Degradation of organic pollutants through activating bisulfite with lanthanum ferrite-loaded biomass carbon

The removal of methylene blue (MB) in water is a challenging task due to its toxicity, carcinogenicity and resistance to biodegradation. Accordingly, a novel composite catalyst (BC@LF) was prepared by loading lanthanum ferrite (LaFeO3) on biomass carbon (BC) to activate bisulfite (BS) for methylene MB removal in this study. Characterization via scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) indicated that LaFeO3 was successfully loaded on BC. X-ray photoelectron spectroscopy (XPS) analysis suggested that Fe(III) was the main active site for BS activation. It was found that 99.4% MB was removed within 60 min in BC@LF/BS system. Sulfate radical (SO4˙−) and hydroxyl radicals (HO˙) were proved to be responsible for MB removal in the BC@LF/BS system and SO5˙− might also be involved in MB removal. The degradation efficiency of MB in the BC@LF/BS system decreased with increasing pH, while the adsorption efficiency of BC@LF for MB improved with increasing pH. Additionally, BC@LF exhibited good reusability for BS activation in successive uses. The BC@LF/BS system exhibited favorable removal effect for various organic compounds, indicating that it has good applicability in the treatment of organic wastewater.