Via the strategy of charge balance,one new pillared layered metal-organic framework [Zn2（TNB）（2-nim）]（H3TNB = 4,4？,4？？-nitrilotribenzoicacid,2-nim = 2-nitroimidazole）（1） was successfully synthesized based o...Via the strategy of charge balance,one new pillared layered metal-organic framework [Zn2（TNB）（2-nim）]（H3TNB = 4,4？,4？？-nitrilotribenzoicacid,2-nim = 2-nitroimidazole）（1） was successfully synthesized based on mixed ligands,where binuclear [Zn2（CO2）3]~＋ cluster-based cationic layers [Zn2（TNB）]~＋ are connected by deprotonated 2-nitroimidazole.Meanwhile,CO2 adsorption bahaviors and luminescent property of compound 1 were investigated.展开更多
Solid sorbents adsorption is considered as one of the potential options for CO2 capture process. CO2 adsorption on MCM-68 （Si/AI ratio 22） sorbent material was investigated. MCM-68 was synthesized using N,N,N＇,N＇-...Solid sorbents adsorption is considered as one of the potential options for CO2 capture process. CO2 adsorption on MCM-68 （Si/AI ratio 22） sorbent material was investigated. MCM-68 was synthesized using N,N,N＇,N＇-tetraethylbicyclo [2.2.2] oct-7-ene-2,3：5,6-dipyrrolidinium diiodide （TEBOP^2＋（I^＋）2） as a structure-directing agent （SDA）. CO2 adsorption capacity on MCM-68 sorbent was measured at a broad temperature window i.e. 60 ℃, 300 ℃ and at 400 ℃. The presence of ordered mesoporous structure, high surface area （456 me/g） and high thermal stability （TGA analysis up to 900℃） in MCM-68 are thought to be to be advantageous for the CO2 adsorption in broad temperature window.展开更多
Two kinds of molecular sieve materials, TC-5A and PSA-5A, were produced to satisfy with special requirement of manned space flight. Their CO2 adsorption performances were investi- gated and compared through two experi...Two kinds of molecular sieve materials, TC-5A and PSA-5A, were produced to satisfy with special requirement of manned space flight. Their CO2 adsorption performances were investi- gated and compared through two experiments, the thermo gravimetric analysis （TGA） experiment and packed bed column experiment. Besides, some kinetic equations were compared according to the TGA experimental data, and their errors were analyzed. Finally, the classic linear driving force （LDF） model is improved to the new Avrami＇s model, and two models are analyzed based on the packed bed data. The TGA data shows that the CO2 loading has an approximately linear relation- ship with the CO2 concentration, and the best fit adsorption temperature range is from 283 to 303 K. The packed bed column results show that water vapor in air can affect the CO2 adsorption performance badly. The new Avrami＇s model is proved more suitable to reflect the complex adsorption mechanism for two molecular sieves. The materials are proved having much better adsorption capacity than the other adsorbents with room temperature and low CO2 concentration （≤ 1.0% in volume）, and they can meet the aerospace requirements. This work will benefit the optimal design and simulation of the air revitalization （AR） system for Chinese manned spacecraft.展开更多
Photocatalytic conversion of“greenhouse gas”CO2is considered to be one of the most effective ways to alleviate current energy and environmental problems without additional energy consumption and pollutant emission.T...Photocatalytic conversion of“greenhouse gas”CO2is considered to be one of the most effective ways to alleviate current energy and environmental problems without additional energy consumption and pollutant emission.The performance of many traditional semiconductor photocatalysts is not efficient enough to satisfy the requirements of practical applications because of their limited specific surface area and low CO2adsorption capacity.Therefore,the exploration of photocatalysts with high CO2uptake is significant in the field of CO2conversion.Recently the porous materials appeared to be a kind of superior candidate for enriching the CO2molecules on the surface of photocatalysts for catalytic conversion.This paper first summarizes the advances in the development of nanoporous adsorbents for CO2capture.Three main classes of porous materials are considered:inorganic porous materials,metal organic frameworks,and microporous organic polymers.Based on systematic research on CO2uptake,we then highlight the recent progress in these porous‐material‐based photocatalysts for CO2conversion.Benefiting from the improved CO2uptake capacity,the porous‐material‐based photocatalysts exhibited remarkably enhanced efficiency in the reduction of CO2to chemical fuels,such as CO,CH4,and CH3OH.Based on reported recent achievements,we predict a trend of development in multifunctional materials with both high adsorption capability and photocatalytic performance for CO2utilization.展开更多
Carbon dioxide （CO2） adsorption on a standard metal-organic framework MIL-101 and a pentaethylenehexamine modified MIL-101 （PEHA- MIL-101） are investigated and compared in this study. The adsorbent samples were ch...Carbon dioxide （CO2） adsorption on a standard metal-organic framework MIL-101 and a pentaethylenehexamine modified MIL-101 （PEHA- MIL-101） are investigated and compared in this study. The adsorbent samples were characterized by XRD, FT-IR and nitrogen adsorption- desorption isotherms analysis. CO2 adsorption capacity was measured by a volumetric method. MIL-101 and PEHA-MIL-101 exhibited CO2 adsorption capacities of 0.85 and 1.3 mmO1CO2/gadsorbent at 10 bar and 298 K, respectively. It is observed that CO2 adsorption capacity was fairly improved about 50% after amine modification.展开更多
The Al-pillared montmorillonite-supported alkaline earth metal 5M/Al-PILC(PILC = pillared clay, M = Mg, Ca, Sr, and Ba) and x Mg/Al-PILC( x = 1, 3, 5, and 7 wt.%) samples were prepared using an impregnation method. Ph...The Al-pillared montmorillonite-supported alkaline earth metal 5M/Al-PILC(PILC = pillared clay, M = Mg, Ca, Sr, and Ba) and x Mg/Al-PILC( x = 1, 3, 5, and 7 wt.%) samples were prepared using an impregnation method. Physical properties of the materials were determined by means of X-ray diffraction(XRD) and N2 adsorption-desorption, and their CO2 adsorption behaviors were investigated using the thermogravimetric analyzer(TG), CO2 temperatureprogrammed desorption(CO2-TPD), and in situ diffuse reflectance infrared transform spectroscopy(in situ-DRIFTS) techniques. It is shown that 5 Mg/Al-PILC possessed the highest CO2 adsorption capacity(2.559 mmol/g). The characterization results indicate that Alpillaring increased the specific surface area of montmorillonite, which was beneficial for the adsorption of CO2. The CO2 adsorption process on the sample was mainly chemical adsorption, and alkalinity was the main factor influencing its adsorption capacity. The alkalinity of the sample was enhanced by loading an appropriate amount of alkaline earth metal, and the adsorbed CO2 was present in the form of bicarbonate and carbonate. In addition, the 5Mg/Al-PILC sample exhibited an excellent regeneration efficiency. We believe that the outcome of this research would provide a good option for developing highly effective CO2 adsorption materials.展开更多
Amine-functionalized mesoporous silica was prepared by using lauric acid and N-stearoyl-l-glutamic acid as structure directing agents via the S-N+-I- mechanism and applied to CO2 adsorption at room temperature. With ...Amine-functionalized mesoporous silica was prepared by using lauric acid and N-stearoyl-l-glutamic acid as structure directing agents via the S-N+-I- mechanism and applied to CO2 adsorption at room temperature. With γ-aminopropyltriethoxysilane as co-structure directing agent and due to the direct electrostatic interaction with anionic surfactant, most of the amino groups were uniformly distributed at the inner surface of pores and the per- formance was stable. The amine-functionalized mesoporous silica was characterized by Fourier transform infrared spectrometer, X-ray diffraction, nitrogen physisorption and thermogravimetric analysis. The CO2 adsorption capacity was measured by digital recording balance. At the room temperature and under the atmospheric pressure, the adsorption capacity of LAA-AMS-0.2 for CO2 and N2 is 1.40 mmol·g-1 and 0.03 mmol·g-1, respectively, indicating high separation coefficient of CO2/N2.展开更多
A novel,porous and doubly interpenetrated MOF（FJU-29） was synthesized and characterized by FT-IR,TGA and X-ray single-crystal/powder diffraction.FJU-29 crystallizes in monoclinic,space group C2/c with a = 22.2890（7...A novel,porous and doubly interpenetrated MOF（FJU-29） was synthesized and characterized by FT-IR,TGA and X-ray single-crystal/powder diffraction.FJU-29 crystallizes in monoclinic,space group C2/c with a = 22.2890（7）,b = 10.9175（2）,c = 21.5601（7） ？,β = 112.908（4）o,V = 4832.7（3） ？~3,Z = 8,Mr = 450.26,D_c = 1.238 g/cm^3,F（000） = 1832,μ（CuKα） = 5.885 mm^（-1）,R = 0.0585 and wR = 0.1544 for 4789 observed reflections（I 〉 2s（I））,and R = 0.0726 and wR = 0.1627 for all data.FJU-29 possesses paddle-wheel {Co_2（COO）_4} clusters bridged by bi-pyrazolate naphthalene diimide ligands（H_2NDI） and H_2BDC to from a 3D framework with a pcu-topology.The desolvated FJU-29a shows the BET surface area of 560.44 m^2·g^（-1） accompanies with discriminating uptakes in CO_2 and N_2.The adsorption selectivity determined by ideal adsorbed solution theory（IAST） indicated that FJU-29 a has high CO_2/N_2（18/85） selectivity（75.5） at 296 K and 100 kPa.The relatively high selectivity further implies that FJU-29 a is a potential material for practical flue gas purification.展开更多
Mesoporous carbon adsorbents, having high nitrogen content, were synthesized via nanocasting technique with melamine-formaldehyde resin as precursor and mesoporous silica as template. A series of adsorbents were prepa...Mesoporous carbon adsorbents, having high nitrogen content, were synthesized via nanocasting technique with melamine-formaldehyde resin as precursor and mesoporous silica as template. A series of adsorbents were prepared by varying the carbonization temperature from 400 to 700°C. Adsorbents were characterized thoroughly by nitrogen sorption, X-ray diffraction（XRD）, scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, thermogravimetric analysis（TGA）, elemental（CHN） analysis, Fourier transform infrared（FTIR） spectroscopy and Boehm titration. Carbonization temperature controlled the properties of the synthesized adsorbents ranging from surface area to their nitrogen content, which play major role in their application as adsorbents for CO2 capture.The nanostructure of these materials was confirmed by XRD and TEM. Their nitrogen content decreased with an increase in carbonization temperature while other properties like surface area, pore volume, thermal stability and surface basicity increased with the carbonization temperature. These materials were evaluated for CO2 adsorption by fixed-bed column adsorption experiments. Adsorbent synthesized at 700°C was found to have the highest surface area and surface basicity along with maximum CO2 adsorption capacity among the synthesized adsorbents. Breakthrough time and CO2 equilibrium adsorption capacity were investigated from the breakthrough curves and were found to decrease with increase in adsorption temperature. Adsorption process for carbon adsorbent-CO2 system was found to be reversible with stable adsorption capacity over four consecutive adsorption-desorption cycles. From three isotherm models used to analyze the equilibrium data, Temkin isotherm model presented a nearly perfect fit implying the heterogeneous adsorbent surface.展开更多
Herein, we report the effects of doped K and Al on the carbon dioxide （CO2） adsorption performance of the Li4SiO4-based adsorbents. The CO2 adsorption capacity of 0.8 wt% K and 1.5 wt% AI doped Li4SiO4 is ～2.2 time...Herein, we report the effects of doped K and Al on the carbon dioxide （CO2） adsorption performance of the Li4SiO4-based adsorbents. The CO2 adsorption capacity of 0.8 wt% K and 1.5 wt% AI doped Li4SiO4 is ～2.2 times and ～1.3 times higher than that of the pristine Li4SiO4 at 500 and 600℃, respectively. The kinetic study further indicated that the reaction rates of the lithium diffusion process is greatly improved by K and AI doping, and the lithium diffusion rate of 0.8 wt% K and 1.5 wt% AI doped Li4SiO4 is ～2 times higher than that of the pristine Li4SiO4 at 575-650 ℃. K and AI doping increases the adsorption capacity of Li4SiO4-based adsorbents, and widens its effective adsorption temperature range展开更多
Microporous hypercross-linked conjugated quinonoid chromophores represent a novel class of amorphous polymers, synthesized by the reaction of anthracene with dimethoxy methane in the presence of FeCl3 catalyst. Their ...Microporous hypercross-linked conjugated quinonoid chromophores represent a novel class of amorphous polymers, synthesized by the reaction of anthracene with dimethoxy methane in the presence of FeCl3 catalyst. Their N2 adsorption isotherms confirm their microporous nature. Diffuse reflectance UV-Visible（DRS UV-Vis） spectroscopy confirms their matrix built with the conjugated quinonoids by their broad light absorption characteristics extending from 1000 nm to 200 nm with the absorbance maximum close to 400 nm. The catalyst cross-linked anthracene with ―CH2― bridges and subsequently dehydrogenating them to form quinonoids. Their Fourier transform infrared（FTIR） spectra showed their characteristic quinonoid vibrations between 1600 and 1700 cm-1. The synthesis of polymers was carried out at 30, 40, 50, 60, 70 and 80 ℃, but the quinonoid content of the polymer obtained at 80 ℃ was higher than that of the others. Their scanning electron microscopy（SEM） images showed microspheres of 1 to 5 μm size built with tiny particles. Their surfaces were not smooth. The polymer synthesized at 80 ℃ showed 5.1 wt% CO2 sorption at 25 ℃ and 0.1 MPa, but when it was recross-linked, the CO2 sorption increased to 8 wt%. Hence, hypercross-linked conjugated quinonoid chromophores of anthracene are good for sorption of CO2.展开更多
A new metal–organic framework {[Zn2（bpta）（bpy-ee）（H2O）2]·x solve}n（1）（H4bpta = biphenyl-2,20,6,60-tetracarboxylic acid and bpy-ee = 1,2-bis（4-pyridyl）ethylene） has been obtained under hydrothermal co...A new metal–organic framework {[Zn2（bpta）（bpy-ee）（H2O）2]·x solve}n（1）（H4bpta = biphenyl-2,20,6,60-tetracarboxylic acid and bpy-ee = 1,2-bis（4-pyridyl）ethylene） has been obtained under hydrothermal condition, and structurally characterized by single-crystal X-ray diffraction. Complex 1 reveals a threedimensional（3D） “pillar-layered” framework with non-flexible linker, in which some different structure characters can be found compared to that of some related other “pillar-layered” MOFs based on flexible pillar linkers. It demonstrates the impact of the flexibility of pillar linker on the final structure in this system. In addition, the selective CO2 adsorption performance of 1 was also investigated.展开更多
The global greenhouse effect makes it urgent to deal with the increasing greenhouse gases. In this paper the performance of MgO-decorated carbon nanotubes for CO2 adsorption is investigated through first principles ca...The global greenhouse effect makes it urgent to deal with the increasing greenhouse gases. In this paper the performance of MgO-decorated carbon nanotubes for CO2 adsorption is investigated through first principles calculations. The results show that the MgO-decorated carbon nanotubes can adsorb CO2 well and are relatively insensitive to O2 and N2 at the same time. The binding energy arrives at 1.18 eV for the single-MgO-decorated carbon nanotube adsorbing one CO2 molecule, while the corresponding values for O2 and N2 are 0.55 eV and 0.06 eV, respectively. In addition, multi-molecule adsorption is also proved to be very satisfactory. These results indicate that MgO-decorated carbon nanotubes have great potential applications in industrial and environmental processes.展开更多
The mesoporous silica modifed with magnesium ox- ide （MgO） was syntbesized by one step method and impregnating method, respectively. The samples were characterized by small angle X-Ray diffraction （XRD）, N2 adsorp...The mesoporous silica modifed with magnesium ox- ide （MgO） was syntbesized by one step method and impregnating method, respectively. The samples were characterized by small angle X-Ray diffraction （XRD）, N2 adsorption-desorption and transmission electron microscopy （TEM）, and the carbon dioxide adsorption capacity was analyzed by thermal gravimetric analysis （TGA）. Compared with the original mesoporous silica （20.7 mg/g）, the CO2 adsorption capacity of MgO-modified mesoporous silica processed by one step method increases to 32.9 mg/g. Although its surface area greatly decreases compared with that of the original mesoporous silica, the MgO-modified mesoporous silica prepared by impregnating reaches an adsorptive value of 31.1 mg/g because the number of basic sites increases on the surface of the mesoporous silica.展开更多
A series of amine-based adsorbents were synthesized using siliceous MCM-41 individually impregnated with four different amines（ethylenediamine（EDA）,diethylenetriamine（DETA）,tetraethylenepentamine（TEPA） and pent...A series of amine-based adsorbents were synthesized using siliceous MCM-41 individually impregnated with four different amines（ethylenediamine（EDA）,diethylenetriamine（DETA）,tetraethylenepentamine（TEPA） and pentaethylenehexamine（PEHA）） to study the effect of amine chain length and loading weight on their CO2 adsorption performances in detail.The adsorbents were characterized by FT-IR,elemental analysis,and thermo-gravimetric analysis to confirm their structure properties.Thermo-gravimetric analysis was also used to evaluate the CO2 adsorption performance of adsorbents.Longer chain amine-based materials can achieve higher amine loadings and show better thermal stability.The CO2 adsorption capacities at different temperatures indicate that the CO2 adsorption is thermodynamically controlled over EDAMCM41 and DETA-MCM41,while the adsorption over TEPA-MCM41 and PEHA-MCM41 is under kinetic control at low temperature.The chain length of amines affects the CO2 adsorption performance and the adsorption mechanism significantly.The results also indicate that CO2 adsorption capacity can be enhanced despite of high operation temperatures,if appropriate amines（TEPA and PEHA） are applied.However,adsorbents with short chain amine exhibit higher adsorption and desorption rates due to the collaborative effect of rapid reaction mechanisms of primary amines and less diffusion resistance of shorter chain length amines.展开更多
In this work, the effects of different methods of activation on CO2 adsorption performance of activated carbon were studied. Activated carbons were prepared from biochar, obtained from fast pyrolysis of white wood, us...In this work, the effects of different methods of activation on CO2 adsorption performance of activated carbon were studied. Activated carbons were prepared from biochar, obtained from fast pyrolysis of white wood, using three different activation methods of steam activation, CO2 activation and Potassium hydroxide（KOH） activation. CO2 adsorption behavior of the produced activated carbons was studied in a fixed-bed reactor set-up at atmospheric pressure, temperature range of 25–65°C and inlet CO2 concentration range of10–30 mol% in He to determine the effects of the surface area, porosity and surface chemistry on adsorption capacity of the samples. Characterization of the micropore and mesopore texture was carried out using N2 and CO2 adsorption at 77 and 273 K, respectively.Central composite design was used to evaluate the combined effects of temperature and concentration of CO2 on the adsorption behavior of the adsorbents. The KOH activated carbon with a total micropore volume of 0.62 cm3/g and surface area of 1400 m2/g had the highest CO2 adsorption capacity of 1.8 mol/kg due to its microporous structure and high surface area under the optimized experimental conditions of 30 mol% CO2 and 25°C. The performance of the adsorbents in multi-cyclic adsorption process was also assessed and the adsorption capacity of KOH and CO2 activated carbons remained remarkably stable after50 cycles with low temperature（160°C） regeneration.展开更多
Reliable estimation of the pore size distribution(PSD) in porous materials such as metal–organic frameworks(MOFs) and zeolitic imidazolate frameworks(ZIFs) is crucial for accurately assessing adsorption capacity and ...Reliable estimation of the pore size distribution(PSD) in porous materials such as metal–organic frameworks(MOFs) and zeolitic imidazolate frameworks(ZIFs) is crucial for accurately assessing adsorption capacity and corresponding selectivity. In this study, the so-called zeolitic imidazolate framework-7(ZIF-7) is successfully synthesized via relatively fast and convenient microwave technique. The morphology and structure of the obtained MOF were characterized by XRD, SEM and N_2 and CO_2adsorption/desorption isotherms at 77 K and0 °C respectively. Then, to determine the PSD of the fabricated MOF, carbon dioxide isotherms are experimentally measured at various temperatures up to atmospheric pressure. Afterward, the experimental CO_2 isotherms data are utilized in two recently proposed in-house algorithms of SHN1 and SHN2 to extract the true PSD of manufactured ZIF-7. The obtained results revealed that median pore diameter of the fabricated ZIF-7 is estimated around 0.404 nm and 0.370 nm by using CO_2 isotherms at 273 K and 298 K respectively. These values are in good agreement with the real pore diameter of 0.42 nm. Moreover, experimental data of water adsorption isotherms over four different MOFs, borrowed from literature, are employed to illustrate further effectiveness of the above algorithms on successful determination of the corresponding pore size distributions. All predicted PSDs are proved to be in good agreement with those obtained from independent methods such as topology and morphology studies.展开更多
TiO2 nanotubes （TiNT） were prepared by a hydrothermal treatment and modified by three kinds of amines,namely ethylenediamine,polyetherimide and tetraethylenepentamine （TEPA）,to study their CO2 adsorption propertie...TiO2 nanotubes （TiNT） were prepared by a hydrothermal treatment and modified by three kinds of amines,namely ethylenediamine,polyetherimide and tetraethylenepentamine （TEPA）,to study their CO2 adsorption properties from gas streams.The resultant samples were characterized by X-ray diffraction,transmission electron microscopy,and infrared spectroscopy,as well as low temperature N 2 adsorption.CO2 capture was investigated in a dynamic packed column at 30℃.TEPA-modified TiO2 nanotubes showed the highest adsorption capacity of 167.64 mg/g because it had the highest amino-group content among the three amines.CO2 fixation on TiNT impregnated by TEPA was investigated at 30,50,and 70℃,and the adsorption capacity increased slightly with temperature.Following the adsorption step,the sorbents were regenerated by temperature programmed desorption,and the TiNT-TEPA sample,as CO2 sorbent,was found to be readily regenerated and energy-efficient.The cycle test also revealed that the TiNT-TEPA adsorbent is fairly stable,with only a 5% drop in the adsorption capacity after 10 adsorption/desorption cycles.In addition,the CO2 adsorption behavior was investigated with the deactivation model,and which showed an excellent prediction for the TiNT-TEPA breakthrough curves.展开更多
In order to better understand the prevailing mechanism of CO2 storage in coal and estimate CO2 sequestration capacity of a coal seam and enhanced coalbed methane recovery （ECBM） with CO2 injection into coal, we inve...In order to better understand the prevailing mechanism of CO2 storage in coal and estimate CO2 sequestration capacity of a coal seam and enhanced coalbed methane recovery （ECBM） with CO2 injection into coal, we investigated the preferential adsorption of CH4 and CO2 on coals. Adsorption of pure CO2, CH4 and their binary mixtures on high-rank coals from Qinshui Basin in China were employed to study the preferential adsorption behaviour. Multiple regression equations were presented to predict CH4 equi- librium concentration from equilibrium pressure and its initial-composition in feed gas. The results show that preferential adsorption of CO2 on coals over the entire pressure range under competitive sorption conditions was observed, however, preferential adsorption of CH4 over CO2 on low-volatile bituminous coal from higher CH4-compostion in source gas was found at up to 1O MPa pressure. Preferential adsorp- tion of CO2 increases with increase of CH4 concentration in source gas, and decreases with increasing pressure. Although there was no systematic investigation of the effect of coal rank on preferential adsorp- tion, there are obvious differences in preferential adsorption of gas between low-volatile bituminous coal and anthracite. The obtained preferential adsorption gives rise to the assumption that CO2 sequestration in coal beds with subsequent CO2-ECBM might be an ootion in Qinshui Basins, China.展开更多
CO2is the main greenhouse gas which causes global climatic changes on larger scale. Many techniques have been utilised to capture CO2. Membrane gas separation is a fast growing CO2 capture technique, particularly gas ...CO2is the main greenhouse gas which causes global climatic changes on larger scale. Many techniques have been utilised to capture CO2. Membrane gas separation is a fast growing CO2 capture technique, particularly gas separation by composite membranes. The separation of CO2 by a membrane is not just a process to physically sieve out of CO2 through the controlled membrane pore size. It mainly depends upon diffusion and solubility of gases, particularly for composite dense membranes. The blended components in composite membranes have a high capability to adsorb CO2. The adsorption kinetics of the gases may directly affect diffusion and solubility. In this study, we have investigated the adsorption behaviour of CO2 in pure and composite membranes to explore the complete understanding of diffusion and solubility of CO2 through membranes. Pure cellulose acetate（CA） and cellulose acetatetitania nanoparticle（CA-TiO2） composite membranes were fabricated and characterised using SEM and FTIR analysis. The results indicated that the blended CA-TiO2 membrane adsorbed more quantity of CO2 gas as compared to pure CA membrane. The high CO2 adsorption capacity may enhance the diffusion and solubility of CO2 in the CA-TiO2 composite membrane, which results in a better CO2 separation. The experimental data was modelled by Pseudo first-order, pseudo second order and intra particle diffusion models.According to correlation factor R2, the Pseudo second order model was fitted well with experimental data. The intra particle diffusion model revealed that adsorption in dense membranes was not solely consisting of intra particle diffusion.展开更多
基金financially supported 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Via the strategy of charge balance,one new pillared layered metal-organic framework [Zn2（TNB）（2-nim）]（H3TNB = 4,4？,4？？-nitrilotribenzoicacid,2-nim = 2-nitroimidazole）（1） was successfully synthesized based on mixed ligands,where binuclear [Zn2（CO2）3]~＋ cluster-based cationic layers [Zn2（TNB）]~＋ are connected by deprotonated 2-nitroimidazole.Meanwhile,CO2 adsorption bahaviors and luminescent property of compound 1 were investigated.
文摘Solid sorbents adsorption is considered as one of the potential options for CO2 capture process. CO2 adsorption on MCM-68 （Si/AI ratio 22） sorbent material was investigated. MCM-68 was synthesized using N,N,N＇,N＇-tetraethylbicyclo [2.2.2] oct-7-ene-2,3：5,6-dipyrrolidinium diiodide （TEBOP^2＋（I^＋）2） as a structure-directing agent （SDA）. CO2 adsorption capacity on MCM-68 sorbent was measured at a broad temperature window i.e. 60 ℃, 300 ℃ and at 400 ℃. The presence of ordered mesoporous structure, high surface area （456 me/g） and high thermal stability （TGA analysis up to 900℃） in MCM-68 are thought to be to be advantageous for the CO2 adsorption in broad temperature window.
基金the financial support of the Open Funding Project of National Key Laboratory of Human Factors Engineering(No.SYFD14005181K)
文摘Two kinds of molecular sieve materials, TC-5A and PSA-5A, were produced to satisfy with special requirement of manned space flight. Their CO2 adsorption performances were investi- gated and compared through two experiments, the thermo gravimetric analysis （TGA） experiment and packed bed column experiment. Besides, some kinetic equations were compared according to the TGA experimental data, and their errors were analyzed. Finally, the classic linear driving force （LDF） model is improved to the new Avrami＇s model, and two models are analyzed based on the packed bed data. The TGA data shows that the CO2 loading has an approximately linear relation- ship with the CO2 concentration, and the best fit adsorption temperature range is from 283 to 303 K. The packed bed column results show that water vapor in air can affect the CO2 adsorption performance badly. The new Avrami＇s model is proved more suitable to reflect the complex adsorption mechanism for two molecular sieves. The materials are proved having much better adsorption capacity than the other adsorbents with room temperature and low CO2 concentration （≤ 1.0% in volume）, and they can meet the aerospace requirements. This work will benefit the optimal design and simulation of the air revitalization （AR） system for Chinese manned spacecraft.
基金supported by the National Natural Science Foundation of China(21771070,21571071)~~
文摘Photocatalytic conversion of“greenhouse gas”CO2is considered to be one of the most effective ways to alleviate current energy and environmental problems without additional energy consumption and pollutant emission.The performance of many traditional semiconductor photocatalysts is not efficient enough to satisfy the requirements of practical applications because of their limited specific surface area and low CO2adsorption capacity.Therefore,the exploration of photocatalysts with high CO2uptake is significant in the field of CO2conversion.Recently the porous materials appeared to be a kind of superior candidate for enriching the CO2molecules on the surface of photocatalysts for catalytic conversion.This paper first summarizes the advances in the development of nanoporous adsorbents for CO2capture.Three main classes of porous materials are considered:inorganic porous materials,metal organic frameworks,and microporous organic polymers.Based on systematic research on CO2uptake,we then highlight the recent progress in these porous‐material‐based photocatalysts for CO2conversion.Benefiting from the improved CO2uptake capacity,the porous‐material‐based photocatalysts exhibited remarkably enhanced efficiency in the reduction of CO2to chemical fuels,such as CO,CH4,and CH3OH.Based on reported recent achievements,we predict a trend of development in multifunctional materials with both high adsorption capability and photocatalytic performance for CO2utilization.
文摘Carbon dioxide （CO2） adsorption on a standard metal-organic framework MIL-101 and a pentaethylenehexamine modified MIL-101 （PEHA- MIL-101） are investigated and compared in this study. The adsorbent samples were characterized by XRD, FT-IR and nitrogen adsorption- desorption isotherms analysis. CO2 adsorption capacity was measured by a volumetric method. MIL-101 and PEHA-MIL-101 exhibited CO2 adsorption capacities of 0.85 and 1.3 mmO1CO2/gadsorbent at 10 bar and 298 K, respectively. It is observed that CO2 adsorption capacity was fairly improved about 50% after amine modification.
基金supported by the National Natural Science Foundation of China (Nos. 21277008 and 20777005)the National Key Research and Development Program of China (No. 2017YFC0209905)。
文摘The Al-pillared montmorillonite-supported alkaline earth metal 5M/Al-PILC(PILC = pillared clay, M = Mg, Ca, Sr, and Ba) and x Mg/Al-PILC( x = 1, 3, 5, and 7 wt.%) samples were prepared using an impregnation method. Physical properties of the materials were determined by means of X-ray diffraction(XRD) and N2 adsorption-desorption, and their CO2 adsorption behaviors were investigated using the thermogravimetric analyzer(TG), CO2 temperatureprogrammed desorption(CO2-TPD), and in situ diffuse reflectance infrared transform spectroscopy(in situ-DRIFTS) techniques. It is shown that 5 Mg/Al-PILC possessed the highest CO2 adsorption capacity(2.559 mmol/g). The characterization results indicate that Alpillaring increased the specific surface area of montmorillonite, which was beneficial for the adsorption of CO2. The CO2 adsorption process on the sample was mainly chemical adsorption, and alkalinity was the main factor influencing its adsorption capacity. The alkalinity of the sample was enhanced by loading an appropriate amount of alkaline earth metal, and the adsorbed CO2 was present in the form of bicarbonate and carbonate. In addition, the 5Mg/Al-PILC sample exhibited an excellent regeneration efficiency. We believe that the outcome of this research would provide a good option for developing highly effective CO2 adsorption materials.
基金Supported by Tianjin Hi-tech Support Program Key Projects, China (2009F3-0005)
文摘Amine-functionalized mesoporous silica was prepared by using lauric acid and N-stearoyl-l-glutamic acid as structure directing agents via the S-N+-I- mechanism and applied to CO2 adsorption at room temperature. With γ-aminopropyltriethoxysilane as co-structure directing agent and due to the direct electrostatic interaction with anionic surfactant, most of the amino groups were uniformly distributed at the inner surface of pores and the per- formance was stable. The amine-functionalized mesoporous silica was characterized by Fourier transform infrared spectrometer, X-ray diffraction, nitrogen physisorption and thermogravimetric analysis. The CO2 adsorption capacity was measured by digital recording balance. At the room temperature and under the atmospheric pressure, the adsorption capacity of LAA-AMS-0.2 for CO2 and N2 is 1.40 mmol·g-1 and 0.03 mmol·g-1, respectively, indicating high separation coefficient of CO2/N2.
基金Financially supported by the National Natural Science Foundation of China(21273033,21673039 and 21573042)
文摘A novel,porous and doubly interpenetrated MOF（FJU-29） was synthesized and characterized by FT-IR,TGA and X-ray single-crystal/powder diffraction.FJU-29 crystallizes in monoclinic,space group C2/c with a = 22.2890（7）,b = 10.9175（2）,c = 21.5601（7） ？,β = 112.908（4）o,V = 4832.7（3） ？~3,Z = 8,Mr = 450.26,D_c = 1.238 g/cm^3,F（000） = 1832,μ（CuKα） = 5.885 mm^（-1）,R = 0.0585 and wR = 0.1544 for 4789 observed reflections（I 〉 2s（I））,and R = 0.0726 and wR = 0.1627 for all data.FJU-29 possesses paddle-wheel {Co_2（COO）_4} clusters bridged by bi-pyrazolate naphthalene diimide ligands（H_2NDI） and H_2BDC to from a 3D framework with a pcu-topology.The desolvated FJU-29a shows the BET surface area of 560.44 m^2·g^（-1） accompanies with discriminating uptakes in CO_2 and N_2.The adsorption selectivity determined by ideal adsorbed solution theory（IAST） indicated that FJU-29 a has high CO_2/N_2（18/85） selectivity（75.5） at 296 K and 100 kPa.The relatively high selectivity further implies that FJU-29 a is a potential material for practical flue gas purification.
基金the financial support from Department of Science and Technology (DST) and All India Council of Technical Education (AICTE)New Delhi under their research scheme no. DST/IS-STAC/CO2-SR-154/12(G) and 8023/RID/RPS-66/2010-11 respectivelythe financial support from DST-INSPIRE under its Assured Opportunity for Research Careers (AORC) scheme having scheme no. DST/INSPIRE FELLOWSHIP/2012/398
文摘Mesoporous carbon adsorbents, having high nitrogen content, were synthesized via nanocasting technique with melamine-formaldehyde resin as precursor and mesoporous silica as template. A series of adsorbents were prepared by varying the carbonization temperature from 400 to 700°C. Adsorbents were characterized thoroughly by nitrogen sorption, X-ray diffraction（XRD）, scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, thermogravimetric analysis（TGA）, elemental（CHN） analysis, Fourier transform infrared（FTIR） spectroscopy and Boehm titration. Carbonization temperature controlled the properties of the synthesized adsorbents ranging from surface area to their nitrogen content, which play major role in their application as adsorbents for CO2 capture.The nanostructure of these materials was confirmed by XRD and TEM. Their nitrogen content decreased with an increase in carbonization temperature while other properties like surface area, pore volume, thermal stability and surface basicity increased with the carbonization temperature. These materials were evaluated for CO2 adsorption by fixed-bed column adsorption experiments. Adsorbent synthesized at 700°C was found to have the highest surface area and surface basicity along with maximum CO2 adsorption capacity among the synthesized adsorbents. Breakthrough time and CO2 equilibrium adsorption capacity were investigated from the breakthrough curves and were found to decrease with increase in adsorption temperature. Adsorption process for carbon adsorbent-CO2 system was found to be reversible with stable adsorption capacity over four consecutive adsorption-desorption cycles. From three isotherm models used to analyze the equilibrium data, Temkin isotherm model presented a nearly perfect fit implying the heterogeneous adsorbent surface.
基金supported by the National Natural Science Foundation of China(Nos. 21476160, 21476159]the Natural Science Foundation of Tianjin(Nos.15JCYBJC23000,15JCZDJC37400)
文摘Herein, we report the effects of doped K and Al on the carbon dioxide （CO2） adsorption performance of the Li4SiO4-based adsorbents. The CO2 adsorption capacity of 0.8 wt% K and 1.5 wt% AI doped Li4SiO4 is ～2.2 times and ～1.3 times higher than that of the pristine Li4SiO4 at 500 and 600℃, respectively. The kinetic study further indicated that the reaction rates of the lithium diffusion process is greatly improved by K and AI doping, and the lithium diffusion rate of 0.8 wt% K and 1.5 wt% AI doped Li4SiO4 is ～2 times higher than that of the pristine Li4SiO4 at 575-650 ℃. K and AI doping increases the adsorption capacity of Li4SiO4-based adsorbents, and widens its effective adsorption temperature range
基金financially supported by the Korea CCS R&D Centrefunded by the Ministry of Education,Science and Technology of the Korean Government
文摘Microporous hypercross-linked conjugated quinonoid chromophores represent a novel class of amorphous polymers, synthesized by the reaction of anthracene with dimethoxy methane in the presence of FeCl3 catalyst. Their N2 adsorption isotherms confirm their microporous nature. Diffuse reflectance UV-Visible（DRS UV-Vis） spectroscopy confirms their matrix built with the conjugated quinonoids by their broad light absorption characteristics extending from 1000 nm to 200 nm with the absorbance maximum close to 400 nm. The catalyst cross-linked anthracene with ―CH2― bridges and subsequently dehydrogenating them to form quinonoids. Their Fourier transform infrared（FTIR） spectra showed their characteristic quinonoid vibrations between 1600 and 1700 cm-1. The synthesis of polymers was carried out at 30, 40, 50, 60, 70 and 80 ℃, but the quinonoid content of the polymer obtained at 80 ℃ was higher than that of the others. Their scanning electron microscopy（SEM） images showed microspheres of 1 to 5 μm size built with tiny particles. Their surfaces were not smooth. The polymer synthesized at 80 ℃ showed 5.1 wt% CO2 sorption at 25 ℃ and 0.1 MPa, but when it was recross-linked, the CO2 sorption increased to 8 wt%. Hence, hypercross-linked conjugated quinonoid chromophores of anthracene are good for sorption of CO2.
基金financially supported by the 973 program (Nos 2014CB845600 and 2012CB821700)NNSF of China (Nos 21531005, 21421001, and 2129017)MOE Innovation Team (No. IRT13022) of China
文摘A new metal–organic framework {[Zn2（bpta）（bpy-ee）（H2O）2]·x solve}n（1）（H4bpta = biphenyl-2,20,6,60-tetracarboxylic acid and bpy-ee = 1,2-bis（4-pyridyl）ethylene） has been obtained under hydrothermal condition, and structurally characterized by single-crystal X-ray diffraction. Complex 1 reveals a threedimensional（3D） “pillar-layered” framework with non-flexible linker, in which some different structure characters can be found compared to that of some related other “pillar-layered” MOFs based on flexible pillar linkers. It demonstrates the impact of the flexibility of pillar linker on the final structure in this system. In addition, the selective CO2 adsorption performance of 1 was also investigated.
基金Project supported by the National Natural Science foundation of China (Grant No.60925016)
文摘The global greenhouse effect makes it urgent to deal with the increasing greenhouse gases. In this paper the performance of MgO-decorated carbon nanotubes for CO2 adsorption is investigated through first principles calculations. The results show that the MgO-decorated carbon nanotubes can adsorb CO2 well and are relatively insensitive to O2 and N2 at the same time. The binding energy arrives at 1.18 eV for the single-MgO-decorated carbon nanotube adsorbing one CO2 molecule, while the corresponding values for O2 and N2 are 0.55 eV and 0.06 eV, respectively. In addition, multi-molecule adsorption is also proved to be very satisfactory. These results indicate that MgO-decorated carbon nanotubes have great potential applications in industrial and environmental processes.
基金Supported by the National Natural Science Foundation of China(51272183)the Program for Discipline Leader in Wtthan(201051730563)the self-determined and innovative research funds of Wuhan University
文摘The mesoporous silica modifed with magnesium ox- ide （MgO） was syntbesized by one step method and impregnating method, respectively. The samples were characterized by small angle X-Ray diffraction （XRD）, N2 adsorption-desorption and transmission electron microscopy （TEM）, and the carbon dioxide adsorption capacity was analyzed by thermal gravimetric analysis （TGA）. Compared with the original mesoporous silica （20.7 mg/g）, the CO2 adsorption capacity of MgO-modified mesoporous silica processed by one step method increases to 32.9 mg/g. Although its surface area greatly decreases compared with that of the original mesoporous silica, the MgO-modified mesoporous silica prepared by impregnating reaches an adsorptive value of 31.1 mg/g because the number of basic sites increases on the surface of the mesoporous silica.
基金supported by the National Natural Science Foundation of China(91434120)the Fundamental Research Funds for the Central Universities(2014ZD06),and the 111 Project(No.B12034)
文摘A series of amine-based adsorbents were synthesized using siliceous MCM-41 individually impregnated with four different amines（ethylenediamine（EDA）,diethylenetriamine（DETA）,tetraethylenepentamine（TEPA） and pentaethylenehexamine（PEHA）） to study the effect of amine chain length and loading weight on their CO2 adsorption performances in detail.The adsorbents were characterized by FT-IR,elemental analysis,and thermo-gravimetric analysis to confirm their structure properties.Thermo-gravimetric analysis was also used to evaluate the CO2 adsorption performance of adsorbents.Longer chain amine-based materials can achieve higher amine loadings and show better thermal stability.The CO2 adsorption capacities at different temperatures indicate that the CO2 adsorption is thermodynamically controlled over EDAMCM41 and DETA-MCM41,while the adsorption over TEPA-MCM41 and PEHA-MCM41 is under kinetic control at low temperature.The chain length of amines affects the CO2 adsorption performance and the adsorption mechanism significantly.The results also indicate that CO2 adsorption capacity can be enhanced despite of high operation temperatures,if appropriate amines（TEPA and PEHA） are applied.However,adsorbents with short chain amine exhibit higher adsorption and desorption rates due to the collaborative effect of rapid reaction mechanisms of primary amines and less diffusion resistance of shorter chain length amines.
基金Funding for this research is provided by Natural Sciences and Engineering Research Council (NSERC) of Canada
文摘In this work, the effects of different methods of activation on CO2 adsorption performance of activated carbon were studied. Activated carbons were prepared from biochar, obtained from fast pyrolysis of white wood, using three different activation methods of steam activation, CO2 activation and Potassium hydroxide（KOH） activation. CO2 adsorption behavior of the produced activated carbons was studied in a fixed-bed reactor set-up at atmospheric pressure, temperature range of 25–65°C and inlet CO2 concentration range of10–30 mol% in He to determine the effects of the surface area, porosity and surface chemistry on adsorption capacity of the samples. Characterization of the micropore and mesopore texture was carried out using N2 and CO2 adsorption at 77 and 273 K, respectively.Central composite design was used to evaluate the combined effects of temperature and concentration of CO2 on the adsorption behavior of the adsorbents. The KOH activated carbon with a total micropore volume of 0.62 cm3/g and surface area of 1400 m2/g had the highest CO2 adsorption capacity of 1.8 mol/kg due to its microporous structure and high surface area under the optimized experimental conditions of 30 mol% CO2 and 25°C. The performance of the adsorbents in multi-cyclic adsorption process was also assessed and the adsorption capacity of KOH and CO2 activated carbons remained remarkably stable after50 cycles with low temperature（160°C） regeneration.
文摘Reliable estimation of the pore size distribution(PSD) in porous materials such as metal–organic frameworks(MOFs) and zeolitic imidazolate frameworks(ZIFs) is crucial for accurately assessing adsorption capacity and corresponding selectivity. In this study, the so-called zeolitic imidazolate framework-7(ZIF-7) is successfully synthesized via relatively fast and convenient microwave technique. The morphology and structure of the obtained MOF were characterized by XRD, SEM and N_2 and CO_2adsorption/desorption isotherms at 77 K and0 °C respectively. Then, to determine the PSD of the fabricated MOF, carbon dioxide isotherms are experimentally measured at various temperatures up to atmospheric pressure. Afterward, the experimental CO_2 isotherms data are utilized in two recently proposed in-house algorithms of SHN1 and SHN2 to extract the true PSD of manufactured ZIF-7. The obtained results revealed that median pore diameter of the fabricated ZIF-7 is estimated around 0.404 nm and 0.370 nm by using CO_2 isotherms at 273 K and 298 K respectively. These values are in good agreement with the real pore diameter of 0.42 nm. Moreover, experimental data of water adsorption isotherms over four different MOFs, borrowed from literature, are employed to illustrate further effectiveness of the above algorithms on successful determination of the corresponding pore size distributions. All predicted PSDs are proved to be in good agreement with those obtained from independent methods such as topology and morphology studies.
基金supported by the Industry-Academia Cooperation Innovation Fund Projects of Jiangsu Province(No.BY2012025)
文摘TiO2 nanotubes （TiNT） were prepared by a hydrothermal treatment and modified by three kinds of amines,namely ethylenediamine,polyetherimide and tetraethylenepentamine （TEPA）,to study their CO2 adsorption properties from gas streams.The resultant samples were characterized by X-ray diffraction,transmission electron microscopy,and infrared spectroscopy,as well as low temperature N 2 adsorption.CO2 capture was investigated in a dynamic packed column at 30℃.TEPA-modified TiO2 nanotubes showed the highest adsorption capacity of 167.64 mg/g because it had the highest amino-group content among the three amines.CO2 fixation on TiNT impregnated by TEPA was investigated at 30,50,and 70℃,and the adsorption capacity increased slightly with temperature.Following the adsorption step,the sorbents were regenerated by temperature programmed desorption,and the TiNT-TEPA sample,as CO2 sorbent,was found to be readily regenerated and energy-efficient.The cycle test also revealed that the TiNT-TEPA adsorbent is fairly stable,with only a 5% drop in the adsorption capacity after 10 adsorption/desorption cycles.In addition,the CO2 adsorption behavior was investigated with the deactivation model,and which showed an excellent prediction for the TiNT-TEPA breakthrough curves.
基金supported by the National Natural Science Foundation of China(Nos.51174127 and 21176145)the Natural Science Foundation of Shandong Province(No.ZR2011DM005)the Open Research Fund Program of Key Laboratory of Mine Disaster Prevention and Control(Shandong University of Science and Technology)(No.MDPC0806)
文摘In order to better understand the prevailing mechanism of CO2 storage in coal and estimate CO2 sequestration capacity of a coal seam and enhanced coalbed methane recovery （ECBM） with CO2 injection into coal, we investigated the preferential adsorption of CH4 and CO2 on coals. Adsorption of pure CO2, CH4 and their binary mixtures on high-rank coals from Qinshui Basin in China were employed to study the preferential adsorption behaviour. Multiple regression equations were presented to predict CH4 equi- librium concentration from equilibrium pressure and its initial-composition in feed gas. The results show that preferential adsorption of CO2 on coals over the entire pressure range under competitive sorption conditions was observed, however, preferential adsorption of CH4 over CO2 on low-volatile bituminous coal from higher CH4-compostion in source gas was found at up to 1O MPa pressure. Preferential adsorp- tion of CO2 increases with increase of CH4 concentration in source gas, and decreases with increasing pressure. Although there was no systematic investigation of the effect of coal rank on preferential adsorp- tion, there are obvious differences in preferential adsorption of gas between low-volatile bituminous coal and anthracite. The obtained preferential adsorption gives rise to the assumption that CO2 sequestration in coal beds with subsequent CO2-ECBM might be an ootion in Qinshui Basins, China.
基金supported by Higher Education Commission (HEC) Pakistan
文摘CO2is the main greenhouse gas which causes global climatic changes on larger scale. Many techniques have been utilised to capture CO2. Membrane gas separation is a fast growing CO2 capture technique, particularly gas separation by composite membranes. The separation of CO2 by a membrane is not just a process to physically sieve out of CO2 through the controlled membrane pore size. It mainly depends upon diffusion and solubility of gases, particularly for composite dense membranes. The blended components in composite membranes have a high capability to adsorb CO2. The adsorption kinetics of the gases may directly affect diffusion and solubility. In this study, we have investigated the adsorption behaviour of CO2 in pure and composite membranes to explore the complete understanding of diffusion and solubility of CO2 through membranes. Pure cellulose acetate（CA） and cellulose acetatetitania nanoparticle（CA-TiO2） composite membranes were fabricated and characterised using SEM and FTIR analysis. The results indicated that the blended CA-TiO2 membrane adsorbed more quantity of CO2 gas as compared to pure CA membrane. The high CO2 adsorption capacity may enhance the diffusion and solubility of CO2 in the CA-TiO2 composite membrane, which results in a better CO2 separation. The experimental data was modelled by Pseudo first-order, pseudo second order and intra particle diffusion models.According to correlation factor R2, the Pseudo second order model was fitted well with experimental data. The intra particle diffusion model revealed that adsorption in dense membranes was not solely consisting of intra particle diffusion.
