Journal of CO2 Utilization
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2018
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IF 5.503
Shuai Wang,Dongfang Liu,Jihe Zhao,Xiaojiang Li,Daixue Xu,Yuan Gu,Hongsheng Lu
In this paper, a practical and environmental friendly method was successfully developed by using CO 2 -Triggered switchable water additive to reversibly emulsify and demulsify diesel, aims to provide guidance for recovering oil substances in waste oil-based drill cuttings. In this new method, N, N, N', N'-tetramethyl-1, 6-hexanediamine(TMHDA) was a switchable water additive whose aqueous solution can switch the ionic strength by addition and removal CO 2 . Then it can be used to separate diesel through reversibly emulsification and demulsification. The nuclear magnetic resonance hydrogen spectrum ( 1 H NMR) and conductivity demonstrated TMHDA have better switching performance. Then, diesel/naphthenic acid mixtures have been used for modeling the application of recovering oil substances in waste oil-based drill cuttings. When the acid value≥1.76mgKOH/g (the oil and TMHDA solution were 5 mL), diesel can be emulsified. The material produced by TMHDA and naphthenic acid have a strong surface activity so that the oil/water interfacial tension was less than 0.1 mN·m −1 . The demulsification performance was illustrated by change of the ionic strength, pH and the content of oil in the aqueous phase during the breaking process. Brief provided two optimization strategies of recycling of TMHDA additive. Finally, the possible mechanism of the new method was discussed.
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NEW JOURNAL OF CHEMISTRY
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2018
·Vol. 42
·期 12
·10016-10023
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IF 3.201
Fenglei Liu,Yizhu Kuang,Shuoyu Wang,Shuixia Chen,Wenhao Fu
A molecularly imprinted solid amine adsorbent was successfully synthesized via a facile crosslinking reaction based on polyethyleneimine (PEI) as the skeleton, glycol diglycidyl ether (GDGE) as cross-linker and CO2 molecules as template. FT-IR, FT-Raman, 13C NMR spectroscopy and TGA were employed to characterize the chemical structure and thermal stability of the solid amine adsorbent. The experimental results showed that the amine content of the molecularly imprinted polymer polyethyleneimine spheres (MIP-PEIs) could reach as high as 11.41 mmol g−1, and the material exhibited a lower CO2 diffusion resistance during CO2 adsorption. The CO2 adsorption capacity of MIP-PEIs (6.58 mmol g−1) was higher than that of non-imprinted NIP-PEIs (5.87 mmol g−1). The presence of water markedly increased the CO2 adsorption capacity by promoting the chemical adsorption of CO2 on the solid amine adsorbent. The pseudo-second order model could accurately describe the CO2 adsorption process on the MIP-PEIs from the beginning to the end. Moreover, this adsorbent also exhibited good regeneration performance, retaining almost the same adsorption amount of CO2 as the fresh material after ten adsorption–desorption cycles.
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ENERGY & FUELS
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2018
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IF 3.024
Yuning Meng,Xindian Wang,Feng Zhang,Zhibing Zhang,Youting Wu
Dual amino functionalized ionic liquid tetramethylammonium lysinate ([N1111][Lys]) was synthesized and mixed with 2-[2-(dimethylamino)ethoxy]ethanol (DMEE) to obtain a series of nonwater absorbents for CO2 capture. The density and viscosity of the IL hybrids were measured. Using dual-vessel absorption system, CO2 absorption capacity and rate were investigated over a wide range of IL mass fractions (5–100%) to evaluate the influence of DMEE content, and 20% was chosen for further studies including influences of temperature and regeneration performances. Mass transfer coefficients with constant absorption area were calculated from apparent absorption rate constant. Fourier transform infrared (FT-IR) and 13C NMR spectra were applied to indicate the absorption process and mechanism. This new nonwater mixed system was proved to have high absorption capacities and prominent regeneration efficiency under mild conditions (80 °C).
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GREEN CHEMISTRY
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2018
·Vol. 20
·期 18
·4236-4244
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IF 8.586
Xiaoyan Pei,Dazhen Xiong,Yuanchao Pei,Huiyong Wang,Jianji Wang
Phase separation of microemulsions plays an important role in many applications such as oil recovery, nanomaterials synthesis, and chemical reactions. However, reversible switching from ionic liquid-based microemulsions to complete oil–water phase separation has not been reported so far. In this work, we developed a novel class of stimuli-responsive microemulsions composed of CO2-responsive ionic liquids, n-pentanol and water. The microstructures and phase behavior of the microemulsion systems before and after the bubbling of CO2 were investigated by electrical conductivity, dynamic light scattering, small-angle X-ray scattering, cryogenic transmission electron microscopy, and optical microscopy. It was found that these microemulsions could be reversibly switched from W/O monophase to complete oil–water phase separation upon alternate bubbling and removal of CO2 at atmospheric pressure. Furthermore, 13C NMR spectroscopy was used to understand the CO2-driven reversible phase separation of the microemulsions. The results suggest that the mechanism behind the reversible phase separation involved the reversible formation of bicarbonate and carbamate from the reaction between CO2 and the anions of the ionic liquids in the presence of water, which resulted in the increase of ionic strength (or vice versa) in the mixture. Using the microemulsions as microreactors, the phase separation protocol was applied in the Knoevenagel reaction for an efficient coupling of a chemical reaction, product separation, and recycling of the microemulsions.
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JOURNAL OF MEMBRANE SCIENCE
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2018
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IF 6.578
Jinhui Zhang,Qingping Xin,Xu Li,Mingya Yun,Rui Xu,Shaofei Wang,Yifan Li,Ligang Lin,Xiaoli Ding,Hui Ye,Yuzhong Zhang
Mixed matrix membranes (MMMs) are challenged by the non-ideal interfacial morphologies that leads to the weakened gas separation performances and mechanical strength . Filler surface modification with organosilanes is an effective approach to build the linkage between polymer and the fillers. In this study, we fabricated MMMs by introducing aminosilane functionalized graphene oxide (f-GO) nanosheets into Pebax ® 1657 matrix. The introduction of f-GO decreased the crystallinity and increased chain mobility of Pebax matrix. Benefiting from the improved filler dispersion, semi-interpenetrated Pebax chains in the Si-O-Si network at the interface, and the high intrinsic mechanical strength of GO, the MMMs exhibit a 1.7-times higher Young's modulus and 1.1-times higher break strength. The amino groups on GO help to construct a facilitated transport pathway along the polymer-filler interface. With greatly improved CO 2 separation performances in dry state, the membranes exhibited even higher performances in humidified state. Particularly, Pebax/f-GO-0.9% membrane showed a high CO 2 permeability of 934.3 Barrer, and a CO 2 /CH 4 selectivity of 40.9, a CO 2 /N 2 selectivity of 71.1, surpassing the Robeson upper bound and quite promising for carbon capture.
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ENERGY
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2018
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IF 4.968
Pan Zhang,XiangFeng Tian,Dong Fu
A tray tower was designed to verify the absorption performance of CO 2 in 1-butyl-3-methylimidazolium glycinate ([Bmim][Gly]), 1-butyl-3-methylimidazolium lysinate ([Bmim][Lys]) and tetramethylammonium glycinate ([N 1111 ][Gly]) activated MDEA ( N -methyldiethanolamine) aqueous solutions. The simulated flue gas was composed of 15% (mole fraction) CO 2 and 85% N 2 and the experiments were performed at 313.2 K. To find a suitable absorbent composition, the mass fractions of MDEA and amino acid ionic liquids (AAILs) respectively ranged from 0.200 to 0.400 and 0.025 to 0.100. The removal efficiency of CO 2 ( η CO 2 ) and the overall volumetric mass transfer coefficient ( K G a v ) were determined. The effects of absorbent composition ( w ), absorbent flow rate ( L ), gas flow rate ( G ) and plate number ( N p ) on η CO 2 and K G a v were demonstrated. Our results showed that, when activated by AAILs, MDEA aqueous solution was able to absorb CO 2 in tray tower efficiently, and both η CO 2 and K G a v were significantly increased, e.g., in the case of w MDEA = 0.200, η CO 2 and K G a v were increased from 43.48% to 95.55% and from 0.0069 (kmol m −3 h −1 ·kPa −1 ) to 0.0350 (kmol m −3 h −1 ·kPa −1 ), respectively, when w [N1111][Gly] was changed from 0 to 0.100, indicating AAILs activated MDEA aqueous solution is of great potential for industrial application in CO 2 capture process.
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ENVIRONMENTAL SCIENCE & TECHNOLOGY
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2018
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IF 6.653
Lidong Wang,Yifeng Zhang,Rujie Wang,Qiangwei Li,Shihan Zhang,Meng Li,Jie Liu,Bo Chen
A novel phase splitter, namely, sulfolane, was proposed to advance the traditional monoethanolamine (MEA) absorption technology for CO2 capture by simultaneously promoting the absorption rate and lowering heat duty. The phase-splitting phenomenon was observed after the CO2 loading level had exceeded 0.73 mol CO2/L, thereby generating a CO2-rich MEA upper layer and a lower layer containing sulfolane. Sulfolane facilitated CO2 absorption because of its strong affinity with acid gases, which resulted in an absorption rate 2.7 times higher than that of the conventional MEA process. The process simulation using Aspen Plus indicated that the regeneration heat with the MEA/sulfolane mixture as a solvent substantially decreased to 2.67 GJ/t-CO2, which was 31% lower than that of the conventional MEA process (3.85 GJ/t-CO2). Moreover, the sensible heat and vaporization heat of MEA/sulfolane were markedly decreased by 62.4% and 47.9%, which could be ascribed to the decreased stripping volume and relatively high CO2 partial pressure caused by liquid–liquid phase separation. The proposed system is proved to be a promising candidate for the advancement of CO2 capture techniques with high CO2 absorption capacity, rapid absorption rate, and low-energy penalty.
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PubMed
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2018
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IF 11.698
Weiyi Chen,Bin Han,Chen Tian,Xueming Liu,Shujie Liang,Hong Deng,Zhang Lin
Reducing carbon dioxide (CO 2 ) to various value-added chemical products by photocatalysis could effectively alleviate the serious problems of global warming and energy shortages. Currently, most commonly prepared photocatalysts present poor performance under visible light irradiation. In this study, we adopted a facile, scalable and controllable approach to prepare ultrathin two-dimensional (2D) porous Co 3 O 4 catalysts (Co 3 O 4 -NS) by air calcining of the ultrathin metal-organic framework (MOFs) nanosheet templates to validly reduce CO 2 with a Ru-based photosensitizer under visible light irradiation. Benefitting from the structural nature of MOFs precursors, the calcined Co 3 O 4 -NS inherit the morphology of 2D and well-developed porosity, which support the transport of electrons, enhance the adsorption of CO 2 molecules, and render abundant catalytic sites for CO 2 activation. As a result, the CO generation rate is approximately 4.52 μmol·h −1 with selectivity of 70.1%, which is superior to the Co 3 O 4 bulk catalysts (Co 3 O 4 -BK). Additionally, density functional theory (DFT) calculations reveal that the model of Co 3 O 4 monolayer has stronger CO 2 adsorption energy than that of the Co 3 O 4 bulk, which is beneficial for the CO 2 -to-CO conversion. This MOF-engaged strategy provides new insight into the controlled synthesis of advanced ultrathin holey nanosheets to improve the efficiency of photocatalytic CO 2 reduction.
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RSC Advances
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2018
·Vol. 8
·期 63
·35989-35997
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IF 2.936
Halidan Maimaiti,Abuduheiremu Awati,Dedong Zhang,Gunisakezi Yisilamu,Bo Xu
To obtain high-efficiency, low-cost, environmentally friendly carbon-based photocatalytic material, we synthesized coal-based carbon dots with sp2 carbon structure and multilayer graphene lattice structure by the hydrogen peroxide (H2O2) oxidation method to strip nano-scale crystalline carbon in the coal structure and link with oxygen-containing groups such as the hydroxyl group. N, S co-doped aminated coal-based carbon nanoparticles (NH2-CNPs) were then obtained by thionyl chloride chlorination and ethylenediamine passivation. The physical properties and chemical structure of the synthesized NH2-CNPs were studied and the photocatalytic CO2 reduction performance was tested. The results show that NH2-CNPs are vesicle-type spherical particles with particle size of 42.16 ± 7.5 nm and have a mesoporous structure that is capable of adsorbing CO2. A defect structure was formed on the surface of the NH2-CNPs due to the doping of N and S elements, thereby significantly improving the ability to photogenerate electrons under visible light along with the ability to efficiently separate the photo-generated carriers. The photocatalytic reduction products of CO2 over NH2-CNPs were CH3OH, CO, C2H5OH, H2 and CH4. After 10 hours of reaction, the total amount of products was 807.56 μmol g−1 cat, the amount of CH3OH was 618.7 μmol g−1 cat, and the calculated selectivity for conversion of CO2 to CH3OH was up to 76.6%.
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PubMed
高影响因子
POLYMER
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2018
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IF 3.483
Shuangbin Fu,Yusheng Qin,Lijun Qiao,Xianhong Wang,Fosong Wang
In the past decade, poly(carbonate ether)polyols, or CO 2 -polyols, have been synthesized by the copolymerization of CO 2 and propylene oxide (PO) with a double metal cyanide (DMC) catalyst in the presence of various chain transfer agents. CO 2 -polyols show great potential use as substitutes for polyols derived from fossil feedstock in the polyurethane industry. Brookfield viscosity tests have revealed the importance of primary hydroxyl (1° OH) content in the reactivity of CO 2 -polyols; in particular, the low 1° OH content of CO 2 -polyols severely limits their application in foam materials . Incorporation of more carbonate linkages has proven to be only moderately efficient for preparing CO 2 -polyols with high 1° OH content, e.g., 19 F NMR spectroscopy indicates that the 1° OH content of a CO 2 -polyol can increase from 13% to 39% when the carbonate content in the CO 2 -polyol is increased from 26.1% to 80.0%. In this study, the PO end-capping route was developed using a strong Lewis acid, such as tris(pentafluorophenyl)borane (FAB) as a catalyst, and a CO 2 -polyol with 1° OH content of 60% was synthesized.
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Journal of CO2 Utilization
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2018
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IF 5.503
Xu Jiang,Faliang Gou,Chenze Qi
A series of C 2 v -symmetric diphenylporphyrin complexes containing a metal ion (Mg, Al, Mn, Fe, Co, Zn) have been synthesized and applied as catalysts for the solvent-free cycloaddition of epoxides and carbon dioxide under atmospheric pressure and mild temperature, in concert with phenyltrimethylammonium tribromide (PTAT) as a co-catalyst. The activity of these catalysts deeply relies on their coordinated metal species. [5,15-Diphenylporphyrin]manganese(III) chloride ( DPP-MnCl ) has been found to be the most effective catalyst under optimal reaction conditions. It's worth mentioning that the cycloaddition of phenyl glycidyl ether (GPE) and CO 2 proceeded successfully by DPP-MnCl /PTAT even at 25 °C and atmospheric pressure. Moreover, preliminary kinetic investigations of this cycloaddition were carried out by using catalysts DPP-MnCl , DPP-CoCl and DPP-Zn , revealing that the (phenoxymethyl)ethylene carbonate (PEC) formation with the lowest activation energy is catalyzed by DPP-MnCl . Furthermore, a Lewis acid-base dual cooperative catalytic mechanism has been carefully proposed in light of the catalyst systems and the experimental results.
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JOURNAL OF CHEMICAL THERMODYNAMICS
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2018
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IF 2.631
Min Xiao,Helei Liu,Hongxia Gao,Zhiwu Liang
In this work, the equilibrium CO 2 solubilities of five tertiary amines, namely Triethanolamine (TEA), N-methylethanolamine (MDEA), 2-(Dimethylamino)ethanol (DMEA), 3-dimethyl-amino-1-propanol (3DMA1P), and Diethylethanolamine (DEEA) were measured over the temperature range of 298.15–313.15 K, and at CO 2 partial pressures up to 60.8 kPa. The activity-structure relationship was studied on the molecular level to account for the differences in equilibrium CO 2 solubility. The M-KE model was applied to correlate the vapor-liquid-equilibrium data of the five tertiary amine-H 2 O-CO 2 systems. Results show that the model is able to correlate experimental data very well and gives reasonable prediction results with average absolute deviation (AAD) of 2.5% for TEA, 3.3% for MDEA, 1.3% for DMEA, 1.0% for 3DMA1P and 0.8% for DEEA. In addition, the CO 2 absorption heat was calculated using the Clausius-Clapeyron equation. The potential for the five amines to be considered as alternative solvents for CO 2 capture was evaluated in terms of equilibrium CO 2 solubility, second order reaction rate constant and CO 2 absorption heat.
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