Renewable biomass-derived carbon materials have attracted increasing research attention as promising electrode materials for electrochemical energy storage devices, such as sodium-ion batteries (SIBs), due to their outstanding electrical conductivity, hierarchical porous structure, intrinsic heteroatom doping, and environmental friendliness. Here, we investigate the potential of hierarchical N-doped porous carbon (NPC) derived from jackfruit rags through a facile pyrolysis as an anode material for SIBs. The cycling performance of NPC at 1 A/g for 2000 cycles featured a stable reversible capacity of 122.3 mA·h/g with an outstanding capacity retention of 99.1%. These excellent electrochemical properties can be attributed to the unique structure of NPC; it features hierarchical porosity with abundant carbon edge defects and large specific surface areas. These results illuminate the potential application of jackfruit rags-derived porous carbon in SIBs.
Aiming at disclosing the quantitative effects of Coulomb forces on the filtration efficiency of aerosol particles, a three-dimensional random fiber model was established to describe the microstructure of fibrous filters. Then, computational models including the flow model, particle model, and electric field model were constructed to estimate the filtration efficiency using the Fluent custom user-defined function program, neglecting the non-uniformity of the fiber potential and the particle charge distribution. The simulation results using the established models agreed with the data in the literature. In particular, the electric field force was found to be one of the important factors required to improve the filtration efficiency estimation accuracy for the ultrafine particles. Moreover, the variation tendencies of the filtration efficiency and the pressure drop of fibrous filters were studied based on the influence factors of the fiber potential, particle charge-to-mass ratio, solid volume fraction, fiber diameter, and face velocity. The established models and estimated results will provide important guidance on the design of high-efficiency particulate air filters for aerosol particles.
Salt stress affects the growth and development of plants, which results in a decrease in crop quality and yield. In this study, we used tomato seedlings treated with salt and trehalose as experimental materials and analyzed them using the technique for order preference by similarity to ideal solution analysis to select the optimal trehalose concentration for treatment. We also determined the contents of sugar and abscisic acid (ABA) and detected the expression of genes involved in the metabolism of sugar and ABA by quantitative real-time PCR. Results showed that the optimal trehalose concentration was 2 mmol/L for tomato seedlings under salt stress. Exogenous trehalose decreased the starch content and increased the soluble sugar content by affecting the expression of genes related to the metabolism of starch and soluble sugar. Exogenous trehalose altered the accumulation and distribution of sugar by inducing the upregulation of sugar transporter genes. Furthermore, trehalose increased the ABA content to induce salt stress response by regulating the expression of genes related to the synthesis and metabolism of ABA. In conclusion, trehalose can effectively alleviate salt stress and enhance salt tolerance of tomato. These findings provide a novel perspective and a better resource to investigate the salt tolerance mechanism and a new method for alleviating salt stress in tomato.
In this paper, we present a two-dimensional numerical analysis of the conjugate natural convection and radiation heat transfer in a double-space enclosure with two semitransparent walls. Two kinds of boundary conditions are considered, the first being the isothermal process of the opaque wall, and the other the incidence of a constant radiation flux in the left semitransparent wall. The renormalization group k–ε model is adopted to simulate the turbulent flow in the enclosure. To compute the radiation heat transfer in a semitransparent medium, the discrete ordinates model is used. We compare the behaviors of enclosures with single and double semitransparent walls and determine the difference in the results obtained for semitransparent and opaque partitions. The results indicate that a semitransparent partition facilitates a reduction in the heat loss or obtains a higher temperature distribution. The transmittance of a semitransparent wall has a great effect on the thermal and flow characteristics in an enclosure. The change of wall temperature is found to be significant when the thermal conductivity values range from 0.05 to 0.5 W/(m·K), and to be small when ranging from 0.5 to 10 W/(m·K). These conclusions are helpful for green design and energy saving in solar buildings.
2,5-Furandicarboxylic acid (FDCA) is a potential biorenewable chemical for applications including plastics, polyamides, drugs, etc. The selective biosynthesis of FDCA from 5-hydroxymethylfurfural (HMF) by a specific enzyme poses a great challenge. In this study, we reported an efficient strategy to produce FDCA from HMF by the tandem biocatalysis of laccase (CotA-TJ102@UIO-66-NH2) and Novozym 435. For the first step, a nanoparticle metal–organic framework was synthesized as a carrier to immobilize CotA-TJ102@UIO-66-NH2, which was assigned for the production of 5-formyl-2-furancarboxylic acid (FFCA) and featured an enzyme loading of 255.54 mg/g, specific activity of 135.90 U/mg, and solid loading ratio of 99.65%. Under optimal conditions, an ideal FFCA yield of 98.5% was achieved, and the CotA-TJ102@UIO-66-NH2 presented a high recycling capacity after 10 cycles. For the second step, Novozym 435 was applied for the further conversion of FFCA into FDCA, presenting a high FDCA yield of 95.5% under the optimized conditions. Novozym 435 also exhibited a high recyclability after eight cycles. As a result, the tandem biocatalysis strategy provided a 94.2% FDCA yield from HMF, indicating its excellence as a method for FDCA production.
Samples of sufu, a traditional food product made by fermenting soybeans, were collected in the city of Anshun in Southwest China and their bacterial diversity was investigated. Nine samples were divided into groups A–C, according to the markets in which they were collected, and the samples were subjected to pyrosequencing of the 16S rRNA V3–V4 regions for evaluation of the bacterial community. A total of 342 operational taxonomic units (OTUs) were determined. One of the samples (B2) included as many as 286 OTUs, and it also displayed the greatest bacterial richness. The most abundant bacterial diversity was shown in group B. Firmicutes was the dominant phylum in groups A and B, while Proteobacteria was the dominant phylum in group C. Lactobacillus was the prevailing genus in group A, Tetragenococcus in group B, and Empedobacter in group C. The bacterial composition of sufu depends, to a large degree, on the manufacturer. The obtained results showed regional differences in the bacterial community patterns of sufu products, which could contribute to a better understanding of the fermentation and ripening bioprocesses of sufu.
In this study, the effects of ZrO2 carrier precursors, MoO3 loading, and washing treatment on the catalytic performance of MoO3/ZrO2 toward sulfur-resistant methanation were investigated. All the catalysts were prepared by co-precipitation method and further characterized by N2 adsorption–desorption, H2-temperature-programmed reduction, X-ray diffraction, Raman spectroscopy and transmission electron microscopy. The prepared MoO3/ZrO2 catalysts were tested in a continuous-flow pressurized fixed bed reactor for CO methanation. The results revealed that the carrier precursors, MoO3 loading, and washing treatment affected not only the crystalline phase of Mo species but also the grain size of ZrO2 carrier and consequently influenced the MoO3/ZrO2 activity toward sulfur-resistant methanation. The 25 wt% MoO3/ZrO2 catalyst prepared using Zr(NO3)4·5H2O as the precursor and treated by water washing displayed the best activity for sulfur-resistant methanation due to its greater number of octahedral Mo species and smaller ZrO2 grain size.
Existing methods for synthesizing p-benzoquinone have drawbacks with respect to environmental protection, production scale, or industrial value. Therefore, it is imperative that a simple and environmentally friendly alternative be developed. The approach that involves preparing p-benzoquinone by the catalytic oxidation of benzene with hydrogen peroxide (H2O2) over copper-modified titanium silicalite-1 (Cu/TS-1) has a certain superiority due to its green synthesis and mild reaction conditions. In this study, Cu/TS-1 catalyst was prepared by the wet impregnation of TS-1 with an aqueous solution of Cu(NO3)2 and then characterized by X-ray diffraction, Fourier transform infrared spectroscopy, diffuse reflectance UV–Vis spectroscopy, scanning electron microscopy, inductively coupled plasma mass spectrometry, X-ray fluorescence, and analysis of the N2 adsorption–desorption isotherms. The results reveal that Cu species exist mainly in the form of amorphous CuO that is well dispersed on the surface of catalysts, with no major change in the molecular sieve framework. After optimizing the reaction conditions, a desirable p-benzoquinone selectivity (88.4%) and benzene conversion (18.3%) were obtained when the doping of Cu in Cu/TS-1 is 1.95 wt%. In addition, Cu/TS-1 can be conveniently regenerated, showing a slight decrease in catalytic capability after initial use, which then stabilizes in subsequent circulations. The satisfactory stability and low cost of synthesizing Cu/TS-1 give this method considerable potential for further industrialization.
Black clay (BC) was used as a catalyst for the decolorization of Azure B dye by Fenton process. BC was modified by acid, alkali, distilled water, and calcination to check their changes in characterization and efficiency on decolorization of Azure B. Among three modified catalysts, maximum decolorization was obtained by acid-modified BC (AMBC) catalyst due to the highest removal of impurities, comparatively. The characterization of AMBC was done by Fourier-transform infrared spectroscopy and X-ray diffraction spectroscopy which show the presence of metal ion. The BET surface area, pore volume, pore size, and density of AMBC were calculated to be 79.402 m2/g, 0.0608 m3/g, 0.00306 nm, and 16 g/cm3, respectively. The highest decolorization of 97.59% was achieved only in 10 min using AMBC at optimized calcination of 100 °C and 3 h of aging. AMBC was considered as the main catalyst for optimizing the different process parameters. Optimized conditions were obtained: pH 2, 0.2 mL of H2O2, catalyst dose 0.3 g, room temperature (30 °C), and stirring speed 400 r/min. The catalyst has showed excellent stability and reusability. It could remove more than 85% of color even after four cycles of run and less than negligible leaching of iron. AMBC has good recycling ability among other modified catalysts. To check the selectivity of catalyst, different dyes such as Congo red and mixed dye (mixture of Azure B and Congo red) decolorization were studied. In the present work, kinetic study was also carried out and a three-stage decolorization process was found.
The phase equilibrium data of CO2–hydrocarbon binary mixtures are important for the design and operation of CO2 flooding, coal liquefaction, and supercritical extraction processes. Numerous pieces of binary phase equilibrium data have been obtained. Thus, models for the accurate calculation of binary and multicomponent mixtures must be developed on the basis of existing data. In this work, 3578 vapor–liquid phase equilibrium data points for 10 CO2–hydrocarbon binary mixtures, including CO2–butane, CO2–pentane, CO2–isopentane, CO2–hexane, CO2–benzene, CO2–heptane, CO2–octane, CO2–nonane, CO2–decane, and CO2–undecane, were collected. The PR and PR-BM equations of state (EOS) in combination with relevant mixing rules were used to calculate the phase equilibrium data of the CO2–hydrocarbon binary mixtures. The binary interaction parameter k ij in the PR EOS was temperature independent, whereas parameters in the PR-BM EOS were functions of temperature. Thus, the phase equilibrium data and other thermodynamic properties of the binary and multicomponent mixtures at different temperatures and pressures can be calculated by using the parameters obtained in this work. The PR-BM EOS performed better than the PR EOS, and the average absolute deviations over the temperature range of 255.98–408.15 K calculated by the PR EOS and PR-BM EOS were less than 5.74% and 3.36%, respectively. The results calculated by the two EOS were compared with those calculated by other models, such as PPR78, PR + LCVM + UNIFAC, KIE + PR EOS + HV, and PSRK. The phase equilibrium data of CO2–butane–decane, CO2–hexane–decane, and CO2–octane–decane ternary mixtures were calculated by the two EOS. The average overall deviations for the CO2 mole fractions calculated by the two EOS were less than 7.66%.
1,3-Dihydroxyacetone (DHA), a natural ketose, is widely used in the chemical, cosmetic, and pharmaceutical industries. The current method for DHA production is Gluconobacter oxydans (G. oxydans) fermentation, but the high concentration of glycerol in the fermentation broth inhibits cells growth. To overcome this obstacle, in this study, we overexpressed the glycerol transporter (GlpFp) by the use of promoters P tufB, P gmr, P glp1, and P glp2 in G. oxydans 621H. The results show that the glycerol tolerances of strains overexpressing GlpF were all much better than that of the control strain. The glycerol dehydrogenase gene (Gdh) was overexpressed by the promoters P tufB and P gdh, which increased the DHA titer by 12.7% compared with that of the control group. When GlpF and Gdh genes were co-overexpressed in G. oxydans 621H, the OD600 value of the engineered strains all increased, but the DHA titers decreased in different degrees, as compared with strains that overexpressed only Gdh. This study provides a reference for future research on DHA production.
To clarify the preparation mechanisms of fluorinated ordered mesoporous carbon materials (FOMCs), the dissipative particle dynamics method was used to simulate the self-assembly process of the amphiphilic triblock poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) copolymer Pluronic F127 in the aqueous system. The self-assembly mechanisms in aqueous phase and the formation mechanisms of micropores and mesopores were investigated. It was found that the mesoporous structure of the FOMCs was formed by the hydrophobic segments of F127, while the pore wall was formed by both the hydrophilic segments and the carbon precursor in the system. The microporous structure on the pore wall was constructed by the carbon source in the hydrophilic segments’ spaces after the template was removed. Our findings could provide understanding and knowledge for the synthesis of mesoporous carbon by the self-assembly method on the mesoscopic scale.