SSZ-13 membranes with high separation performances were prepared using ball-milled nanosized seeds by once hydrothermal synthesis.Separation performances of SSZ-13 membranes in CO2/CH4 and N2/CH4 mixtures were enhance...SSZ-13 membranes with high separation performances were prepared using ball-milled nanosized seeds by once hydrothermal synthesis.Separation performances of SSZ-13 membranes in CO2/CH4 and N2/CH4 mixtures were enhanced after synthesis modification.Single-gas permeances of CO2,N2 and CH4 and ideal selectivities were recorded through SSZ-13 membranes.The effects of temperature,pressure,feed flow rate and humidity on separation performance of the membranes were discussed.Three membranes prepared after synthesis modifications had an average CO2 permeance of 1.16×10-6 mol·(m2·s·Pa)-1(equal to 3554 GPU)with an average CO2/CH4 selectivity of 213 in a 50 vol%/50 vol%CO2/CH4 mixture.It suggests that membrane synthesis has a good reproducible.The membrane also displayed a N2 permeance of 1.07×10-7 mol·(m2·s·Pa)-1(equal to 320 GPU)with a N2/CH4 selectivity of 13 for a 50 vol%/50 vol%N2/CH4 mixture.SSZ-13 membrane displayed stable and good separation performance in the wet CO2/CH4 mixture for a long test period over 100 h at 348 K.The current SSZ-13 membranes show great potentials for the simultaneous removals of CO2 and N2 in natural gas purification as a facile process suitable for industrial application.展开更多
In this paper,blend membranes from polyvinyl acetate(PVAc)and block copolymer poly(amide-12-b-ethylene oxide)(Pebax1074)are prepared by solution casting and solvent evaporation method.Although they are homogeneous on ...In this paper,blend membranes from polyvinyl acetate(PVAc)and block copolymer poly(amide-12-b-ethylene oxide)(Pebax1074)are prepared by solution casting and solvent evaporation method.Although they are homogeneous on a macro-scale,the observations from DSC and SEM indicate micro-phase separation for PVAc/Pebax1074 blend membranes.With the increase of Pebax1074 content,gas permeabilities of CO2,H2,N2and CH4all increase greatly.PVAc/Pebax1074 blend membranes with high PVAc content are appropriate for CO2/CH4separation.The temperature dependence of gas permeability is divided into rubbery region and glassy region.The activation energies of permeation in rubbery region are smaller than those in glassy region,and they all decrease with increasing Pebax1074 content.For N2,H2and CH4,their gas permeation properties are mainly influenced by the dual-mode sorption and hydrostatic pressure effect.But for CO2,its permeability increases with the increase of pressure due to CO2-induced plasticization effect,which is more obvious for PVAc/Pebax1074 blend membranes with high PVAc content.展开更多
Poly（amide-6-b-ethylene oxide）（Pebax1657）/1-butyl-3-methylimidazo-lium bis[trifluoromethyl）sulfonyl]-imide（[Bmim][Tf2N]） blend membranes with different [Bmim][Tf2N] contents were prepared via solution casting a...Poly（amide-6-b-ethylene oxide）（Pebax1657）/1-butyl-3-methylimidazo-lium bis[trifluoromethyl）sulfonyl]-imide（[Bmim][Tf2N]） blend membranes with different [Bmim][Tf2N] contents were prepared via solution casting and solvent evaporation method. The permeation properties of the blend membranes for CO2, N2,CH4 and H2 were studied, and the physical properties were characterized by differential scanning calorimeter（DSC） and X-ray diffraction（XRD）. Results showed that [Bmim][Tf2N] was dispersed as amorphous phase in the blend membranes, which caused the decrease of Tg（PE） and crystallinity（PA）. With the addition of [Bmim][Tf2N], the CO2 permeability increased and reached up to approximately 286 Barrer at 40 wt%[Bmim][Tf2N], which was nearly double that of pristine Pebax1657 membrane. The increase of CO2 permeability may be attributed to high intrinsic permeability of [Bmim][Tf2N], the increase of fractional free of volume（FFV） and plasticization effect. However, the CO2 permeability reduced firstly when the [Bmim][Tf2N]content was below 10 wt%, which may be due to that the small ions of [Bmim][Tf2N] in the gap of polymer chain inhibited the flexibility of polymer chain; the interaction between Pebax1657 and [Bmim][Tf2N]decreased the content of EO units available for CO2 transport and led to a more compact structure. For Pebax1657/[Bmim][Tf2N] blend membranes, the permeabilities of N2, H2 and CH4decreased with the increase of feed pressure due to the hydrostatic pressure effect, while CO2 permeability increased with the increase of feed pressure for that the CO2-induced plasticization effect was stronger than hydrostatic pressure effect.展开更多
Membranes with ultramicropores have shown great promise in gas separations.However,achieving high separation selectivity for gas with similar kinetic diameters,such as hydrogen(H_(2))and carbon dioxide(CO_(2)),remains...Membranes with ultramicropores have shown great promise in gas separations.However,achieving high separation selectivity for gas with similar kinetic diameters,such as hydrogen(H_(2))and carbon dioxide(CO_(2)),remains a challenge due to the difficulty in precisely controlling ultramicropores distribution.Herein,we developed a polybenzoxazine polymer-derived carbon molecular sieve(CMS)membrane with uniformly concentrated ultramicropores of 3.5Åto separate H_(2) and CO_(2).This membrane demonstrated a high selectivity of 67.6,with a H_(2) permeance of 118.7 GPU,outperforming most reported samples.The isosteric heat of adsorption(Q_(st))for CO_(2) in these ultramicropores reached 43.1 kJ·mol^(-1),approximately twice that of physical adsorption,indicating that CO_(2) were effectively confined within the concentrated ultramicropores.Permeation tests revealed that the activation energy for CO_(2) permeation in the ultramicropores was 11.3 kJ·mol^(-1),one order of magnitude higher than that for H_(2)(1.3 kJ·mol^(-1)).This significant difference in activation energy magnifies the difference of diffusion rate between H_(2) and CO_(2).The distinct behavior between the free surface diffusion of H_(2) and the activated surface diffusion of CO_(2) is the key to achieving a high H_(2)/CO_(2) separation performance.This discovery presents a promising approach for separating H_(2) and CO_(2) using CMS membranes.展开更多
Talc has found a steadily increasing number of uses such as cosmetics, steatite and cordierite ceramics, for pitch control in the paper industry and as a reinforcing filler in rubber, etc. In this research, the amenab...Talc has found a steadily increasing number of uses such as cosmetics, steatite and cordierite ceramics, for pitch control in the paper industry and as a reinforcing filler in rubber, etc. In this research, the amenability of some Egyptian carboniferous finely disseminated talc ores to beneficiation by flotation was investigated on laboratory scale. The original talc sample is characterized by low MgO content (25.40%), low SiO<sub>2</sub> (45.71%), high CaO content (6.32%) and high L.O.I. (11.35%), indicating its low grade. Attrition scrubbing of the crushed ores was found to be an unconventional process, not only for fine talc production, but also for proper separation of the harder carbonaceous gangue. Talc pre-concentrates, less than 0.074 μm, were prepared by attrition scrubbing in the laboratory having 8.40% L.O.I. with a yield reaching 74.70%. Cleaner talc concentrate with L.O.I. content averaging 6.70% was obtained by flotation in the presence of Aerofroth 71 with a yield reaching 64.71%. This was relatively improved by the use of a selective (quaternary amine) talc collector and in presence of a selective carbonate depressant (soda ash). Flotation of the fine ground talc (less than 22 μm) produced a talc concentrate assaying 6.90% L.O.I. with a yield recovery of 62.91%. However, different talc concentrates obtained by just natural floatability or by the use of small dose of Aerofroth 71, or by the application of quaternary amine in presence of carbonate depressant, satisfy the requirement of paper coating, ceramics production, functional filler, and pharmaceuticals applications. Tailings could also be used in carpets, roofs, and tiles production industries.展开更多
Membrane gas separation is one of the most promising technologies for the separation of carbon dioxide （CO2） from various gas streams. One application of this technology is the treatment of flue gases from combustio...Membrane gas separation is one of the most promising technologies for the separation of carbon dioxide （CO2） from various gas streams. One application of this technology is the treatment of flue gases from combustion processes for the purpose of carbon capture and storage. For this application, poly（ethylene oxide）-containing block copolymers such as Pebax or PolyActiveTM polymer are well suited. The thin-film composite membrane that is considered in this overview employs PolyActiveTM polymer as a selective layer material. The membrane shows excellent CO2 permeances of up to 4 m^3（STP）.（m^2·h·bar）^-1 （1 bar = 105 Pa） at a carbon dioxide/nitrogen （CO2/N2） selectivity exceeding 55 at ambient temperature. The membrane can be manufactured reproducibly on a pilot scale and mounted into fiat-sheet membrane modules of different designs. The operating performance of these modules can be accurately predicted by specifically developed simulation tools, which employ single-gas permeation data as the only experimental input. The performance of membranes and modules was investigated in different pilot plant studies, in which flue gas and biogas were used as the feed gas streams. The investigated processes showed a stable separation performance, indicating the applicability of PolyActiveTM polymer as a membrane material for industrialscale gas processing.展开更多
Porous carbon membranes were favorably fabricated through the pyrolysis of polyacrylonitrile（PAN） precursors, which were prepared with a template-free technique-thermally induced phase separation. These carbon membr...Porous carbon membranes were favorably fabricated through the pyrolysis of polyacrylonitrile（PAN） precursors, which were prepared with a template-free technique-thermally induced phase separation. These carbon membranes possess hierarchical pores, including cellular macropores across the whole membranes and much small pores in the matrix as well as on the pore walls. Nitrogen adsorption indicates micropores（1.47 and 1.84 nm） and mesopores（2.21 nm） exist inside the carbon membranes, resulting in their specific surface area as large as 1062 m2/g. The carbon membranes were used to adsorb organic dyes（methyl orange, Congo red, and rhodamine B） from aqueous solutions based on their advantages of hierarchical pore structures and large specific surface area. It is particularly noteworthy that the membranes present a selective adsorption towards methyl orange, whose molecular size（1.2 nm） is smaller than those of Congo red（2.3 nm） and rhodamine B（1.8 nm）. This attractive result can be attributed to the steric structure matching between the molecular size and the pore size, rather than electrostatic attraction. Furthermore, the used carbon membranes can be easily regenerated by hydrochloric acid, and their recovery adsorption ratio maintains above 90% even in the third cycle. This work may provide a new route for carbon-based adsorbents with hierarchical pores via a template-free approach, which could be promisingly applied to selectively remove dye contaminants in aqueous effluents.展开更多
This study focused on CO<sub>2</sub> separation technology with adsorption. This paper describes the analysis carried out by a CO<sub>2</sub> pressure swing adsorption simulation to scale up th...This study focused on CO<sub>2</sub> separation technology with adsorption. This paper describes the analysis carried out by a CO<sub>2</sub> pressure swing adsorption simulation to scale up the absorber. An unsteady one-dimensional balance model was constructed by considering the material, energy, and momentum. In the CO<sub>2</sub> breakthrough test, the beginning time and CO<sub>2</sub> concentration at outlet of CO<sub>2</sub> breakthrough in the calculation were almost equivalent to that of experiment results. The correlation consistency of the calculation results with the analysis model and the experimental results obtained by a bench scale experiment was evaluated. The transport phenomena in the adsorber were investigated at the adsorption, rinse, and desorption steps according to the calculation results. The starting time of CO<sub>2</sub> breakthrough obtained by the analysis is equal to that obtained by the adsorption breakthrough experiment. This confirms that the CO<sub>2</sub> adsorption, and the temperature and velocity distribution in the adsorber, change as a function of the adsorption, rinse, and desorption steps, respectively. Additionally, the CO<sub>2</sub> concentration of the captured gas and the amount of CO<sub>2</sub> quantity were 93.4% per day and 2.9 ton/day, respectively. These values are equal to those obtained by the bench scale experiment.展开更多
Adsorptive separation of acetylene/carbon dioxide mixtures by porous materials is an important and challenging task due to their similar sizes and physical properties.Here,remarkable acetylene/carbon dioxide separatio...Adsorptive separation of acetylene/carbon dioxide mixtures by porous materials is an important and challenging task due to their similar sizes and physical properties.Here,remarkable acetylene/carbon dioxide separation featuring a high dynamic breakthrough capacity for acetylene(4.3 mmol·g^(–1))as well as an ultralow acetylene regeneration energy(29.5 kJ·mol^(–1))was achieved with the novel TiF_(6)^(2–)-pillared material ZU-100(TIFSIX-bpy-Ni).Construction of a pore structure with abundant TiF_(6)^(2–)anion sites and pores with appropriate sizes enabled formation of acetylene clusters through hydrogen bonds and intermolecular interactions,which afforded a high acetylene capacity(8.3 mmol·g^(–1))and high acetylene/carbon dioxide uptake ratio(1.9)at 298 K and 1 bar.Moreover,the NbO_(5)^(2–)anion-pillared material ZU-61 investigated for separation of acetylene/carbon dioxide.In addition,breakthrough experiments were also conducted to further confirm the excellent dynamic acetylene/carbon dioxide separation performance of ZU-100.展开更多
The development of metal-organic frameworks(MOFs)with highly efficient adsorption and separation of acet-ylene is very important and challenging in chemical industry due to the explosive nature of acetylene.Porous MOF...The development of metal-organic frameworks(MOFs)with highly efficient adsorption and separation of acet-ylene is very important and challenging in chemical industry due to the explosive nature of acetylene.Porous MOFs can be constructed by inserting a second auxiliary ligand,which allows the use of large ligands to construct non-interpenetrated structures and increase pore utilization.Herein,SNNU-205 is successfully synthesized,which connects two sets of interpenetrated structures to form a double walled cage-within-cage structure by using the introduction of a second auxiliary ligand.The modified pore environment enables SNNU-205 to efficiently selectively adsorb C_(2)H_(2)over CO_(2).At 298 K and 1 atm,SNNU-205 can uptake much more C_(2)H_(2)(76.3 cm^(3)g1)than CO_(2)(47.3 cm^(3)g^(-1)),resulting in a high substance ratio of C_(2)H_(2)-to-CO_(2)(1.6).More importantly,the ideal adsorbed solution theory selectivity calculations and column breakthrough tests further indicate SNNU-205 to be promising adsorbents for C_(2)H_(2)adsorption and purification.展开更多
Carbon nanotube sorting,i.e.,the separation of a mixture of tubes into different electronic types and further into species with a specifi c chirality,is a fascinating problem of both scientifi c and technological impo...Carbon nanotube sorting,i.e.,the separation of a mixture of tubes into different electronic types and further into species with a specifi c chirality,is a fascinating problem of both scientifi c and technological importance.It is one of those problems that are easy to describe but diffi cult to solve.Single-stranded DNA forms stable complexes with carbon nanotubes and disperses them effectively in water.A particular DNA sequence of alternating guanine(G)and thymine(T)nucleotides((GT)n,with n=10 to 45)self-assembles into an ordered supramolecular structure around an individual nanotube,in such a way that the electrostatic properties of the DNA-carbon nanotube hybrid depend on tube structure,enabling nanotube separation by anion-exchange chromatography.This review provides a summary of the separation of metallic and semiconducting tubes,and purification of single(n,m)tubes using the DNA-wrapping approach.We will present our current understanding of the DNA-carbon nanotube hybrid structure and separation mechanisms,and predict future developments of the DNA-based approach.展开更多
An AnMBR-PN/A system was developed for mainstream sewage treatment.To verify the efficient methanation and subsequent chemolitrophic nitrogen removal,a long-term experiment and analysis of microbial activity were carr...An AnMBR-PN/A system was developed for mainstream sewage treatment.To verify the efficient methanation and subsequent chemolitrophic nitrogen removal,a long-term experiment and analysis of microbial activity were carried out.AnMBR performance was less affected by the change of hydraulic retention time(HRT),which could provide a stable influent for subsequent PN/A units.The COD removal efficiency of AnMBR was>93%during the experiment,85.5%of COD could be recovered in form of CH4.With the HRT of PN/A being shortened from 10 to 6 h,nitrogen removal efficiency(NRE)of PN/A increased from 60.5%to 80.4%,but decreased to 68.8%when the HRTPN/A further decreased to 4 h.Microbial analysis revealed that the highest specific ammonia oxidation activity(SAOA)and the ratio of SAOA to specific nitrate oxidation activity(SNOA)provide stable NO_(2)^(−)-N/NH_(4)^(+)-N for anammox,and anammox bacteria(mainly identified as Candidatus Brocadia)enriched at the bottom of Anammox-UASB might play an important role in nitrogen removal.In addition,the decrease of COD in Anammox-UASB indicated partial denitrification occurred,which jointly promoted nitrogen removal with anammox.展开更多
Multiphase CFD is used to design a compact fluidized bed sorber for CO2 removal from flue gases using sodium or potassium carbonate pellets. The sorber sizes are much smaller than commercial amine absorbers and smalle...Multiphase CFD is used to design a compact fluidized bed sorber for CO2 removal from flue gases using sodium or potassium carbonate pellets. The sorber sizes are much smaller than commercial amine absorbers and smaller than other proposed dry adsorbers. The size reduction is due to the elimination of dilute regions that cause bypassing. With proper solids feeding we eliminated the usual core-annular regime found in circulating fluidized beds.展开更多
A new complex plant for carbonization and composting of municipal wastes proposed for Gero City is introduced. The separated combustible waste and non-separated combustible waste are carbonized in two fluidized carbon...A new complex plant for carbonization and composting of municipal wastes proposed for Gero City is introduced. The separated combustible waste and non-separated combustible waste are carbonized in two fluidized carbonization furnaces in the plant, and the coke produced is used in steelworks. The separated garbage and forest-wastes are mixed with dried septic-tank sludge to produce high quality compost for farms. This use of waste materials in the complex plant considerably lowers the amount of waste going to land-fills, and in addition, creates lower total emission of dioxins and carbon dioxide into the environment.展开更多
基金the financial support of this study from National Key Research and Development Program of China(No.2017YFB0603402)the National Natural Science Foundation of China(No.21576131,21938007 and 21366013)support of Jiangsu College Student Innovation Training Project(201910291049Z)。
文摘SSZ-13 membranes with high separation performances were prepared using ball-milled nanosized seeds by once hydrothermal synthesis.Separation performances of SSZ-13 membranes in CO2/CH4 and N2/CH4 mixtures were enhanced after synthesis modification.Single-gas permeances of CO2,N2 and CH4 and ideal selectivities were recorded through SSZ-13 membranes.The effects of temperature,pressure,feed flow rate and humidity on separation performance of the membranes were discussed.Three membranes prepared after synthesis modifications had an average CO2 permeance of 1.16×10-6 mol·(m2·s·Pa)-1(equal to 3554 GPU)with an average CO2/CH4 selectivity of 213 in a 50 vol%/50 vol%CO2/CH4 mixture.It suggests that membrane synthesis has a good reproducible.The membrane also displayed a N2 permeance of 1.07×10-7 mol·(m2·s·Pa)-1(equal to 320 GPU)with a N2/CH4 selectivity of 13 for a 50 vol%/50 vol%N2/CH4 mixture.SSZ-13 membrane displayed stable and good separation performance in the wet CO2/CH4 mixture for a long test period over 100 h at 348 K.The current SSZ-13 membranes show great potentials for the simultaneous removals of CO2 and N2 in natural gas purification as a facile process suitable for industrial application.
基金supported by the National Science and Technology Planning Project (No.2011BAC08B00)the National High Technology Research and Development Program of China (863 Program)(No.2012AA03A611)
文摘In this paper,blend membranes from polyvinyl acetate(PVAc)and block copolymer poly(amide-12-b-ethylene oxide)(Pebax1074)are prepared by solution casting and solvent evaporation method.Although they are homogeneous on a macro-scale,the observations from DSC and SEM indicate micro-phase separation for PVAc/Pebax1074 blend membranes.With the increase of Pebax1074 content,gas permeabilities of CO2,H2,N2and CH4all increase greatly.PVAc/Pebax1074 blend membranes with high PVAc content are appropriate for CO2/CH4separation.The temperature dependence of gas permeability is divided into rubbery region and glassy region.The activation energies of permeation in rubbery region are smaller than those in glassy region,and they all decrease with increasing Pebax1074 content.For N2,H2and CH4,their gas permeation properties are mainly influenced by the dual-mode sorption and hydrostatic pressure effect.But for CO2,its permeability increases with the increase of pressure due to CO2-induced plasticization effect,which is more obvious for PVAc/Pebax1074 blend membranes with high PVAc content.
基金supported by the National High Technology Research and Development Program of China(863 Program)(No.2012AA03A611)
文摘Poly（amide-6-b-ethylene oxide）（Pebax1657）/1-butyl-3-methylimidazo-lium bis[trifluoromethyl）sulfonyl]-imide（[Bmim][Tf2N]） blend membranes with different [Bmim][Tf2N] contents were prepared via solution casting and solvent evaporation method. The permeation properties of the blend membranes for CO2, N2,CH4 and H2 were studied, and the physical properties were characterized by differential scanning calorimeter（DSC） and X-ray diffraction（XRD）. Results showed that [Bmim][Tf2N] was dispersed as amorphous phase in the blend membranes, which caused the decrease of Tg（PE） and crystallinity（PA）. With the addition of [Bmim][Tf2N], the CO2 permeability increased and reached up to approximately 286 Barrer at 40 wt%[Bmim][Tf2N], which was nearly double that of pristine Pebax1657 membrane. The increase of CO2 permeability may be attributed to high intrinsic permeability of [Bmim][Tf2N], the increase of fractional free of volume（FFV） and plasticization effect. However, the CO2 permeability reduced firstly when the [Bmim][Tf2N]content was below 10 wt%, which may be due to that the small ions of [Bmim][Tf2N] in the gap of polymer chain inhibited the flexibility of polymer chain; the interaction between Pebax1657 and [Bmim][Tf2N]decreased the content of EO units available for CO2 transport and led to a more compact structure. For Pebax1657/[Bmim][Tf2N] blend membranes, the permeabilities of N2, H2 and CH4decreased with the increase of feed pressure due to the hydrostatic pressure effect, while CO2 permeability increased with the increase of feed pressure for that the CO2-induced plasticization effect was stronger than hydrostatic pressure effect.
基金supported by the National Key Research and Development Program of China(No.2021YFA1500300)the National Natural Science Foundation of China(No.22275027).
文摘Membranes with ultramicropores have shown great promise in gas separations.However,achieving high separation selectivity for gas with similar kinetic diameters,such as hydrogen(H_(2))and carbon dioxide(CO_(2)),remains a challenge due to the difficulty in precisely controlling ultramicropores distribution.Herein,we developed a polybenzoxazine polymer-derived carbon molecular sieve(CMS)membrane with uniformly concentrated ultramicropores of 3.5Åto separate H_(2) and CO_(2).This membrane demonstrated a high selectivity of 67.6,with a H_(2) permeance of 118.7 GPU,outperforming most reported samples.The isosteric heat of adsorption(Q_(st))for CO_(2) in these ultramicropores reached 43.1 kJ·mol^(-1),approximately twice that of physical adsorption,indicating that CO_(2) were effectively confined within the concentrated ultramicropores.Permeation tests revealed that the activation energy for CO_(2) permeation in the ultramicropores was 11.3 kJ·mol^(-1),one order of magnitude higher than that for H_(2)(1.3 kJ·mol^(-1)).This significant difference in activation energy magnifies the difference of diffusion rate between H_(2) and CO_(2).The distinct behavior between the free surface diffusion of H_(2) and the activated surface diffusion of CO_(2) is the key to achieving a high H_(2)/CO_(2) separation performance.This discovery presents a promising approach for separating H_(2) and CO_(2) using CMS membranes.
文摘Talc has found a steadily increasing number of uses such as cosmetics, steatite and cordierite ceramics, for pitch control in the paper industry and as a reinforcing filler in rubber, etc. In this research, the amenability of some Egyptian carboniferous finely disseminated talc ores to beneficiation by flotation was investigated on laboratory scale. The original talc sample is characterized by low MgO content (25.40%), low SiO<sub>2</sub> (45.71%), high CaO content (6.32%) and high L.O.I. (11.35%), indicating its low grade. Attrition scrubbing of the crushed ores was found to be an unconventional process, not only for fine talc production, but also for proper separation of the harder carbonaceous gangue. Talc pre-concentrates, less than 0.074 μm, were prepared by attrition scrubbing in the laboratory having 8.40% L.O.I. with a yield reaching 74.70%. Cleaner talc concentrate with L.O.I. content averaging 6.70% was obtained by flotation in the presence of Aerofroth 71 with a yield reaching 64.71%. This was relatively improved by the use of a selective (quaternary amine) talc collector and in presence of a selective carbonate depressant (soda ash). Flotation of the fine ground talc (less than 22 μm) produced a talc concentrate assaying 6.90% L.O.I. with a yield recovery of 62.91%. However, different talc concentrates obtained by just natural floatability or by the use of small dose of Aerofroth 71, or by the application of quaternary amine in presence of carbonate depressant, satisfy the requirement of paper coating, ceramics production, functional filler, and pharmaceuticals applications. Tailings could also be used in carpets, roofs, and tiles production industries.
基金funded by the Helmholtz Association of German Research Centersthe funding given by the German Federal Ministry for Economic Affairs and Energy to finance the research project METPORE Ⅱ (03ET2016)+2 种基金the METPORE Ⅱ project partnersSSC Strategic Science Consult GmbHBORSIG Membrane Technology GmbH
文摘Membrane gas separation is one of the most promising technologies for the separation of carbon dioxide （CO2） from various gas streams. One application of this technology is the treatment of flue gases from combustion processes for the purpose of carbon capture and storage. For this application, poly（ethylene oxide）-containing block copolymers such as Pebax or PolyActiveTM polymer are well suited. The thin-film composite membrane that is considered in this overview employs PolyActiveTM polymer as a selective layer material. The membrane shows excellent CO2 permeances of up to 4 m^3（STP）.（m^2·h·bar）^-1 （1 bar = 105 Pa） at a carbon dioxide/nitrogen （CO2/N2） selectivity exceeding 55 at ambient temperature. The membrane can be manufactured reproducibly on a pilot scale and mounted into fiat-sheet membrane modules of different designs. The operating performance of these modules can be accurately predicted by specifically developed simulation tools, which employ single-gas permeation data as the only experimental input. The performance of membranes and modules was investigated in different pilot plant studies, in which flue gas and biogas were used as the feed gas streams. The investigated processes showed a stable separation performance, indicating the applicability of PolyActiveTM polymer as a membrane material for industrialscale gas processing.
基金financially supported by the National Natural Science Foundation of China(No.21174124)K.C.Wong Magna Fund in Ningbo University
文摘Porous carbon membranes were favorably fabricated through the pyrolysis of polyacrylonitrile（PAN） precursors, which were prepared with a template-free technique-thermally induced phase separation. These carbon membranes possess hierarchical pores, including cellular macropores across the whole membranes and much small pores in the matrix as well as on the pore walls. Nitrogen adsorption indicates micropores（1.47 and 1.84 nm） and mesopores（2.21 nm） exist inside the carbon membranes, resulting in their specific surface area as large as 1062 m2/g. The carbon membranes were used to adsorb organic dyes（methyl orange, Congo red, and rhodamine B） from aqueous solutions based on their advantages of hierarchical pore structures and large specific surface area. It is particularly noteworthy that the membranes present a selective adsorption towards methyl orange, whose molecular size（1.2 nm） is smaller than those of Congo red（2.3 nm） and rhodamine B（1.8 nm）. This attractive result can be attributed to the steric structure matching between the molecular size and the pore size, rather than electrostatic attraction. Furthermore, the used carbon membranes can be easily regenerated by hydrochloric acid, and their recovery adsorption ratio maintains above 90% even in the third cycle. This work may provide a new route for carbon-based adsorbents with hierarchical pores via a template-free approach, which could be promisingly applied to selectively remove dye contaminants in aqueous effluents.
文摘This study focused on CO<sub>2</sub> separation technology with adsorption. This paper describes the analysis carried out by a CO<sub>2</sub> pressure swing adsorption simulation to scale up the absorber. An unsteady one-dimensional balance model was constructed by considering the material, energy, and momentum. In the CO<sub>2</sub> breakthrough test, the beginning time and CO<sub>2</sub> concentration at outlet of CO<sub>2</sub> breakthrough in the calculation were almost equivalent to that of experiment results. The correlation consistency of the calculation results with the analysis model and the experimental results obtained by a bench scale experiment was evaluated. The transport phenomena in the adsorber were investigated at the adsorption, rinse, and desorption steps according to the calculation results. The starting time of CO<sub>2</sub> breakthrough obtained by the analysis is equal to that obtained by the adsorption breakthrough experiment. This confirms that the CO<sub>2</sub> adsorption, and the temperature and velocity distribution in the adsorber, change as a function of the adsorption, rinse, and desorption steps, respectively. Additionally, the CO<sub>2</sub> concentration of the captured gas and the amount of CO<sub>2</sub> quantity were 93.4% per day and 2.9 ton/day, respectively. These values are equal to those obtained by the bench scale experiment.
基金This work was financially supported by the Zhejiang Provincial Natural Science Foundation of China(Grant No.LR20B060001)the National Natural Science Foundation of China(Grant Nos.22122811,21938011,and 21890764)the Research Computing Center in College of Chemical and Biological Engineering at Zhejiang University.
文摘Adsorptive separation of acetylene/carbon dioxide mixtures by porous materials is an important and challenging task due to their similar sizes and physical properties.Here,remarkable acetylene/carbon dioxide separation featuring a high dynamic breakthrough capacity for acetylene(4.3 mmol·g^(–1))as well as an ultralow acetylene regeneration energy(29.5 kJ·mol^(–1))was achieved with the novel TiF_(6)^(2–)-pillared material ZU-100(TIFSIX-bpy-Ni).Construction of a pore structure with abundant TiF_(6)^(2–)anion sites and pores with appropriate sizes enabled formation of acetylene clusters through hydrogen bonds and intermolecular interactions,which afforded a high acetylene capacity(8.3 mmol·g^(–1))and high acetylene/carbon dioxide uptake ratio(1.9)at 298 K and 1 bar.Moreover,the NbO_(5)^(2–)anion-pillared material ZU-61 investigated for separation of acetylene/carbon dioxide.In addition,breakthrough experiments were also conducted to further confirm the excellent dynamic acetylene/carbon dioxide separation performance of ZU-100.
基金supported by the National Natural Science Foundation of China(22101244)the Natural Science Foundation of Shandong Province(ZR2021QB044).
文摘The development of metal-organic frameworks(MOFs)with highly efficient adsorption and separation of acet-ylene is very important and challenging in chemical industry due to the explosive nature of acetylene.Porous MOFs can be constructed by inserting a second auxiliary ligand,which allows the use of large ligands to construct non-interpenetrated structures and increase pore utilization.Herein,SNNU-205 is successfully synthesized,which connects two sets of interpenetrated structures to form a double walled cage-within-cage structure by using the introduction of a second auxiliary ligand.The modified pore environment enables SNNU-205 to efficiently selectively adsorb C_(2)H_(2)over CO_(2).At 298 K and 1 atm,SNNU-205 can uptake much more C_(2)H_(2)(76.3 cm^(3)g1)than CO_(2)(47.3 cm^(3)g^(-1)),resulting in a high substance ratio of C_(2)H_(2)-to-CO_(2)(1.6).More importantly,the ideal adsorbed solution theory selectivity calculations and column breakthrough tests further indicate SNNU-205 to be promising adsorbents for C_(2)H_(2)adsorption and purification.
基金Work conducted in our lab is supported by DuPont and US National Science Foundation.
文摘Carbon nanotube sorting,i.e.,the separation of a mixture of tubes into different electronic types and further into species with a specifi c chirality,is a fascinating problem of both scientifi c and technological importance.It is one of those problems that are easy to describe but diffi cult to solve.Single-stranded DNA forms stable complexes with carbon nanotubes and disperses them effectively in water.A particular DNA sequence of alternating guanine(G)and thymine(T)nucleotides((GT)n,with n=10 to 45)self-assembles into an ordered supramolecular structure around an individual nanotube,in such a way that the electrostatic properties of the DNA-carbon nanotube hybrid depend on tube structure,enabling nanotube separation by anion-exchange chromatography.This review provides a summary of the separation of metallic and semiconducting tubes,and purification of single(n,m)tubes using the DNA-wrapping approach.We will present our current understanding of the DNA-carbon nanotube hybrid structure and separation mechanisms,and predict future developments of the DNA-based approach.
基金This work was supported by the National Natural Science Foundation of China(Nos.52070148 and 52270049)the Shaanxi Provincial Key Program for Science and Technology Development(China)(No.2022KWZ-25)the Japan Society for the Promotion of Science(No.P20794).
文摘An AnMBR-PN/A system was developed for mainstream sewage treatment.To verify the efficient methanation and subsequent chemolitrophic nitrogen removal,a long-term experiment and analysis of microbial activity were carried out.AnMBR performance was less affected by the change of hydraulic retention time(HRT),which could provide a stable influent for subsequent PN/A units.The COD removal efficiency of AnMBR was>93%during the experiment,85.5%of COD could be recovered in form of CH4.With the HRT of PN/A being shortened from 10 to 6 h,nitrogen removal efficiency(NRE)of PN/A increased from 60.5%to 80.4%,but decreased to 68.8%when the HRTPN/A further decreased to 4 h.Microbial analysis revealed that the highest specific ammonia oxidation activity(SAOA)and the ratio of SAOA to specific nitrate oxidation activity(SNOA)provide stable NO_(2)^(−)-N/NH_(4)^(+)-N for anammox,and anammox bacteria(mainly identified as Candidatus Brocadia)enriched at the bottom of Anammox-UASB might play an important role in nitrogen removal.In addition,the decrease of COD in Anammox-UASB indicated partial denitrification occurred,which jointly promoted nitrogen removal with anammox.
基金the Thailand Research Fund (TRF) under the Research Career Development Project
文摘Multiphase CFD is used to design a compact fluidized bed sorber for CO2 removal from flue gases using sodium or potassium carbonate pellets. The sorber sizes are much smaller than commercial amine absorbers and smaller than other proposed dry adsorbers. The size reduction is due to the elimination of dilute regions that cause bypassing. With proper solids feeding we eliminated the usual core-annular regime found in circulating fluidized beds.
文摘A new complex plant for carbonization and composting of municipal wastes proposed for Gero City is introduced. The separated combustible waste and non-separated combustible waste are carbonized in two fluidized carbonization furnaces in the plant, and the coke produced is used in steelworks. The separated garbage and forest-wastes are mixed with dried septic-tank sludge to produce high quality compost for farms. This use of waste materials in the complex plant considerably lowers the amount of waste going to land-fills, and in addition, creates lower total emission of dioxins and carbon dioxide into the environment.
