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

Abstract

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− was predominant in the Fe3C/N@BsB + PMS system with its maximum accumulation concentration of 29.6 μM. 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.