The gas/liquid spiral separator, a key component in the compressed air system, was used to remove liquid and oil from gas stream by centrifugal and gravitational forces. To optimize the design of the separator,the rel...The gas/liquid spiral separator, a key component in the compressed air system, was used to remove liquid and oil from gas stream by centrifugal and gravitational forces. To optimize the design of the separator,the relationship between the performance and structural parameters of separators is studied. Computational fluid dynamics (CFD) method is employed to simulate the flow fields and calculate the pressure drop and separation efficiency of air-liquid spiral separators with different structural parameters. The RSM (Reynolds stress model)turbulence model is used to analyze the highly swirling flow fields while the stochastic trajectory model is used to simulate the traces of liquid droplets in the flow field. A simplified calculation formula of pressure drop in spiral structures is obtained by modifying Darcy's equation and verified by experiment.展开更多
Metal-Organic Frameworks(MOFs)have emerged as promising materials for gas adsorption and separation due to their exceptional surface area,tunable porosity,and versatility in functionalization.This paper explores the m...Metal-Organic Frameworks(MOFs)have emerged as promising materials for gas adsorption and separation due to their exceptional surface area,tunable porosity,and versatility in functionalization.This paper explores the mechanisms of gas adsorption in MOFs,including physical adsorption,chemisorption,and synergistic effects,which contribute to their efficiency in capturing and separating gases.The applications of MOFs in key areas such as carbon dioxide capture,hydrogen storage,natural gas separation,and air purification are discussed,highlighting their potential to address pressing environmental and energy challenges.Additionally,the use of MOFs in selective gas separation,membranes,and adsorption-based technologies like Pressure Swing Adsorption(PSA)and Vacuum Swing Adsorption(VSA)is explored,emphasizing their advantages over traditional materials.Despite challenges related to scalability,stability,and cost,MOFs hold great promise for advancing gas separation technologies in the near future,offering more efficient,sustainable,and environmentally friendly solutions.展开更多
Hydrate-based gas separation offers a promising approach for coalbed methane recovery,reaching energy conservation and emissions reduction.This study innovatively applied high-gravity technology to enhance hydrate for...Hydrate-based gas separation offers a promising approach for coalbed methane recovery,reaching energy conservation and emissions reduction.This study innovatively applied high-gravity technology to enhance hydrate formation in separating 25%CH_(4)/67%N_(2)/8%O_(2) for achieving rapid and efficient methane recovery.Systematic investigations were conducted at 283.2 K and 3.0 MPa with tetrahydrofuran at a molar concentration of 5.56%and L-tryptophan at a mass concentration of 0.5%additives,first evaluating liquid flow rate effects(0–20 mL/min)on mixed hydrate kinetic performance and separation efficiency,followed by rotating speed optimization(0–1200 r·min^(-1))under the optimal liquid flow rate.The high-gravity system amplified the gas–liquid contact area by~1155 times through cascaded liquid supply and secondary shear effects,methane molecules entered the hydrate phase rapidly under the highest driving force with the significantly intensified mass transfer.Optimal conditions(20 mL/min,600 r·min^(-1))yielded an exceptional initial hydrate growth rate of 58.59 mmol/(mol·h)and methane recovery of 50.76%,about 71.33 and 0.58 times higher than the static system,respectively.Gas chromatography and Raman spectrometer analyses revealed superior methane enrichment in hydrate phase at 90%gas uptake completion,with a concurrent 41.17%reduction in process duration.These findings demonstrate the efficacy of high-gravity-enhanced hydrate technology for coalbed methane separation,offering valuable insights for optimizing clean energy utilization.展开更多
Polymers of intrinsic microporosity(PIMs)have received considerable attention for making high-performance membranes for carbon dioxide separation over the last two decades,owing to their highly permeable porous struct...Polymers of intrinsic microporosity(PIMs)have received considerable attention for making high-performance membranes for carbon dioxide separation over the last two decades,owing to their highly permeable porous structures.However,challenges regarding its relatively low selectivity,physical aging,and plasticisation impede relevant industrial adoptions for gas separation.To address these issues,several strategies including chain modification,post-modification,blending with other polymers,and the addition of fillers,have been developed and explored.PIM-1 is the most investigated PIMs,and hence here we review the stateof-the-arts of the modification strategies of PIM-1 critically and discuss the progress achieved for addressing the aforementioned challenges via meta-analysis.Additionally,the development of PIM-1-based thin film composite membranes is commented as well,shedding light on their potential in industrial gas separation.We hope that the review can be a timely snapshot of the relevant state-of-the-arts of PIMs guiding future design and optimisation of PIMs-based membranes for enhanced performance towards a higher technology readiness level for practical applications.展开更多
Sustainable development for our life is important task,which is driven by key materials and technologies.In this roadmap,we discuss three main aspects in addressing environmental questions,green chemical processes and...Sustainable development for our life is important task,which is driven by key materials and technologies.In this roadmap,we discuss three main aspects in addressing environmental questions,green chemical processes and energy challenges.They are included,such as gas treatment and separation,wastewater treatment,waste gas treatment,solid waste treatment,lithium extraction,hydrogen production,water splitting,CO_(2) reduction,photocatalytic clean technologies,plastic degradation,fuel cells,lithium batteries,sodium batteries,aqueous batteries,solid state batteries,metal air batteries and supercapacitors.Their status,challenges,progress and future perspectives are also discussed.We hope that this paper can give clear views on sustainable development in materials and technologies.展开更多
The supersonic nozzle is a new apparatus which can be used to condense and separate water and heavy hydrocarbons from natural gas.The swirling separation of natural gas in the convergent-divergent nozzle was numerical...The supersonic nozzle is a new apparatus which can be used to condense and separate water and heavy hydrocarbons from natural gas.The swirling separation of natural gas in the convergent-divergent nozzle was numerically simulated based on a new design which incorporates a central body. Axial distribution of the main parameters of gas flow was investigated,while the basic parameters of gas flow were obtained as functions of radius at the nozzle exit.The effect of the nozzle geometry on the swirling separation was analyzed.The numerical results show that water and heavy hydrocarbons can be condensed and separated from natural gas under the combined effect of the low temperature（-80℃） and the centrifugal field（482,400g,g is the acceleration of gravity）.The gas dynamic parameters are uniformly distributed correspondingly in the radial central region of the channel,for example the distribution range of the static temperature and the centrifugal acceleration are from -80 to -55℃and 220,000g to 500,000g,respectively,which would create good conditions for the cyclone separation of the liquids.However,high gradients of gas dynamic parameters near the channel walls may impair the process of separation.The geometry of the nozzle has a great influence on the separation performance. Increasing the nozzle convergent angle can improve the separation efficiency.The swirling natural gas can be well separated when the divergent angle takes values from 4°to 12°in the convergent-divergent nozzle.展开更多
The separation of gas molecules with similar physicochemical properties is of high importance but practically entails a substantial energy penalty in chemical industry. Meanwhile, clean energy gases such as H_2 and CH...The separation of gas molecules with similar physicochemical properties is of high importance but practically entails a substantial energy penalty in chemical industry. Meanwhile, clean energy gases such as H_2 and CH_4 are considered as promising candidates for the replacement of traditional fossil fuels. However, the technologies for the storage of these gases are still immature. In addition, the release of anthropogenic toxic gases into the atmosphere is a worldwide threat of growing concern. Both in academia and industry, considerable research efforts have been devoted to developing advanced porous materials for the effective and energy-efficient separation, storage, or capture of the related gases. In contrast to conventional inorganic porous materials such as zeolites and activated carbons, metal–organic frameworks(MOFs) are considered as a type of promising materials for gas separation and storage. In this contribution, we review the recent research advance of MOFs in some relevant applications, including CO_2 capture, O_2 purification, separation of light hydrocarbons, separation of noble gases, storage of gases(CH_4,H_2, and C_2 H_2) for energy, and removal of some gaseous air pollutants(NH_3, NO_2, and SO_2). Finally, an outlook regarding the challenges of the future research of MOFs in these directions is given.展开更多
To improve the separation performance of a supersonic gas separation device for the treatment of gas mixture with a single heavy component, a novel structure with shorter settlement distance was constructed and a meth...To improve the separation performance of a supersonic gas separation device for the treatment of gas mixture with a single heavy component, a novel structure with shorter settlement distance was constructed and a method of droplet enlargement was applied. A series of experiments were carried out in the improved separation device under various conditions, using air-ethanol vapor as the medium and micro water droplets as nucleation cen- ters. The effects of the inlet pressure, temperature and relative humidity, the swirling intensity, and mass flow rate of water on the separation performance were investigated. The separation was improved by increasing the inlet pressure and relative humidity. With the decrease of swirling intensity and mass flow rate of water, the separation efficiency increased first and then decreased. The inlet temperature had a slight effect on the separation. The results showed that the separation performance was effectively improved using the proposed structure and method, and the best separation in this study was obtained with the ethanol removal rate about 55% and dew point depression 27 K. The addition of water had little pollution to the air-ethanol vapor system since the water carry-over rate was within the range of -2 %-0 in most cases.展开更多
Underwater transportation of bubbles and gases has essential applications in manipulating and using gas,but achieving this function at the microscopic level remains a significant challenge.Here,we report a strategy to...Underwater transportation of bubbles and gases has essential applications in manipulating and using gas,but achieving this function at the microscopic level remains a significant challenge.Here,we report a strategy to self-transport gas in water along a laser-induced open superhydrophobic microchannel with a width less than 100μm.The femtosecond laser can directly write superhydrophobic and underwater superaerophilic microgrooves on the polytetrafluoroethylene(PTFE)surfaces.In water,the single laser-induced microgroove and water medium generate a hollow microchannel.When the microchannel connects two superhydrophobic regions in water,the gas spontaneously travels from the small region to the large area along this hollow microchannel.Gas self-transportation can be extended to laser-drilled microholes through a thin PTFE sheet,which can even achieve anti-buoyancy unidirectional penetration.The gas can overcome the bubble’s buoyance and spontaneously travel downward.The Laplace pressure difference drives the processes of spontaneous gas transportation and unidirectional bubble passage.We believe the property of gas self-transportation in the femtosecond laser-structured open superhydrophobic and underwater superaerophilic microgrooves/microholes has significant potential applications related to manipulating underwater gas.展开更多
Three gas separation technologies,chemical absorption,membrane separation and pressure swing adsorption,are usually applied for CO2 capture from flue gas in coal-fired power plants.In this work,the costs of the three ...Three gas separation technologies,chemical absorption,membrane separation and pressure swing adsorption,are usually applied for CO2 capture from flue gas in coal-fired power plants.In this work,the costs of the three technologies are analyzed and compared.The cost for chemical absorption is mainly from $30 to $60 per ton(based on CO2 avoided),while the minimum value is $10 per ton(based on CO2 avoided).As for membrane separation and pressure swing adsorption,the costs are $50 to $78 and $40 to $63 per ton(based on CO2 avoided),respectively.Measures are proposed to reduce the cost of the three technologies.For CO2 capture and storage process,the CO2 recovery and purity should be greater than 90%.Based on the cost,recovery,and purity,it seems that chemical absorption is currently the most cost-effective technology for CO2 capture from flue gas from power plants.However,membrane gas separation is the most promising alternative approach in the future,provided that membrane performance is further improved.展开更多
The permeation of various pure gas （H2, He, Ne, CH4 and At） through carbon membranes is investigated using a dual control volume grand canonical molecular dynamics method. A two-dimensional slit pore is employed ins...The permeation of various pure gas （H2, He, Ne, CH4 and At） through carbon membranes is investigated using a dual control volume grand canonical molecular dynamics method. A two-dimensional slit pore is employed instead of the one-dimensional pore. Compared with the experiments, simulation results show that the improvement of pore model is very necessary. The effects of membrane thickness, pore width and temperature on gas permeance and ideal separation factor are also discussed. Results show that gas permeates through membrane according to Knudsen diffusion in large pore, while Knudsen diffusion is accompanied by molecular sieving in small pore. Moreover, methane is easily adsorbed on the membrane surface due to strong attractive interactions of membrane and shows higher permeance than that of Knudsen flow. In addition, it is noted that when membrane thickness is thin enough the permeance of gas does not decrease with the increase of membrane thickness due to the strong adsorption until membrane resistance becomes dominant.展开更多
The application of swirl tube cyclone for gas-liquid separation is attractive due to its small size and weight. However, very scarce information on the performance of the swirl tube cyclone especially at high operatin...The application of swirl tube cyclone for gas-liquid separation is attractive due to its small size and weight. However, very scarce information on the performance of the swirl tube cyclone especially at high operating pressure emulating actual field condition was published in journals. Performance assessment was usually done at a low operating pressure using either air-water, air-fine particle mixtures or dense gas such as SF6 . This paper fills the existing gaps and reports the initial findings on the performance assessment of a horizontal swirl tube cyclone for gas-liquid separation operating at a flow rate of 5 MMSCFD at 40-60 bar operating pressure.展开更多
Oxygen diffusion and oxygen selective adsorption properties of rare earths material YBa_2Cu_3O_(7-x) (YBCO) were investigated by thermogravimetric, oxygen static adsorption and selectivity adsorption experiments. The ...Oxygen diffusion and oxygen selective adsorption properties of rare earths material YBa_2Cu_3O_(7-x) (YBCO) were investigated by thermogravimetric, oxygen static adsorption and selectivity adsorption experiments. The results show that YBCO is a very good deoxidizing material. The oxygen desorption of YBCO begins remarkably at about 400 ℃, mass loss can arrive at 1.2% of its original quantity at 800 ℃. Oxygen can be completely absorbed back into the sample again when temperature descends to 400 ℃. The oxygen adsorption selectivity, reproducibility and oxygen adsorption under very low oxygen partial pressure make the material desirable for air separation and gas purification. High purity nitrogen gas was produced with the YBCO molecular sieves in the air separation and gas purification experiments. 0.017 m^3 of high purity nitrogen (>99.9999%) can be obtained with 1 kg YBCO molecular sieve in one cycle. As a deoxidant, an obvious advantage of YBCO is that no hydrogen is needed in its applications.展开更多
Natural gas, as a very important source of energy and chemical feedstock, can be used in place of coal to lower net carbon dioxide emissions.Membrane separation technology is an attractive alternative for natural gas ...Natural gas, as a very important source of energy and chemical feedstock, can be used in place of coal to lower net carbon dioxide emissions.Membrane separation technology is an attractive alternative for natural gas purification where the impurities represented by acid gases(CO_(2) and H_(2)S) as well as inert gases(N_(2)) must be removed to meet the transportation and usage specifications. From the economic benefits viewpoint,asymmetric membranes are required for industrial manufacture and applications. This paper aims to review the latest development of various kinds of asymmetric membranes for natural gas purification, mainly focusing on CO_(2) removal from CH_(4), including H_(2)S and N_(2) separation from CH_(4) as well. According to material types, polymeric, inorganic, mixed-matrix and carbon molecular sieve membranes are introduced. The associated fabrication approaches and transport properties are discussed for each kinds of asymmetric membranes. Towards the practical implementation, an emphasis is placed on hollow fiber asymmetric structure for these polymeric, mixed-matrix and carbon molecular sieve membranes.展开更多
This paper reports on a new microporous composite silica membrane prepared via acid-catalyzed polymeric route of sol-gel method with tetraethylorthosilicate(TEOS)and a bridged silsesquioxane[1,2-bis(triethoxysilyl)eth...This paper reports on a new microporous composite silica membrane prepared via acid-catalyzed polymeric route of sol-gel method with tetraethylorthosilicate(TEOS)and a bridged silsesquioxane[1,2-bis(triethoxysilyl)ethane, BTESE]as precursors.A stable nano-sized composite silica sol with a mean volume size of^5 nm was synthesized. A 150 nm-thick defect-free composite silica membrane was deposited on disk support consisting of macroporous α-Al2O3 and mesoporousγ-Al2O3 intermediate layer by using dip-coating approach,followed by calcination under pure nitrogen atmosphere.The composite silica membranes exhibit molecular sieve properties for small gases like H2,CO2,O2,N2,CH4 and SF6 with hydrogen permeances in the range of(1-4)×10 -7mol·m -2·s -1·Pa -1(measured at 200°C,3.0×105 Pa).With respect to the membrane calcined at 500°C,it is found that the permselectivities of H 2 (0.289 nm)with respect to N2(0.365 nm),CH4(0.384 nm)and SF6(0.55 nm)are 22.9,42 and>1000,respectively, which are all much higher than the corresponding Knudsen values(H2/N2=3.7,H2/CH4=2.8,and H2/SF6=8.5).展开更多
A rigid aromatic diamine monomer containing di-tert-butylbenzene and dimethyl groups,3,3'-dimethyl-4,4'-diaminophenyl-3",5"-di-tert-butyltoluene,was successfully synthesized by a simple coupling reac...A rigid aromatic diamine monomer containing di-tert-butylbenzene and dimethyl groups,3,3'-dimethyl-4,4'-diaminophenyl-3",5"-di-tert-butyltoluene,was successfully synthesized by a simple coupling reaction using 3,5-di-tert-butylbenzaldehyde and o-toluidine as starting materials.A series of novel polyimides(PI 3a-3c)with large pendant groups were prepared with the obtained diamine monomer and three different commercial aromatic dianhydrides(3,3',4,4'-biphenyltetracarboxylic dianhydride,4,4'-oxydiphthalic anhydride,and 4,4'-(hexafluoroisopropylidene)diphthalic anhydride)by one-step high temperature polycondensation.The prepared polyimides exhibited high solubility and good membrane forming ability:they could be dissolved not only in some high boiling solvents such as DMF,NMP,DMAc,and m-Cresol at room temperature,but also in some low boiling solvents such as CHCl3,CH2Cl2,and THF.Their solubility in most solvents could exceed 10 wt%,and the flexible membranes could be obtained by casting their solutions.The prepared membranes exhibited good gas separation properties.The permeability coefficients of PI 3c for CO2 and O2 were up to 124.6 and 42.8 barrer,respectively,and the selectivity coefficients for CO2/CH4 and O2/N2 were 14.7 and 3.3,respectively.The membranes had light color and good optical transmission.Their optical transmittance at 450 nm wavelength was in the range of 67%-79%,and the cutoff wavelength was in the range of 310-348 nm.They also had good thermal properties with glass transition temperature(Tg)values in the range of 264-302℃.In addition,these membranes possessed good mechanical properties with tensile strength ranging between 77.8-87.4 MPa,initial modulus ranging between 1.69-1.82 GPa,and elongation at break ranging between 4.8%-6.1%.展开更多
This research discusses the separation of methane gas from three different gas mixtures,CH4/H2 S,CH4/N2 and CH4/CO2,using a modified silicon carbide nanosheet(Si CNS)membrane using both molecular dynamics(MD)and compu...This research discusses the separation of methane gas from three different gas mixtures,CH4/H2 S,CH4/N2 and CH4/CO2,using a modified silicon carbide nanosheet(Si CNS)membrane using both molecular dynamics(MD)and computational fluid dynamics(CFD)methods.The research examines the effects of different structures of the Si CNSs on the separation of these gas mixtures.Various parameters including the potential of the mean force,separation factor,permeation rate,selectivity and diffusivity are discussed in detail.Our MD simulations showed that the separation of CH4/H2 S,and CH4/CO2 mixtures was successful,while simulation demonstrated a poor result for the CH4/N2 mixture.The effect of temperature on the diffusivity of gas is also discussed,and a correlation is introduced for diffusivity as a function of temperature.The evaluated value for diffusivity is then used in the CFD method to investigate the permeation rate of gas mixtures.展开更多
Mixed matrix hollow fiber membranes（MMHFMs）filled with metal-organic frameworks（MOFs）have great potential for energy-efficient gas separation processes,but the major hurdle is polymer/MOFs interfacial defects and ...Mixed matrix hollow fiber membranes（MMHFMs）filled with metal-organic frameworks（MOFs）have great potential for energy-efficient gas separation processes,but the major hurdle is polymer/MOFs interfacial defects and membrane plasticization.Herein,lab-synthesized MIL-53 was post-functionalized by aminosilane grafting and subsequently incorporated into Ultem-1000 polymer matrix to fabricate high performance MMHFMs.SEM,DLS,XRD and TGA were performed to characterize silane-modified MIL-53（S-MIL-53）and prepared MMHFMs.Moreover,the effect of MOFs loading was systematically investigated first;then gas separation performance of MMHFMs for pure and mixed gas was evaluated under different pressures.MMHFMs containing post-functionalized S-MIL-53 achieved remarkable gas permeation properties which was better than model predictions.Compared to pure HFMs,CO2permeance of MMHFM loaded with 15%S-MIL-53 increased by 157%accompanying with 40%increase for CO2/N2selectivity,which outperformed the MMHFM filled with naked MIL-53.The pure and mixed gas permeation measurements with elevated feed pressure indicated that incorporation of S-MIL-53 also increased the resistance against CO2plasticization.This work reveals that post-modified MOFs embedded in MMHFMs facilitate the improvement of gas separation performance and suppression of membrane plasticization.展开更多
A series of organosilica sols are prepared by the polymeric sol–gel method using 1,2-bis(triethoxysilyl)ethane(BTESE)as the precursor.Particle size distributions of the BTESE-derived sols are systematically investiga...A series of organosilica sols are prepared by the polymeric sol–gel method using 1,2-bis(triethoxysilyl)ethane(BTESE)as the precursor.Particle size distributions of the BTESE-derived sols are systematically investigated by carefully adjusting the synthesis parameters(i.e.,water ratios,acid ratios and solvent ratios)in the sol process.In certain conditions,increasing the water ratio or the acid ratio tends to cause larger sol sizes and bimodal particle size distributions.However,higher solvent ratios lead to smaller sol sizes and unimodal particle size distributions.The organosilica membranes prepared from the optimized sols show excellent H_2 permeances(up to 4.2×10^(-7)mol·m^(-2)·s^(-1)·Pa^(-1))and gas permselectitivies(H_2/CO_2 is 9.5,H_2/N_2 is 50 and H_2/CH_4 is 68).This study offers significant insights into the relationship between the sol synthesis parameters,sol sizes and membrane performance.展开更多
The design and development of highly permeable,selective and stable polymer membranes are great challenges in the gas separation industry.Herein,we constructed two intrinsic microporous polyimides(6FPCA and 6FMCA)deri...The design and development of highly permeable,selective and stable polymer membranes are great challenges in the gas separation industry.Herein,we constructed two intrinsic microporous polyimides(6FPCA and 6FMCA)derived from two isometric diamines(PCA and MCA),which were synthesized by palladium catalyzed C—N coupling reaction.The PCA and MCA diamines contain a hollow beaded structure of 2,2′-paracyclophane as a building block with a specified window size of 3.09Å.The chemical structures of monomers,polyimides were confirmed by NMR,FTIR,and elementary analysis.6FPCA and 6FMCA exhibit good solubility,excellent thermal stability,and mechanical properties.6FPCA exhibits much larger microporosity(434 versus 120 m2·g−1),FFV(0.22 versus 0.15),d-spacing(6.9 versus 5.9Å),and over 10 times higher permeability with a very little decrease in selectivity than the corresponding polyimide(6FpA)with a plane structure,which remarkably increased their separation performance from far below the 2008 Robeson Upper bounds to reach these limitations for O2/N2 and CO2/CH4.Additionally,the 6FPCA also demonstrates good plasticization resistance,moderate aging properties,and high CO2/CH4 mixed-gas separation performance.These results indicate that paracyclophane subunit can be successfully incorporated into polymers to enhance their ultra-microporosity and separation properties,which open a new avenue for developing high performance gas separation membranes with topological ultra-micropores.展开更多
文摘The gas/liquid spiral separator, a key component in the compressed air system, was used to remove liquid and oil from gas stream by centrifugal and gravitational forces. To optimize the design of the separator,the relationship between the performance and structural parameters of separators is studied. Computational fluid dynamics (CFD) method is employed to simulate the flow fields and calculate the pressure drop and separation efficiency of air-liquid spiral separators with different structural parameters. The RSM (Reynolds stress model)turbulence model is used to analyze the highly swirling flow fields while the stochastic trajectory model is used to simulate the traces of liquid droplets in the flow field. A simplified calculation formula of pressure drop in spiral structures is obtained by modifying Darcy's equation and verified by experiment.
文摘Metal-Organic Frameworks(MOFs)have emerged as promising materials for gas adsorption and separation due to their exceptional surface area,tunable porosity,and versatility in functionalization.This paper explores the mechanisms of gas adsorption in MOFs,including physical adsorption,chemisorption,and synergistic effects,which contribute to their efficiency in capturing and separating gases.The applications of MOFs in key areas such as carbon dioxide capture,hydrogen storage,natural gas separation,and air purification are discussed,highlighting their potential to address pressing environmental and energy challenges.Additionally,the use of MOFs in selective gas separation,membranes,and adsorption-based technologies like Pressure Swing Adsorption(PSA)and Vacuum Swing Adsorption(VSA)is explored,emphasizing their advantages over traditional materials.Despite challenges related to scalability,stability,and cost,MOFs hold great promise for advancing gas separation technologies in the near future,offering more efficient,sustainable,and environmentally friendly solutions.
基金The financial support from the Nature Scientific Foundation of Heilongjiang Province(No.YQ2022E041)the Postdoctoral Research Start-up Funds in Heilongjiang Province(No.2023BSH14)the Basic scientific research project of Heilongjiang Provincial University(No.2024-KYYWF-1090)。
文摘Hydrate-based gas separation offers a promising approach for coalbed methane recovery,reaching energy conservation and emissions reduction.This study innovatively applied high-gravity technology to enhance hydrate formation in separating 25%CH_(4)/67%N_(2)/8%O_(2) for achieving rapid and efficient methane recovery.Systematic investigations were conducted at 283.2 K and 3.0 MPa with tetrahydrofuran at a molar concentration of 5.56%and L-tryptophan at a mass concentration of 0.5%additives,first evaluating liquid flow rate effects(0–20 mL/min)on mixed hydrate kinetic performance and separation efficiency,followed by rotating speed optimization(0–1200 r·min^(-1))under the optimal liquid flow rate.The high-gravity system amplified the gas–liquid contact area by~1155 times through cascaded liquid supply and secondary shear effects,methane molecules entered the hydrate phase rapidly under the highest driving force with the significantly intensified mass transfer.Optimal conditions(20 mL/min,600 r·min^(-1))yielded an exceptional initial hydrate growth rate of 58.59 mmol/(mol·h)and methane recovery of 50.76%,about 71.33 and 0.58 times higher than the static system,respectively.Gas chromatography and Raman spectrometer analyses revealed superior methane enrichment in hydrate phase at 90%gas uptake completion,with a concurrent 41.17%reduction in process duration.These findings demonstrate the efficacy of high-gravity-enhanced hydrate technology for coalbed methane separation,offering valuable insights for optimizing clean energy utilization.
基金funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 872102the China Scholarship Council(CSC,file no.202006240076)-University of Manchester joint studentship for supporting the PhD researchthe special innovation project fund from the Institute of Wenzhou,Zhejiang University(No.XMGL-KJZX-202204)。
文摘Polymers of intrinsic microporosity(PIMs)have received considerable attention for making high-performance membranes for carbon dioxide separation over the last two decades,owing to their highly permeable porous structures.However,challenges regarding its relatively low selectivity,physical aging,and plasticisation impede relevant industrial adoptions for gas separation.To address these issues,several strategies including chain modification,post-modification,blending with other polymers,and the addition of fillers,have been developed and explored.PIM-1 is the most investigated PIMs,and hence here we review the stateof-the-arts of the modification strategies of PIM-1 critically and discuss the progress achieved for addressing the aforementioned challenges via meta-analysis.Additionally,the development of PIM-1-based thin film composite membranes is commented as well,shedding light on their potential in industrial gas separation.We hope that the review can be a timely snapshot of the relevant state-of-the-arts of PIMs guiding future design and optimisation of PIMs-based membranes for enhanced performance towards a higher technology readiness level for practical applications.
基金supported by the Russian Science Foundation(No.22-13-00035)the National Outstanding Young Scientists Fund(No.52125002)+14 种基金the National Key Research and Development Program of China(Nos.2023YFC3904800 and 2022YFB4002501)the National Natural Science Foundation of China(Nos.52400228,52300139,22308063,52103340,U22A20418,22578302,52202208,52400163,52205054,22075171,52177214,22405201,52371072,52171078,52377218)the Key Research and Development Project of Science and Technology Department of Zhejiang Province(No.2024C03284(SD2))the Research Development Fund of Zhejiang A&F University(No.2024LFR042)the President Research Funds from Xiamen University(No.ZK1111)Nanqiang Youth Scholar program of Xiamen University,the Young Elite Scientists Sponsorship Program by CAST(No.2023QNRC001)Natural Science Foundation of Xiamen(No.3502z202471037)Open Fund of the State Environmental Protection Key Laboratory of Urban Air Particulate Matter Pollution Prevention and Control,College of Environmental Science and Engineering,Nankai University(No.NKPMLF202409)the Key Project of Research and Development Plan of Jiangxi Province(No.20243BBI91001)Natural Science Foundation of Shanghai(No.23ZR1423400)the Postdoctoral Science Research Program of Shaanxi(No.2023BSHEDzZ159)Xidian University Specially Funded Project for Interdisciplinary Exploration(No.TZJH2024062)the Open Project of Yunnan Precious Metals Laboratory Co.,Ltd.(No.YPML-20240502058)the Fundamental Research Program of Shanxi Province(No.202303021212159)the Natural Science Foundation of Shanxi Normal University(No.JCYJ2024017).
文摘Sustainable development for our life is important task,which is driven by key materials and technologies.In this roadmap,we discuss three main aspects in addressing environmental questions,green chemical processes and energy challenges.They are included,such as gas treatment and separation,wastewater treatment,waste gas treatment,solid waste treatment,lithium extraction,hydrogen production,water splitting,CO_(2) reduction,photocatalytic clean technologies,plastic degradation,fuel cells,lithium batteries,sodium batteries,aqueous batteries,solid state batteries,metal air batteries and supercapacitors.Their status,challenges,progress and future perspectives are also discussed.We hope that this paper can give clear views on sustainable development in materials and technologies.
基金supported by the National High Technology Research and Development Program of China("863 program",No.2007AA09Z301) the National Major Science&Technology Specific Projects(No.2008ZX05017-004)
文摘The supersonic nozzle is a new apparatus which can be used to condense and separate water and heavy hydrocarbons from natural gas.The swirling separation of natural gas in the convergent-divergent nozzle was numerically simulated based on a new design which incorporates a central body. Axial distribution of the main parameters of gas flow was investigated,while the basic parameters of gas flow were obtained as functions of radius at the nozzle exit.The effect of the nozzle geometry on the swirling separation was analyzed.The numerical results show that water and heavy hydrocarbons can be condensed and separated from natural gas under the combined effect of the low temperature（-80℃） and the centrifugal field（482,400g,g is the acceleration of gravity）.The gas dynamic parameters are uniformly distributed correspondingly in the radial central region of the channel,for example the distribution range of the static temperature and the centrifugal acceleration are from -80 to -55℃and 220,000g to 500,000g,respectively,which would create good conditions for the cyclone separation of the liquids.However,high gradients of gas dynamic parameters near the channel walls may impair the process of separation.The geometry of the nozzle has a great influence on the separation performance. Increasing the nozzle convergent angle can improve the separation efficiency.The swirling natural gas can be well separated when the divergent angle takes values from 4°to 12°in the convergent-divergent nozzle.
基金supported from the Natural Science Foundation of China (Grant Nos. 21771012, 21601008 and 21576006)the National Natural Science Fund for Innovative Research Groups (Grant No. 51621003)the China Postdoctoral Science Foundation (Grant No. 2016M600879)
文摘The separation of gas molecules with similar physicochemical properties is of high importance but practically entails a substantial energy penalty in chemical industry. Meanwhile, clean energy gases such as H_2 and CH_4 are considered as promising candidates for the replacement of traditional fossil fuels. However, the technologies for the storage of these gases are still immature. In addition, the release of anthropogenic toxic gases into the atmosphere is a worldwide threat of growing concern. Both in academia and industry, considerable research efforts have been devoted to developing advanced porous materials for the effective and energy-efficient separation, storage, or capture of the related gases. In contrast to conventional inorganic porous materials such as zeolites and activated carbons, metal–organic frameworks(MOFs) are considered as a type of promising materials for gas separation and storage. In this contribution, we review the recent research advance of MOFs in some relevant applications, including CO_2 capture, O_2 purification, separation of light hydrocarbons, separation of noble gases, storage of gases(CH_4,H_2, and C_2 H_2) for energy, and removal of some gaseous air pollutants(NH_3, NO_2, and SO_2). Finally, an outlook regarding the challenges of the future research of MOFs in these directions is given.
基金Supported by the Natural Science Foundation of Liaoning Province, China （20052193） and Ph.D. Programs Foundation of Ministry of Education o f China （20070141045）.
文摘To improve the separation performance of a supersonic gas separation device for the treatment of gas mixture with a single heavy component, a novel structure with shorter settlement distance was constructed and a method of droplet enlargement was applied. A series of experiments were carried out in the improved separation device under various conditions, using air-ethanol vapor as the medium and micro water droplets as nucleation cen- ters. The effects of the inlet pressure, temperature and relative humidity, the swirling intensity, and mass flow rate of water on the separation performance were investigated. The separation was improved by increasing the inlet pressure and relative humidity. With the decrease of swirling intensity and mass flow rate of water, the separation efficiency increased first and then decreased. The inlet temperature had a slight effect on the separation. The results showed that the separation performance was effectively improved using the proposed structure and method, and the best separation in this study was obtained with the ethanol removal rate about 55% and dew point depression 27 K. The addition of water had little pollution to the air-ethanol vapor system since the water carry-over rate was within the range of -2 %-0 in most cases.
基金the National Science Foundation of China under the Grant Nos.61875158 and 61805192the National Key Research and Development Program of China under the Grant No.2017YFB1104700+1 种基金the International Joint Research Laboratory for Micro/Nano Manufacturing and Measurement Technologiesthe Fundamental Research Funds for the Central Universities。
文摘Underwater transportation of bubbles and gases has essential applications in manipulating and using gas,but achieving this function at the microscopic level remains a significant challenge.Here,we report a strategy to self-transport gas in water along a laser-induced open superhydrophobic microchannel with a width less than 100μm.The femtosecond laser can directly write superhydrophobic and underwater superaerophilic microgrooves on the polytetrafluoroethylene(PTFE)surfaces.In water,the single laser-induced microgroove and water medium generate a hollow microchannel.When the microchannel connects two superhydrophobic regions in water,the gas spontaneously travels from the small region to the large area along this hollow microchannel.Gas self-transportation can be extended to laser-drilled microholes through a thin PTFE sheet,which can even achieve anti-buoyancy unidirectional penetration.The gas can overcome the bubble’s buoyance and spontaneously travel downward.The Laplace pressure difference drives the processes of spontaneous gas transportation and unidirectional bubble passage.We believe the property of gas self-transportation in the femtosecond laser-structured open superhydrophobic and underwater superaerophilic microgrooves/microholes has significant potential applications related to manipulating underwater gas.
基金Supported by the National High Technology Research and Development Program of China (2007AA03Z229)the Fundamental Research Funds for the Central Universities (2009ZM0185)
文摘Three gas separation technologies,chemical absorption,membrane separation and pressure swing adsorption,are usually applied for CO2 capture from flue gas in coal-fired power plants.In this work,the costs of the three technologies are analyzed and compared.The cost for chemical absorption is mainly from $30 to $60 per ton(based on CO2 avoided),while the minimum value is $10 per ton(based on CO2 avoided).As for membrane separation and pressure swing adsorption,the costs are $50 to $78 and $40 to $63 per ton(based on CO2 avoided),respectively.Measures are proposed to reduce the cost of the three technologies.For CO2 capture and storage process,the CO2 recovery and purity should be greater than 90%.Based on the cost,recovery,and purity,it seems that chemical absorption is currently the most cost-effective technology for CO2 capture from flue gas from power plants.However,membrane gas separation is the most promising alternative approach in the future,provided that membrane performance is further improved.
基金Supported by the National Basic Research Program of China (No.2003CB615700), and National Natural Science Foundation ofChina (No.20376037).
文摘The permeation of various pure gas （H2, He, Ne, CH4 and At） through carbon membranes is investigated using a dual control volume grand canonical molecular dynamics method. A two-dimensional slit pore is employed instead of the one-dimensional pore. Compared with the experiments, simulation results show that the improvement of pore model is very necessary. The effects of membrane thickness, pore width and temperature on gas permeance and ideal separation factor are also discussed. Results show that gas permeates through membrane according to Knudsen diffusion in large pore, while Knudsen diffusion is accompanied by molecular sieving in small pore. Moreover, methane is easily adsorbed on the membrane surface due to strong attractive interactions of membrane and shows higher permeance than that of Knudsen flow. In addition, it is noted that when membrane thickness is thin enough the permeance of gas does not decrease with the increase of membrane thickness due to the strong adsorption until membrane resistance becomes dominant.
文摘The application of swirl tube cyclone for gas-liquid separation is attractive due to its small size and weight. However, very scarce information on the performance of the swirl tube cyclone especially at high operating pressure emulating actual field condition was published in journals. Performance assessment was usually done at a low operating pressure using either air-water, air-fine particle mixtures or dense gas such as SF6 . This paper fills the existing gaps and reports the initial findings on the performance assessment of a horizontal swirl tube cyclone for gas-liquid separation operating at a flow rate of 5 MMSCFD at 40-60 bar operating pressure.
基金Project supported by the Science and Technology of Henan Province (991110343)
文摘Oxygen diffusion and oxygen selective adsorption properties of rare earths material YBa_2Cu_3O_(7-x) (YBCO) were investigated by thermogravimetric, oxygen static adsorption and selectivity adsorption experiments. The results show that YBCO is a very good deoxidizing material. The oxygen desorption of YBCO begins remarkably at about 400 ℃, mass loss can arrive at 1.2% of its original quantity at 800 ℃. Oxygen can be completely absorbed back into the sample again when temperature descends to 400 ℃. The oxygen adsorption selectivity, reproducibility and oxygen adsorption under very low oxygen partial pressure make the material desirable for air separation and gas purification. High purity nitrogen gas was produced with the YBCO molecular sieves in the air separation and gas purification experiments. 0.017 m^3 of high purity nitrogen (>99.9999%) can be obtained with 1 kg YBCO molecular sieve in one cycle. As a deoxidant, an obvious advantage of YBCO is that no hydrogen is needed in its applications.
基金the National Natural Science Foundation of China(21922805,91934303,21776125)the Topnotch Academic Programs Project of Jiangsu Higher Education Institutions(TAPP)for financial support。
文摘Natural gas, as a very important source of energy and chemical feedstock, can be used in place of coal to lower net carbon dioxide emissions.Membrane separation technology is an attractive alternative for natural gas purification where the impurities represented by acid gases(CO_(2) and H_(2)S) as well as inert gases(N_(2)) must be removed to meet the transportation and usage specifications. From the economic benefits viewpoint,asymmetric membranes are required for industrial manufacture and applications. This paper aims to review the latest development of various kinds of asymmetric membranes for natural gas purification, mainly focusing on CO_(2) removal from CH_(4), including H_(2)S and N_(2) separation from CH_(4) as well. According to material types, polymeric, inorganic, mixed-matrix and carbon molecular sieve membranes are introduced. The associated fabrication approaches and transport properties are discussed for each kinds of asymmetric membranes. Towards the practical implementation, an emphasis is placed on hollow fiber asymmetric structure for these polymeric, mixed-matrix and carbon molecular sieve membranes.
基金Supported by the National Natural Science Foundation of China(20906047)the State Key Laboratory of Chemical Engineering(SKL-ChE-09A01)the State Key Laboratory of Materials-Oriented Chemical Engineering(ZK201002)
文摘This paper reports on a new microporous composite silica membrane prepared via acid-catalyzed polymeric route of sol-gel method with tetraethylorthosilicate(TEOS)and a bridged silsesquioxane[1,2-bis(triethoxysilyl)ethane, BTESE]as precursors.A stable nano-sized composite silica sol with a mean volume size of^5 nm was synthesized. A 150 nm-thick defect-free composite silica membrane was deposited on disk support consisting of macroporous α-Al2O3 and mesoporousγ-Al2O3 intermediate layer by using dip-coating approach,followed by calcination under pure nitrogen atmosphere.The composite silica membranes exhibit molecular sieve properties for small gases like H2,CO2,O2,N2,CH4 and SF6 with hydrogen permeances in the range of(1-4)×10 -7mol·m -2·s -1·Pa -1(measured at 200°C,3.0×105 Pa).With respect to the membrane calcined at 500°C,it is found that the permselectivities of H 2 (0.289 nm)with respect to N2(0.365 nm),CH4(0.384 nm)and SF6(0.55 nm)are 22.9,42 and>1000,respectively, which are all much higher than the corresponding Knudsen values(H2/N2=3.7,H2/CH4=2.8,and H2/SF6=8.5).
基金This work was finanially supported by the Key Research Project of Jiangsu Province(No.BE2017645)Scientifc Research and Innovation Project for Graduate Students in Jiangsu Province(No.KYCX19-1757)。and a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions of China。
文摘A rigid aromatic diamine monomer containing di-tert-butylbenzene and dimethyl groups,3,3'-dimethyl-4,4'-diaminophenyl-3",5"-di-tert-butyltoluene,was successfully synthesized by a simple coupling reaction using 3,5-di-tert-butylbenzaldehyde and o-toluidine as starting materials.A series of novel polyimides(PI 3a-3c)with large pendant groups were prepared with the obtained diamine monomer and three different commercial aromatic dianhydrides(3,3',4,4'-biphenyltetracarboxylic dianhydride,4,4'-oxydiphthalic anhydride,and 4,4'-(hexafluoroisopropylidene)diphthalic anhydride)by one-step high temperature polycondensation.The prepared polyimides exhibited high solubility and good membrane forming ability:they could be dissolved not only in some high boiling solvents such as DMF,NMP,DMAc,and m-Cresol at room temperature,but also in some low boiling solvents such as CHCl3,CH2Cl2,and THF.Their solubility in most solvents could exceed 10 wt%,and the flexible membranes could be obtained by casting their solutions.The prepared membranes exhibited good gas separation properties.The permeability coefficients of PI 3c for CO2 and O2 were up to 124.6 and 42.8 barrer,respectively,and the selectivity coefficients for CO2/CH4 and O2/N2 were 14.7 and 3.3,respectively.The membranes had light color and good optical transmission.Their optical transmittance at 450 nm wavelength was in the range of 67%-79%,and the cutoff wavelength was in the range of 310-348 nm.They also had good thermal properties with glass transition temperature(Tg)values in the range of 264-302℃.In addition,these membranes possessed good mechanical properties with tensile strength ranging between 77.8-87.4 MPa,initial modulus ranging between 1.69-1.82 GPa,and elongation at break ranging between 4.8%-6.1%.
文摘This research discusses the separation of methane gas from three different gas mixtures,CH4/H2 S,CH4/N2 and CH4/CO2,using a modified silicon carbide nanosheet(Si CNS)membrane using both molecular dynamics(MD)and computational fluid dynamics(CFD)methods.The research examines the effects of different structures of the Si CNSs on the separation of these gas mixtures.Various parameters including the potential of the mean force,separation factor,permeation rate,selectivity and diffusivity are discussed in detail.Our MD simulations showed that the separation of CH4/H2 S,and CH4/CO2 mixtures was successful,while simulation demonstrated a poor result for the CH4/N2 mixture.The effect of temperature on the diffusivity of gas is also discussed,and a correlation is introduced for diffusivity as a function of temperature.The evaluated value for diffusivity is then used in the CFD method to investigate the permeation rate of gas mixtures.
基金the financial support from the National Natural Science Foundation of China(No.21436009)
文摘Mixed matrix hollow fiber membranes（MMHFMs）filled with metal-organic frameworks（MOFs）have great potential for energy-efficient gas separation processes,but the major hurdle is polymer/MOFs interfacial defects and membrane plasticization.Herein,lab-synthesized MIL-53 was post-functionalized by aminosilane grafting and subsequently incorporated into Ultem-1000 polymer matrix to fabricate high performance MMHFMs.SEM,DLS,XRD and TGA were performed to characterize silane-modified MIL-53（S-MIL-53）and prepared MMHFMs.Moreover,the effect of MOFs loading was systematically investigated first;then gas separation performance of MMHFMs for pure and mixed gas was evaluated under different pressures.MMHFMs containing post-functionalized S-MIL-53 achieved remarkable gas permeation properties which was better than model predictions.Compared to pure HFMs,CO2permeance of MMHFM loaded with 15%S-MIL-53 increased by 157%accompanying with 40%increase for CO2/N2selectivity,which outperformed the MMHFM filled with naked MIL-53.The pure and mixed gas permeation measurements with elevated feed pressure indicated that incorporation of S-MIL-53 also increased the resistance against CO2plasticization.This work reveals that post-modified MOFs embedded in MMHFMs facilitate the improvement of gas separation performance and suppression of membrane plasticization.
基金Supported by the National Natural Science Foundation of China(21276123,21490581)the National High Technology Research and Development Program of China(2012AA03A606)+1 种基金the "Summit of the Six Top Talents" Program of Jiangsu Province(2011-XCL-021)the Open Research Fund Program of Collaborative Innovation Center of Membrane Separation and Water Treatment(2016YB01)
文摘A series of organosilica sols are prepared by the polymeric sol–gel method using 1,2-bis(triethoxysilyl)ethane(BTESE)as the precursor.Particle size distributions of the BTESE-derived sols are systematically investigated by carefully adjusting the synthesis parameters(i.e.,water ratios,acid ratios and solvent ratios)in the sol process.In certain conditions,increasing the water ratio or the acid ratio tends to cause larger sol sizes and bimodal particle size distributions.However,higher solvent ratios lead to smaller sol sizes and unimodal particle size distributions.The organosilica membranes prepared from the optimized sols show excellent H_2 permeances(up to 4.2×10^(-7)mol·m^(-2)·s^(-1)·Pa^(-1))and gas permselectitivies(H_2/CO_2 is 9.5,H_2/N_2 is 50 and H_2/CH_4 is 68).This study offers significant insights into the relationship between the sol synthesis parameters,sol sizes and membrane performance.
基金financially supported by the National Natural Science Foundation of China (Nos. 22078245 and 21861016)YLU-DNL Fund (No. 2022009)
文摘The design and development of highly permeable,selective and stable polymer membranes are great challenges in the gas separation industry.Herein,we constructed two intrinsic microporous polyimides(6FPCA and 6FMCA)derived from two isometric diamines(PCA and MCA),which were synthesized by palladium catalyzed C—N coupling reaction.The PCA and MCA diamines contain a hollow beaded structure of 2,2′-paracyclophane as a building block with a specified window size of 3.09Å.The chemical structures of monomers,polyimides were confirmed by NMR,FTIR,and elementary analysis.6FPCA and 6FMCA exhibit good solubility,excellent thermal stability,and mechanical properties.6FPCA exhibits much larger microporosity(434 versus 120 m2·g−1),FFV(0.22 versus 0.15),d-spacing(6.9 versus 5.9Å),and over 10 times higher permeability with a very little decrease in selectivity than the corresponding polyimide(6FpA)with a plane structure,which remarkably increased their separation performance from far below the 2008 Robeson Upper bounds to reach these limitations for O2/N2 and CO2/CH4.Additionally,the 6FPCA also demonstrates good plasticization resistance,moderate aging properties,and high CO2/CH4 mixed-gas separation performance.These results indicate that paracyclophane subunit can be successfully incorporated into polymers to enhance their ultra-microporosity and separation properties,which open a new avenue for developing high performance gas separation membranes with topological ultra-micropores.
