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The study of the catalytic behavior of phenol oxidation by hydrogen peroxide in presence of iron has shown that both heterogeneous and homogeneous catalytic systems behave similarly. For both systems, the reaction has been found sensitive to the pH, the highest phenol conversion and TOC abatement being obtained at a pH value close to 3.7. However, the heterogeneous catalytic system appears to be less sensitive to the pH and more efficient in TOC abatement than the homogeneous one. The measurement of OH° (h) production by an ESR spin trapping technique using DMPO as trapping agent strongly suggests that the main active species are hydroxyl (OH°) and/or hydroperoxyl (HO2°) radicals. The very low amount of iron dissolved by the reaction (less than 2% of the initial content) after more than 350h of work in a continuous flow reactor is a very promising result to develop a catalytic continuous flow process for industrial wastewater purification. 相似文献
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Dayana DArc de Fátima Palhares Luiz Gustavo Martins Vieira Jo?o Jorge Ribeiro Damasceno 《International Journal of Hydrogen Energy》2018,43(9):4265-4275
Electrolysis is a relatively simple process for obtaining hydrogen and can be combined with use of renewable energy sources, such as solar photovoltaic energy, for clean, sustainable gas production. This study designed a cylindrical electrolytic cell made of acrylic and 304 stainless steel electrodes to produce hydrogen. The electrolyte used was sodium hydroxide (NaOH 2–5 mol L?1), and the direct current voltages applied were 2.0, 2.7, and 3.4 V. The maximum hydrogen production was achieved with 5.0 mol L?1 NaOH and 3.4 V electric voltage. The system was connected to a photovoltaic panel of 20 W and exposed to solar radiation from 10 a.m. to 2 p.m. Approximately 2 L of hydrogen was produced within a period, and an average irradiance of 800.0 W m?2 ± 60 W m?2 was achieved. The system was stable throughout the tests. 相似文献
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The nonlinear effect of alkyl chain length in the membrane interactions of phenolipids: Evidence by X‐ray diffraction analysis
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Shashank Mishra Liliane G. Hubert-Pfalzgraf Stéphane Daniele Marc Rolland Erwann Jeanneau Bernadette Jouguet 《Inorganic chemistry communications》2009,12(2):97-100
In order to obtain a better anhydrous precursor for various applications in materials science and catalysis, thermal dehydration reactions of Y(TFA)3(H2O)3 (TFA = trifluoroacetate) (A) were investigated. Thermal treatment of A at different temperatures under vacuum (5 × 10?2 mm) for several hours failed to give totally anhydrous yttrium trifluoroacetate (as indicated by IR). Two different complexes, a partially dehydrated [Y(μ,η1:η1-TFA)3(THF)(H2O)]1∞·THF (1) and a partially hydrolyzed [Y4(μ3-OH)4(μ,η1:η1-TFA)6(η1-TFA)(η2-TFA)(THF)3(DMSO)(H2O)] · 6THF (2), were obtained with good and moderate yield, respectively, by crystallization of two different thermally treated batches of A from THF (or THF + DMSO) at room temperature. More efficient dehydration of A could be achieved at 200 °C in a furnace, the obtained anhydrous yttrium tris-trifluoroacetate giving Y(TFA)3(THF)2 (3) on crystallization from THF. All the products were characterized by elemental analyses, FT-IR and 1H NMR spectroscopy as well as thermo-gravimetric analysis. In addition, single crystal X-ray structures are reported for 1 and 2, which show either a terminal (η1 and η2) or bridging (μ,η1:η1) bonding behavior of the TFA ligand. 相似文献
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Transposase-mediated mobilization of the element Minos has been studied in the Drosophila melanogaster genome. Excision and transposition of a nonautonomous Minos transposon in the presence of a Minos transposase gene was detected with a dominant eye color marker carried by the transposon. Frequencies of excision in somatic tissues and in the germ line were higher in flies heterozygous for the transposon than in homozygotes or hemizygotes. Transposition of a X chromosome-linked insertion of Minos into new autosomal sites occurred in 1-12% of males expressing transposase, suggesting that this system is usable for gene tagging and enhancer trapping in Drosophila. Sequence analysis of PCR-amplified donor sites after excision showed precise restoration of the original target sequence in approximately 75% of events in heterozygotes and the presence of footprints or partially deleted elements in the remaining events. Most footprints consisted of the four terminal bases of the transposon, flanked by the TA target duplication. Sequencing of a chromosomal donor site that was directly cloned after excision showed a characteristic two-base mismatch heteroduplex in the center of the 6-bp footprint. Circular extrachromosomal forms of the transposon, presumably representing excised Minos elements, could be detected only in the presence of transposase. A model for chromatid repair after Minos excision is discussed in which staggered cuts are first produced at the ends of the inverted repeats, the broken chromatid ends are joined, and the resulting heteroduplex is subsequently repaired. The model also suggests a simple mechanism for the production of the target site duplication and for regeneration of the transposon ends during reintegration. 相似文献
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Regioselective synthesis of diacylglycerol rosmarinates and evaluation of their antioxidant activity in fibroblasts
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Paul Mathieu Rémi Bascou Francisco Sebastian Navarro Oliva Alla Nesterenko Anh-Tu Ngo Isabelle Lisiecki Erwann Guénin Fahmi Bedoui 《Polymer Engineering and Science》2023,63(3):830-840
We report the feasibility of electrospinning of protein-polymer multilayered scaffolds with selected materials such as non-hydrolyzed silk sericin (SS), polyethylene oxide (PEO), and polylactic acid (PLA), with tuned fiber size and properties for each layer. We present a new innovative way for the electrospinning (ES) of non-hydrolyzed SS mixed with PEO yielding fibers with an average diameter ranging between 120 and 150 nm. Different SS:PEO ratios have been electrospun to study the effect of the concentration of SS protein on the fibers size and shape, as well and their electrospinnability. Electrospun SS:PEO fibers display weak to no mechanical resistance (non-measurable) and their deposition onto a sturdier scaffold is necessary to allow their use in biomedical and/or pharmaceutical fields. Therefore, bilayer scaffolds have been fabricated consisting of a PLA support and SS:PEO fibers obtained from the optimized SS:PEO ratio (1.2:4). They are composed of a sturdy hydrophobic layer of PLA fibers and a layer of sticky hydrophilic SS:PEO fibers. The scaffolds have been characterized extensively by Fourier transforms infra-red (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and their resistance to mechanical stress. Finally, hydrophobicity of both layers has been determined by measuring the contact angle of water droplets on the scaffolds, further proving the bilayer nature of the scaffolds. 相似文献