Curcumin-mediated balsa wood-derived 3D magnetic biochar with dual active sites to activate peroxymonosulfate for PFOA removal

Perfluorooctanoic acid (PFOA) is one of the most commonly detected perfluorinated compounds, and now poses a significant threat to animal, plant and human health as an emerging pollutant. Using balsa wood as a natural template and potassium ferrocyanide as a precursor, curcumin-mediated Fe3C/N-embedded 3D magnetic biochar (Fe3C/N@BsB) was obtained in this study via a facile in-situ pyrolysis method. Featured with dual metallic and non-metallic active centers, Fe3C/N@BsB was then utilized for activating peroxymonosulfate (PMS) to degrade PFOA in water. The experimental data indicated that a degradation efficiency of 82.9% and defluorination efficiency of 71.4% were achieved for PFOA at room temperature and pH 3.0. Coexisting 50 mM Cl in water had no significant impact, while HCO3 and HA showed inhibitory effects on PFOA degradation. By the identification and quantification of free radicals, SO4 similar to was predominant in the Fe3C/N@BsB + PMS system with its maximum accumulation concentration of 29.6 mu M. Under the attack of active species, PFOA degradation occurred gradually to produce short-chain by-products for subsequent mineralization. Finally, the recyclability of Fe3C/N@BsB and its catalytic degradability in tap water and Yellow River water were also evaluated. This study not only demonstrates the enormous potential of Fe3C/N@BsB + PMS system for the removal of emerging PFOA in water, but also provides good theoretical support for the resource utilization of balsa wood.