Innovative spherical Fe-Mn layered double hydroxides (LDH) for the degradation of sulfisoxazole through activated periodate: Efficacy and mechanistic insights

Advanced oxidation technology based on peroxides is widely regarded as an efficient method for treating emerging contaminants. However, the precise mechanism by which layered double hydroxides (LDHs) enhance oxidant activation requires further investigation. In this study, a spherical Fe-Mn LDH (S-FML) with improved crystallinity using a simple hydrothermal method. Compared to granular Fe-Mn LDH (G-FML), S-FML demonstrated superior periodate (PI) activation efficiency and outstanding stability. Intensive mechanistic studies have shown that the synergistic action of Fe²⁺ and Mn²⁺ in S-FML plays a key role in the degradation reaction. Three primary pathways for SIZ degradation and a reduction in solution toxicity post-reaction were identified through analysis of degradation intermediates and density functional theory (DFT) calculations. This research offers valuable theoretical insights and a scientific foundation for designing high-performance heterogeneous catalysts and elucidating the efficient activation mechanisms of PI for emerging pollutant treatment.