1. First utilization of magnetically-assisted photocatalytic iron ▫$oxide-TiO_2$▫ nanocomposites for the degradation of the problematic antibiotic ciprofloxacin in an aqueous environmentJosip Radić, Gregor Žerjav, Lucija Jurko, Perica Bošković, Lidija Fras Zemljič, Alenka Vesel, Andraž Mavrič, Martina Gudelj, Olivija Plohl, 2024, izvirni znanstveni članek Opis: The emergence of antimicrobial resistance due to antibiotics in the environment presents significant public health, economic, and societal risks. This study addresses the need for effective strategies to reduce antibiotic residues, focusing on ciprofloxacin degradation. Magnetic iron oxide nanoparticles (IO NPs), approximately 13 nm in size, were synthesized and functionalized with branched polyethyleneimine (bPEI) to obtain a positive charge. These IO-bPEI NPs were combined with negatively charged titanium dioxide NPs (TiO2@CA) to form magnetically photocatalytic IO-TiO2 nanocomposites. Characterization techniques, including X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), infrared spectroscopy (IR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), electrokinetic measurements, and a vibrating sample magnetometer (VSM), confirmed the successful formation and properties of the nanocomposites. The nanocomposites exhibited a high specific surface area, reduced mobility of photogenerated charge carriers, and enhanced photocatalytic properties. Testing the photocatalytic potential of IO-TiO2 with ciprofloxacin in water under UV-B light achieved up to 70% degradation in 150 min, with a degradation rate of 0.0063 min−1. The nanocomposite was magnetically removed after photocatalysis and successfully regenerated for reuse. These findings highlight the potential of IO-TiO2 nanocomposites for reducing ciprofloxacin levels in wastewater, helping curb antibiotic resistance.
Ključne besede: photocatalytic degradation, magnetic iron oxide-TiO2 nanocomposites, hetero-agglomeration, multifunctionality, antibiotic ciprofloxacin, antimicrobial resistance
Objavljeno v RUNG: 09.09.2024; Ogledov: 1922; Prenosov: 8
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2. PHOTOLYSIS AND ECOTOXICITY OF THE ANTIBIOTIC CIPROFLOXACINKetevan Neparidze, 2017, diplomsko delo Opis: Over the last few decades, numerous pharmaceuticals coming from domestic sewage, livestock, hospitals and industries have been determined in ground, surface and drinking waters. A common example of these pollutants are fluoroquinolones, which are powerful antibiotics used in human and veterinary medicine. The presence of fluoroquinolones in the environment even at low concentration constitutes a threat to ecosystems and human health because they can lead to bacterial resistance issues. Up to now the environmental impacts of fluoroquinolones and their degradation products are not fully understood but it is known that they can negatively affect plants and aquatic organisms. In this study the degradation of ciprofloxacin (CIP) present in synthetic freshwater was investigated under simulated sunlight. Concentrations before and after degradation were determined using HPLC-DAD. The mineralisation rate of the treated solution was monitored on a total organic carbon analyser. The ecotoxicity of the initial samples and the degradation mixtures was assessed on organisms belonging to different trophic levels: a marine bacterium (Vibrio fischeri), a freshwater invertebrate (Daphnia magna) and seed clover (Trifolium repens). In parallel, the EC50 of CIP was determined for all organisms. The Vibrio fischeri and Trifolium repens tests showed that EC50 value was more than 250 mg/L and for Daphnia magna was 190 mg/L. Photolysis of CIP showed that after 90 min of irradiation, CIP was almost totally degraded (99%). Photolysis process of CIP led to the formation of toxic by-products towards Vibrio fischeri. The toxicity test results on Trifolium repens did not show significant difference between the control and the treated plants. Thus, CIP and its degradation products have no effect on the germination or root length of Trifolium repens. Tests on Daphnia magna after 240 min irradiation showed a 94% reduction of the toxic effect. Non-purgeable organic carbon (NPOC) analysis showed that there is no significant mineralisation of the sample even after 240 min of irradiation.
Ključne besede: Key words: fluoroquinolones, ciprofloxacin, photolysis, toxicity tests, EC50 determination
Objavljeno v RUNG: 31.01.2017; Ogledov: 7726; Prenosov: 326
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