Impregnating Lattice Sulfur into Iron Crystal Allows Anaerobic Degradation of Extracellular Antibiotic Resistance Genes

Lattice sulfur-impregnated nanoscale zerovalent iron (S-nFe⁰) has been recognized as a promising groundwater remediation agent. However, little information is available on its reactivity with ubiquitous extracellular antibiotic resistance genes (eARGs) in anaerobic groundwater, and how S content and speciation affect their interactions. Here, the efficient anaerobic degradation of eARGs by S-nFe⁰ (6 log within 5 min), resulting in completely inhibited transformation is showed. The removal rate of eARGs by S-nFe⁰ (0.26 mg m^-2 min^-1) is correlated well with the S-induced hydrophobicity and electron transfer ability of materials, and this reactivity improvement (up to 22-fold) compared to nFe⁰ largely depended on the S content and speciation. Multiple measurements are applied to verify the degradation of eARGs and their interactions with materials, where Fe-O-P coordination, hydrophobic interaction, and electron transfer play critical roles. The application potential of S-nFe⁰ is strongly supported by their long-term reactivity and stability in real groundwater and universal reactivity with multiple eARGs. These findings elucidate the mechanistic role of lattice S in the degradation of eARGs by S-nFe⁰, unveil binding sites and interactions between eARGs and S-nFe⁰, and will advance understanding toward better design of S-nFe° for eARGs-contaminated groundwater remediation.