; Degradation; Field emission; Manganese; O2[rad]− radicals; Oxygen; Scanning electron microscopy; Surface chemistry; X-rays; Catalytic oxidation; O2− radicals; Ce-OMS-2; Ciprofloxacin
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2015.08.029

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•Ce significantly changed the surface properties of OMS-2 for better activity.•Ce(0.48)-OMS-2 was highly effective for CIP degradation under ambient conditions.•The release of Mn(II) was much lower than the EU directives (<0.05mgL−1).•The piperazine and quinolone moiety of CIP was destructed by Mn(IV) and O2−.•Surface labile oxygen was responsible for Mn(II) reoxidation and O2− generation.
A novel Ce-doped manganese oxide octahedral molecular sieve (Ce-OMS-2) was prepared by a reflux method and characterized by field emission scanning electron microscope, high resolution transmission electron microscopy, Fourier-transform infrared spectra, nitrogen adsorption/desorption isotherms, X-ray diffraction and X-ray photoelectron spectroscopy. The Ce(0.48)-OMS-2 with Ce/Mn molar ratio of 0.48 was highly effective and stable for the degradation of ciprofloxacin in water. The characterized results indicated that Ce mainly entered the tunnel structure of OMS-2, significantly increasing the BET surface area from 72m2/g for OMS-2 to 304m2/g for Ce(0.48)-OMS-2. Moreover, the surface oxygen defects and surface labile oxygen significantly increased after the introduction of Ce into OMS-2, being determined by the O1s spectra and O2-TPD analysis. The ESR and activity tests under different conditions suggested that the reduced manganese Mn(II) could interact with surface labile oxygen to form O2− and Mn(IV), resulting in the high activity of Ce(0.48)-OMS-2 to degrade the piperazine ring and the quinolone moiety of CIP into small molecular products. Simultaneously, the release of Mn(II) was inhibited by the electron transfer process on the micro-interface of Ce(0.48)-OMS-2.