Fe3C-porous carbon derived from Fe2O3 loaded MOF-74(Zn) for the removal of high concentration BPA: The integrations of adsorptive/catalytic synergies and radical/non-radical mechanisms

Highlights: • Fe₃C loaded porous carbon composites (Fe₃C-C) was prepared via pyrolysis approach. • Fe₃C-C/PMS exhibits prominent adsorptive and catalytic performance for BPA removal. • Fe₃C and porous carbon dominate radical and non-radical pathway respectively. • Synergy was obtained by combining Fe₃C with porous carbon. • Fe₃C-C shows a wide pH application range and strong adaptability to complicated water. In this study, novel Fe₃C-porous carbon composites (Fe₃C-C) were prepared via the pyrolysis of Fe₂O₃ loaded MOF-74(Zn), which could integrate both strong adsorption properties and excellent peroxymonosulfate (PMS) activating performance for the removal of bisphenol A (BPA) in water. Results indicated that the composite obtained at 1000 °C (Fe₃C-C1000) exhibited optimal catalytic capability. Specifically, 0.1 mM BPA could be completely removed by 0.1 g/L Fe₃C-C1000 within 10 min after the adsorption enrichment. Afterwards, the mechanism of Fe₃C-C/PMS system was unveiled based on quenching tests, electron spin resonance analysis, electrochemical analysis, PMS consumption detection and solvent exchange (H₂O to D₂O) test. The BPA degradation pathways were also analyzed through identifying its decomposition intermediates. Results showed that the Fe₃C and porous carbon constituents could activate PMS via radical and non-radical mechanisms respectively, and BPA was readily degraded through both pathways. Additionally, it was found that the Fe₃C-C1000/PMS system could maintain conspicuous catalytic performance in a variety of complicated water matrices with wide pH application range and long-time use stability. This study suggests a new insight for the design and development of novel catalyst which can be used for the removal of refractory organic contaminants with high concentrations in water media.