Efficient activation of persulfate by a novel lignin hydrogel supported Fe/Cu nanoparticles for bisphenol A degradation

In this work, a novel lignin hydrogel-supported Fe/Cu nanocomposite (LH-Fe/Cu) was synthesized for the degradation of bisphenol A (BPA) in aqueous solution through persulfate (PS) activation, namely the LH-Fe/Cu-Ps system. The detailed property data demonstrated that the unique three-dimensional (3D) structure of the lignin hydrogel facilitates the dispersion of magnetic nanoparticles (Fe/Cu particles), thereby enhancing the maximum exposure of Fe/Cu particles. The three-dimensional architecture of lignin hydrogel enhances the availability of attachment sites for Fe/Cu, PS, and BPA, facilitating efficient electron transfer between Fe/Cu and PS, thereby promoting the degradation of BPA. The degradation rate of BPA in the LH-Fe/Cu-PS system reached 98.58 % within 6 min with 0.06 g/L catalyst and 0.8 mM PS. The effects of humic acid (HA) and inorganic anion on the degradation process were also studied. The quenching experiment demonstrated that the LH-Fe/Cu-PS system predominantly generates active free radicals, namely SO₄^.-, ^.OH, and O₂^.-, with SO₄^.- being the primary species. The degradation mechanism and pathway of BPA were predicted through density functional theory (DFT) calculations and intermediate analysis. The LH-Fe/Cu-PS system exhibits remarkable efficacy in the degradation of water pollutants and holds significant potential for application in the treatment of organic wastewater.