| 1. |
- Can, Quan, et al.
(författare)
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Carotenoids particle formation by supercritical fluid technologies
- 2009
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Ingår i: Chinese Journal of Chemical Engineering. - 1004-9541 .- 2210-321X. ; 17:2, s. 344-349
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Tidskriftsartikel (refereegranskat)abstract
- Based on the solubility in supercritical CO2, two strategies in which CO2 plays different roles are used to make quercetine and astaxanthin particles by supercritical fluid technologies. The experimental results showed that micronized quercetine particles with mean particle size of 1.0-1.5 μm can be made via solution enhanced dispersion by supercritical fluids (SEDS) process, in which CO2 worked as turbulent anti-solvent; while for astaxanthin, micronized particles with mean particle size of 0.3-0.8 μm were also made successfully by rapid expansion supercritical solution (RESS) process.
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| 2. |
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| 3. |
- Ji, Yuanhui, et al.
(författare)
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Progress in the study on the phase equilibria of the CO2-H2O and CO2-H2O-NaCl systems
- 2007
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Ingår i: Chinese Journal of Chemical Engineering. - 1004-9541 .- 2210-321X. ; 15:3, s. 439-448
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Tidskriftsartikel (refereegranskat)abstract
- To study the feasibility of CO2 geological sequestration, it is needed to understand the complicated multiple-phase equilibrium and the densities of aqueous solution with CO2 and multi-ions under wide geological conditions (273.15-473.15 K, 0-60 MPa), which are also essential for designing separation equipments in chemical or oil-related industries. For this purpose, studies on the relevant phase equilibria and densities are reviewed and analyzed and the method to improve or modify the existing model is suggested in order to obtain more reliable predictions in a wide temperature and pressure range. Besides, three different models (the electrolyte non random two-liquid (ELECNRTL), the electrolyte NRTL combining with Helgeson model (ENRTL-HG), Pitzer activity coefficient model combining with Helgeson model (PITZ-HG)) are used to calculate the vapor-liquid phase equilibrium of CO2-H2O and CO2-H2O-NaCl systems. For CO2-H2O system, the calculation results agree with the experimental data very well at low and medium pressure (0-20 MPa), but there are great discrepancies above 20 MPa. For the water content at 473.15 K, the calculated results agree with the experimental data quite well. For the CO2-H2O-NaCl system, the PITZ-HG model show better results than ELECNRTL and ENRTL-HG models at the NaCl concentration of 0.52 mol•L-1. Bur for the NaCl concentration of 3.997 mol•L-1, using the ELECNRTL and ENRTL-HG models gives better results than using the PITZ-HG model. It is shown that available experimental data and the thermodynamic calculations can satisfy the needs of the calculation of the sequestration capacity in the temperature and pressure range for disposal of CO2 in deep saline aquifers. More experimental data and more accurate thermodynamic calculations are needed in high temperature and pressure ranges (above 398.15 K and 31.5 MPa).
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| 4. |
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| 5. |
- Dai, Zhengxing, et al.
(författare)
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Prediction and verification of heat capacities for pure ionic liquids
- 2021
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Ingår i: Chinese Journal of Chemical Engineering. - : Elsevier. - 1004-9541 .- 2210-321X. ; 31, s. 169-176
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Tidskriftsartikel (refereegranskat)abstract
- The heat capacity of ionic liquids is an important physical property, and experimental measuring is usually used as a common method to obtain them. Owing to the huge number of ionic liquids that can be potentially synthesized, it is desirable to acquire theoretical predictions. In this work, the Conductor-like Screening Model for Real Solvents (COSMO-RS) was used to predict the heat capacity of pure ionic liquids, and an intensive literature survey was conducted for providing a database to verify the prediction of COSMO-RS. The survey shows that the heat capacity is available for 117 ionic liquids at temperatures ranging 77.66-520 K since 2004, and the 4025 data points in total with the values from 76.37 to 1484 J·mol-1·K-1 have been reported. The prediction of heat capacity with COSMO-RS can only be conducted at two temperatures (298 and 323 K). The comparison with the experimental data proves the prediction reliability of COSMO-RS, and the average relative deviation (ARD) is 8.54%. Based on the predictions at two temperatures, a linear equation was obtained for each ionic liquid, and the heat capacities at other temperatures were then estimated via interpolation and extrapolation. The acquired heat capacities at other temperatures were then compared with the experimental data, and the ARD is only 9.50%. This evidences that the heat capacity of a pure ionic liquid follows a linear equation within the temperature range of study, and COSMO-RS can be used to predict the heat capacity of ionic liquids reliably.
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| 6. |
- Daniel, Geoffrey, et al.
(författare)
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Inocula selection in microbial fuel cells based on anodic biofilm abundance of Geobacter sulfurreducens
- 2016
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Ingår i: Chinese Journal of Chemical Engineering. - : Elsevier BV. - 1004-9541. ; 24, s. 379-387
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Tidskriftsartikel (refereegranskat)abstract
- Microbial fuel cells (MFCs) rely on microbial conversion of organic substrates to electricity. The optimal performance depends on the establishment of a microbial community rich in electrogenic bacteria. Usually this microbial community is established from inoculation of the MFC anode chamber with naturally occurring mixed inocula. In this study, the electrochemical performance of MFCs and microbial community evolution were evaluated for three inocula including domestic wastewater (DW), lake sediment (LS) and biogas sludge (BS) with varying substrate loading (L-sub) and external resistance (R-ext) on the MFC. The electrogenic bacterium Geobacter sulfurreducens was identified in all inocula and its abundance during MFC operation was positively linked to the MFC performance. The LS inoculated MFCs showed highest abundance (18%+/- 1%) of G. sulfurreducens, maximum current density [I-max = (690 +/- 30) mA.m(-2)] and coulombic efficiency (CE = 29% +/- 1%) with acetate as the substrate. I-max and CE increased to (1780 +/- 30) mA.m(-2) and 58% +/- 1%, respectively, after decreasing the R-ext from 1000 Omega to 200 Omega, which also correlated to a higher abundance of G. sulfurreducens (21% +/- 0.7%) on the MFC anodic biofilm. The data obtained contribute to understanding the microbial community response to L-sub and R-ext for optimizing electricity generation in MFCs. (c) 2015 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.
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| 7. |
- Fan, Tengteng, et al.
(författare)
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CO2/N2 separation using supported ionic liquid membranes with green and cost-effective [Choline][Pro]/PEG200 mixtures
- 2016
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Ingår i: Chinese Journal of Chemical Engineering. - : Elsevier BV. - 1004-9541 .- 2210-321X. ; 24:11, s. 1513-1521
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Tidskriftsartikel (refereegranskat)abstract
- The high price and toxicity of ionic liquids (ILs) have limited the design and application of supported ionic liquid membranes (SILMs) for CO2 separation in both academic and industrial fields. In this work, [Choline][Pro]/polyethylene glycol 200 (PEG200) mixtures were selected to prepare novel SILMs because of their green and cost-effective characterization, and the CO2/N2 separation with the prepared SILMs was investigated experimentally at temperatures from 308.15 to 343.15 K. The temperature effect on the permeability, solubility and diffusivity of CO2 was modeled with the Arrhenius equation. A competitive performance of the prepared SILMs was observed with high CO2 permeability ranged in 343.3-1798.6 barrer and high CO2/N2 selectivity from 7.9 to 34.8. It was also found that the CO2 permeability increased 3 times by decreasing the viscosity of liquids from 370 to 38 mPa·s. In addition, the inherent mechanism behind the significant permeability enhancement was revealed based on the diffusion-reaction theory, i.e. with the addition of PEG200, the overall resistance was substantially decreased and the SILMs process was switched from diffusion-control to reaction-control.
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| 8. |
- Gao, Qingwei, et al.
(författare)
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Effect of dimethyl carbonate on the behavior of water confined in carbon nanotube
- 2021
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Ingår i: Chinese Journal of Chemical Engineering. - : Elsevier. - 1004-9541 .- 2210-321X. ; 31, s. 177-185
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Tidskriftsartikel (refereegranskat)abstract
- The dehydration of water by dimethyl carbonate (DMC) is of great significance for its application in electrochemistry and oil industry. With the rapid development of nanomaterial, one-dimensional (e.g. carbon nanotube (CNT)) and two-dimensional (e.g. lamellar graphene) materials have been widely used for molecular sieving. In this work, the molecular behavior of dimethyl carbonate/water mixture confined in CNT with varying diameters was studied based on molecular dynamics simulation. Due to different van der Waals interactions for the components in the mixtures with the solid surface, DMC molecules are preferentially adsorbed on the inner surface of the pore wall and formed an adsorption layer. Comparing with the pure water molecules confined in CNT, the adsorption DMC layer shows notable effect on the local compositions and microstructures of water molecules under nanoconfinement, which may result in different water mobility. Our analysis shows that the surface-induced DMC molecules can destroy the hydrogen bonding network of water molecules and result in an uniform and dispersed distribution of water molecules in the tube. These clear molecular understandings can be useful in material design for membrane separation.
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| 9. |
- He, Hanbing, et al.
(författare)
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Kinetics for Preparation of K2Ti2O5 Using TiO2 Microparticles and Nanoparticles as Precursors
- 2014
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Ingår i: Chinese Journal of Chemical Engineering. - : Elsevier BV. - 1004-9541 .- 2210-321X. ; 22:10, s. 1105-1110
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Tidskriftsartikel (refereegranskat)abstract
- The formation mechanism of K2Ti2O5 was investigated with TiO2 microparticles and nanoparticles as precursors by thermogravimetric (TG) technique. A method of direct multivariate non-linear regression was applied for simultaneous calculation of solid-state reaction kinetic parameters from TG curves. TG results show more regular decrease from initial reaction temperature with TiO2 nanoparticles as raw material compared with TiO2 microparticles, while mass losses finish at similar temperatures under the experimental conditions. From the mechanism and kinetic parameters, the reactions with the two materials are complex consecutive processes, and reaction rate constants increase with temperature and decrease with conversion. The reaction proceedings could be significantly hindered when the diffusion process of reactant species becomes rate-limiting in the later stage of reaction process. The reaction active sites on initial TiO2 particles and formation of product layers may be responsible to the changes of reaction rate constant. The calculated results are in good agreement with experimental ones.
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| 10. |
- Huang, Xianzhu, et al.
(författare)
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Flow-resistance analysis of nano-confined fluids inspired from liquid nano-lubrication: A review
- 2017
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Ingår i: Chinese Journal of Chemical Engineering. - : Elsevier. - 1004-9541 .- 2210-321X. ; 25:11, s. 1552-1562
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Tidskriftsartikel (refereegranskat)abstract
- How to reduce flow resistance of nano-confined fluids to achieve a high flux is a new challenge for modern chemical engineering applications, such as membrane separation and nanofluidic devices. Traditional models are inapplicable to explain the significant differences in the flow resistance of different liquid–solid systems. On the other hand, friction reduction in liquid nano-lubrication has received considerable attention during the past decades. Both fields are exposed to a common scientific issue regarding friction reduction during liquid–solid relative motion at nanoscale. A promising approach to control the flow resistance of nano-confined fluids is to reference the factors affecting liquid nano-lubrication. In this review, two concepts of the friction coefficient derived from fluid flow and tribology were discussed to reveal their intrinsic relations. Recent progress on low or ultra-low friction coefficients in liquid nano-lubrication was summarized based on two situations. Finally, a new strategy was introduced to study the friction coefficient based on analyzing the intermolecular interactions through an atomic force microscope (AFM), which is a cutting-point to build a new model to study flow-resistance at nanoscale.
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