Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences
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Tetrathiafulvalene derivative as a new hole-transporting material for highly efficient perovskite solar cell
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A facile nanocomposite strategy to fabricate a rGO–MWCNT photothermal layer for efficient water evaporation
No full textSolar-driven water evaporation assisted by photothermal membranes is considered as one of the
sustainable and cost-effective strategies for pure water generation and wastewater treatment. Herein,
we report a facile but effective approach to improve the photothermal performance by combining 2D
reduced graphene oxide (rGO) and 1D multi-walled carbon nanotubes (MWCNTs), which have different
nanomorphologies. The photothermal layer can be easily deposited on different substrate materials via
simple vacuum assistance. Such a composite photothermal layer shows a rough surface with
a controllable nano-structure, which can thus optimize solar light harvesting. On the other hand, the
formation of a loose internal porous structure and suitable wettability ensure water transport inside the
photothermal layer during evaporation. The surface temperature reaches as high as 78 C even under
one sun irradiation (1 kW m 2), which is 10 C higher than the result of pure rGO membranes. When
loaded on a PVDF substrate, the rGO–MWCNT based membrane is flexible and shows an obvious
improvement in the evaporation rate, about 79.0% and 8.9% higher than those of pure rGO and MWCNT
membranes, respectively. The solar thermal conversion efficiency can reach up to 80.4% without any
extra accessory for thermal management. Based on our results, the nanocomposite strategy is facile and
effective for the development of novel photothermal membranes for high-efficiency evaporation, and
contributes to the widespread application in the fields of desalination and wastewater treatment
化学工程
No full textGas-liquid reactors are widely applied in many industrial processes. The performance of these reactors is strongly dependent on the bubble size and its distribution. In addition, the bubble size distribution also affects directly the flow pattern, heat transfer, and mass transfer in the reactor. However, the initial diameter of the bubbles from the gas distributor is usually obtained from experience, which leads to that the accuracy of the numerical simulation related closely to the experience of the researchers. As we know, the drag force is the resistance exerted by the fluid on the bubbles, and it is a basic parameter required in the numerical simulation of multiphase flow. Up to date, the drag coefficient adopted in the computational fluid dynamics does not take into account the interaction between bubbles, i.e., the mesoscale effect of the bubble group on the drag coefficient is usually ignored. Therefore, the precise models for predicting the initial bubble diameter and mesoscale drag coefficient are urgently demanded to provide guidance for the simulation of gas-liquid multiphase flow.
The models for calculating the initial bubble diameter and drag coefficient of bubble swarm can be derived on the basis of a large amount of accurate experimental observations and measurements. There are many experimental methods to study the gas-liquid multiphase flow, in which the digital image analysis (DIA) has been widely used because it is a non-intrusive technique and does not disturb the flow field in the reactor. Additionally, the DIA technique can intuitively and accurately get the information of gas holdup, bubble shape and size distribution. However, there will be more than 40% of the bubbles overlapping each other in the image when the gas holdup exceeds 1%, and the existing DIA technique cannot recognize the overlapping bubbles precisely. This is the reason why limited experimental study on the drag coefficient of bubble swarm is available.
In view of the problems aforementioned, we first develop a method for efficiently recognizing elliptical overlapping bubble swarms, which was then used in the experimental studies on the initial bubble diameter and the drag coefficient of bubble swarm. The contents and achievements of this paper are as follows:
(1) In response to the problem that the overlapping bubbles cannot be effectively identified by the existing DIA technique, an efficient, reliable, non-parametric and automated analytical method was established in this work. Firstly, the critical points of the ellipses are obtained by deleting the redundant quasi-collinear points; then the connecting points of overlapping bubbles are obtained by using a novel vector rotation method; finally, the various segments of overlapping bubbles are classified and merged according to the combined principle of the average distance derivation and the globle minimum deviation. In this work, the method is successfully applied to analyze the computer-generated synthetic images and a real industrial bubble image. The results show that the method developed in this study is reliable, robust, and universal.
(2) An experimental system was set up to investigate the influence of variable parameters on the initial bubble diameter. The initial bubbles, which were generated through several needles, were captured by a high-speed camera. The initial bubble diameter could be obtained by the image processing method established in chapter 2. The effect of the gas hole diameter on the initial bubble diameter was studied by using four types of needles with different inner diameters. In addition, the effect of the liquid viscosity on the initial bubble diameter was investigated by using four glycerol aqueous solutions with different concentrations. Moreover, the effect of the liquid surface tension on the initial bubble diameter was also studied by using four SDBS aqueous solutions with different concentrations. Finally, a model for the prediction of the initial bubble diameter was derived by fitting all the experimental data. Comparison between the predictions and experimental results indicates that the model has a wide application range and high accuracy.
(3) For the mesoscale drag coefficient of bubble swarm, the rising behavior of bubble swarm in turbulent water is captured by a high-speed camera. The Sauter diameter, local gas holdup and the velocity of bubble swarm are obtained by the image processing method established in Chapter 2. Subsequently, the terminal slip velocity of bubble swarm is obtained and compared with that of the single bubble.中
The flaky Cd film on Cu plate substrate: An active and efficient electrode for electrochemical reduction of CO2 to formate
No full textEfficient electrochemical reduction of CO2 to formate was studied on a Cu/Cd composite electrode in 0.5 M KHCO3 aqueous solution, which was prepared by vacuum evaporation coating Cd film on the Cu plate substrate. The results showed that a novel flaky Cd film was deposited on the Cu plate substrate successfully. The performance of formate production on the Cu/Cd composite electrode was related to the electrolysis potential and the thickness of Cd film. The electrocatalytic activity of Cu/Cd composite electrode toward CO2 reduction was enhanced in comparison with pure Cu plate and Graphite-Paper/Cd (G-P/Cd) electrodes. The maximum Faradaic efficiency of 76.2% for formate production has been obtained with high stability and current densities of 10.6 mA cm(-2) at -1.8 V (vs. Ag/AgCl) on the composite electrode with depositing a similar to 300 nm thick Cd film on the Cu substrate
Graphene boosted Cu2GeS3 for advanced lithium-ion batteries
No full textGermanium-based materials as the anode for lithium ion batteries (LIBs) have been investigated extensively because of their high theoretical capacities. However, ternary germanium-based sulfides as the anode material for LIBs have been rarely investigated until now. In this work, we successfully synthesized a novel ternary Cu2GeS3 (CGS) incorporated with reduced graphene oxide (CGS@RGO) and measured their lithium storage performance. As a result, the binder-free CGS@RGO anodes deliver excellent stable cycling properties and high rate capabilities. These improved properties can be ascribed to the introduction of RGO, which acts as a buffer to accommodate the large volume change and maintain the structural integrity of the electrode. More importantly, this work opens an opportunity to develop novel Ge-based anodes for high performance LIBs
Selective water-based oxychlorination of phenol with hydrogen peroxide catalyzed by manganous sulfate
No full textAn efficient method for the selective oxychlorination of phenol to 2,4-dichlorophenol catalyzed by manganous(II) sulfate is developed using hydrogen chloride as a chlorinating source, hydrogen peroxide as an oxidant and water as a solvent. The catalyst has high activity and selectivity under mild conditions. The products are automatically isolated from aqueous solution, which also contains the catalyst at the end of the reaction, and hence product separation and catalyst recycling are both simple in this system. The performance of manganous(II) sulfate with the oxidative chlorinating system HCl/H2O2 indicates that this is a promising synthetic method for the manufacture of various 2,4-dichlorophenol derivatives
Enhanced methane hydrate formation with SDS-coated Fe3O4 nanoparticles as promoters
No full textNano metal fluids have been applied to promote the formation of natural gas hydrates. In this work, the sol of SDS@Fe3O4 (named as SDS@Fe3O4) were prepared and used as promoters in methane hydrate formation. Compared with SDS, SDS@Fe3O4 produced much better promotion and the main superiority was that SDS@Fe3O4 could significantly shorten the induction periods of hydrate formation. When SDS was used, the induction periods lasted about 40-60 min, while when SDS@Fe3O4 was used at the same concentrations, hydrates nucleated within 10 min, especially, even no obvious induction periods were observed when SDS@Fe3O4 was used in some experiments. Particle size showed significant influences on the promotion of SDS@Fe3O4 to methane hydrate formation and smaller particles resulted in rapider hydrate formation. In addition, SDS@Fe3O4 showed excellent repeatability during the hydrate formation-dissociation cycles. (C) 2017 Elsevier B.V. All rights reserved
Hansen Solubility Parameters of Coal Tar-Derived Typical PAHs Using Turbidimetric Titration and an Extended Hansen Approach
No full textThe advantage of selectivity for coal tar extraction can be obtained by using the solubility parameter of Hansen theory as a guide. However, most of the Hansen solubility parameters (dispersion contributions, (delta)(d); polarity contributions, (delta)(p); hydrogen bonding contributions, (delta)(hb)) of coal tar components (e.g., polycyclic aromatic hydrocarbons, PAHs) were inadequate. This study estimated the Hansen solubility parameters of naphthalene, acenaphthene, anthracene, phenanthrene, pyrene, and fluoranthene from coal tar by applying a new approach regulated by turbidimetric titration and a calculating program based on the method of exhaustion. The extended Hansen approach was used to verify the new approach and evaluate the solubility of the six PAH components in different solvents. The results show that the new method can clearly identify the differences in Hansen solubility parameters caused by various combinations of benzene rings among some isomers (e.g., anthracene and phenanthrene). Among the six PAH compounds, high relativity between their Hansen solubility parameters and solubility data was revealed, indicating an excellent reliability of the new method. An extended Hansen approach is appropriate for the estimation of solubility for the six PAHs with acceptable deviations. Moreover, the relationship between the Hansen solubility sphere and the extended Hansen approach was successfully presented by regression analysis
Aquichromatium aeriopus gen. nov., sp nov., A Non-phototrophic Aerobic Chemoheterotrophic Bacterium, and Proposal of Aquichromatiaceae fam. nov in the Order Chromatiales
No full textA gram-staining negative, non-motile, aerobic chemoheterotrophic, ovoid or short rod-shaped bacterium, designated as J89(T), was isolated from a seawater sample collected from the coast of Yellow Sea in Qingdao, China. The strain grew at salinities of 1.0-6.0% (w/v) NaCl (optimum, 3.0%). Growth occurred at pH 6.0-9.0 (optimum, pH 7.0) and at 10-35 degrees C (optimum, 25-30 degrees C). The genomic DNA G+C content was determined to be 59.3 mol%. Q-8 was detected as the respiratory quinone. The major fatty acids (>10%) were summed feature 3 (C-16:1 omega 7c and/or C-16:1 omega 6c), summed feature 8 (C-18:1 omega 7c and/or C-18:1 omega 6c), and C-16:0. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, two unidentified phospholipids, and an unidentified polar lipid. Comparison of the 16S rRNA gene sequence indicated that the strain was most closely related (<91%) to members of the order Chromatiales in the class Gammaproteobacteria. Phylogenetic analyses showed that this strain represented a distinct phylogenetic lineage in the order Chromatiales and could not be assigned to any of the defined families in the order. On the basis of low sequence similarities and differential characteristics of strain J89(T) from the genera of neighboring families, the strain is proposed to be a representative of a novel genus Aquichromatium gen. nov. A new family Aquichromatiaceae with the type genus Aquichromatium is proposed. Strain J89(T) (=MCCC 1K03281T=CMRC C2017206T) is the type strain of the type species Aquichromatium aeriopus sp. nov