ACS Applied Polymer Materials
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2023
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IF 5
Qian Liu,Junjie Liu,Peiyu Jia,Tian Yu,Ning Qi,Wei Zhou,Nanwen Li,Zhiquan Chen
In this work, two series of poly(benzoxazole-co-imide) membranes were synthesized through thermal rearrangement (TR) reaction at 450 °C. Different kinds and proportions of the nonrearrangeable (non-TR-able) diamines were incorporated into the rearrangeable (TR-able) precursors to modify the free volume structure of the resulting membranes. Results of positron annihilation measurements exhibit that the increase of TR-able content or number of methyl groups leads to an increase of both free volume size and fractional free volume, while the incorporation of non-TR-able diamines obviously improves the mechanical properties of the membranes. The pure gas permeability shows a perfect linear relationship with the fractional free volume of the samples, confirming the decisive effect of the free volume structure on gas transport. Meanwhile, the gas selectivity is also found to depend on the fractional free volume. In addition, the high fractional free volume obtained by TR reaction leads to exceptionally high H2/CH4 separation performance, with majority of the samples exceeding the 2008 Robeson upper bound. The plasticization resistivity of the membranes is also enhanced by the TR reaction. Our study exhibits that the free volume structure of the poly(benzoxazole-co-imide) membranes can be tailored for appropriate gas separation performance. Furthermore, our results show that positron annihilation technique is an effective tool for exploring the microstructural information on gas separation membranes.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2023
·
IF 8.6
Yang Jiao,Qi Wu,Wei Lai,Hongyan Liu,Haitao Zhang,King Lun Yeung,Shuangjiang Luo
Polybenzimidazole membranes with excellent size-sieving and plasticization resistance have attracted extensive attention for helium recovery from natural gas. Herein, we present a novel approach to fabricating polybenzimidazole membranes with exceptional gas selectivities and enhanced plasticization resistance. The strategy involves in-situ crosslinking of triptycene-containing polybenzimidazole membranes using 1,3,5-benzenetricarbonyl trichloride as the crosslinking agent. The crosslinking process tightens the polymer chains, resulting in reduced inter-segmental distance and fractional free volume, which significantly boosts the He/CH 4 and He/N 2 selectivities compared to non-crosslinked triptycene-containing polybenzimidazole membranes. The TPBI@CL 24 membrane exhibits a high mixed-gas He/CH 4 selectivity of 465 under a ternary 0.3:49.4:50.3 He/CO 2 /CH 4 (v/v/v) mixture at 100 PSIA and 35 °C. Moreover, the microporosity is feasibly tailored by controlling the crosslinking degree. Notably, the TPBI@CL x membranes demonstrate remarkable plasticization resistance under high-pressure three-component mixed-gas feed. The TPBI@CL 24 membrane experiences only a 9 % decrease in the mixed-gas He/CH 4 selectivity when the feed pressure increases from 100 to 500 PSIA at 35 °C, rendering the TPBI@CL x membranes with versatile separation performance applicable for industrial He recovery from natural gas.
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JOURNAL OF MEMBRANE SCIENCE
·
2023
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IF 9.5
Bingyu Zhao,Haojie Li,Yuxiu Yu,Yaodong Liu
Carbon molecular sieve membranes (CMSMs) have exhibited significant potential in gas separation applications, particularly in the realm of hydrogen and carbon dioxide separation. Poly(furfuryl alcohol) (PFA) represents a cost-efficient and sustainable precursor utilized in the synthesis of CMSMs. Nonetheless, PFA-based CMSMs have exhibited suboptimal performance and frequently necessitate supplementary supporting layers. In the present investigation, we have explored various acids as catalysts for the in-situ self-polymerization of PFA. Our findings reveal that PFA membrane catalyzed by sulfuric acid exhibits the most favorable performance, yielding a hydrogen permeability of 1394.4 Barrer and a H 2 /CH 4 selectivity of 404.1. These values exceed the Robeson upper limits established in 2019. The enhanced gas separation performance of the sulfuric acid catalyzed PFA-based CMSM could be attributed to the increased furan ring opening and higher polymerization degree achieved through this catalytic process. Furthermore, our investigation delved into the addition of poly(styrene-co-acrylonitrile) (SAN) into the PFA membrane, yielding a CMSM featuring both dense and porous layers. With the addition of 6 wt% SAN in PFA membrane, the resulting CMSM exhibited a hydrogen permeability of 3126.4 Barrer, underscoring the potential for high-performance CMSMs made from the economical PFA precursor. The optimization of the PFA polymerization process and the incorporation of SAN, hold the promise of further elevating the performance of PFA-based CMSMs, and these advancements will substantially contribute to the advancement of sustainable and efficient gas separation technologies.
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PETROLEUM SCIENCE AND TECHNOLOGY
·
2023
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IF 1.5
Xiong Ying,Zhou Houan,Zhou Lang,Pu Junhong
In this paper, a dithiocarbamate-type flocculant DTC-TETA was prepared by using triethylenetetramine as the material and combination of DTC-TETA and polyacrylamide was used for the coagulation-flocculation of flowback water from shale gas hydraulic fracturing (FWSG). The coagulation-flocculation process was optimized by using turbidity as index and the recommended process was as follows: DTC-TETA dosage 200 mg/L, anionic polyacrylamide AN905 dosage 1 mg/L, flocculation stirring speed 200 rpm, flocculation stirring time 3 min and settlement time 5 min. The turbidity of FWSG can be reduced to be 13 NTU from the initial turbidity of more than 2000 NTU under the recommended process. The performance of DTC-TETA was much better than that of polyaluminum chloride and the Fe2+ in FWSG also can be removed. The function mechanism of DTC-TETA was investigated through the studies of zeta potential change of suspended solids and structural characteristics of flocs. The results confirmed that the flocs were developed by the network formed by the coordination reaction between DTC-TETA and Fe2+, which can filter out suspended solids. This study signifies that both suspended solids and Fe2+ ion can be removed by using DTC-TETA as flocculant, which is a new choice for the FWSG treatment.
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PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
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2023
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IF 3.3
Xueying Wang,Qian Ma,Qi Zhang,Yi Wang,Lingyu Li,Dongheng Zhao,Zhiqiang Liu
Porous double-channel α-Fe 2 O 3 /SnO 2 heterostructures with tunable surface/interface transport mechanism have been originally fabricated by the electrospinning and subsequent calcination process. With the increase of Sn content from 0 to 5 mol%, the morphology of α-Fe 2 O 3 -based materials changed from porous fibers to ribbons with both sides curled inward. Double-channel structure can provide more active sites and enhanced adsorption capacity with the large specific surface areas of 233.2 m 2 /g. The optimal α-Fe 2 O 3 /SnO 2 composites exhibit the highest response value (32.38) and fastest response/recovery times (33/58 s) than those of other samples to 100 ppm N,N-dimethylformamide (DMF) at 360 °C. Meanwhile, good cycling and long-term stability and high gas selectivity of the composites are conductive to the feasible detection to DMF under high temperature (≥360 °C) condition. The enhanced gas-sensitive properties of α-Fe 2 O 3 /SnO 2 composites at high temperature are closely related to phase composition, unique morphology, efficient n-n heterojunction and accelerated surface/interface charge transfer process. Significantly, the porous double-channel α-Fe 2 O 3 /SnO 2 composite is expected to be a potential candidate for DMF vapor detection in the dye or pesticide industry to prevent DMF explosion under high temperature conditions in the future.
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ENERGY
·
2023
·
IF 9
Fang Wang,Jinchi Mu,Wenjing Lin,Yuehan Cao,Yuhan Wang,Shuai Leng,Lihong Guo,Ying Zhou
CO 2 capture is currently the most effective way to reduce global carbon emissions, which leads to the emergence of novel gas hydrate method. In this work, the significant role of graphene oxide (GO) in enhancing the dynamic behaviors of post-combustion CO 2 capture via the hydrate formation was investigated. Firstly, at the gas-liquid interface, the induction of GO increased the amount of gas transfer, and shortened the induction time for the hydrate nucleation at the heterogeneous nucleation sites provided by GO, which attracted CO 2 molecules assembling on the GO layer to participate in the hydrate nucleation based on the molecular dynamics (MD) simulations. More importantly, the hydrate growth rate was nearly doubled in 0.05 wt% GO and 4 mol% tetrahydrofuran (THF) mixed accelerators than that in pure THF and sodium dodecyl sulfate (SDS) mixed systems, which greatly boosted the gas storage capacity of CO 2 in the form of compact solid hydrates. Consequently, CO 2 separation efficiency achieved up to 76 % in the GO based accelerators, enhanced by 23.2 % compared to that in pure THF and the SDS mixed systems. The present study could provide insights into the development of new type of nanomaterial accelerators for CO 2 capture via the gas hydrate method.
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MOLECULES
·
2021
·Vol. 26
·期 19
·5797
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IF 4.412
Yanyan Lu,Jianbo Wang,Gang Shen,Jiuling Liu,Hongwei Zhu,Junning Zhao,Shitang He
Introduction: A novel analytical method using fast gas chromatography combined with surface acoustic wave sensor (GC-SAW) was developed for rapid determination of the pharmacological volatiles of turmeric (Curcuma longaL.). Methods: The volatile compounds in 20 turmeric samples, collected from different parts and different origins, were assessed by the fast GC-SAW. In addition, gas chromatography–mass spectrometry (GC-MS) was employed to confirm the chemical composition of the main volatiles. The digital fingerprint of turmeric was established and analysed by principal component analysis and cluster analysis. Results: Curcumene (9.1%), β-sesquiphellandrene (5.1%) and ar-turmerone (69.63%) were confirmed as the main pharmacological volatiles of turmeric. The content of ar-turmerone in lateral rhizome turmeric was significantly higher than that of top rhizome and ungrouped turmeric. The contents of curcumene and β-sesquiphellandrene in top rhizome turmeric were higher than those in lateral and ungrouped turmeric. The 20 turmeric samples were divided into four categories, which reflected the quality characteristics of the turmeric from different parts and origins. Conclusion: The GC-SAW method can rapidly and accurately detect pharmacologically volatiles of turmeric, and it can be used in the quality control of turmeric.Keywords:gas chromatography–surface acoustic wave sensor;gas chromatography-mass spectrometry;turmeric;pharmacological volatiles;determination;quality control
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PubMed
高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
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2021
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IF 7.46
Weijia Li,Lingchu Huang,Tong Wang,Xidong Hao,Bin Wang,Qi Lu,Xishuang Liang,Fengmin Liu,Fangmeng Liu,Chenguang Wang,Geyu Lu
The development of high-performance gas sensors for detecting trace amount of CH 3 OH is an essential and a challenging task for safety using fuel cell vehicles (FCVs). In this work, the metal oxides (SnO 2 , In 2 O 3 , CuO) are employed as the catalyst carrier materials in fuel cell type sensors for the first time to replace traditional carbon, with which the Pt/MO x based fuel cell type sensors are fabricated. Among them, Pt/SnO 2 based sensor displays the lowest detection limit because SnO 2 carrier can not only support Pt particles but also provide an appropriate number of electrons for Pt, which is beneficial to reduce the adsorption strength of the intermediates and then improves the catalytic ability. The detection limit is as low as 0.5 ppm, the lowest of the various types of CH 3 OH sensors that work at room temperature. Moreover, the Pt/SnO 2 based fuel cell type sensor displays the characters of high selectivity, good repeatability and robust moisture resistance. To the best of our knowledge, this is the first report employing MO x as the catalyst carrier materials in fuel cell type sensors.
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MICROCHEMICAL JOURNAL
·
2020
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IF 3.594
Zhongping Huang,Chaochao Tu,Huijun Liu,Lili Wang,Zuoyi Zhu,Ichi Watanabe
An on-line two-step pyrolytic methylation technique combined with gas chromatography was developed for rapid analysis of free and bonded fatty acids in Polysorbate 80 respectively. Free fatty acids in Polysorbate 80 were transformed to their corresponding fatty acid methyl esters in the presence of tetramethylammonium acetate (TMAAc) in the first step with a vertical microfurnace pyrolyzer at 300 °C. After the analysis of free fatty acids, bonded fatty acids were then transformed into methyl esters in the presence of tetramethylammonium hydroxide (TMAH) at 300 °C. The effects of pyrolytic methylation temperature, TMAAc concentration and ratio to Polysorbate 80 were evaluated. The range of linearity, reproducibility, the detection limits (LODs), and the quantitation limits (LOQs) were also investigated using linoleic (C18:2), oleic (C18:1), stearic (C18:0) acids. The recoveries ranged from 92.2 to 105.0%. The RSDs of intra-day and inter-day precision were in the range of 2.89–5.9% (n = 6) and 4.4–7.2% (n = 3) respectively. Compositions of free and bonded fatty acids in five Polysorbate 80 samples were analyzed respectively to evaluate the feasibility of the proposed method. The results prove that the proposed method is simple, solvent saving and environmentally friendly since it avoids off-line derivatization and solvent extraction, and has a potential application in the high quality control of Polysorbate 80.
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Catalysis Science & Technology
·
2020
·Vol. 10
·期 8
·2343-2352
·
IF 5.721
Ziheng Zhen,Wenxiang Tang,Wei (Willy) Chu,Tao Zhang,Li Lv,Shengwei Tang
The dispersity and the neighboring degree of different sites play crucial roles in the catalytic performance of dual site catalysts. The solution of precursors was encapsulated into microdroplets by forming a microemulsion. The average diameter of microdroplets was about 45 nm. This guaranteed that the dosage of precursors was at the attogram level and only about a thousand precursor molecules were encapsulated in each microdroplet. An anti-solvent extraction method was applied to extract water from the microdroplets with acetonitrile. The precursors co-precipitated in the microdroplets due to the loss of water. The encapsulated precursors in the microdroplets co-precipitated together in nanoscale space, so the neighboring degree of the two precursors was improved significantly. The prepared catalyst was characterized by ICP-OES, BET, XRD, H2-TPR, TEM and XPS. Compared with the Cu–ZnO/Al2O3 (CZA) catalysts prepared by the conventional impregnation method, the CZA catalysts prepared by the proposed strategy had much stronger interaction and a better neighboring degree of the dual active sites. They also showed very good catalytic performance for the reverse water gas shift (RWGS) reaction. The CO2 conversion of the designed CZA catalysts was about 1–2 times higher than that of the CZA catalysts prepared by the conventional impregnation method at 0.1 MPa, 300–400 °C and a CO2/H2 mole ratio of 1.
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ENERGY & FUELS
·
2020
·
IF 3.421
Minjie Gao,Yucui Hou,Qi Zhang,Ying Sun,Shuhang Ren,Weize Wu
In this work, we designed three kinds of functional deep eutectic solvents (DESs) to capture SO2 in simulated flue gas. The DESs were composed of imidazole (Im), 2-methylimidazole, and 2-ethylimidazole as the hydrogen-bond acceptor (HBA) and H2O as the hydrogen-bond donor (HBD). The absorption results showed that the mole absorption capacities of 2.1 vol % SO2 by the three DESs at 40 °C were all about 1 mol of SO2/mol of HBA. Im–H2O DES (nHBA/nHBD = 1:4) shows a mass absorption capacity of 0.331 g of SO2/g of DES, which is the highest value reported in the literature. The mole ratio of HBD/HBA, flow rate of flue gas, and other acid gases in flue gas did not influence the absorption capacity of SO2. The absorption capacity decreased when the temperature increased. The absorption capacity of SO2 was almost the same after absorbing and desorbing 5 times. Furthermore, the results of 1H nuclear magnetic resonance and Fourier transform infrared analyses showed that SO2 was interacted with Im by forming Im sulfite.
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JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING
·
2020
·
IF 3.706
Xuan Li,Weian Huang,Jinsheng Sun,Xiaoping Li,Jianghong Jia,Wenguang Duan,Jie Sun
During drilling, completion and fracturing operations, aqueous phase from working fluids can invade into rock formations and engender phase trapping damage in the near well region. This formation damage can diminish the gas relative permeability and hinder the gas well productivity in tight gas sandstone reservoirs. In this study, we investigated the mixed surfactants system of cationic surfactant (SDCSA-1) and nonionic fluorinated surfactant (FC-0) at varied mixing mole ratios and concentrations to reduce the formation damage. Results showed that the minimum surface tension of mixed surfactants solution was relatively low with around 20 mN/m. In addition, surfactant mixtures altered the wettability of sandstone rock from water wetting to intermediate wetting condition. An optimal mixed system was obtained when the concentration is 10-4 mol/L and mole ratio of individual surfactants is 1:1. The mechanism of wettability alteration of surfactants to liquid/rock interface was further determined by adsorption experiments, atomic force microscopy(AFM) tests, and energy dispersive spectrum(EDS) tests. Two sets of spontaneous imbibition experiments were conducted including parallel imbibition tests and sequential imbibition tests. We observed that mixed surfactants solution can prominently prevent liquid invasion into sandstone rocks. We further calculated the capillary pressure to quantitatively examine the capillary effects of different imbibed fluids. When sandstone sample was treated by mixed surfactants, the capillary pressure decreased from 7.81 MPa to 0.97 MPa. Core displacement tests revealed that the liquid saturation of core sample filled with surfactants mixture decreased from 100% to 35.48% and the its gas permeability recovered to 72.86% of the core without liquid after gas flooding. NMR tests also confirmed that surfactant mixtures can be more easily drained than brine from pores in tight sandstone. Consequently, we proposed an improved method to mitigate water blocking damage based on wettability alteration by mixed cationic surfactant and nonionic fluoro-surfactant system.
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