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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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Structure, Properties, Photocatalytic and Antibacterial Activity and Applications of Zinc Oxide Nanoparticles—An Overview
摘要： Nanotechnology is a science that deals with various structures of matter at the scale of a billionth of a meter. It is also the study of changing matter at the nanometres scales to create novel structures and devices. A nano particle is the most fundamental unit component in the fabrication of a nanostructure and is far smaller than the world of everyday’s objects that are described by Newton’s laws of motion. But on the other side, a nanoparticle is bigger than atoms or simple molecules that are governed by quantum mechanics. In general, the size of a nano particle is seen in the range 1–100 nm. Nanoparticles have physical and chemical properties that are different from bulk metals like low melting points, high specific surface areas, good optical properties, mechanical strengths and specific magnetizations. No wonder, nanotechnology plays a significant role in electronics, medicine and other fields. Recent growth of zinc oxides (ZnO) as semiconducting materials with novel, unique optical and magnetic properties has made them to be the versatile and suitable materials for electronic, spintronic, optoelectronic, photocatalytic examination along with antibacterial applications. From the above-said applications, the present review paper specifically focuses on finding the right material with excellent optical features for photocatalytic and antibacterial applications.
关键词： Nanotechnology,Photocatalytic Evaluation,ZnO Nanoparticles,Antibacterial Study
更新于2025-09-09 09:28:46
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Effect of Synthesis Temperature on Structural, Optical, and Magnetic Properties of ZnO Nanoparticles Synthesized by Combustion Method
摘要： ZnO nanoparticles at different temperatures were synthesized by using the combustion method. The effect of synthesis temperature on the properties of the nanoparticles was studied by using XRD, FESEM, EDS, TEM, photoluminescence (PL), Raman, diffuse reflectance spectra (DRS), and VSM characterization techniques. The XRD results reveal that the grown nanoparticles have a hexagonal wurtzite structure without any impurities and agreed with EDS results. FESEM and TEM micrographs show that the ZnO nanoparticles possess a spherical shape with agglomeration free, and the size increases with increase of synthesis temperature. From DRS studies, it was noticed that the band gap decreases with increase of synthesis temperature. In PL studies, blue peak at 465 nm may be due to defect-related transitions. A sharp intense peak in Raman spectra at 485 cm?1 represents E2H mode is a characteristic of a hexagonal wurtzite structure. The magnetic studies show that the magnetization decreases from 0.0172 to 0.0042 emu/g as the synthesis temperature increases from 400 to 550 °C. ZnO synthesized at 500 °C has a large squareness ratio. These materials are potential candidates for memory devices.
关键词： Combustion method,Spintronics,Ferromagnetism,ZnO nanoparticles
更新于2025-09-09 09:28:46
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ZnO nanoparticles modified with an amphipathic peptide show improved photoprotection in skin
摘要： ZnO nanoparticles of different sizes were functionalized with an amphipathic peptide and its effect on nanoparticle stabilization and UV photoprotective activity was studied in this article. The peptide modified nanoparticles exhibited lower aggregation, significant reduction in Zn2+ leaching in-vitro and even inside the cells for smaller particle sizes, reduced photocatalytic activity and reduced cellular toxicity under UV-B treated conditions. In addition, the peptide modified 60 nm sized ZnO nanoparticles showed lower genotoxicity, lower oxidative stress induction levels, less DNA damage responses and less immunogenic potential than the bare counterparts in presence of UV-B rays. They localized more in the stratum corneum and epidermis ex-vivo indicating better retention in epidermis and demonstrated improved UV-B protection and/or skin integrity in SKH-1 mice in-vivo as compared to unmodified nanoparticles and commercial UV protective agents tested. To our knowledge, this is the first report on application of peptide modified ZnO nanoparticles for improved photoprotection.
关键词： UV-B rays,ZnO nanoparticles,cytotoxicity,cell penetrating peptide,photoprotection
更新于2025-09-09 09:28:46
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Green synthesis, characterization and antifungal and photocatalytic activity of Pithecellobium dulce peel–mediated ZnO nanoparticles
摘要： Zinc oxide (ZnO) nanoparticles (NPs) were synthesized by a conventional method using Pithecellobium dulce peel extract. The phytochemicals present in the peel act as stabilizing agents. The ZnO NPs were characterized by UV-vis spectroscopy, X-ray diffraction (XRD), scanning electron microscopy, and transmission electron microscopy. The XRD pattern confirmed the formation of crystals, which exactly matched with JCPDS card no.36-1451. The nondestructive XRD pattern showed a hexagonal crystalline nature, and scanning electron microscopy revealed a spherical shape. Further, the ZnO NPs exhibited excellent photodegradation efficiency with regard to the dye methyleneblue (MB), a major water pollutant released by the textile industry. A kinetic study of photodegradation of MB showed 63% degradation and a rate constant of 0.00812 min-1. The antifungal activity of the ZnO NPs resulted in 37.81% and 63.57% inhibition of the growth of Aspergillus flavus and 40.21% and 43.04% of growth inhibition of Aspergillus niger at 500 and 1000ppm of ZnO NPs, respectively.
关键词： Photocatalytic activity,Methylene blue,Antifungal,Pithecellobium dulce,ZnO nanoparticles
更新于2025-09-04 15:30:14
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Towards understanding the enhancement of antibacterial activity in manganese doped ZnO nanoparticles
摘要： In this work we focus on enhancing the antibacterial activity of ZnO nanoparticles by Mn doping, synthesized using a wet-chemical method. The as-obtained precursor powders were deeply investigated by thermal analyses correlated with the evolved gas analysis (TG-DTA-FT-IR) and by in situ high-temperature XRD to elucidate the thermally induced processes and to understand the manganese doped ZnO nanoparticles formation. The hexagonal wurtzite-type structure and the morphological characteristics of the thermally treated samples have been investigated by X-ray diffraction, and HRTEM. An average particle size ranging between 10 to 29 nm and a polyhedral and spherical morphology with a tendency to form aggregates were evidenced by TEM images. Optical absorption measurements reveal that the band gap of ZnO decreased from 3.19 to 2.99 eV, which confirmed the existence of Zn-O-Mn interaction. The incorporation of the Mn ions into the ZnO lattice has been studied by EPR spectroscopy and also, the generation of reactive oxygen species (ROS) has been evidenced by using the EPR coupled with the spin trapping probe technique. Here, we report that in addition to altering the crystallite size, morphology and optical absorption characteristics of ZnO, the introduction of Mn dopant also improves the antibacterial efficiency against pathogenic microorganisms, namely Escherichia coli and Bacillus cereus.
关键词： Mn doping,antibacterial activity,ZnO nanoparticles,reactive oxygen species,wet-chemical synthesis
更新于2025-09-04 15:30:14