Hierarchical De@NiCo-LDH as high-efficiency catalyst for peroxymonosulfate activation toward enhanced ofloxacin degradation

In this study, a hierarchical activator (De@NiCo-LDH nanocomposite) was successfully fabricated through in-situ growth of nickel–cobalt layered double hydroxide (NiCo-LDH) nanosheets on diatomaceous earth (De) substrates. The material’s structural and chemical properties were systematically characterized using SEM, XRD, FTIR, XPS, and BET analyses. The optimized De@NiCo-LDH/PMS system demonstrated exceptional catalytic performance, achieving 96.6 % ofloxacin (OFL) degradation efficiency via peroxymonosulfate (PMS) activation. Mechanism investigations, including radical quenching experiments and electron paramagnetic resonance (EPR) analysis, identified singlet oxygen ( 1 O 2 ) as the predominant reactive species governing OFL degradation. Critical to the activation mechanism were the synergistic redox cycles of surface-bound Ni 2+ /Ni 3+ and Co 2+ /Co 3+ couples, which facilitated continuous electron transfer for PMS activation. Furthermore, the catalyst exhibited robust reusability (>85 % efficiency retention after 3 cycles), multi-pollutant versatility, and remarkable environmental compatibility, as evidenced by the low ecotoxicity of treated effluents in phytotoxicity assays. These findings underscore the potential of De@NiCo-LDH as a sustainable and high-efficiency heterogeneous catalyst for advanced oxidation processes in antibiotic-contaminated water remediation.