Highly efficient adsorption and catalytic degradation of aflatoxin B1 by a novel porous carbon material derived from Fe-doped ZIF-8

Abstract

The development of peroxymonosulfate (PMS) catalysts with sufficient active sites and high mass transfer capacity is a desirable but challenging aspect in advanced oxidation processes. In this work, an Fe/N-co-doped porous carbon (Fe/N-PC) material derived from silica-coated Fe-doped zeolitic imidazolate framework-8 (Fe-ZIF-8) was developed and used as catalyst for the degradation of aflatoxin B1 (AFB1). Fe-ZIF-8 introduced additional Fe-N sites with high catalytic PMS activity. Importantly, the strategy of silica coating on the surface of Fe-ZIF-8 effectively prevented the aggregation of catalyst particles during the pyrolysis process and introduced a hierarchical porous structure in Fe/N-PC, significantly improving the mass transfer of reactants on the catalyst. As a result, Fe/N-PC possessed a much higher adsorption capacity for AFB1 (202.8 mg g−1) than other reported carbon adsorbents and exhibited fast degradation of AFB1 with ultra-high removal efficiency (99.88%) within 30 min. Singlet oxygen (1O2) was proved to be the dominant reactive species for AFB1 degradation. In addition, four degradation products were identified, and two possible degradation pathways were proposed. The double bond of the terminal furan ring or the methoxy group was destroyed, which implied that the toxicity of the degradation products was significantly reduced. Based on the above results, Fe/N-PC can be considered an efficient catalyst for the removal of hard-to-degrade AFB1 in practical applications.