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On the improvement of visible-responsive photodegradation through artificial cilia
摘要： Photocatalysts as a semiconductor material are widely used in the field of water and environment cleaning applications as it equips with favorite features such as chemical and physical stability, easy availability, inexpensive, and non-toxic in nature. Additionally, photocatalysts can convert the light energy of the irradiation into the chemical energy of the electron-hole pairs. Most commonly used TiO2 can function as the efficient photocatalysts in the presence of light. However it is a material which majorly requires UV light for its activation, and it is not practically being useful. In this aspect, the proposed study demonstrated that with a combination of SnFe2O4 nanoparticles with magnetic artificial cilia, a highly efficient catalytic activity can be achieved under the visible light due to the rapid and uniform mixing within the microfluidic device with least energy budget. To identify the optimal advanced oxidation process using the selected photocatalyst running with the microfluidics, a micro-particle image velocimetry analysis was carried out through three modes of artificial cilia rotation. The study also determined the evolution curves of the degradation rate with respect to time for all of three modes of cilia rotation, and a superior performance was achieved with a maximum degradation rate of 81.7% in 60 minutes using the presented design concept.
关键词： micro-particle image velocimetry,Photodegradation,photocatalyst,artificial cilia
更新于2025-09-23 15:21:21
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Controlled Synthesis of Mesoporous Single-Crystalline TiO2 Nanoparticles for Efficient Photocatalytic H2 Evolution
摘要： Mesoporous single-crystals have emerged as a unique family of functional materials, exhibiting excellent performance in various applications, owing to their well-defined accessible mesoporosity and highly single-crystalline structures. Precise tailoring structures of mesoporous single-crystals at the nanoscale remains an unsolved scientific and technical challenge. Herein, we report a facile and general approach for the synthesis of mesoporous single-crystalline TiO2 nanoparticles (designated as MSC-TNs) with distinctive traits including tunable morphologies, controllable particle sizes, well dispersity, high hydrophilicity, well-defined mesoporosity and single-crystal nature. Specifically, the amount of water employed in the precursor solution was seen to give fine control over the particle sizes and morphologies of MSC-TNs. MSC-TNs with different sizes show excellent photocatalytic activity in production of hydrogen from water. Under the illumination of 300 W Xe lamp, MSC-TNs were shown to provide good photodegradation performance with Rhodamine 6G, as well as H2 production when loaded 1 wt % Pt. In a CH3OH solution H2 was evolved with a rate of 8.98 mmol h-1 g-1, which is significantly higher than with commercial P25 nanoparticles (4.02 mmol h-1 g-1).
关键词： Water Purification,Photodegradation,Photocatalysis,TiO2,Mesoporous
更新于2025-09-23 15:21:01
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Photocatalytic degradation of tetracycline hydrochloride over rugby-like ?2-Ga <sub/>2</sub> O <sub/>3</sub> with a 3D hierarchically assembled porous structure for environmental remediation
摘要： A novel rugby-like β-Ga2O3 with 3D hierarchically assembled porous structures was successfully constructed through a facile precipitation-calcination method. The synthesized Ga2O3 materials were used to the photocatalytic degradation of tetracycline hydrochloride (TC·HCl) and the effects of calcination temperature on photocatalytic activity were discussed. The conversions of TC·HCl over Ga2O3-900 was 99.0% for Ga2O3-900 after 25 min UV-light irradiation, which was higher than those of commercial Ga2O3 (71.2%) and P25 (82.9%). The best photocatalytic activity of Ga2O3-900 could be attributed to the large specific surface area, intrinsic electronic properties and stable 3D hierarchically assembled porous structure. Based on the liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) analysis, the photocatalytic mechanism of Ga2O3 and feasible degradation pathway of TC·HCl were proposed. We believe that the present study can exploit an effective avenue to design the photocatalysts with 3D hierarchical porous structures to meet ever-increasing environmental remediation requirements.
关键词： β-Ga2O3,photodegradation pathway,nano-porous structures,tetracycline hydrochloride,optical properties
更新于2025-09-23 15:21:01
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Preparation and Characterization of Low-Molecular-Weight Natural Rubber Latex via Photodegradation Catalyzed by Nano TiO2
摘要： Natural rubber is one of the most important renewable biopolymers used in many applications due to its special properties that cannot be easily mimicked by synthetic polymers. To sustain the existence of natural rubber in industries, modifications have been made to its chemical structure from time to time in order to obtain new properties and to enable it to be employed in new applications. The chemical structure of natural rubber can be modified by exposure to ultraviolet light to reduce its molecular weight. Under controlled conditions, the natural rubber chains will be broken by photodegradation to yield low-molecular-weight natural rubber. The aim of this work was to obtain what is known as liquid natural rubber via photodegradation, with titanium dioxide nanocrystals as the catalyst. Titanium dioxide, which was firstly synthesized using the sol–gel method, was confirmed to be in the form of an anatase, with a size of about 10 nm. In this work, the photodegradation was carried out in latex state and yielded low-molecular-weight natural rubber latex of less than 10,000 g/mol. The presence of hydroxyl and carbonyl groups on the liquid natural rubber (LNR) chains was observed, resulting from the breaking of the chains. Scanning electron microscopy of the NR latex particles showed that titanium dioxide nanocrystals were embedded on the latex surface, but then detached during the degradation reaction.
关键词： latex state,liquid natural rubber,photodegradation,TiO2 anatase,UV light
更新于2025-09-23 15:21:01
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Bisretinoids mediate light sensitivity resulting in photoreceptor cell degeneration in mice lacking the receptor tyrosine kinase Mer
摘要： The receptor tyrosine kinase Mer is expressed by retinal pigment epithelial (RPE) cells and participates in photoreceptor outer-segment phagocytosis, a process enabling membrane renewal. Mutations in the gene encoding MERTK cause blinding retinitis pigmentosa in humans. Targeted Mertk disruption in mice causes defective RPE-mediated phagocytosis of the outer segments, leading to deposition of autofluorescent debris at the RPE–photoreceptor cell interface, followed by photoreceptor cell degeneration. Here, we show that retinaldehyde adducts (bisretinoid fluorophores) that form in photoreceptor outer segments occupy the unphagocytosed outer segment debris that accumulates in Mertk-/- mice. Bisretinoids measured by HPLC were elevated in Mertk-/- mice compared with wild-type animals. Bisretinoids were also more abundant in albino Mertk-/- mice expressing leucine at position 450 of the isomerase RPE65 (Rpe65-Leu450) rather than the variant methionine (Rpe65-450Met) that yields lower bisretinoid levels. In Royal College of Surgeons rats having dysfunctional Mertk, bisretinoids were higher than in wild-type rats. Intensities of in vivo fundus autofluorescence were higher in Mertk-/- mice than in wild-type mice and peaked earlier in albino Mertk-/-/Rpe65-Leu450 mice than in albino Mertk-/-/Rpe65-450Met mice. Of note, the rate of photoreceptor cell degeneration was more rapid in albino Mertk-/- mice exposed to higher levels of intraocular light (albino versus pigmented mice) and in mice carrying Rpe65-Leu450 than in Rpe65-450Met mice, revealing a link between bisretinoid accumulation and light-mediated acceleration of photoreceptor cell degeneration. In conclusion, the light sensitivity of photoreceptor cell degeneration arising from Mertk deficiency is consistent with the known phototoxicity of bisretinoids.
关键词： Mertk-/-,Mertk,retinal pigment epithelium,lipofuscin,phagocytosis,retina,photodegradation,bisretinoid
更新于2025-09-23 15:21:01
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Effect of Toxic Metal Ions on Photosensitized Singlet Oxygen Generation for Photodegradation of Polyaromatic Hydrocarbon Derivatives and Inactivation of <i>Escherichia coli</i>
摘要： Here we report an experimental study of the effect of toxic metal ions on photosensitized singlet oxygen generation for photodegradation of PAH derivatives, Anthracene-9,10-dipropionic acid disodium salt (ADPA) and 1,5-dihydroxynapthalene (DHN) and photoinactivation of E. coli bacteria by using cationic meso-tetra(N-methyl-4-pyridyl)porphine tetrachloride (TMPyP) as a singlet oxygen photosensitizer. Three s-block metals ions, such as Na+, K+, and Ca2+ and five toxic metals such as Cd2+, Cu2+, Hg2+, Zn2+, and Pb2+ were studied. The s-block metal ions showed no change of the rate of photodegradation of ADPA or DHN by TMPyP whereas a dramatic change in the photodegradation of ADPA and DHN were observed in the presence of toxic metals. The maximum photodegradation rate constants of ADPA and DHN were observed for Cd2+ ions [(3.91 ± 0.20) × 10-3 s-1 and (7.18 ± 0.35) × 10-4 s-1, respectively]. Strikingly, the photodegradation of ADPA and DHN was almost completely inhibited in the presence of Hg2+ ions and Cu2+ ions. A complete inhibition of growth of E. coli was observed upon visible irradiation of E. coli solutions with TMPyP and toxic metal ions particularly, Cd2+, Hg2+, Zn2+, and Pb2+ ions, except for Cu2+ ions where a significantly slow inhibition of E. coli’s growth was observed.
关键词： E. coli,photodegradation,toxic metal ions,photosensitized singlet oxygen generation,PAH derivatives,TMPyP,photoinactivation
更新于2025-09-23 15:21:01
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Synthesis and Application of Fe-Doped WO3 Nanoparticles for Photocatalytic Degradation of Methylparaben Using Visible–Light Radiation and H2O2
摘要： Synthesis of WO3 and Fe-doped WO3 nanoparticles is done by use of Microwave irradiation technique. X-ray powder diffraction confirmed the formation of a monoclinic crystalline structure. The as-prepared samples are characterised by transmission electron microscope, Braunuer, Emmett and Teller, Raman spectroscopy, photoluminescence, X-ray photoelectron spectroscopy and ultraviolet diffuse reflectance spectroscopy. Confirmation of the morphology of the nanostructures showed ovoid-like form. The photocatalytic activity of WO3 and nominal percentage of Fe-doped WO3 (3, 5 and 10 wt%) are evaluated for the degradation of methylparaben (MeP) in aqueous solution after being irradiated with visible light. The results show that 5 wt% Fe–WO3 is the best dopant in the photodegradation of MeP at 50.8% with H2O2. A chemometric model analysis is applied to estimate both individual and interaction factors that included pH, contact time, hydrogen peroxide (H2O2) concentration and catalyst dosage. The optimal conditions at pH 3, 10 mg, 5 wt% Fe–WO3 and 120 min are achieved.
关键词： Nanostructures,Dopant,Microwave,Methylparaben,Photodegradation
更新于2025-09-23 15:21:01
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Improvement of photocurrent and progesterone degradation by employing WO3 films modified with platinum and silver nanoparticles
摘要： The effect of silver (Ag0) and platinum (Pt0) metallic nanoparticles (NPs) on WO3 film was investigated by studying the photocurrent response under polychromatic irradiation. The structural phase revealed by X-ray diffraction (XRD) analysis indicates a monoclinic crystal nanostructure. WO3, Ag0/WO3, and Pt0/WO3 electrodes were used to degrade 0.35 mg L-1 progesterone hormone in aqueous solution under polychromatic irradiation for 3h. These studies on degradation were investigated under conditions of heterogeneous photocatalysis (HP) and electrochemically assisted HP (EHP). For photodegradation of progesterone, higher performance was achieved when WO3 was functionalized and when the EHP configuration was adopted with bias at +0.7 V vs Ag/AgCl. This work reveals that the incorporation of metallic NPs onto a semiconductor increases its efficiency, preventing electron-hole recombination in the photocatalyst and photoelectrochemical limitations of WO3 due surface plasmon resonance (SPR) and the trapping state. Therefore, efficient advances in the degradation of organic contaminants during water treatment can be realized based on this study.
关键词： Progesterone photodegradation,Polychromatic irradiation,Metals nanoparticles,WO3 films,Photocurrent density
更新于2025-09-23 15:21:01
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Photocatalytic degradation enhancements of dyes with bi-functionalized zones of modified nanoflower like TiO2 with Pt-C3N4 under sunlight irradiation
摘要： In this work, a novel method was proposed to photodegradation of organic dyes as important pollutants in wastewaters of textile industries. A one-step hydrothermal method was used to directly synthesis nanoflower like TiO2 on ordinary glass (OG) and modified with Pt-C3N4 nanotubes (NFs TiO2/Pt-C3N4) via electrophoretic deposition (EPD) method. Its photocatalytic activity investigated for degradation of three dyes under sunlight irradiation. The properties of NFs TiO2/Pt-C3N4 NTs were characterized by SEM, FT-IR, EDS, and XRD. Reduction of band gap energy and improvement of light absorption in the visible region for the modified photocatalyst were evaluated by using Tauc’s plot method. The experimental result showed that the NFs TiO2/Pt-C3N4 NTs achieved degradation efficiency of <97% at 240 min, towards methylene blue (MB), methyl violet (MV) and malachite green (MG) which are higher than pure TiO2 (68%, 83%, and 71%, respectively). Also as a new strategy, a part of the NFs TiO2/Pt-C3N4 NTs was used as a photoanode of the dye-sensitized solar cell (DSSC) and the other part, placed at a solution as a degradation zone. So with this bi-functionalized system, the degradation time was reduced from 240 min to 120 min with the same degradation efficiency.
关键词： Nanoflowers of TiO2,Pt-C3N4 nanotubes,dye-sensitized solar cells,photodegradation,bi-functionalized system
更新于2025-09-23 15:21:01
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An efficient and robust exfoliated bentonite/Ag <sub/>3</sub> PO <sub/>4</sub> /AgBr plasmonic photocatalyst for degradation of parabens
摘要： Efficient visible-light-driven heterojunction photocatalysts have attracted broad interest owing to their promising adsorption and degradation performances in the removal of organic pollutants. In this study, a mesoporous exfoliated bentonite (EB)/Ag3PO4/AgBr (30%) photocatalyst was obtained by stripping and exfoliating bentonite as the support for loading Ag3PO4 and AgBr. The particle size ranges of Ag3PO4 and AgBr were about 10–30 nm and 5–10 nm, respectively. The exfoliated bentonite could greatly improve the dispersion and adsorption of Ag3PO4 and AgBr, and significantly enhance the stability of the material during paraben photodegradation. 0.2 g L?1 methylparaben (MPB) was completely decomposed over the EB/Ag3PO4/AgBr (30%) in 40 min under visible light irradiation. In addition, the photocatalytic activity of EB/Ag3PO4/AgBr (30%) remained at about 91% after five recycling runs manifesting that EB/Ag3PO4/AgBr (30%) possessed excellent stability. Radical quenching tests revealed that holes (h+) and hydroxyl radicals (?OH) were the major radicals. They attacked the side chain on the benzene ring of parabens, which were gradually oxidized to the intermediates, such as benzoic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, azelaic acid, and eventually became CO2 and H2O. The enhancement of photocatalytic activity and photo-stability could be ascribed to the stable structural characteristics, enlarged surface area, high absorption ability, and improved light absorption ability from loading Ag3PO4 onto EB. Meanwhile, the matched energy levels of Ag3PO4 and AgBr made the photoelectron–hole pairs separate and transfer effectively at the interfaces. As a result, the photocatalytic properties of EB/Ag3PO4/AgBr (30%) composites were enhanced.
关键词： heterojunction photocatalysts,exfoliated bentonite,Ag3PO4/AgBr,paraben photodegradation,visible-light-driven
更新于2025-09-23 15:19:57