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Ciprofloxacin degradation in UV/chlorine advanced oxidation process: Influencing factors, mechanisms and degradation pathways
摘要： Ciprofloxacin (CIP) is a widely used third generation fluoroquinolone antibiotics, and has been often detected in wastewater treatment plants. Finding an effective way to remove them from wastewater is of great concern. Ultraviolet (UV)/chlorine advanced oxidation process (AOP) has many advantages in micropollutant removal. In this study, CIP degradation in UV/chlorine process was investigated. Only 41.2% of CIP was degraded by UV photolysis and 30.5% by dark chlorination in 30 min, while 98.5% of CIP was degraded by UV/chlorine process in 9 min. HCO3- had markedly inhibition, NO3- and SO42- had slight inhibition, and Cl- had a marginal inhibition on the CIP degradation in UV/chlorine system. The degradation of CIP in UV/chlorine process was mainly attributed to the attack of reactive species. The relative contributions of hydrated electrons (eaq-), hydroxyl radicals (HO.), chlorine atoms (Cl.), and UV photolysis were investigated. Under neutral condition in aqueous solution, CIP degradation had highest pseudo first-order reaction rate constants, in which eaq- followed by Cl., HO., and UV photolysis. The intermediates and byproducts were identified and the degradation pathway was proposed. The total organic chlorine (TOCl) and biotoxicity were further assessed. CIP and natural organic matters (NOMs) were removed efficiently in real water. UV/chlorine showed the potential for the wastewater treatment containing CIP.
关键词： advance oxidation process,UV/chlorine process,UV photolysis,reactive species,wastewater,Ciprofloxacin
更新于2025-09-10 09:29:36
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Sunlight Assisted Photocatalytic Degradation of Ciprofloxacin in Water Using Fe Doped ZnO Nanoparticles for Potential Public Health Applications
摘要： Antibiotic residues in the aquatic environment have the potential to induce resistance in environmental bacteria, which ultimately might get transferred to pathogens making treatment of diseases difficult and poses a serious threat to public health. If antibiotic residues in the environment could be eliminated or reduced, it could contribute to minimizing antibiotic resistance. Towards this objective, water containing ciprofloxacin was treated by sunlight-assisted photocatalysis using Fe-doped ZnO nanoparticles for assessing the degradation potential of this system. Parameters like pH, temperature, catalytic dosage were assessed for the optimum performance of the system. To evaluate degradation of ciprofloxacin, both spectrophotometric as well as microbiological (loss of antibiotic activity) methods were employed. 100 mg/L Fe-doped ZnO nanoparticle catalyst and sunlight intensity of 120,000–135,000 lux system gave optimum performance at pH 9 at 30 °C and 40 °C. Under these conditions spectrophotometric analysis showed complete degradation of ciprofloxacin (10 mg/L) at 210 min. Microbiological studies showed loss of antibacterial activity of the photocatalytically treated ciprofloxacin-containing water against Staphylococcus aureus (108 CFU) in 60 min and for Escherichia coli (108 CFU) in 75 min. The developed system, thus possess a potential for treatment of antibiotic contaminated waters for eliminating/reducing antibiotic residues from environment.
关键词： antibiotic residues,ciprofloxacin,Fe-doped ZnO nanoparticles,aquatic environment,sunlight,photocatalysis
更新于2025-09-10 09:29:36
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Quantum confinement chemistry of CdS QDs plus hot electron of Au over TiO2 nanowire protruding to be encouraging photocatalyst towards nitrophenol conversion and ciprofloxacin degradation
摘要： Solar light harvesting science is ascertained to be the topmost effective green technique in alleviating environmental pollutants. In this respect, we report a visible light active TiO2/Au/CdS QDs nanocomposite which manifested upgraded photocatalytic activity towards the transformation of 2-nitrophenol, 4-nitrophenol, and degradation of ciprofloxacin. Here, TiO2 nanowire is synthesized by a molten flux method with high product yield and crystallinity with organized dimensions. Au nanoparticles are successfully integrated in between TiO2-CdS composite by Reverse Turkevich method. The prepared composites are meticulously characterized by different physical and optoelectronic techniques to inspect the crystal structure, phase purity, optical properties, nanostructured morphology and electrochemical properties. The plasmonic direct hot electron transfer (DET) mechanism is confirmed from UV-Vis DRS spectra. The prepared composite produces 2.98 mA/cm2 of current density under light irradiation. A Longer lifetime of electrons is found from Bode phase plot i.e. 97.4 μs for TiO2/1%Au/3%CdS QDs owing to the integrative cooperation effect of high aspect ratio of TiO2 nanowire, quantum size effect of CdS and the direct hot electron transfer by Au nanoparticle.
关键词： TiO2 nanowire,2-nitrophenol,DET,4-nitrophenol,ciprofloxacin,CdS QDs
更新于2025-09-09 09:28:46
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A novel 3D-structured flower-like bismuth tungstate/mag-graphene nanoplates composite with excellent visible-light photocatalytic activity for ciprofloxacin degradation
摘要： 3D structured flower-like bismuth tungstate/magnetic-graphene nanoplates (Bi2WO6/mag-GNPs) composite was first synthetised for degradation of ciprofloxacin (CIP). The morphological properties of Bi2WO6/mag-GNPs were characterized by SEM, XRD and DRS. The results revealed the synthesized Bi2WO6/mag-GNPs had the enhanced photocatalytic activity because of the synergistic effects of Bi2WO6, grapheme and Fe3O4. The photocatalytic degradation rate of Bi2WO6/mag-GNPs toward CIP was almost 6.0 times of mag-GNPs, 2.0 times and 1.7 times of Bi2WO6 and Bi2WO6/GNPs, respectively. Moreover, the Bi2WO6/mag-GNPs particles could be easily separated and recycled. The construction of Bi2WO6/mag-GNPs effectively resolved the separation of photocatalyst and improved the photocatalysis activity of Bi2WO6.
关键词： bismuth tungstate,graphene nanoplates,3D structure,ciprofloxacin,photocatalysis
更新于2025-09-04 15:30:14
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Visible active reduced graphene oxide loaded Titania for photodecomposition of ciprofloxacin and its antibacterial activity
摘要： The reduced Graphene Oxide based titanium dioxide (rGO-TiO2) nanocomposite was synthesized by a simple hydrothermal preparation and characterized by X-ray Diffraction Analysis (XRD), UV–Vis absorption spectroscopy (UV), Fourier Transform Infrared spectroscopy (FT-IR), Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The XRD pattern of rGO-TiO2 indicates the presence of anatase TiO2 and average crystalline size of particles is 32 nm. The optical band gaps of TiO2, GO and rGO-TiO2 nanocomposite are 3.24 eV, 4.3 eV and 2.7 eV respectively. Comparison of efficiencies of three catalysts shows that ciprofloxacin degrades at a faster rate under visible light irradiation in the presence of rGO-TiO2 at 60 min than in presence of pure TiO2 commercial TiO2-P25. Higher photocatalytic decomposition efficiency of rGO-TiO2 is explained by its reduced electron-hole recombination and visible light activity. The kinetics of photodecomposition reaction was analyzed. Antibacterial activity analysis of rGO-TiO2 nanoparticles reveals that it is more active against S. aureus than E.coli.
关键词： Titania,Antibacterial activity,Photocatalytic decomposition,Ciprofloxacin,Reduced graphene oxide
更新于2025-09-04 15:30:14