查看更多>>摘要：Bacteria, viruses, and temperatures change can affect the preservation of food and medicines, so it is necessary to develop an intelligent textile for antibacterial and thermal regulation. In this paper, we used coaxial electrospinning technology to achieve antibacterial thermo-regulating intelligent textiles. The polyacrylonitrile (PAN)/curcumin is the sheath, and n-octadecane is the core. The composite fiber has excellent comprehensive properties. When the curcumin concentration is 10 wt%, the antibacterial effect is the best, and the bacteriostatic rate is 100%. When the core feed rate is 0.25 mL/h, the latent heat can reach 123.94 J/g. The multifunctional textiles have potential application value in the clothing fabrics, preservation and storage quality of functional foods, biomedical products, and other fields.
查看更多>>摘要：Carbon nitrides (g-C3N4) is considered to be the prospective semiconductor photocatalyst for photocat-alytic H2 evolution. Nevertheless, it suffers from low charge transfer efficiency and fewer metal active sites. Thereby, Ni-Sn3O4/g-C3N4 photocatalysts were constructed by anchoring Ni-doped Sn3O4 micro-flowers on g-C3N4 via a feasible and straightforward solvothermal treatment. The prepared Ni-Sn3O4/g-C3N4 S-scheme heterojunction could improve the transfer and separation efficiency of photo-generated electron-hole pairs by facilitating the electrons transfer from Ni-Sn3O4 to g-C3N4. Moreover, the photocat-alytic H2 production performance was ameliorated due to the established internal electric field and the energy band bending in Ni-Sn3O4/g-C3N4 S-scheme heterojunction. Meanwhile, the doping Ni in Sn3O4 exposed more active sites in Ni-Sn3O4/g-C3N4 heterojunction for producing H2. As a result, Ni-Sn3O4/g-C3N4-5 photocatalyst exhibited outstanding H2 yields of 1961 pmol h~(-1) g~(-1) under visible light irradiation in comparison with pure Ni-Sn3O4 (12 umol h~(-1) g~(-1)) and bared g-C3N4 (1391 μmol h~(-1) g~(-1)). Furthermore, the S-scheme mechanism in Ni-Sn3O4/g-C3N4 heterojunction for producing H2 by oxidizing H2O was proposed. This study provides helpful guide for developing efficient g-C3N4-based photocatalytic systems.
查看更多>>摘要：Novel g-C3N4/SnS2 van der Waals heteroj unctions were fabricated via SnS2 crystals embedded superior thin g-C3N4 nanosheets for efficient photocatalytic oxidation and reduction activities simultaneously. S-scheme charge migration path was confirmed through test and density functional theory (DFT) calculation. Two dimensional (2D)/2D interfaces, powerful internal electric field (IEF) and band bending effect together expedited charge transfer. Photocatalytic removal of organic pollutants and hydrogen evolution were employed to evaluate photocatalytic performance. Particularly, the g-C3N4/SnS2 heterojunctions exhibited excellent 2,4-dichlorophenol (2,4-DCP) photooxidation and Cr(VI) photoreduction activities at the same time. 85% of Cr(VI) and 94% of 2,4-DCP were removed in the mixed solution after visible light irradiation for 2h(λ> 420 nm). The hydrogen evolution rate enhanced to ~6.58 times of g-C3N4. DFT simulation matched with test for narrowed band gap and enhanced IEF (accelerating photogenerated carrier transfer). This work provided new insights for constructing S-scheme multifunctional g-C3N4-based photocatalyst.
查看更多>>摘要：Despite the low cost of paper substrates, the lack of appropriate device fabrication techniques has hampered the overall efficacy of paper-based sensors. Addressing this issue, in this work, we develop a multi-walled carbon nanotube (MWCNTs) coated paper substrate-based biosensor using a novel method of wax deposition followed by vacuum filtration to design dedicated hydrophobic and hydrophilic channels for label-free, highly selective, and sensitive detection of cholesterol. Detailed morphological characterization studies reveal the uniform deposition of MWCNTs on the paper substrate (~15-20 nm average diameter). Upon exposure to cholesterol, an excellent dynamic range of response over three orders of magnitude from 10 nM-75 μM and 100 μM-8 mM concentration range with a limit of detection of 3.2 nM (3 S/m) was obtained. The Michaelis-Menten constant (Km) was found to be 0.0093 μM. In addition, the fabricated biosensor exhibited excellent reproducibility, stability and high specificity to cholesterol with negligible response from interfering analytes. The excellent response of the fabricated biosensor can be attributed to the modulation of electrical properties due to electrostatic gating effect and direct electron transfer between MWCNTs and cholesterol due to the bioconjugation of Cholesterol oxidase (ChOx). The strategy employed here addresses some major challenges faced by the current methods of using rigid substrates and liquid electrolyte based analytical methods for detection of cholesterol. Furthermore, the sensor could successfully measure concentrations of cholesterol in saliva. This work provides a promising platform for developing low cost, interference free, disposable paper-based biosensors for point of care diagnostics.
查看更多>>摘要：Water purification is a global issue, and most traditional methods have several drawbacks. As a result, new methods and materials must be devised to address the problem of water filtration. The hydrophobic TiO2-ZnO/rGO has been synthesized via single-step hydrothermal methods for the efficiency and effective indigo carmine (IC) solution degradation. The characterization of hydrophobic TiO2-ZnO/rGO has shown that the material has a high contact angle value of around 103.6°. Several photocatalytic parameters, pH of IC solution, the dosage of catalyst, and light intensity, were optimized for obtaining the highest degradation efficiency. The results of the photocatalytic study showed that the IC dye degradation process was controlled by superoxide anion radical (-O^ radicals) to produce more specific products. Modifications with hydrophobic compounds such as hexamethyldisilizane (HDMS) showed that they could increase the photocatalytic properties and reusability of the material with a degradation percentage value of up to 95% with a constant rate of 0.0361 min~(-1). Based on these results, this material has the potential to be further developed for micro and complex photodegradation and self-cleaning materials.
查看更多>>摘要：The anticorrosion and antibiofouling of marine engineering equipments have strong demands, especially for antibiofouling. In this work, an in-situ growth layered double hydroxide (LDH) coating on aluminum alloys (AA) 7075 was prepared and then modified by sodium pyrithione (SPT) to increase the anticorrosion and antibiofouling performance. Results indicated that CoAl-LDHs and CoAl-LDHs-SPT coatings had been successfully prepared according to TEM, XRD, XPS, Raman spectra, and SEM analysis results. The (012) plane of LDHs with a interplanar spacing of 0.26 nm was recognized from TEM images. The content of SPT in CoAl-LDHs-SPT is 38.79 wt.%. Electrochemical impedance spectroscopy (EIS) and polarization curvies demonstrate that the corrosion resistance of AA 7075 was largely improved in the presence of CoAl-LDHs and CoAl-LDHs-SPT coatings while the anticorrosion performance of CoAl-LDHs-SPT coating was better. The corrosion resistance of Co-Al LDHs-SPT coating increased by about two orders of magnitude compared with the bare AA 7075. The surface analysis results show that only a few Pseudomonas aeruginosa and Spirulina cells attached to the CoAl-LDHs coating surface, and no biofouling cells were observed for the CoAl-LDHs-SPT coating. Co-Al LDHs-SPT coating possessed the best anticorrosion and antibiofouling properties due to the presence of SPT compared with the CoAl-LDHs coating.
查看更多>>摘要：In this work, a nanocomposite phase change material (PCM) has been designed by combining two-dimensional lamellar anhydrous calcium sulfate with polyethylene glycol (PEG). We report a facile strategy to controllably fabricate two-dimensional lamellar anhydrous calcium sulfate (LAH) with the average thickness of 28.63 nm from phosphogypsum (PG) through ethylenediamine tetraacetic acid disodium (Na2EDTA) induction in glycerol and ethylene glycol solutions at 98 °C. The obtained 2D lamellar CaSO4 was a slit-type mesoporous material stacked by the nanosheet of calcium sulfate. It has a specific surface area of 70.02 m~2/g, which is 10 times larger than phosphogypsum. Na2EDTA acts as a crystal habit-directing agent to regulate crystal morphology through nonclassical nanoparticle-mediated crystallization processes, resulting in the crystalline morphology tending to be lamellar. Lamellar anhydrous calcium sulfate phase change composites (LAHPCMs) were prepared with 2D lamellar anhydrous nano-CaSO4 and polyethylene glycol (PEG). The LAHPCMs had a high latent heat storage capacity (92.99 J/g). Lamellar anhydrous calcium sulfate phase change composites have good thermal stability and durability, structure stability, and good liquid leakage resistance. These results provide the possibility for phosphogypsum to be used for energy storage and thermal insulation.
查看更多>>摘要：The development of highly efficient, economical and environmentally friendly catalytic systems is of great significance from the green chemistry point of view. In this paper, we presented a succinct approach to create a heterogeneous acid-base bifunctional catalyst for one-pot tandem reaction from the commercially available textile fiber. The ultra-high strength textile fiber polyetheretherketone (PEEK) was func-tionalized by a post-grafting method to combine two antagonistic active functions in a synergistic catalyst, and the resulting fiber samples were characterized in detail by morphology, mechanical properties, elemental analysis, X-ray photoelectron spectroscopy, inductively coupled plasma-atomic emission spectrometry, X-ray diffraction, Fourier transform infrared spectroscopy, ultraviolet-visible spectrum, nuclear magnetic resonance spectroscopy and thermogravimetric analysis, and further revealed that the amines and the heteropolyacid were immobilized by acid-base interactions in the PEEK surface layer with sufficient stability. Moreover, the acid-base bifunctional catalyst can be successfully applied in the acceleration of the one-pot tandem deacetalization-Knoevenagel reactions with high-efficiency (lower catalyst dosage 0.3 mol%, higher product yields 81-92%), whereas the homogeneous catalysts were unable to initiate the reaction due to their mutual neutralization in solution, and the catalytic mechanism was elucidated by comparison. Furthermore, the fibrous catalyst could maintain its activities more than 10 cycles with a simple post-processing, and the mediated system was capable of enlarging to the gram-scale, which are envisaged for industrial operations and cleaner productions.
Henrique GasparettoAna Luiza Barrachini NunesFernanda de Castilhos
11页
查看更多>>摘要：Soybean oil extraction using two green solvents was investigated from solvent selection to thermodynamics: ethyl acetate and 1-butanol. The screening of the solvents was performed using the Hansen parameters and Infinite Dilution Activity Coefficient (IDAC) obtained through the COnductor-like Screening MOdels-Segment Activity Coefficient (COSMO-SAC) theory. The solvent selection was performed on ethyl acetate and 1-butanol in comparison with ethanol, a well-studied green solvent, and hexane, a non-renewable and industrially used solvent. The effects of temperature and solvent/solid ratio on the yield of soybean oil extraction were investigated through response surface methodology (RSM). The RSM obtained satisfactory statistical results, with R_(adj)~2 of 0.9958 for ethyl acetate and 0.9729 for 1-butanol. The kinetic of the extractions were evaluated using two different models: mass transfer kinetic and So and Macdonald. The last one obtained the best correlation to the data (R~2 > 0.9964). The thermodynamic assessment showed endothermic, and spontaneous processes for both solvents. 1-Butanol, ethyl acetate, and hexane have a better performance on the yield of soybean oil extraction than using ethanol; however, ethyl acetate is the best candidate to replace the industrial use of hexane due to its highest rate of soybean oil extraction at the process beginning.
查看更多>>摘要：Three novel tetraaryldiamines are synthesized and applied as an interlayer between zinc oxide (ZnO) and photoactive layers in PTB7-Th:PC71BM solar cells. The arylamines have an optical bandgap of 3.0-3.4 eV and do not interfere with the light-harvesting window of our polymenfullerene combination. They enhance the power conversion efficiency from 7.48% in the control device to 8.95%, 8.18%, and 7.84% in PN-, PA-, and PAP-based devices, respectively. The dependence of photovoltaic parameters on the deposition conditions of the interlayer reveals that the current density and fill factor are the main parameters that increase when tetraaryldiamines are used as an interlayer. The external quantum efficiency increases from 73.1% in the bare ZnO device to 77.7-82.0% in the interlayer-incorporated devices. The power loss owing to the series and shunt resistances is reduced by a suitable alignment of the electronic energy levels with the interlayer and enhanced charge transfer through the components. Interlayer-incorporated devices also show a superior environmental stability compared to devices using bare ZnO. The results of this study should help advance the engineering strategies for organic solar cells with enhanced performances.
NSTL