LANGMUIR
·
2016
·
IF 3.993
Yunlei Shi,Dazhen Xiong,Huiyong Wang,Yang Zhao,Jianji Wang
The creation of CO2-responsive materials that undergo structural transition between micelle and vesicle is of great importance from both theoretical and practical points of view. In this work, we have developed a series of CO2-responsive single-tailed amphiphilic ionic liquids (ILs) composed of N-alkyl-N-methyldiethanolamine cation [CnMDEA]+ (n = 8, 10, 12, 14, 16, 18) and 2-pyrrolidinone [2-Pyr]− anion. The aggregation behavior and self-assembly structures of the ILs in aqueous solution have been investigated by conductivity, surface tension, dynamic light scattering, cryogenic transmission electron microscopy, small-angle X-ray scattering, and nuclear magnetic resonance spectroscopy. For the first time, CO2 driven reversible switching of self-assembly between spherical micelle and unilamellar vesicle is found for [CnMDEA][2-Pyr] (n = 16, 18) in aqueous solutions at 20 °C and atmospheric pressure. It is shown that the mechanism behind the reversible micelle to vesicle transition involves the formation of carbamate anion from the reaction between [2-Pyr]− and CO2.
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PubMed
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2016
·
IF 1.835
Yangyang Bian,Shufeng Shen,Yue Zhao,Ya-nan Yang
Aqueous amino acid salt (AAS) solutions could be attractive absorbents for CO2 removal from flue gases. Density, viscosity, and solubility of N2O in aqueous potassium salts of lysine, histidine, and arginine were measured over the temperature range from (293 to 353) K and molality concentration range from (0.26 to 3.6) mol·kg–1. Experimental results were correlated well with empirical correlations. The ion specific parameters (hAA–), based on the Weisenberger and Schumpe model, were fitted using the solubility data of N2O in the aforementioned AAS systems, valid up to 328 K. The models using temperature dependence of hAA– predict well within 2.5% AAD. The physical solubility of CO2 in the aqueous AAS solutions was also estimated.
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高影响因子
AICHE JOURNAL
·
2016
·Vol. 63
·期 1
·257-265
·
IF 2.98
Haizhou Lin,Qingang Xiong,Yuan Zhao,Jingping Chen,Shurong Wang
In this work, a green reaction system of CO 2 -water-isopropanol was developed for 5-hydroxymethylfurfural (HMF) production. The conversion of fructose in a CO 2 -water system was first investigated, and the results showed this system could promote the formation of HMF compared to a pure water system. Then, isopropanol was introduced into the CO 2 -water system and the HMF formation became better because the solvent effect of isopropanol increased the tautomeric composition of fructofuranose, which was easy to form HMF. The existence of isopropanol was found to greatly suppress secondary reactions where HMF was converted to levulinic acid and insoluble humin. Meanwhile, the effects of reaction parameters on the conversion of fructose to HMF in the CO 2 -water-isopropanol system were analyzed, and a high HMF yield of 67.14% was obtained. Finally, to further illustrate the merits of CO 2 -water-isopropanol system, productions of HMF from other carbohydrates were tested and satisfactory yields were achieved. © 2016 American Institute of Chemical Engineers AIChE J , 63: 257–265, 2017
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高影响因子
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
·
2016
·Vol. 81
·期 3
·844-849
·
IF 1.473
Guo Xingzhong,Ding Li,Ren Jing,Yang Hui
Abstract Nanocrystalline lithium zirconate (Li 2 ZrO 3 ) was successfully prepared by an epoxide-mediated sol–gel process. The compositions and morphologies of Li 2 ZrO 3 were characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy, and the CO 2 capture-regeneration properties of Li 2 ZrO 3 were investigated by thermogravimetric analysis. The introduction of propylene oxide as an acid scavenger increases the pH value of the system to mediate the sol–gel transition. The as-dried xerogel is amorphous and the nano-sized Li 2 ZrO 3 crystallites with a tetragonal phase precipitate after heat-treatment at 650 °C. The nanocrystalline tetragonal-Li 2 ZrO 3 exhibits a better CO 2 capture properties, possessing an adsorption capacity as high as 21 wt.% at 550 °C and a good stability confirmed by CO 2 capture-regeneration cycles. Graphical Abstract Nanocrystalline Li 2 ZrO 3 possessing good CO 2 capture properties was successfully prepared by an epoxide-mediated sol–gel process.
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高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2017
·
IF 2.323
Yangyang Bian,Yue Zhao,Shufeng Shen
Potassium prolinate + water + ethanol (ProK/W/Eth) solution has potential use as a liquid-to-solid phase-changing absorbent for energy-efficient CO2 capture process. In this study, the equilibrium solubility of CO2 in ProK/W/Eth solutions was measured in a stirred equilibrium cell at a temperature range from 293 to 343 K and CO2 partial pressures up to 200 kPa. Density and viscosity were also measured at temperatures from 293 to 333 K and ProK molality up to 6.09 mol·kg–1 ethanol. Moreover, the CO2 loading and cyclic capacity were compared with aqueous monoethanolamine (MEA) and aqueous ProK solution. The solubility data were well-represented using a Soft model with AAD within 8.0%. The data of density and viscosity were also correlated with empirical models. The predicted results matched well the experimental data with AAD within 0.37% for density and 1.38% for viscosity.
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高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2017
·
IF 9.446
Ying Wang,Lina Zhang,Xiaoyan Zhang,Zizhong Zhang,Yuecong Tong,Fuying Li,Jeffrey C.-S. Wu,Xuxu Wang
A novel hollow spherical 3D structure of β-SiC with an open mouth was successfully fabricated by an environmentally friendly approach starting from ethylsilicate interaction with the P123 and glucose. The proposed growth mechanism of SiC hollow spheres was revealed step by step with SEM and XRD. When the as-prepared SiC was applied for the photocatalytic reduction of CO 2 with pure water, it was found to be highly active for the conversion CO 2 into mainly CH 4 hydrocarbon products due to its unique electronic structure, hollow morphology and high BET surface area. Moreover, the photocatalytic activity of the hollow spherical SiC can be greatly improved by loading Pt cocatalyst. The optimal 2.0 wt% Pt loading led to a stable CH 4 evolution as high as 16.8 μmol/g/h (or 376.4 μl/g/h) with the simulated solar light irradiation, which is higher than that of many reported metal oxides (Pt/TiO 2 , CdS/WO 3 , Zn 2 GeO 4 , CeO 2 and g-C 3 N 4 /NaNbO 3 et al.) under similar experimental conditions. This work provides a new strategy for the architecture of thermally and chemically stable non-metallic carbide with unique hollow spherical structure to be a potential nonmetallic photocatalyst for CO 2 reduction into CH 4 .
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高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2017
·Vol. 100
·期 7
·2832-2839
·
IF 2.841
Wenhao Xia,Biyi Xu,Huanan Duan,Xiaoyi Tang,Yiping Guo,Hongmei Kang,Hua Li,Hezhou Liu
Li 7 La 3 Zr 2 O 12 (LLZO) has been reported to react in humid air to form Li 2 CO 3 on the surface, which decreases ionic conductivity. To study the reaction mechanism, 0.5-mol Ta-doped LLZO (0.5Ta–LLZO) pellets are exposed in dry (humidity ~5%) and humid air (humidity ~80%) for 6 weeks, respectively. After exposure in humid air, the formation of Li 2 CO 3 on the pellet surface is confirmed experimentally and the room-temperature ionic conductivity is found to drop from 6.45×10 −4 S cm −1 to 3.61×10 −4 S cm −1 . Whereas for the 0.5Ta–LLZO samples exposed in dry air, the amount of formed Li 2 CO 3 is much less and the ionic conductivity barely decreases. To further clarify the reaction mechanism of 0.5Ta–LLZO pellets with moisture, we decouple the reactions between 0.5Ta–LLZO with water and CO 2 by immersing 0.5Ta–LLZO pellets in deionized water for 1 week and then exposing them to ambient air for another week. After immersion in deionized water, Li + /H + exchange occurs and LiOH H 2 O forms on the surface, which is a necessary intermediate step for the Li 2 CO 3 formation. Based on these observations, a reaction model is proposed and discussed.
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高影响因子
ENERGY & FUELS
·
2017
·
IF 3.091
Kuan Huang,Jia-Yin Zhang,Xing-Bang Hu,You-Ting Wu
The development of ionic liquid-based absorbents for selective separation of H2S from CO2 is of interest to the natural gas industry. In this work, a series of tertiary-amine functionalized protic ionic liquids (TA-PILs) were synthesized by neutralizing one of the tertiary amine groups in diamine compounds with acetic acid, leaving the other tertiary amine group as the functional site for selective absorption of H2S. To overcome the high viscosity of pure ionic liquids, TA-PILs were dissolved in water to give mixed absorbents. The effects of TA-PIL species, TA-PIL concentration, and experimental temperature on the solubilities of H2S and CO2, and absorption kinetics of H2S and CO2 in aqueous TA-PILs were investigated systematically. The reaction equilibrium constants and absorption enthalpy of H2S and CO2 in aqueous TA-PILs were also calculated by correlating the solubility data with a reaction equilibrium thermodynamic model. Results demonstrated that aqueous TA-PILs have high absorption capacities for H2S. Although the equilibrium selectivities of H2S/CO2 in aqueous TA-PILs are minimized, they still display significant kinetic selectivities for the two gases. More importantly, the TA-PILs designed are featured with low cost and facile synthesis, making them more attractive than other functionalized ionic liquids reported in the literature for application in selective separation of H2S from CO2.
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高影响因子
CELLULOSE
·
2017
·Vol. 25
·期 1
·205-216
·
IF 3.417
Xu Qinqin,Song Longchu,Zhang Lihua,Hu Gang,Chen Qin,Liu Enhui,Liu Yu,Zheng Qiang,Xie Haibo,Li Nanwen
The reversible reaction of the hydroxyl groups in cellulose with CO 2 in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) results in a rapid and effective derivative dissolution of cellulose in DMSO, by which a series of cellulose acetate propionate (CAP) and cellulose acetate butyrate (CAB) with various degrees of substitution (DS) were synthesized controllably without adding external catalysts. Wherein DBU not only achieves the dissolution of cellulose, but also acts as an efficient organocatalyst for the subsequent cellulose derivatization. The DS of CAB and CAP can be tuned by changing the feed molar ratio of propionic (butyric) anhydride/acetic anhydride and the reaction temperature. The structural and thermal properties of the products were characterized by several analytical techniques including NMR, FT-IR, and TGA. The CO 2 /DBU/DMSO dissolution system provides a new platform for controllable synthesis of mixed cellulose esters with high efficiency under mild conditions.
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高影响因子
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
·
2017
·Vol. 84
·期 3
·422-431
·
IF 1.575
Kong Yong,Zhang Jiayue,Shen Xiaodong
Abstract Amine hybrid titania/silsesquioxane composite aerogel (AHTSA) was prepared by an one-pot sol–gel process without any catalyst. The sol-gel reaction mechanism of AHTSA was proposed. The use of 3-aminopropyltriethoxysilane (APTES) plays as an “internal catalyst” and promotes the formation of gel during sol–gel process. The morphology, microstructure, pore structure and CO 2 capture performances of AHTSA were investigated. AHTSA exhibits microstructure of the typical silica aerogels with colloidal structure. Moreover, AHTSA has a large number of macropores which favor the CO 2 adsorption. Thermogravimetric analysis reveals that AHTSA has a high CO 2 /N 2 selectivity in CO 2 /N 2 mixture gas. CO 2 adsorption capacity with dry and humid 1 vol% CO 2 is as high as 4.19 and 5.04 mmol/g, respectively. Correspondingly, amine efficiency under dry and humid conditions is 0.37 and 0.44, respectively. AHTSA has very short adsorption halftime below 4 min, and its CO 2 adsorption capacity do not show obvious attenuation after 30 adsorption-regeneration cycles, indicating AHTSA is a dynamic and regenerable sorbent. Graphical abstract
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高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2017
·Vol. 135
·期 5
·45765
·
IF 1.86
Leiqing Hu,Jun Cheng,Yannan Li,Jianzhong Liu,Junhu Zhou,Kefa Cen
To optimize the CO 2 permeation and CO 2 /H 2 separation performance of hollow fiber-supported polydimethylsiloxane (PDMS) membranes, the effect of the viscosity of the PDMS coating solution on surface morphologies, thickness of PDMS layer, and solution intrusion into surface pores of hollow fiber supports was investigated. Increases in both stirring time and standing time could increase the viscosity of the PDMS solution. The PDMS layer thickness increased when the coating solution viscosity increased, whereas the surface roughness of the PDMS layer markedly decreased and then slightly changed. Moreover, when the stirring time of the PDMS coating solution was 9 min and the standing time was increased from 2 min to 25 min, the CO 2 permeance first decreased, then increased to ∼2250 GPU probably due to the decreased intrusion depth, and finally decreased because of the substantially increased thickness of the PDMS layer. However, the CO 2 /H 2 selectivity increased to 3.4 with an increase in coating solution viscosity. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 45765.
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高影响因子
APPLIED ENERGY
·
2017
·
IF 7.182
Tao Wang,Wei Yu,Yann Le Moullec,Fei Liu,Yili Xiong,Hui He,Jiahui Lu,Emily Hsu,Mengxiang Fang,Zhongyang Luo
Using an inert, immiscible organic component as the purging gas is an innovative technology in the CO 2 stripping process. It allows stripping at a lower temperature and overcomes the inherent problem of high energy consumption in steam-based CO 2 stripping processes. This work focused on developing a novel, direct non-aqueous gas stripping process and exploiting its potential for energy saving through experiments. An elaborate pre-screening of carrier gases was conducted through hydrocarbon, alcohols, aldehydes, ketones, and their isomers, etc. Pentane, hexane, and cyclohexane were selected as the carrier candidates for their good immiscibility with water/amine, low vaporization energy, mild condensation conditions, and low toxicity. The effects of carrier gas category, carrier gas flow rate , and rich solvent feeding temperature on the stripping performance were investigated. Pentane was found to be the superior carrier gas due to its low heat of vaporization, high regeneration rate, and low energy requirement. A unique phenomenon of water evaporation from the solvent was discovered in the organic gas stripping process, providing a promising approach to break the gas-liquid interface for enhanced diffusion kinetics . The feasibility of low temperature CO 2 stripping was analyzed by varying the rich solvent feeding temperature (70–100 °C). With pentane as the stripping gas, it was interesting to find an optimum rich-feed temperature lower than 90 °C, indicating great potential for a reduction in the overall energy requirement. Under the optimal conditions, the energy consumption during CO 2 regeneration, using pentane as the carrier gas, was 2.38 GJ/t CO 2 , 38.8% lower than that of the conventional stripping process. Furthermore, parasitic issues, such as water loss and solvent loss, were discussed. An improved direct non-aqueous gas stripping process with two-stage compression was used to tackle the carrier gas recovery problem. The simulation results show that more than 98% of the carrier gas can be recovered through preliminary separation approaches.
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高影响因子
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