Salt-ion etching induced transformation of granular ZIF-8 into Fe-doped nanosheets for activating peracetic acid toward pollutant degradation.

Conventional water treatment processes exhibit inherent limitations in the removal of trace emerging micropollutants. To address this challenge, we rationally designed ultrathin Fe-doped nanosheets via a one-step etching strategy using ferrous sulfate. This approach simultaneously transformed pristine granular ZIF-8 into a layered architecture and facilitated the uniform incorporation of iron active sites. The as-prepared catalyst was subsequently employed in a visible-light-driven peracetic acid (PAA) activation system for the efficient degradation of micropollutants. The etching treatment not only substantially increased the specific surface area of the nanosheets relative to their bulk counterparts but also ensured homogeneous dispersion of Fe species, thereby establishing stable Fe2+/Fe3+ redox cycling centers that significantly accelerate electron transfer kinetics. In the ZIF-8-Fe-Nanosheets/PAA/simulated sunlight system, sulfamethazine (SMT) achieved near-complete degradation within 50 min. Moreover, the catalyst exhibited excellent broad-spectrum degradation activity, robust pH adaptability across a range of 3-9, and strong resistance to coexisting matrix constituents in real water samples. Radical quenching experiments identified hydroxyl radicals (•OH) and singlet oxygen (1O2) as the dominant reactive oxygen species. Three plausible SMT degradation pathways were proposed, and toxicity assessment using quantitative structure-activity relationship analysis indicated lower biotoxicity of the transformation products compared to the parent compound. Overall, this work validates the Fe-doped nanosheet catalyst as an efficient PAA activator, and more broadly, paves the way for expanding PAA-based catalytic oxidation toward practical water treatment.