Sustainable remediation of tetracycline-contaminated soil: A Fe-g-C₃N₄ nanozyme driven abiotic-biotic strategy

The remediation of tetracycline-contaminated agricultural soils faces a fundamental challenge, as conventional methods often fail to combine efficient degradation with ecological recovery. Herein, we developed a Fe-deposited graphitic carbon nitride (Fe-C₃N₄) nanozyme that drives a synergistic abiotic-biotic process for sustainable soil remediation. The Fe-C₃N₄ achieved 32.79 % removal of tetracycline hydrochloride (TCH), exhibiting a 2.3-fold higher degradation rate constant compared to pristine g-C₃N₄. Mechanistic investigations unveiled the dual functionality of this nanozyme: as a robust photo-Fenton catalyst that continuously generates reactive oxygen species (•OH and •O₂^-) via self-sustaining Fe²⁺/Fe³⁺ cycling for TCH oxidative degradation, and acts as a biogeochemical modulator that actively reshapes the soil microbe. This modulation significantly enriches key antibiotic-degrading genera (e.g., Bacillus by 230 % and Sphingomonas by 180 %), boosts key enzyme activities (dehydrogenase by 301 % and catalase by 214 %), and enhances microbial biodiversity (Shannon index by 246 %). This study establishes a sustainable nanozyme-mediated strategy that effectively bridges catalytic oxidation with microbial metabolism, offering a promising solution for the remediation of antibiotic-contaminated soils while restoring ecological health.