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- 2019
- charge – discharge energy efficiency
- Lithium-ion battery
- degradation diagnosis
- photovoltaic surplus energy
- working electric vehicle
- Electrical Engineering and Automation
- Ritsumeikan University
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Adsorption and photocatalytic oxidation of ibuprofen using nanocomposites of TiO2 nanofibers combined with BN nanosheets: Degradation products and mechanisms
摘要： This study investigated the adsorption and photocatalytic activity of TiO2-boron nitride (BN) nanocomposites for the removal of contaminants of emerging concern in water using ibuprofen as a model compound. TiO2 nanofibers wrapped by BN nanosheets were synthesized by electrospinning method. Characterization of the nanocomposite photocatalysts indicated the BN nanosheets improved the light absorbance and reduced the recombination of the photoexcited charge carriers (e- and h+). The photocatalytic oxidation products and mechanisms of ibuprofen by the TiO2-BN catalysts were elucidated using a multiple analysis approach by high performance liquid chromatography, ultraviolet absorbance, dissolved organic carbon, fluorescence excitation-emission matrices, and electrospray ionization–liquid chromatography–tandem mass spectrometry. The experimental results revealed that the photocatalytic oxidation by the TiO2-BN nanocomposites is a multi-step process and the interactions between ibuprofen molecules and the TiO2-BN nanocomposites govern the adsorption process. The increasing BN nanosheet content in the TiO2 nanofibers facilitated the breakdown of ibuprofen degradation intermediates (hydroxyibuprofen, carboxyibuprofen, and oxypropyl ibuprofen). Kinetic modeling indicated both adsorption and photocatalytic oxidation of ibuprofen by the TiO2-BN nanocomposites followed the first-order kinetic model. The photocatalytic oxidation rate increased with the increasing BN content in the nanocomposite catalysts, which was attributed to the enhanced light absorption capacity and the separation efficiency of the photoexcited electron (e-)-hole (h+) pairs. Multiple photocatalytic cycles were conducted to investigate the reusability and regeneration of the nanofibers for ibuprofen degradation.
关键词： adsorption,titanium dioxide boron-nitride nanocomposites,photocatalytic degradation mechanisms,degradation intermediates,photocatalytic oxidation
更新于2025-09-23 15:23:52
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Valorization of mutant Bacillus licheniformis M09 supernatant for green synthesis of silver nanoparticles: photocatalytic dye degradation, antibacterial activity, and cytotoxicity
摘要： The present study reports the optimization of a green method for the synthesis of silver nanoparticles (AgNPs) via reduction of Ag+ ions using cell-free supernatant of mutant Bacillus licheniformis M09. UV–Visible spectroscopy showing an absorption peak at ~ 430 nm confirmed the synthesis of AgNPs. Transmission electron microscope (TEM) analysis exhibited spherical AgNPs within the size range of 10–30 nm. Fourier transform infrared (FTIR) measurements assured the presence of effective functional molecules which could be responsible for stabilizing the AgNPs. X-ray diffraction (XRD) pattern verified the crystalline nature of AgNPs. Furthermore, the synthesized AgNPs showed an excellent photocatalytic degradation of methylene blue dye in less than 3 h under visible light proving their potential as a catalytic agent for bioremediation for next-generation dye degradation in effluent treatment. The AgNPs demonstrated antimicrobial activity against Gram-positive and Gram-negative foodborne pathogens which endorsed its suitability as agents to extend shelf-life in food packaging and food safety applications. The results also revealed a strong concentration-dependent cytotoxicity of AgNPs against human breast adenocarcinoma cells (MCF-7), while 15.07 μg/mL of IC50 was attained. The outcome suggests the possible application of these AgNPs in nanomedicine formulations. Thus, these findings propose promising ways for the valorization of the waste fermentation supernatant left after cell harvesting and desired metabolite extraction.
关键词： Methylene blue,Antibacterial,Photocatalytic dye degradation,Cytotoxicity effects,Bacillus licheniformis M09,Silver nanoparticles
更新于2025-09-23 15:23:52
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Activated carbons with adsorbed cations as photocatalysts for pollutants degradation in aqueous medium
摘要： Oxidized activated carbon (AC) based on commercial coconut-shell carbon Aquacarb 607C has been prepared. This AC has micro-mesoporous structure and contains surface carboxyl and phenol/enol groups. Cu- and Co-containing ACs have been synthesized via ion-exchange in acid medium. According to potentiometric titration and XPS data, cation-exchanged forms of AC contain about 0.5% of metal ions. Such cation-containing ACs possess narrowed band gap compared oxidized AC as it is observed for doped oxides. Oxidized and cation-containing ACs have been tested as catalysts in photodegradation of dyes and phenol under UV- and visible irradiation. Initial oxidized AC is photoactive toward rhodamine B and methyl orange under UV illumination but inactive under visible light. For the first time it is shown that cation-exchanged forms of AC have enhanced activity towards rhodamine B, methyl orange and phenol in both UV and visible region. Therefore, the principal possibility of improving the photocatalytic properties of AC by introducing a minimal amount of copper and cobalt cations is shown.
关键词： Cation-exchanged forms,Decolourisation and mineralization,UV and visible irradiation,Activated carbon,Photocatalytic degradation
更新于2025-09-23 15:23:52
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E‐Waste Based V <sub/>2</sub> O <sub/>5</sub> /RGO/Pt Nanocomposite for Photocatalytic Degradation of Oxytetracycline
摘要： The increasing prevalence of antibiotics in the environment has promoted the development of antibiotic resistant microorganisms, and novel approaches are needed to effectively remove antibiotics from water and mitigate this worldwide problem. A reduced graphene oxide-V2O5 (RGOV) nanocomposite was synthesized and used for photocatalytic degradation of the antibiotic oxytetracycline (OTC) in aqueous solution. The Sol–Gel method was employed for V2O5 synthesis from e-waste-based vanadium nitrate, and a one pot solvothermal method was used to synthesize RGOV. Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction spectroscopy (XRD), transmission electron microscopy (TEM) with energy dispersive analysis of X-rays (EDAX) confirmed V-O-C bonds on the surface of the RGOV nanocomposites. A decrease in the band gap of V2O5 from 2.21 to 2.13 eV was supported by diffuse reflectance ultraviolet–visible spectrophotometry. OTC adsorption onto the nanocomposite increased with an increase in RGO concentration and saturated at 17% for RGOV with 30% graphene oxide. The composite degraded 90% of the OTC present in aqueous solution (50 mg/L). Platinum (1%) doping further increased OTC degradation by the nanocomposite to 98.7%. Optimum conditions for maximum OTC degradation are (1) an initial OTC concentration of 50 mg/L, (2) a RGOV nanocomposite dose of 0.5 g/L, and (3) a 40 min incubation time. Our results support the potential use of RGOV nanocomposite for OTC photodegradation.
关键词： vanadium pentoxide,photocatalytic degradation,nanocomposite,E-waste,RGO,oxytetracycline
更新于2025-09-23 15:23:52
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[Mo3S13]2? modified TiO2 coating on non-woven fabric for efficient photocatalytic mineralization of acetone
摘要： Improving the photocatalytic efficiency of commercial TiO2 has important significance for practical application of TiO2 based photocatalysts. A novel photocatalyst [Mo3S13]2?/TiO2 was fabricated by combining [Mo3S13]2? with commercial TiO2 by an impregnation method. This composite photocatalyst presented a remarkable enhancement on photocatalytic mineralization of acetone in comparison with commercial TiO2. The optimum loading amount of [Mo3S13]2? was 1.7wt%, which is more efficient than the Pt/TiO2 (1.5wt%). Electrochemical impedance spectroscopy (EIS) showed the smooth electron transfer pathway in [Mo3S13]2?/TiO2 composite, facilitating the photo-charges separation during the photocatalysis process. Reactive oxygen species scavenging test illustrated that superoxide radical (?O2?), hydroxyl radical (?OH) and photo-induced hole (h+) were all contributing to the acetone degradation. The [Mo3S13]2?/TiO2 photocatalyst was deposited on non-woven fabrics which showed obvious promotion on the photocatalytic degradation of acetone in comparison with pristine commercial TiO2.
关键词： TiO2,[Mo3S13]2?,Photocatalytic oxidation,VOCs degradation,Non-woven fabrics
更新于2025-09-23 15:23:52
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[IEEE 2017 IEEE International Integrated Reliability Workshop (IIRW) - Fallen Leaf Lake, CA (2017.10.8-2017.10.12)] 2017 IEEE International Integrated Reliability Workshop (IIRW) - Silicon dioxide degradation in strongly non-uniform electric field
摘要： The new experimental evidence of field-induced trap generation in the tunnel oxide of SuperFlash? memory cells has been presented. It was shown that the negative voltage stress generates the highest local electric field in the oxide close to the floating gate tip. The effect of electric stress on the degradation of tunneling characteristics has been studied for the cells with the different tunneling geometry. The reliability aspects of field-induced trap generation are discussed. It has been concluded that the analyzed degradation mechanism is not critical for the SuperFlash technology.
关键词： floating gate,program-erase cycling endurance,memory reliability,oxide degradation,electron tunneling,Flash memory,electron trapping
更新于2025-09-23 15:23:52
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Ag/Ag2O/BiNbO4 structure for simultaneous photocatalytic degradation of mixed cationic and anionic dyes
摘要： In principle, n-type and p-type semiconductors are respectively responsible for photo-catalytic degradation of cationic dyes (e.g., methylene blue) and anionic dyes (e.g., acid red 1), governed by photoelectrons in the former and photo-holes in the later system. Hence, we present a new strategy: design and fabrication of photocatalytic structures to match the redox potentials of mixed basic/acidic dyes as well as the reactive oxygen species (ROS). For the ?rst time Ag/Ag2O/BiNbO4 structure is (1) designed to match the redox potentials of basic/acidic dyes as well as ROS, (2) fabricated using photoreduction to control the Ag/Ag2O/BiNbO4 interfaces, and (3) able to simultaneously degrade 84% methylene blue dye (MB) in 240 min and 88% acid red 1 (AR) in 25 min under LED light irradiation, corresponding to 7 wt% Ag loading. To the best of our knowledge, this is the ?rst photocatalytic degradation study on mixed basic and acidic dyes using a single catalyst. We also tested the new redox potential matching strategy in mixed basic dyes (MB and rhodamine B (RhB)). As expected our experimental results reproduced well our model predictions: in particular, results support our proposed hydroxyl radical (?OH) mechanism, which is initiated by photo-holes. Therefore, this new design strategy, which consists of matching band structures of the photocatalyst with redox potentials of dyes and ROS, has immediate implications to general photocatalytic applications beyond dye degradation and water-splitting.
关键词： Methylene blue,Nanostructures,Rhodamine B,Photocatalysis,Dye degradation,Acid red,Mixed dyes
更新于2025-09-23 15:23:52
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Functionalization of silicon nanowires by iron oxide and copper for degradation of phenol
摘要： Iron oxide (Fe3O4) and copper-functionalized silicon nanowires (SiNWs) from silicon powder mesh < 500 with a spherical structure have been successfully synthesized as a heterogeneous catalyst for the degradation of phenol. This synthesized catalyst was prepared by nanosilicon wire powders. SiNWs have attracted much attention due their potential application in nanoscale devices such as field effect transistors, chemical or biological sensors, battery electrodes and photovoltaics. The SiNW properties were reinforced by functionalization. The synthesis of this catalyst was done by an in situ method for the decoration of SiNWs. Magnetic metal oxide compounds have been chosen not only to accelerate the catalyst recovery but also to improve the time duration of pollution elimination. Also, Cu nanoparticles were added in order to evaluate the catalytic property. In this work, the maximum amount of phenol degradation was obtained near 99.99%. Hybrid surface morphologies were characterized by scanning electron microscopy, X-ray diffraction, transmission electron microscopy, the Brunauer–Emmette–Teller model and high-performance liquid chromatography.
关键词： Mesoporous,Fe3O4–Cu-SiNWs catalyst,Phenol degradation,Sphere
更新于2025-09-23 15:23:52
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Graphitic Carbon Nitride with Carbon Vacancies for Photocatalytic Degradation of Bisphenol A
摘要： Photocatalysis is intensely employed to remove refractory organic pollutants in water, but suffers from low efficiency due to rapid recombination of photogenerated electrons and holes. Here, carbon vacancies modified g-C3N4 (VC-C3N4) is prepared via a handy two-step calcination method and firstly applied in the photocatalytic removal of bisphenol A (BPA). Compared to pristine g-C3N4, the photocatalytic degradation activity of VC-C3N4 for BPA is largely enhanced, whose kinetic constant (k) of BPA degradation is 1.65 times as that of pristine g-C3N4. The enhanced photocatalytic performance of VC-C3N4 is ascribed to critical role of carbon vacancies: On the one hand, carbon vacancies serve as the reservoir of photogenerated electrons to inhibit the recombination of photogenerated holes and electrons. On the other hand, carbon vacancies as conversion centers transfer trapped photogenerated electrons to absorbed O2 for generation of abundant superoxide radical (?O2-), which takes a dominant effect in the photocatalytic degradation process.
关键词： ?O2- species,bisphenol A,carbon vacancies,g-C3N4,photocatalytic degradation
更新于2025-09-23 15:23:52
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Non-destructive inspection of food and technical oils by terahertz spectroscopy
摘要： Quality control and non-destructive monitoring are of notable interest of food and pharmaceutical industries. It relies on the ability of non-invasive inspection which can be employed for manufacturing process control. We hereby apply terahertz (THz) time-domain spectroscopy as non-destructive technique to monitor pure and degraded oils as well as hydrocarbon chemicals. Significant differences in the spectra of refractive index (RI) and absorption coefficient arising from the presence of ester linkages in the edible and technical oils were obtained. Explicit increase from 1.38 to 1.5 of the RI in all THz spectrum range was observed in hydrocarbons and mono-functional esters with the increase of molar mass. This fact is in contrast of RI dependence on molar mass in multi-functional esters, such as Adipate or vegetable oils, where it is around 1.54. Degradation products, Oleic Acid (OA) and water in particular, lead only to some changes in absorption coefficient and RI spectra of vegetable oils. We demonstrate that complex colloidal and supramolecular processes, such as dynamics of inverse micelles and oil hydrolysis, take part during oil degradation and are responsible for non-uniform dependence of optical properties on extent of degradation.
关键词： absorption coefficient,terahertz spectroscopy,oils,degradation,non-destructive inspection,refractive index
更新于2025-09-23 15:23:52