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The rapid discharge of antibiotic pollutants from pharmaceutical industries into natural water sources poses a significant threat to human health and the environment. Conventional water treatment methods often fail to effectively remove these contaminants, leading to a pressing need for eco-friendly degradation approaches. This study focused on synthesizing pure and iron-doped zinc sulfide (ZnS) nanoparticles using a microwave-assisted technique in aqueous solution to evaluate their photocatalytic efficiency in degrading the antibiotic cephalexin. High-resolution transmission electron microscopy (TEM) characterized the synthesized nanoparticles, revealing crystalline structures approximately 5 nm in size. The photocatalytic capacity was assessed using a spectrophotometric method, demonstrating that both pure and iron-doped ZnS nanostructures exhibit higher efficiency in degrading cephalexin under UV irradiation. These findings underscore the potential of ZnS nanostructures for photocatalytic applications in environmental remediation, particularly in degrading resistant antibiotic pollutants, highlighting their role in addressing organic pollution in water sources.
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This content will become publicly available on June 22, 2026
Fe-Doped ZnS Quantum Dot Photocatalysts for the Degradation of Cefalexin in Water
This study reports the synthesis, structural characterization, adsorption studies, nanoscale interaction, and photocatalytic application of pure and Fe-doped ZnS quantum dots for the degradation of the antibiotic cefalexin in aqueous solution. Nanoparticles were synthesized via the microwave-assisted method, and Fe doping was introduced at a 1% molar ratio. HRTEM images confirmed quasi-spherical morphology and high crystallinity, with particle sizes averaging 2.4 nm (pure) and 3.5 nm (doped). XRD analysis showed a consistent cubic ZnS structure. UV-vis spectra showed strong absorption at 316 nm for both samples, and PL measurements revealed emission quenching upon Fe doping. Photocatalytic tests under UV light demonstrated significantly higher degradation rates of 10 ppm cefalexin with Fe-doped ZnS, reaching near-complete removal within 90 min. Adsorption experiments revealed higher affinity and adsorption capacity of Fe-doped ZnS toward cefalexin compared to pure ZnS, as demonstrated by the Freundlich isotherm analyses, contributing significantly to enhanced photocatalytic degradation performance. High-resolution QTOF LC-MS analysis confirmed the breakdown of the β-lactam and thiazolidine rings of cefalexin and the formation of low-mass degradation products, including fragments at m/z 122.0371, 116.0937, and 318.2241. These findings provide strong evidence for the structural destruction of the antibiotic and validate the enhanced photocatalytic performance of Fe-doped ZnS.
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- Award ID(s):
- 2313252
- PAR ID:
- 10610083
- Publisher / Repository:
- MDPI
- Date Published:
- Journal Name:
- Micro
- Volume:
- 5
- Issue:
- 3
- ISSN:
- 2673-8023
- Page Range / eLocation ID:
- 31
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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