Interlayer-confined strategy to modulate alkaline reaction microenvironment for in-situ degradation of ofloxacin

In advanced oxidation processes designed for the mineralization of organic contaminants, the acidic microenvironment in the peroxymonosulfate (PMS) activation system poses a major threat to the stability of active species. In this study, we developed a low-cost Co-Mg–layered double hydroxide (LDH) structure with an OH−-enriched, interlayer-confined alkaline microenvironment around Co sites. This structure exhibited enhanced surface availability and a short reactant diffusion path, which accelerated proton migration and regulated local pH at the slipping plane. Theoretical calculations revealed that CoMg-LDH exhibited high catalytic activity for PMS cleavage and generated high-valence Co-oxo (Co(IV)=O) species in this specific microenvironment. At a natural pH, the optimized system achieved 100 % removal efficiency of the target pollutant (ofloxacin), with negligible Co leaching. It also demonstrated stability in long-term experiments and effectively purified hospital wastewater. Overall, this study provides valuable insights into the in-situ degradation of contaminants through self-regulating catalytic systems.