Adsorption isotherms of carbon dioxide （CO2）, methane （CH4）, and nitrogen （N2） on Hβand sodium exchanged β-zeolite （Naβ） were volumetrically measured at 273 and 303 K. The results show that all isotherms we...Adsorption isotherms of carbon dioxide （CO2）, methane （CH4）, and nitrogen （N2） on Hβand sodium exchanged β-zeolite （Naβ） were volumetrically measured at 273 and 303 K. The results show that all isotherms were of Brunauer type I and well correlated with Langmuir-Freundlich model. After sodium ions exchange, the adsorption amounts of three adsorbates increased, while the increase magnitude of CO2 adsorption capacity was much higher than that of CH4 and N2. The selectivities of CO2 over CH4 and CO2 over N2 enhanced after sodium exchange. Also, the initial heat of adsorption data implied a stronger interaction of CO2 molecules with Na＋ ions in Naβ . These results can be attributed to the larger electrostatic interaction of CO2 with extraframework cations in zeolites. However, Naβ showed a decrease in the selectivity of CH4 over N2, which can be ascribed to the moderate affinity of N2 with Naβ. The variation of isosteric heats of adsorption as a function of loading indicates that the adsorption of CO2 in Naβ presents an energetically heterogeneous profile. On the contrary, the adsorption of CH4 was found to be essentially homogeneous, which suggests the dispersion interaction between CH4 and lattice oxygen atoms, and such interaction does not depend on the exchangeable cations of zeolite.展开更多
A novel ZIF-8-CMC hybrid material was fabricated from the hybridization of ZIF-8 and carboxymethylcellulose(CMC) by impregnation method for n-hexane/3-methylpentane separation.The surface properties of ZIF-8 were tail...A novel ZIF-8-CMC hybrid material was fabricated from the hybridization of ZIF-8 and carboxymethylcellulose(CMC) by impregnation method for n-hexane/3-methylpentane separation.The surface properties of ZIF-8 were tailored by introducing CMC into ZIF-8 nanoparticles.In this work,adsorption separation of n-hexane(nHEX) and 3-methylpentane(3 MP) on ZIF-8-CMC were investigated by batch vapor-phase adsorption and liquid-phase breakthrough adsorption.The adsorption selectivity of nHEX/3 MP reversed from preferable adsorption of nHEX to preferable adsorption of 3 MP upon the increasing of CMC containing in the hybrid materials.As the temperature increases,the adsorption amounts of nHEX and 3 MP decrease.With the increasing of CMC contents,the nHEX uptake decreased,the uptake capacity of 3 MP increased gradually.For liquid-phase breakthrough adsorption,the dynamic adsorption capacity of nHEX also decreased with the increasing of temperature.展开更多
We report a robust pillar-layered metal-organic framework,Zn‑tfbdc‑dabco(tfbdc:tetrafluoroterephthal-ate,dabco:1,4-diazabicyclo[2.2.2]octane),featuring the fluorinated pore environment,for the preferential binding of ...We report a robust pillar-layered metal-organic framework,Zn‑tfbdc‑dabco(tfbdc:tetrafluoroterephthal-ate,dabco:1,4-diazabicyclo[2.2.2]octane),featuring the fluorinated pore environment,for the preferential binding of propane over propylene and thus highly inverse selective separation of propane/propylene mixture.The inverse propane-selective performance of Zn‑tfbdc‑dabco for the propane/propylene separation was validated by single-component gas adsorption isotherms,isosteric enthalpy of adsorption calculations,ideal adsorbed solution theory calculations,along with the breakthrough experiment.The customized fluorinated networks served as a propane-trap to form more interactions with the exposed hydrogen atoms of propane,as unveiled by the simulation studies at the molecular level.With the advantage of inverse propane-selective adsorption behavior,high adsorption capacity,good cycling stability,and low isosteric enthalpy of adsorption,Zn‑tfbdc‑dabco can be a promising candidate adsorbent for the challenging propane/propylene separation to realize one-step purification of the target propylene substance.展开更多
Methane(CH_(4)),as the primary component of natural gas,has the highest hydrogen-to-carbon ratio,making it a clean energy source[1].In contrast to high-concentration methane source derived from oil extraction,low-grad...Methane(CH_(4)),as the primary component of natural gas,has the highest hydrogen-to-carbon ratio,making it a clean energy source[1].In contrast to high-concentration methane source derived from oil extraction,low-grade coal-bed methane(CBM,<30%,predominantly mixed with N_(2)),is difficult to be used directly and often is released into the atmosphere during coal mining for safety reasons[2].The methane emission not only wastes a cleaner energy source but also contributes to global warming,as methane ranks as the second most significant greenhouse gas[3].展开更多
The separation of alicyclic ketones and alicyclic alcohols is one of the challenges in the field of petrochemical industry. However, traditional separation methods suffer from excessive energy consumption,complicated ...The separation of alicyclic ketones and alicyclic alcohols is one of the challenges in the field of petrochemical industry. However, traditional separation methods suffer from excessive energy consumption,complicated operation, and unsatisfactory separation efficiency for substances with similar boiling points.Herein, we offer an innovative method for the separation of alicyclic ketones and alicyclic alcohols employing nonporous adaptive crystals(NACs) of perethylated pillar[5]arene(EtP5) and perethylated pillar[6]arene(Et P6). NACs of EtP5 cannot adsorb either alicyclic ketones or alicyclic alcohols because of the small cavity size of Et P5. By contrast, NACs of Et P6 can separate cyclopentanone from the vapor mixture of cyclopentanone/cyclopentanol(v:v = 1:1) and cyclohexanone from the vapor mixture of cyclohexanone/cyclohexanol(v:v = 1:1) with purities of 99.1% and 100%, respectively. Density functional theory calculations show that the selectivity comes from the thermodynamic stability of the newly formed crystal structure after adsorption of the preferred vip molecule. Moreover, NACs of Et P6 can be reused without losing selectivity and performance.展开更多
Pyridine(Py) and 3-methylpyridine(3-MP) are crucial intermediates in chemical industrial processes.Here,we provide a simple and energy-efficient approach for the isolation of Py and 3-MP by employing crystalline cucur...Pyridine(Py) and 3-methylpyridine(3-MP) are crucial intermediates in chemical industrial processes.Here,we provide a simple and energy-efficient approach for the isolation of Py and 3-MP by employing crystalline cucurbit[6]uril(Q[6]).The crystal exhibit high selectivity for Py from the mixture of Py and 3-MP in both vapor and liquid phases,with separation purities close to 100%.The selectivity is attributed to the varying stability of the host-vip complexes after the absorption of Py or 3-MP,as revealed by the single-crystal structure analysis.ITC experimental results and DFT calculations indicate that,compared to3-MP,Q[6] has a higher binding strength and lower binding energy with Py.In addition,pyridine can be removed from the Q[6] cavity through vacuum heating or organic solvent immersion,enabling Q[6]reuse via reversible vip loading.This method offers a promising approach for high-purity Py and 3-MP separation with significant economic and environmental benefits.展开更多
Aromatic nitro compounds present substantial health and environmental concerns due to their toxic nature and potential explosive properties.Consequently,the development of host–vip molecular recognition systems for...Aromatic nitro compounds present substantial health and environmental concerns due to their toxic nature and potential explosive properties.Consequently,the development of host–vip molecular recognition systems for these compounds serves a dual-purpose:enabling the fabrication of high-performance sensors for detection and guiding the design of efficient adsorbents for environmental remediation.This study investigated the host–vip recognition behavior of perethylated pillar[n]arenes toward two aromatic nitro molecules,1-chloro-2,4-dinitrobenzene and picric acid.Various techniques including^(1)H NMR,2D NOESY NMR,and UV-vis spectroscopy were employed to explore the binding behavior between pillararenes and aromatic nitro vips in solution.Moreover,valuable single crystal structures were obtained to elucidate the distinct solid-state assembly behaviors of these vips with different pillararenes.The assembled solid-state supramolecular structures observed encompassed a 1:1 host–vip inclusion complex,an external binding complex,and an exo-wall tessellation complex.Furthermore,based on the findings from these systems,a pillararene-based test paper was developed for efficient picric acid detection,and the removal of picric acid from solution was also achieved using pillararenes powder.This research provides novel insights into the development of diverse host–vip systems toward hazardous compounds,offering potential applications in environmental protection and explosive detection domains.展开更多
Separation of ternary C6 cyclic hydrocarbons,i.e.,benzene/cyclohexene/cyclohexane mixtures,is crucial but challenging in the petrochemical industry due to their extremely similar molecular sizes and physical propertie...Separation of ternary C6 cyclic hydrocarbons,i.e.,benzene/cyclohexene/cyclohexane mixtures,is crucial but challenging in the petrochemical industry due to their extremely similar molecular sizes and physical properties.Here,we design and synthesize a new Zn-based metal azolate framework(MAF),MAF-40,with a threedimensional(3D)honeycomb-like framework and 1D sugar-coated-berry type pore channels.By virtue of the strong coordination bonds and abundant trifluoromethyl groups embedded in the pores,MAF-40 exhibits excellent thermal stability(up to 400℃)and acid-base stability(within a pH range of 3–11).Moreover,MAF-40 shows ultrahigh benzene selectivity(38.8)from the ternary benzene/cyclohexene/cyclohexane mixtures,attributed to the strong adsorption affinity from fluorine for benzene and markedly different vip diffusion limited by the small aperture,which are confirmed by computational simulations and infrared spectra.Thus,the results indicated that MAF-40 would be a candidate adsorbent for the separation and purification of benzene from C6 cyclic hydrocarbons,and this work provides a new insight of synthesizing stable MOF materials for separating multicomponent chemical mixtures.展开更多
One porous framework [Zn4（μ4-O）（μ4-4-pca）3]·2（DEF）·2（H2O）（1, 4-H2Pca = 4-pyrazolecarboxylic acid, DEF = N,N-diethylformamide） with MOF-5 type topology has been synthesized solvothermally. Signifi...One porous framework [Zn4（μ4-O）（μ4-4-pca）3]·2（DEF）·2（H2O）（1, 4-H2Pca = 4-pyrazolecarboxylic acid, DEF = N,N-diethylformamide） with MOF-5 type topology has been synthesized solvothermally. Significantly, this compound exhibits high capacity of C2 hydrocarbons. C2H2 capacity could compare with the highest value of the reported MOFs, far exceeding that of MOF-5, as well as the high selectivity adsorption of C2s over C1.展开更多
A new type of covalent organic framework(COF)was achieved using combination of structrally rigid and conformationally othorganal building blocks.The N-2-aryl-substituted triazole derivative(NAT-CHO)was prepared with c...A new type of covalent organic framework(COF)was achieved using combination of structrally rigid and conformationally othorganal building blocks.The N-2-aryl-substituted triazole derivative(NAT-CHO)was prepared with co-planar conformation among the three aromatic rings as the“flat”building block.The 4,4,4,4-(ethene-1,1,2,2-tetrayl)tetraaniline)(ETTA)was applied as the“twist”building block.A 2 D sheet of network was obtained through imine formation.The resulting NAT-COF gave excellent thermal and chemical stability,survived aqueous solutions from p H 5 to 13.With large-size building blocks,the porous framework NAT-COF gave efficient gas adsorption with excellent selectivity of C3 propane over C1 me-thane,suggesting its potential application for selective gas capture and separation.展开更多
Copper incorporated MCM-48 molecular sieve adsorbents with different Cu content have been hydrothermally synthesized. The samples have been characterized by various physicochemical methods, including X-ray diffraction...Copper incorporated MCM-48 molecular sieve adsorbents with different Cu content have been hydrothermally synthesized. The samples have been characterized by various physicochemical methods, including X-ray diffraction （XRD）, nitrogen adsorption （N2） and X-ray photoelectron spectroscopy （XPS）. The results reveal that Cu-MCM-48 with mass fraction of copper up to 10 % can still retain the uniform mesoporous framework of MCM-48. The copper in the framework of MCM-48 was easily auto-reduced to Cu（I） in N2 at high temperature, which did not alter the mesoporous structure of MCM-48. The adsorption equilibrium isotherms of ethylene and ethane on these molecular sieve adsorbents have been measured at 30℃. At 100 kPa, the adsorption capacities of ethylene on 5Cu-MCM-48 and 10Cu-MCM-48 are higher than those on MCM-48. The 10Cu-MCM-48 molecular sieve adsorbent has a higher selective adsorption ratio of ethylene to ethane, the separation factor is 3.8, and the amount of ethylene adsorbed is 11.1 ml·g ^-1.展开更多
Two isomeric metal-organic frameworks(MOFs) with 2-dimensional(2D) and 3-dimensional(3D) topologies both comprised of Cu(Ⅱ) and OTf(OTf = trifluoromethanesulfonate) ions were synthesized and characterized.The CO_2,CH...Two isomeric metal-organic frameworks(MOFs) with 2-dimensional(2D) and 3-dimensional(3D) topologies both comprised of Cu(Ⅱ) and OTf(OTf = trifluoromethanesulfonate) ions were synthesized and characterized.The CO_2,CH_4 and N_2 adsorption properties of the two isomeric MOFs were investigated from 263 K to 298 K at0.1 MPa.The results showed that the 2D MOF exhibited a higher selectivity for CO_2 from CO_2/CH_4 and CH_4from CH_4/N_2 compared to the 3D MOF,even though it possessed a lower surface area and pore volume.The higher adsorption heats of gases on the 2D MOF inferred the strong adsorption potential energy in the layered MOFs.Dynamic separation experiments using CO_2/CH_4 and CH_4/N_2 mixtures on the two MOFs proved that the2 D MOF had a longer elution time than the 3D MOF as well as better separation abilities.展开更多
MIL-125 is a metal-organic framework with great potential for the adsorption and separation of xylene isomers.However,MIL-125 is usually synthesized under anhydrous and anaerobic conditions.In this study,homogeneously...MIL-125 is a metal-organic framework with great potential for the adsorption and separation of xylene isomers.However,MIL-125 is usually synthesized under anhydrous and anaerobic conditions.In this study,homogeneously shaped and highly crystalline MIL-125 was synthesized by introducing water-resistant titanium-containing oligomers into the synthesis process.With the assistance of the novel oligomers,MIL-125 can be synthesized in the presence of water,which meets batch-production requirements.The adsorption separation performance of the obtained highly crystalline MIL-125 was also significantly enhanced.The para-xylene/meta-xylene selectivity can reach 13.5 in mesitylene,which is higher than the selectivity values of most previously reported para-selective adsorbents.The MIL-125 xylene separation performance was verified using both batch adsorption and breakthrough experiments in the liquid phase.In addition,the influence of the solvent effect was evaluated through microcalorimetric experiments,liquid-phase adsorption experiments,and theoretical calculations.展开更多
Material based emerging separation techniques are attracting more and more attention as alternatives to the traditional ones such as distillation and extraction,aiming to reduce energy consumption and pollutant emissi...Material based emerging separation techniques are attracting more and more attention as alternatives to the traditional ones such as distillation and extraction,aiming to reduce energy consumption and pollutant emissions.Due to their structure characteristics,zeolites can act as versatile sieves and adsorbents for molecules and have been successfully applied in some very important separation processes.Herein,two major catalogues of zeolite separations,namely membrane separation and adsorptive separation,are discussed and their underlying mechanisms are focused.In the part of membrane separation,the synthesis strategies toward zeolite membranes are introduced and the uniformly-oriented zeolite membranes are emphasized.In the part of the adsorptive separation,the industrial and popular adsorptive separations with the corresponding zeolite adsorbents are summarized.Generally,membrane separation relies on the molecular diffusion behavior within zeolites while adsorptive separation relies on the vip–host interaction in principle.The key challenges and misconceptions in zeolite separations are highlighted throughout the article.展开更多
Adsorptive separation of light hydrocarbons by porous solids provides an energy-efficient alternative to state-of-the-art cryogenic distillation.However,an optimal balance between the cost,performance and stability of...Adsorptive separation of light hydrocarbons by porous solids provides an energy-efficient alternative to state-of-the-art cryogenic distillation.However,an optimal balance between the cost,performance and stability of the sorbent material is yet to be achieved for industrial applications.Here,we report the efficient separation of C2 and C3 hydrocarbons by a faujasite zeolite(Na-X,Si/Al=1.23).A tandem configuration of two fixed-beds packed with Na-X affords complete dynamic separation of the ternary mixture of C_(2)H_(2)/C_(2)H_(4)/C_(2)H_(6)(1/49.5/49.5;v/v/v)under ambient conditions.Pressure-swing desorption on the latter fixed-bed gives ethylene(>99.50%,1.80 mmol g^(-1))and ethane(>99.99%,1.41 mmol g^(-1)).In situ synchrotron X-ray powder diffraction revealed the binding sites for C_(2)H_(2)and C_(2)H_(4)in Na-X.This study highlights the potential application of commercial zeolites for challenging industrial separations.展开更多
Until now, to remove the harmful organic dyes from effluents is an outstanding challenge. The design and synthesis of new porous materials capable of selectively adsorbing dyes are critical to the environment and huma...Until now, to remove the harmful organic dyes from effluents is an outstanding challenge. The design and synthesis of new porous materials capable of selectively adsorbing dyes are critical to the environment and human health. Here, a unique cluster-based cationic metal-organic framework, named{[Zn8（BTA）6（L）5Cl2]·（NO3）3}·5 DMF（NUM-4） was synthesized, which displays one-dimensional（1 D）open channels along a axis in its 3 D supramolecular stacking structure. Benefiting from the nature of cationic framework and high surface area/pore volume, NUM-4 shows rapid and selective adsorption of anionic dyes（MO, AO, CR and MB） based on the charge-exclusive effect. Besides, the adsorbed dyes can be easily released in NH4Cl saturated solution of ethanol.展开更多
Binderless zeolite is considered to be a potential alternative for binder-containing zeolite in the industrial applications of adsorptive separation process. Synthesized binderless zeolite and commercial binder-contai...Binderless zeolite is considered to be a potential alternative for binder-containing zeolite in the industrial applications of adsorptive separation process. Synthesized binderless zeolite and commercial binder-containing product were used in adsorptive separation of n-paraffins from a model oil, with their performance compared. It is indicated that the binderless zeolite exhibits by 25%-35% higher in saturated adsorption capacity and by 115%-130% more adsorption amount at the breakthrough point with much shorter length of mass-transfer zone. Adsorptive separation of n-paraffins from naphtha was carried out in a fixed-bed adsorber containing the synthesized binderless zeolite 5 A under the operating conditions covering a feed space velocity of 90 h-1 and an adsorption temperature of 573 K. As compared to original naphtha, the raffinate shows by 34 units more in research octane number and by around 10% more of potential aromatic content, while the desorption oil exhibits by 13.3% more ethylene yield and by 11.7% higher in total olefins yield.展开更多
Lanthanide-ion imprinted polymers（L-IIPs） were synthesized by stoichiometric amounts of rare earth ions and the cavities in the polymers were created for the corresponding lanthanide ions. The maximum sorption capac...Lanthanide-ion imprinted polymers（L-IIPs） were synthesized by stoichiometric amounts of rare earth ions and the cavities in the polymers were created for the corresponding lanthanide ions. The maximum sorption capacities were estimated to be 125.3, 126.5, 127.6, 128.2 and 129.1 mg/g for Pr, Nd, Sm, Eu and Gd, respectively at p H 6. In the selectivity study, the L-IIPs exhibited good selectivity to the specific rare earth ions in the presence of coexisting cations. The imprinting results were found to be excellent with some rare earth ions over other competitor rare earth ions with the same charges and close ionic radius.展开更多
The adsorptive separation of ethylene from ethane exhibits a less energy-intensive-alternative technique with development potential among all processes for separation of ethylene/ethane currently. In this approach, ze...The adsorptive separation of ethylene from ethane exhibits a less energy-intensive-alternative technique with development potential among all processes for separation of ethylene/ethane currently. In this approach, zeolite 5 A with different particle sizes ranging from 3 340 nm to 440 nm was prepared by hydrothermal synthesis. The effect of particle size on the adsorptive separation performance of zeolite 5 A was investigated. The results show that the particle size has a significant effect on the ethylene IAST(Ideal Adsorbed Solution Theory) selectivity of zeolite 5 A. The zeolite 5 A with a particle size of 710 nm demonstrated the highest ethylene selectivity(5.6). The relatively high crystallinity of zeolite 5 A is in favor of massive adsorption capacities of ethylene and ethane.展开更多
Novel porous aromatic frameworks（PAF-53 and PAF-54） have been obtained by the polymerization of amino compound（p-phenylenediamine and melamine） and cyanuric chloride. They display a certain amount of CO2 adsorptio...Novel porous aromatic frameworks（PAF-53 and PAF-54） have been obtained by the polymerization of amino compound（p-phenylenediamine and melamine） and cyanuric chloride. They display a certain amount of CO2 adsorption capacity and highly selective separation of CO2/CH4 and CO2/N2 as 18.1 and83 by Henry Law respectively. They may be applied as ideal adsorbents to separate and capture CO2.展开更多
基金supported by the Doctoral Program of Higher Education(Project 200402910050)the Program for Changiiang Scholars and Innovative Research Team in University(No.IRT0732)Major Basic Research Project of Natural Science Foundation of Jiangsu Province Colleges(No.08KJA530001)
文摘Adsorption isotherms of carbon dioxide （CO2）, methane （CH4）, and nitrogen （N2） on Hβand sodium exchanged β-zeolite （Naβ） were volumetrically measured at 273 and 303 K. The results show that all isotherms were of Brunauer type I and well correlated with Langmuir-Freundlich model. After sodium ions exchange, the adsorption amounts of three adsorbates increased, while the increase magnitude of CO2 adsorption capacity was much higher than that of CH4 and N2. The selectivities of CO2 over CH4 and CO2 over N2 enhanced after sodium exchange. Also, the initial heat of adsorption data implied a stronger interaction of CO2 molecules with Na＋ ions in Naβ . These results can be attributed to the larger electrostatic interaction of CO2 with extraframework cations in zeolites. However, Naβ showed a decrease in the selectivity of CH4 over N2, which can be ascribed to the moderate affinity of N2 with Naβ. The variation of isosteric heats of adsorption as a function of loading indicates that the adsorption of CO2 in Naβ presents an energetically heterogeneous profile. On the contrary, the adsorption of CH4 was found to be essentially homogeneous, which suggests the dispersion interaction between CH4 and lattice oxygen atoms, and such interaction does not depend on the exchangeable cations of zeolite.
基金supported by the National Natural Science Foundation of China (Nos. 11775037 and 21676030)the Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology (BM212110)The Postgraduate Innovation Project of Changzhou University (KYCX19_1782)。
文摘A novel ZIF-8-CMC hybrid material was fabricated from the hybridization of ZIF-8 and carboxymethylcellulose(CMC) by impregnation method for n-hexane/3-methylpentane separation.The surface properties of ZIF-8 were tailored by introducing CMC into ZIF-8 nanoparticles.In this work,adsorption separation of n-hexane(nHEX) and 3-methylpentane(3 MP) on ZIF-8-CMC were investigated by batch vapor-phase adsorption and liquid-phase breakthrough adsorption.The adsorption selectivity of nHEX/3 MP reversed from preferable adsorption of nHEX to preferable adsorption of 3 MP upon the increasing of CMC containing in the hybrid materials.As the temperature increases,the adsorption amounts of nHEX and 3 MP decrease.With the increasing of CMC contents,the nHEX uptake decreased,the uptake capacity of 3 MP increased gradually.For liquid-phase breakthrough adsorption,the dynamic adsorption capacity of nHEX also decreased with the increasing of temperature.
文摘We report a robust pillar-layered metal-organic framework,Zn‑tfbdc‑dabco(tfbdc:tetrafluoroterephthal-ate,dabco:1,4-diazabicyclo[2.2.2]octane),featuring the fluorinated pore environment,for the preferential binding of propane over propylene and thus highly inverse selective separation of propane/propylene mixture.The inverse propane-selective performance of Zn‑tfbdc‑dabco for the propane/propylene separation was validated by single-component gas adsorption isotherms,isosteric enthalpy of adsorption calculations,ideal adsorbed solution theory calculations,along with the breakthrough experiment.The customized fluorinated networks served as a propane-trap to form more interactions with the exposed hydrogen atoms of propane,as unveiled by the simulation studies at the molecular level.With the advantage of inverse propane-selective adsorption behavior,high adsorption capacity,good cycling stability,and low isosteric enthalpy of adsorption,Zn‑tfbdc‑dabco can be a promising candidate adsorbent for the challenging propane/propylene separation to realize one-step purification of the target propylene substance.
基金supported by the National Natural Science Foundation of China(22225803,22038001,22278011,and 22108007)the Beijing Natural Science Foundation(Z230023)the Beijing Nova Program(Z211100002121094).
文摘Methane(CH_(4)),as the primary component of natural gas,has the highest hydrogen-to-carbon ratio,making it a clean energy source[1].In contrast to high-concentration methane source derived from oil extraction,low-grade coal-bed methane(CBM,<30%,predominantly mixed with N_(2)),is difficult to be used directly and often is released into the atmosphere during coal mining for safety reasons[2].The methane emission not only wastes a cleaner energy source but also contributes to global warming,as methane ranks as the second most significant greenhouse gas[3].
基金supported by the National Natural Science Foundation of China (No. 22101043)the Fundamental Research Funds for the Central Universities (Nos. N2205013, N232410019, N2405013)+2 种基金Natural Science Foundation of Liaoning Province (No. 2023-MSBA-068)the Opening Fund of State Key Laboratory of Heavy Oil Processing (No. SKLHOP202203006)Northeastern University。
文摘The separation of alicyclic ketones and alicyclic alcohols is one of the challenges in the field of petrochemical industry. However, traditional separation methods suffer from excessive energy consumption,complicated operation, and unsatisfactory separation efficiency for substances with similar boiling points.Herein, we offer an innovative method for the separation of alicyclic ketones and alicyclic alcohols employing nonporous adaptive crystals(NACs) of perethylated pillar[5]arene(EtP5) and perethylated pillar[6]arene(Et P6). NACs of EtP5 cannot adsorb either alicyclic ketones or alicyclic alcohols because of the small cavity size of Et P5. By contrast, NACs of Et P6 can separate cyclopentanone from the vapor mixture of cyclopentanone/cyclopentanol(v:v = 1:1) and cyclohexanone from the vapor mixture of cyclohexanone/cyclohexanol(v:v = 1:1) with purities of 99.1% and 100%, respectively. Density functional theory calculations show that the selectivity comes from the thermodynamic stability of the newly formed crystal structure after adsorption of the preferred vip molecule. Moreover, NACs of Et P6 can be reused without losing selectivity and performance.
基金supported by the Guizhou Provincial Basic Research Program(Natural Science) Youth Guidance(Nos.[2024]110,[2024]378)Science and Technology Innovation Team of Natural Science Foundation of Guizhou Province(No.CXTD[2023]005)+3 种基金Science and Technology Innovation Team of Higher Education Department of Guizhou Province(No.QJJ[2023]053)Natural Science Special of Guizhou University(No.202137)Guizhou Provincial Key Laboratory Platform Project(No.ZSYS[2025]008)PhD Foundation of Guizhou University(No.[2021]83)。
文摘Pyridine(Py) and 3-methylpyridine(3-MP) are crucial intermediates in chemical industrial processes.Here,we provide a simple and energy-efficient approach for the isolation of Py and 3-MP by employing crystalline cucurbit[6]uril(Q[6]).The crystal exhibit high selectivity for Py from the mixture of Py and 3-MP in both vapor and liquid phases,with separation purities close to 100%.The selectivity is attributed to the varying stability of the host-vip complexes after the absorption of Py or 3-MP,as revealed by the single-crystal structure analysis.ITC experimental results and DFT calculations indicate that,compared to3-MP,Q[6] has a higher binding strength and lower binding energy with Py.In addition,pyridine can be removed from the Q[6] cavity through vacuum heating or organic solvent immersion,enabling Q[6]reuse via reversible vip loading.This method offers a promising approach for high-purity Py and 3-MP separation with significant economic and environmental benefits.
基金supported by the fundamental research funds of Zhejiang Sci-Tech University(No.22212286-Y)the Natural Science Foundation of Zhejiang Province(No.LQ24B040003)。
文摘Aromatic nitro compounds present substantial health and environmental concerns due to their toxic nature and potential explosive properties.Consequently,the development of host–vip molecular recognition systems for these compounds serves a dual-purpose:enabling the fabrication of high-performance sensors for detection and guiding the design of efficient adsorbents for environmental remediation.This study investigated the host–vip recognition behavior of perethylated pillar[n]arenes toward two aromatic nitro molecules,1-chloro-2,4-dinitrobenzene and picric acid.Various techniques including^(1)H NMR,2D NOESY NMR,and UV-vis spectroscopy were employed to explore the binding behavior between pillararenes and aromatic nitro vips in solution.Moreover,valuable single crystal structures were obtained to elucidate the distinct solid-state assembly behaviors of these vips with different pillararenes.The assembled solid-state supramolecular structures observed encompassed a 1:1 host–vip inclusion complex,an external binding complex,and an exo-wall tessellation complex.Furthermore,based on the findings from these systems,a pillararene-based test paper was developed for efficient picric acid detection,and the removal of picric acid from solution was also achieved using pillararenes powder.This research provides novel insights into the development of diverse host–vip systems toward hazardous compounds,offering potential applications in environmental protection and explosive detection domains.
基金supported by the National Natural Science Foundation of China(Nos.22090061,22488101,22475240,and 22231012)the State Key Laboratory of Catalysis(No.2024SKL-A-010).
文摘Separation of ternary C6 cyclic hydrocarbons,i.e.,benzene/cyclohexene/cyclohexane mixtures,is crucial but challenging in the petrochemical industry due to their extremely similar molecular sizes and physical properties.Here,we design and synthesize a new Zn-based metal azolate framework(MAF),MAF-40,with a threedimensional(3D)honeycomb-like framework and 1D sugar-coated-berry type pore channels.By virtue of the strong coordination bonds and abundant trifluoromethyl groups embedded in the pores,MAF-40 exhibits excellent thermal stability(up to 400℃)and acid-base stability(within a pH range of 3–11).Moreover,MAF-40 shows ultrahigh benzene selectivity(38.8)from the ternary benzene/cyclohexene/cyclohexane mixtures,attributed to the strong adsorption affinity from fluorine for benzene and markedly different vip diffusion limited by the small aperture,which are confirmed by computational simulations and infrared spectra.Thus,the results indicated that MAF-40 would be a candidate adsorbent for the separation and purification of benzene from C6 cyclic hydrocarbons,and this work provides a new insight of synthesizing stable MOF materials for separating multicomponent chemical mixtures.
基金supported financially by the National Natural Science Foundation of China(No.21601080)the Key Scientific Research Projects of Higher Education of He'nan Province(16A150016)
文摘One porous framework [Zn4（μ4-O）（μ4-4-pca）3]·2（DEF）·2（H2O）（1, 4-H2Pca = 4-pyrazolecarboxylic acid, DEF = N,N-diethylformamide） with MOF-5 type topology has been synthesized solvothermally. Significantly, this compound exhibits high capacity of C2 hydrocarbons. C2H2 capacity could compare with the highest value of the reported MOFs, far exceeding that of MOF-5, as well as the high selectivity adsorption of C2s over C1.
文摘A new type of covalent organic framework(COF)was achieved using combination of structrally rigid and conformationally othorganal building blocks.The N-2-aryl-substituted triazole derivative(NAT-CHO)was prepared with co-planar conformation among the three aromatic rings as the“flat”building block.The 4,4,4,4-(ethene-1,1,2,2-tetrayl)tetraaniline)(ETTA)was applied as the“twist”building block.A 2 D sheet of network was obtained through imine formation.The resulting NAT-COF gave excellent thermal and chemical stability,survived aqueous solutions from p H 5 to 13.With large-size building blocks,the porous framework NAT-COF gave efficient gas adsorption with excellent selectivity of C3 propane over C1 me-thane,suggesting its potential application for selective gas capture and separation.
基金Supported by the National Natural Science Foundation of China （20276029） and the Specialized Research Fund for the Doctoral Program of Higher Education of China （20040291005）.
文摘Copper incorporated MCM-48 molecular sieve adsorbents with different Cu content have been hydrothermally synthesized. The samples have been characterized by various physicochemical methods, including X-ray diffraction （XRD）, nitrogen adsorption （N2） and X-ray photoelectron spectroscopy （XPS）. The results reveal that Cu-MCM-48 with mass fraction of copper up to 10 % can still retain the uniform mesoporous framework of MCM-48. The copper in the framework of MCM-48 was easily auto-reduced to Cu（I） in N2 at high temperature, which did not alter the mesoporous structure of MCM-48. The adsorption equilibrium isotherms of ethylene and ethane on these molecular sieve adsorbents have been measured at 30℃. At 100 kPa, the adsorption capacities of ethylene on 5Cu-MCM-48 and 10Cu-MCM-48 are higher than those on MCM-48. The 10Cu-MCM-48 molecular sieve adsorbent has a higher selective adsorption ratio of ethylene to ethane, the separation factor is 3.8, and the amount of ethylene adsorbed is 11.1 ml·g ^-1.
基金Supported by National Natural Science Foundation of China(No.21136007,No.51302184)the National Research Fund for Fundamental Key Projects(No.2014CB260402)
文摘Two isomeric metal-organic frameworks(MOFs) with 2-dimensional(2D) and 3-dimensional(3D) topologies both comprised of Cu(Ⅱ) and OTf(OTf = trifluoromethanesulfonate) ions were synthesized and characterized.The CO_2,CH_4 and N_2 adsorption properties of the two isomeric MOFs were investigated from 263 K to 298 K at0.1 MPa.The results showed that the 2D MOF exhibited a higher selectivity for CO_2 from CO_2/CH_4 and CH_4from CH_4/N_2 compared to the 3D MOF,even though it possessed a lower surface area and pore volume.The higher adsorption heats of gases on the 2D MOF inferred the strong adsorption potential energy in the layered MOFs.Dynamic separation experiments using CO_2/CH_4 and CH_4/N_2 mixtures on the two MOFs proved that the2 D MOF had a longer elution time than the 3D MOF as well as better separation abilities.
文摘MIL-125 is a metal-organic framework with great potential for the adsorption and separation of xylene isomers.However,MIL-125 is usually synthesized under anhydrous and anaerobic conditions.In this study,homogeneously shaped and highly crystalline MIL-125 was synthesized by introducing water-resistant titanium-containing oligomers into the synthesis process.With the assistance of the novel oligomers,MIL-125 can be synthesized in the presence of water,which meets batch-production requirements.The adsorption separation performance of the obtained highly crystalline MIL-125 was also significantly enhanced.The para-xylene/meta-xylene selectivity can reach 13.5 in mesitylene,which is higher than the selectivity values of most previously reported para-selective adsorbents.The MIL-125 xylene separation performance was verified using both batch adsorption and breakthrough experiments in the liquid phase.In addition,the influence of the solvent effect was evaluated through microcalorimetric experiments,liquid-phase adsorption experiments,and theoretical calculations.
基金the financial support by the National Natural Science Fund of China(22121005,22025203)the Frontiers Science Center for New Organic Matter,Nankai University(63181206)the Haihe Laboratory of Sustainable Chemical Transformations,Tianjin。
文摘Material based emerging separation techniques are attracting more and more attention as alternatives to the traditional ones such as distillation and extraction,aiming to reduce energy consumption and pollutant emissions.Due to their structure characteristics,zeolites can act as versatile sieves and adsorbents for molecules and have been successfully applied in some very important separation processes.Herein,two major catalogues of zeolite separations,namely membrane separation and adsorptive separation,are discussed and their underlying mechanisms are focused.In the part of membrane separation,the synthesis strategies toward zeolite membranes are introduced and the uniformly-oriented zeolite membranes are emphasized.In the part of the adsorptive separation,the industrial and popular adsorptive separations with the corresponding zeolite adsorbents are summarized.Generally,membrane separation relies on the molecular diffusion behavior within zeolites while adsorptive separation relies on the vip–host interaction in principle.The key challenges and misconceptions in zeolite separations are highlighted throughout the article.
基金supported by the National Natural Science Fund of China(22121005,22025203)the University of Manchester,and Haihe Laboratory of Sustainable Chemical Transformations,Tianjin。
文摘Adsorptive separation of light hydrocarbons by porous solids provides an energy-efficient alternative to state-of-the-art cryogenic distillation.However,an optimal balance between the cost,performance and stability of the sorbent material is yet to be achieved for industrial applications.Here,we report the efficient separation of C2 and C3 hydrocarbons by a faujasite zeolite(Na-X,Si/Al=1.23).A tandem configuration of two fixed-beds packed with Na-X affords complete dynamic separation of the ternary mixture of C_(2)H_(2)/C_(2)H_(4)/C_(2)H_(6)(1/49.5/49.5;v/v/v)under ambient conditions.Pressure-swing desorption on the latter fixed-bed gives ethylene(>99.50%,1.80 mmol g^(-1))and ethane(>99.99%,1.41 mmol g^(-1)).In situ synchrotron X-ray powder diffraction revealed the binding sites for C_(2)H_(2)and C_(2)H_(4)in Na-X.This study highlights the potential application of commercial zeolites for challenging industrial separations.
基金financially supported by the National Natural Science Foundation of China (Nos. 21371102, 21531005 and 21673120)the Natural Science Foundation of Tianjin (Nos. 16JCZDJC36900 and 15JCZDJC38800)
文摘Until now, to remove the harmful organic dyes from effluents is an outstanding challenge. The design and synthesis of new porous materials capable of selectively adsorbing dyes are critical to the environment and human health. Here, a unique cluster-based cationic metal-organic framework, named{[Zn8（BTA）6（L）5Cl2]·（NO3）3}·5 DMF（NUM-4） was synthesized, which displays one-dimensional（1 D）open channels along a axis in its 3 D supramolecular stacking structure. Benefiting from the nature of cationic framework and high surface area/pore volume, NUM-4 shows rapid and selective adsorption of anionic dyes（MO, AO, CR and MB） based on the charge-exclusive effect. Besides, the adsorbed dyes can be easily released in NH4Cl saturated solution of ethanol.
基金financially supported by the Natural Science Foundation of Shanghai(Grant 16ZR1408100)the National Natural Science Foundation of China(Grant 91634112 and 21878097)the Open Project of State Key Laboratory of Chemical Engineering(SKL-ChE-16C01)
文摘Binderless zeolite is considered to be a potential alternative for binder-containing zeolite in the industrial applications of adsorptive separation process. Synthesized binderless zeolite and commercial binder-containing product were used in adsorptive separation of n-paraffins from a model oil, with their performance compared. It is indicated that the binderless zeolite exhibits by 25%-35% higher in saturated adsorption capacity and by 115%-130% more adsorption amount at the breakthrough point with much shorter length of mass-transfer zone. Adsorptive separation of n-paraffins from naphtha was carried out in a fixed-bed adsorber containing the synthesized binderless zeolite 5 A under the operating conditions covering a feed space velocity of 90 h-1 and an adsorption temperature of 573 K. As compared to original naphtha, the raffinate shows by 34 units more in research octane number and by around 10% more of potential aromatic content, while the desorption oil exhibits by 13.3% more ethylene yield and by 11.7% higher in total olefins yield.
基金Project supported by the Ministry of Science,Technology and Innovation,Malaysia(RDU130505,SBK0260-ST-2016)
文摘Lanthanide-ion imprinted polymers（L-IIPs） were synthesized by stoichiometric amounts of rare earth ions and the cavities in the polymers were created for the corresponding lanthanide ions. The maximum sorption capacities were estimated to be 125.3, 126.5, 127.6, 128.2 and 129.1 mg/g for Pr, Nd, Sm, Eu and Gd, respectively at p H 6. In the selectivity study, the L-IIPs exhibited good selectivity to the specific rare earth ions in the presence of coexisting cations. The imprinting results were found to be excellent with some rare earth ions over other competitor rare earth ions with the same charges and close ionic radius.
基金supported by the National Key R&D Program(2016YFB0301601)
文摘The adsorptive separation of ethylene from ethane exhibits a less energy-intensive-alternative technique with development potential among all processes for separation of ethylene/ethane currently. In this approach, zeolite 5 A with different particle sizes ranging from 3 340 nm to 440 nm was prepared by hydrothermal synthesis. The effect of particle size on the adsorptive separation performance of zeolite 5 A was investigated. The results show that the particle size has a significant effect on the ethylene IAST(Ideal Adsorbed Solution Theory) selectivity of zeolite 5 A. The zeolite 5 A with a particle size of 710 nm demonstrated the highest ethylene selectivity(5.6). The relatively high crystallinity of zeolite 5 A is in favor of massive adsorption capacities of ethylene and ethane.
基金support of the National Natural Science Foundation of China(No.0831002)Major International (Regional) Joint Research Project(No.21120102034)
文摘Novel porous aromatic frameworks（PAF-53 and PAF-54） have been obtained by the polymerization of amino compound（p-phenylenediamine and melamine） and cyanuric chloride. They display a certain amount of CO2 adsorption capacity and highly selective separation of CO2/CH4 and CO2/N2 as 18.1 and83 by Henry Law respectively. They may be applied as ideal adsorbents to separate and capture CO2.
