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Carbon nanotube based metal-organic framework nanocomposites: Synthesis and their photocatalytic activity for decolorization of colored wastewater
摘要： Herein, Materials Institute Lavoisier (MIL-125(Ti))/carbon nanotube (CNT) nanoporous composites (MIL/CNT) were synthesized by hydrothermal method. Different amounts of CNT (0.01 g and 0.03 g) were used to synthesize nanocomposites (denoted as MIL/CNT(0.01) and MIL/CNT(0.03), respectively). The synthesized nanomaterials (MIL, MIL/CNT(0.01) and MIL/CNT(0.03)) were characterized by XRD, FTIR, TGA, BET, SEM, and zeta potential and used for photocatalytic dye degradation. Reactive Black 5 (RB5) was used as a model pollutant. The zeta potential of MIL and MIL/CNT (0.01) were ?27.7 mV and 19.2 mV, respectively. The data showed that that MIL/CNT(0.01) nanocomposite had higher photocatalytic dye degradation due to the synergistic effect of CNT. Dye decolorization by the nanomaterials followed the zero-order kinetics reaction. The decolorization rate was 0.0015, 0.0019, 0.0024 mg/L min for MIL, MIL/CNT(0.01) and MIL/CNT(0.03), with the correlation coefficient of 0.9639, 0.9906, and 0.9757, respectively. The synthesized catalysts were reusable over two cycles.
关键词： Metal-organic framework-carbon nanotube nanocomposite,Photocatalytic dye degradation,Reactive Black 5,Synthesis
更新于2025-09-04 15:30:14
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Rechargeable Photoactive Silk-Derived Nanofibrous Membranes for Degradation of Reactive Red 195
摘要： Constructing nanosized photoactive membrane materials would facilitate the pretreatment of dyeing wastewater and reducing the environmental pollution. However, preparation of such membrane materials remains tremendously challenging. In this work, we fabricate the silk-derived nanofibrous membranes modified with 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BDSNM) that could yield reactive oxygen species (ROS) driven under UV light irradiation. The premise of this study is that BDSNM can store photoactive activity at UV light and release the ROS under dark conditions. The resultant BDSNM exhibited the extra-fine fiber diameter (129 nm), larger surface area (13.8 m2 g?1), superhydrophilicity, fast ROS production, good activity storing capacity and good degradation capacity for reactive red 195 (＞99.9999%) within 30 min. The effective synthesis of such economic and fascinating BDSNM may pave a way for fabrication of the photoactive membranes for dye degradation.
关键词： Degradation,Silk,Photoactive,Dye,Membranes,Rechargeable
更新于2025-09-04 15:30:14
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Two Series of Microporous Lanthanide–Organic Frameworks with Different Secondary Building Units and Exposed Lewis Base Active Sites: Sensing, Dye Adsorption, and Magnetic Properties
摘要： Two series of new lanthanide complexes, {[Ln(L)1.5(H2O)]·DMA·4H2O}n (1-Ln, Ln = Tb, Gd, and Dy) and {[La2(L)3]·4H2O}n (2-La), were prepared successfully by Ln3+ ions and a N-heterocyclic dicarboxylic (2-pyrimidin-5-yl)terephthalic acid (H2L) ligand. The four complexes are three-dimensional (3D) microporous frameworks with different secondary building units (SBUs) and exposed Lewis base active sites. Topology analyses reveal that 1-Ln are the binodal (3,8)-connected tfz-d (43)2(46·618·84) nets and 2-La is a binodal (2,12)-connected (4)6(46·848·1212) net. The photoluminescence of 1-Tb, the dye adsorption of 1-Tb and 2-La, and the magnetism of 1-Dy have been well studied. The luminescent explorations indicate that 1-Tb is a highly efficient probe for sensing Fe3+ and Cr2O72?, respectively. Complexes 1-Tb and 2-La display the unique selective adsorption to Congo red (CR) dyes. Magnetic measurements further indicate that 1-Dy has a slow magnetic relaxation performance.
关键词： lanthanide complexes,dye adsorption,magnetism,photoluminescence,microporous frameworks,Lewis base active sites
更新于2025-09-04 15:30:14
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Applicability of the thin-film approximation in terahertz photoconductivity measurements
摘要： Thin mesoporous photoconductive layers are critically important for efficient water-spitting solar cells. A detailed understanding of photoconductivity in these materials can be achieved via terahertz transient absorption measurements. Such measurements are commonly interpreted using the thin-film approximation. We compare this approximation with a numerical solution of the transfer function without approximations using experimental results for thin-film mesoporous tin oxide (SnO2) samples which range in thickness from 3.3 to 12.6 mm. These samples were sensitized with either a ruthenium polypyridyl complex or a porphyrin dye. The two sensitizers have markedly different absorption coefficients, resulting in penetration depths of 15 mm and 1 mm, respectively. The thin-film approximation results are in good agreement with the numerical work-up for the short penetration length dye. For the longer penetration length samples, the thin-film formula fails even for thicknesses of only 3 mm (cid:2) k/100. The imaginary part of the conductivity calculated using the thin-film formula was significantly larger in magnitude than the value without approximations. This discrepancy between the commonly used thin-film approximation and the numerical solution demonstrates the need for a careful analysis of the thin-film formula.
关键词： thin-film approximation,terahertz photoconductivity,mesoporous SnO2,ruthenium polypyridyl complex,porphyrin dye
更新于2025-09-04 15:30:14
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Two bimetallic metal–organic frameworks capable of direct photocatalytic degradation of dyes under visible light
摘要： Two bimetallic metal–organic frameworks (MOFs), specifically {2[LiM(TDA)2(DMF)]·NH2+(CH3)2}n (M = Co (HNU-29) or Zn (HNU-30), TDA = 2,5-thiophenedicarboxylate), were synthesized by solvothermal methods. X-ray crystal structures of the two MOFs showed them to be isostructural. Thus, in both cases, the metal secondary building units were connected by TDA2? ligands to form a 3D framework whose structure can be simplified to the twofold interpenetrated dia net. HNU-29 showed excellent photocatalytic activity for the degradation of methylene blue (MB) under visible light even without the addition of H2O2 as an electron acceptor, remaining stable even after several cycles of reuse. The MB degradation followed first-order kinetics, and the photocatalytic degradation mechanism was found to be related to the effective ligand-to-metal charge transfer within the framework.
关键词： Photocatalysis,Methylene blue,Metal–organic frameworks,Visible light,Dye degradation
更新于2025-09-04 15:30:14
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Donor-π-acceptor dye-sensitized photoelectrochemical and photocatalytic hydrogen evolution by using Cu2WS4 co-catalyst
摘要： Photoelectrochemical and photocatalytic hydrogen evolution reaction (HER) have been investigated by using metal free donor-acceptor (D-A) and donor-p-acceptor (D-p-A) dyes, which are abbreviated as MC-32 and MC-048, respectively, sensitized TiO2 as a photocatalyst with or without Cu2WS4 co-catalyst. This co-catalyst is synthesized by a low-cost and simple hot injection method, under visible light illumination. The photoactivities of these dyes have been clarified according to their structural, optical and electrochemical properties. Photocatalytic activities have been slightly increased when added the Cu2WS4 co-catalyst (dye/TiO2/Cu2WS4). This catalytic activity is also compared to that of noble metal Pt (dye/TiO2/Pt). It has been found that 121 mmolg-1h-1, 179 mmolg-1h-1, 348 mmolg-1h-1, 212 mmolg-1h-1, 422 mmolg-1h-1 and 1139 mmolg-1h-1 hydrogen have been evolved by using MC-32/TiO2, MC-32/TiO2/Cu2WS4, MC-32/TiO2/Pt, MC-048/TiO2, MC-048/TiO2/Cu2WS4 and MC-048/TiO2/Pt, respectively.
关键词： Dye sensitization,Donor-p-acceptor dyes,Hydrogen evolution
更新于2025-09-04 15:30:14
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Optimization and modeling of UV-TiO <sub/>2</sub> mediated photocatalytic degradation of golden yellow dye through response surface methodology
摘要： In this article, heterogeneous photocatalysis of golden yellow (GY) dye by Evonik p25 titanium dioxide (PTD) and UV radiations was optimized by using central composite design of response surface methodology. The GY dye photocatalysis was expressed as the function of amount of PTD loading (X1), GY dye initial concentration (X2), and UV irradiance intensity (X3). The optimization of degradation conditions was done by measuring two different responses, that is, color removal (Y1) and chemical oxygen demand removal (Y2). The effect of X1, X2, and X3 were studied in the range 0.5–1.5 g/L, 15–35 W/m2, and 10–30 mg/L, respectively. The quadratic model was suggested for Y1 and Y2. The numerical optimization of results was done via Design Expert software. The predictive results obtained were verified by performing actual experiments. The photodegradation kinetics, total organic carbon disappearance, effect of inorganic salts, and H2O2 concentration on GY dye photodegradation were also studied.
关键词： Titanium dioxide,Heterogeneous photocatalysis,Central composite design,Optimization,Golden yellow dye,Response surface methodology
更新于2025-09-04 15:30:14
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Targeted Methotrexate Prodrug Conjugated With Heptamethine Cyanine Dye Improving Chemotherapy and Monitoring Itself Activating by Dual-Modal Imaging
摘要： Theranostic prodrug plays a vital role in reducing the side effects and evaluating the therapeutic efficiency of prodrug in vivo. In particular, small conjugate-based theranostic prodrugs have attracted much attention because of their clear and simple structures. In this work, we synthesized a novel tumor-targeting and glutathione-activated conjugate-based theranostic prodrug (Cy-SS-MTX). The prodrug was constructed by conjugating Cy (IR780) to methotrexate (MTX) via a disulfide bond. The Cy dye as targeting molecule bring prodrug to cancer cells and then the prodrug was activated by the high levels of glutathione in tumor. In cell experiments, the results showed the excellent ability of prodrug to target tumor. Meanwhile, the prodrug apparently improved the anti-tumor ability and hugely reduced toxicity of free MTX on normal cells. Furthermore, owing to intramolecular charge transfer between Cy and MTX, the Cy structure in the prodrug showed an absorption peak at 654 nm in UV-Vis spectroscopy. However, when the disulfide bond of prodrug was broken by glutathione, a new UV-Vis absorption peak at 802 nm of Cy structure in prodrug was arised. At the same time, the fluorescence (FL) emission peak at 750 nm (excitation at 640 nm) would turn into 808 nm (excitation at 745 nm). What’s more, the photoacoustic (PA) signal with excitation at 680 and 808 nm also changed. The experimental results in vivo showed that the prodrug has been successfully utilized for real-timely tracking MTX activation by FL and PA imaging upon near infrared laser excitation and cancer targeting therapy. Our studies further encourage application of small conjugate-based prodrug based on tumor-targeted heptamethine cyanine dye as reporter group for targeted therapy and real-timely tracking activation of drug.
关键词： small conjugate-based prodrug,heptamethine cyanine dye,dual-modal imaging,targeting therapy,monitoring prodrug activation,theranostic
更新于2025-09-04 15:30:14