Unveiling a robust hierarchical De@NiCoFe-LDH for efficient degradation of ofloxacin via peroxymonosulfate activation

This study develops a hierarchical diatomite-supported NiCoFe-LDH (De@NiCoFe-LDH) for peroxymonosulfate (PMS) activation to degrade ofloxacin (OFL). The analysis of SEM, XRD, FTIR, XPS and BET were used to characterize the samples. The as-prepared De@NiCoFe-LDH possesses a high specific surface area and abundant active sites, which contribute to its superior catalytic performance. Under the conditions of 0.2 g/L catalyst, 0.3 mM PMS, 20 mg L −1 OFL, and pH 5.2, 99.7 % of OFL was removed within 40 min, markedly outperforming the unsupported LDH. The removal fitted with the pseudo-first-order reaction kinetics well with rate constant of 0.1470 min −1 . ESR and quenching studies indicate that the OFL degradation proceeds via a mixed radical (SO₄• − , •OH, O₂• − ) / non-radical ( 1 O₂) mechanism, primarily driven by 1 O₂. Mechanism investigation suggested that the redox cycles of Ni 2+ /Ni 3+ , Co 2+ /Co 3+ and Fe 2+ /Fe 3+ on the surface of De@NiCoFe-LDH were crucial for PMS activation. In addition, the ideal reusability and versatility of De@NiCoFe-LDH as well as low-toxicity of treated water endowed the De@NiCoFe-LDH/PMS system with a wide range of applications.