Degradation of norfloxacin by MOF-derived lamellar carbon nanocomposites based on microwave-driven Fenton reaction: Improved Fe(III)/Fe(II) cycle

Abstract

In this paper, a new type of iron-based magnetic nanoparticle material embedding mesoporous carbon (Fe@C700) was prepared by simple pyrolysis of a MIL-101-Fe precursor and employed in the microwave-catalyzed degradation of norfloxacin (NOR) with the presence of H2O2. Characterization results showed successful anchoring of Fe0 nanoparticles in the carbon matrix. Under optimal treatment conditions (Calcination temperature = 700 °C, H2O2 dosage = 40 mM, MW power = 500 W, NOR dosage = 50 mg L−1 and initial pH = 4), the degradation efficiency of NOR reached 95.22%. The catalyst showed exceptional degradation properties over a relatively wide pH range. The mesoporous carbon in the catalyst promoted electron transfer, enhanced the Fe(III)/Fe(II) cycle, increased contact between Fe0 and Fe2+ with H2O2, and accelerated the production of ·OH. Furthermore, density functional theory (DFT) calculations were used to predict the fragile active sites in NOR and to analyze the degradation pathway of NOR in combination with intermediates. Fe@C700 retained good activity after 5 cycles. Reduced toxicity of intermediates predicted by T.E.S.T. compared to NOR. This study presented a new avenue for the rational design of Fe0-carbon composites as microwave-assisted Fenton-like catalysts for potential applications in wastewater treatment.