Phytogenic synthesis of Ag@ZIF-8 using rosemary extract for enhanced visible-light photodegradation of dyes and antibiotics with antibacterial activity

This study presents a green synthesis of silver nanoparticle-decorated zeolitic imidazolate framework-8 (Ag@ZIF-8) using rosemary (Rosmarinus officinalis) extract as a phytogenic reducing agent. The resulting composites were thoroughly characterized by XRD, FT-IR, SEM, TEM, EDX mapping, XPS, DLS, and UV–Vis DRS analyses, confirming successful incorporation of well-dispersed Ag nanoparticles within the ZIF-8 matrix without compromising its crystalline structure. Among the synthesized materials, the Ag@ZIF-8 composite prepared with 6 mM AgNO₃ (RAZ3) exhibited optimal photocatalytic activity, achieving degradation efficiencies of 94.33 % for reactive blue 19 (RB19) and 93.4 % for oxytetracycline (OTC) under visible light within 180 min. The photocatalytic performance was influenced by catalyst dosage, pollutant concentration, and solution pH. Radical scavenger experiments revealed that photogenerated holes (h⁺) and hydroxyl radicals (•OH) were the dominant species in RB19 degradation, while electrons (e⁻) and superoxide radicals (•O₂⁻) played key roles in OTC removal. In addition to its high reusability, the Ag@ZIF-8 composite demonstrated significant antibacterial activity, inhibiting the growth of Escherichia coli, S. aureus, B. subtilis, and P. aeruginosa, with the highest efficiency observed at 50 ppm. The study highlights the potential of Ag@ZIF-8 synthesized via eco-friendly methods as a multifunctional material for wastewater remediation and microbial disinfection.