Enhanced catalytic oxidation of bisphenol A via persulfate oxidation by microwave-assisted preparation of ZnCoxFe2-xO4-loaded rice-husk-carbon

Cobalt-doped ZnFe2O4 supported on rice husk carbon (RHC) has been prepared by a microwave-assisted method as a catalyst for the degradation of bisphenol A (BPA) by persulfate (PS) oxidation. Ferrite is a good absorbing material, RHC contains abundant channels, which provide channels for microwaves(MW) reflecting and scattering, and accelerate the synthesis of ZC1.3FO. In addition, the polarization and synergistic effect of the contact interface between the two phases is enhanced, which not only improves the dispersity of the magnetic material, but also enhances electron delocalization in the mixed material, promoting electron transfer between Co3+/Co2+ and Fe3+/Fe2+, and improving the catalytic activity. Our results have shown the degradation rate of BPA by ZnCo1.3Fe0.7O4-50 wt%RHC (ZC1.3FO-5C) (0.0697 L/mg min) to be 28 times higher than that by ZC1.3FO (0.00251 L/mg min), and the extents of leaching of cobalt and iron were lower than 45 mu g/L. Particle video microscopy (PVM) have been used to confirm improved dispersion of composite particles compared to that of a single catalyst during degradation. Free radical quenching experiments, electron paramagnetic resonance (EPR), and X-ray photoelectron spectroscopy (XPS) have confirmed that BPA degradation was caused by the synergistic action of non-free radical and free radical pathways. Intermediates have been identified by electrospray ionization mass spectrometry (ESI-MS), on the basis of which a degradation pathway of BPA by activated PS oxidation in the presence of ZC1.3FO-5C is proposed. In brief, a ZC1.3FO-5C composite has been prepared by a microwave method to activate PS for the degradation of BPA, realizing the resource utilization of waste ferrous sulfate derived from titanium dioxide production, providing a new concept for the degradation of organic pollutants.

Automated summary

In this study, a cobalt-doped ZnFe2O4 catalyst supported on rice husk carbon (RHC) was prepared by a microwave-assisted method for the degradation of bisphenol A (BPA) by persulfate oxidation. The catalyst showed improved catalytic activity and reduced leaching of cobalt and iron. The degradation pathway of BPA in the presence of the catalyst was proposed. This research provides new insights into the utilization of waste ferrous sulfate and the degradation of organic pollutants.