Asphaltenes, complex aromatic compounds from various carbonaceous sources, could be obtained by solvent dissolution, filtration and adsorption. It was difficult to clarify the molecular structures and chemical propert...Asphaltenes, complex aromatic compounds from various carbonaceous sources, could be obtained by solvent dissolution, filtration and adsorption. It was difficult to clarify the molecular structures and chemical properties of asphaltene due to its structural similarity, composition complexity and source dependences. Many techniques, like Mass spectrometry, Chromatography, Nuclear magnetic resonance spectroscopy, Infrared spectroscopy, Roman spectroscopy, Fluorescence spectroscopy, X-ray diffraction analysis and Small-angle scattering techniques and so on, have revealed some valuable descriptions of asphaltenes chemical compositions and fundamental structures. Moreover, advanced Mass spectrometry,Atomic force microscopy and Scanning tunneling microscopy could provide more clear and essential molecular compounds and structures in asphaltenes. In addition, several asphaltenes models have succeeded to illustrate aggregation properties asphaltene. In this work, the progress on asphaltene separation, characterization and application was summarized, and the similarities and differences between coal-derived asphaltenes and petroleum asphaltenes were compared. Furthermore, the reactivity of asphaltenes has been discussed in the aspect of hydroprocessing, pyrolysis and gasification. Asphaltene was excellent carbon precursor for functional carbon material due to its high aromaticity and carbon yield;several porous carbon nanosheets from asphaltenes that would be prospective electrode materials after being graphitized were shown. Pitch-based carbon fiber derived from coal-derived asphaltenes displayed a tensile strength of 1.0 GPa and elastic modulus of 350 MPa, respectively. These powerful advances will provide asphaltenes promising developments.展开更多
IBC Advanced Technologies’ Molecular Recognition Technology(MRT) SuperLig products selectively and rapidly bind with target species enabling their selective removal from solutions.The MRT process can produce a high p...IBC Advanced Technologies’ Molecular Recognition Technology(MRT) SuperLig products selectively and rapidly bind with target species enabling their selective removal from solutions.The MRT process can produce a high purity separation product of maximum added value at a competitive cost.SuperLig products have high selectivity for many target species which can include metal ions,anions,and neutral molecules.In operation,the SuperLig product is first placed in a packed column.A solution containing a mixture of the target species and other chemical species is then passed through the column.The target species is removed selectively by the SuperLig product,the column is washed to remove residual feed solution,and the target species is recovered by a minimal quantity of eluent.The result is a pure and concentrated species that can be kept for its value or disposed of safely.The process is environmentally and ecologically friendly with no organic solvents being used.This paper provides a review of some examples of applications of MRT to separations of interest to the Chinese metallurgical industry.Included are several applications of MRT,including Pd separations from Pt metal refinery streams and low-grade spent catalyst wastes,Rh recovery from spent auto catalyst and other feeds,Re removal from selected impurity ions,Cd removal from Co electrolyte,Bi removal from Cu electrolyte,In and Ge separations from difficult matrices,and removal of bivalent first transition series and other metal ions from acid mine drainage(Berkeley Pit,Montana).Finally,the potential application of MRT to separations involving the recovery of rare earth metals and Li from low-level waste solutions and end-of-life products is discussed.展开更多
Enantiomers of a-substituted-(2-pyridyl)-methylarfdnes uere separated on SC -7 gas chromatograph with a 20m×0.25mm Chirasil-Val capIlary column,Carrier gas was nitro- gen or hydrogen.The resolution factors(ri.s) ...Enantiomers of a-substituted-(2-pyridyl)-methylarfdnes uere separated on SC -7 gas chromatograph with a 20m×0.25mm Chirasil-Val capIlary column,Carrier gas was nitro- gen or hydrogen.The resolution factors(ri.s) were 1.02 to 1.06.Enantiomers of pyridyl anines were separated to and near to base line.展开更多
A new experiment was made on the developing of bed separations and mining subsidence from Tangshan T2192 working face by equivalent materials simulation.The overburden deformation and the developing of bed separations...A new experiment was made on the developing of bed separations and mining subsidence from Tangshan T2192 working face by equivalent materials simulation.The overburden deformation and the developing of bed separations with working face advanc- ing was simulated by a new model.The results show that the maximum value of bed separations moved forward gradually along with the working face advancing;the maxi- mum value of bed separations is 0.31～0.50 times of mining thickness.The key strata have a great influence upon surface subsidence during the overburden movement process.The mechanics parameters of new experiment are fitted with results in fields perfectly.展开更多
A non-linear non-ideal model, taking into account non-linear competitive isotherms, axial dispersion, film mass transfer, intraparticle diffusion, and port periodic switching, was developed to simulate the dynamics of...A non-linear non-ideal model, taking into account non-linear competitive isotherms, axial dispersion, film mass transfer, intraparticle diffusion, and port periodic switching, was developed to simulate the dynamics of simulated moving bed chromatography (SMBC). The model equations were solved by a new efficient numerical technique of orthogonal collocation on finite elements with periodical movement of concentration vector. The simulated SMBC performance is in accordance with the experimental results reported in the literature for separation of l,1'-bi-2-naphthol enantiomers using SMBC. This model is useful for design, operation, optimization and scale-up of non-linear SMBC for chiral separations with significant non-ideal effects, especially for high solute concentration and small intraparticle diffusion coefficient or large chiral stationary phase particle.展开更多
Constructing a Z-scheme is a significant approach to improve the separation of photogene rated carriers for effective organic pollutant degradation.Herein,a BiVO4/ZnIn2S4(BZ) Z-scheme composite was successfully synthe...Constructing a Z-scheme is a significant approach to improve the separation of photogene rated carriers for effective organic pollutant degradation.Herein,a BiVO4/ZnIn2S4(BZ) Z-scheme composite was successfully synthesized,and applied to photodegrade methyl orange(MO) irradiated by a LED lamp.Anchoring the BiVO4 on the ZnIn2S4 nanoparticles promoted the separation of photogenerated electronholes and broadened the light response range.The detailed characterizations,including surface morphology,elements valence state,and photocurrent performance,demonstrated that the enhanced separation of photogenerated carriers was the pivotal reason for the enhanced photocatalysis reaction.Benefiting from the excellent photocatalytic characteristics,the 5% mass ratio of BZ composite presented the highest MO degradation rate of 0.00997 min^-1,which was 1.9 and 10.3 times greater than the virgin ZnIn2S4 and BiVO4,respectively.Furthermore,the BZ hybrid materials indicated a well photo-stability in the four recycling tests.展开更多
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
Conjugated microporous polymers(CMPs) are a unique class of porous organic materials, which are constructed with π-conjugation structures leading to intrinsic micropores. The CMPs properties such as high surface area...Conjugated microporous polymers(CMPs) are a unique class of porous organic materials, which are constructed with π-conjugation structures leading to intrinsic micropores. The CMPs properties such as high surface area, intrinsic and rich micropores, interlocking and rigid structure, extensive π-conjugation and tunable band-gap, chemical and thermal stability, together with tailored functionalities, contribute to its abundant potential for application in fields such as photocatalysis, optoelectronics, energy storage, and chemical sensors. Recently, CMPs have gained importance in the field of membranes for chemical separation. In this review, we briefly discuss the historical development of CMPs, followed by a detailed description of the progress in state-of-the-art design, preparation, and application of CMPs in membranes. Additionally, we provide inference on the future prospects of CMPs as membranes.展开更多
The chiral separations of four pharmaceutical racemates which contain N-alkyl groups were satisfactorily resolved using SBE-β-CD as a chiral mobile phase additive （CMPA） in a RP-HPLC system （the resolution is 2.70...The chiral separations of four pharmaceutical racemates which contain N-alkyl groups were satisfactorily resolved using SBE-β-CD as a chiral mobile phase additive （CMPA） in a RP-HPLC system （the resolution is 2.701 for ondansetron hydrochloride, 1.996 for sulpiride, 1.293 for clenbuterol hydrochloride and 0.816 for omeprazole）. In addition, the effects of different parameters such as CD type and CD concentration were investigated. The separation mechanism arises through the combination of several potential interactions, including electrostatic interactions as well as hydrogen bonding interactions and hydrophobic inclusion interactions, which allow for the SBE-β-CD-drug complexation with strong stereoselectivity and stability. The resolution also relates to the number and location of N atoms in the enantiomers. This method will be applicable to the isolation of various types of biologically imoortant enantiomers containing N-alkyl groups.展开更多
Favorable physicochemical properties and unique molecular recognition capability endow triptycenebased materials with good potential as stationary phases for gas chromatography (GC). This work reports a new type of tr...Favorable physicochemical properties and unique molecular recognition capability endow triptycenebased materials with good potential as stationary phases for gas chromatography (GC). This work reports a new type of triptycene-based materials functionalized by three benzimidazolium cations with different peripheral alkyl lengths (denoted as TP-3Bim-5C and TP-3Bim-12C) and their GC separation performance. As a result, they shared high resolving performance for the naphthalene isomers but differed for the benzene derivatives with varying polarity. Moreover, their capillary columns exhibited good repeatability and thermal stability. This work presents a facile strategy for tailoring the selectivity of the TP-based stationary phases and demonstrates their promising future for chromatographic analysis.展开更多
We use a LaCoste-Romberg model D gravimeter to measure the gravitational forces at fixed positions when a large cylindrical reservoir is full and when it is empty.The differences determine the intermediate-range force...We use a LaCoste-Romberg model D gravimeter to measure the gravitational forces at fixed positions when a large cylindrical reservoir is full and when it is empty.The differences determine the intermediate-range force at various separations around 50m to about 0.5%accuracy.展开更多
Using two b-cyclodextrin derivatives (CDs) with long chain of acyl groups as chiral stationary phases (CSPs) of capillary gas chromatography (CGC), the enantiomers of racemic allethrone and propargyllone were well res...Using two b-cyclodextrin derivatives (CDs) with long chain of acyl groups as chiral stationary phases (CSPs) of capillary gas chromatography (CGC), the enantiomers of racemic allethrone and propargyllone were well resolved after derived with acetyl chloride. The enantiomer excess values (e.e.%) of 1S-allethrone and 1S-propargyllone were also determined successfully using these CDs.展开更多
Membrane technology has become one of the most promising separation technologies for its energy saving, high separation efficiency, environmental friendliness, and economic feasibility. Covalent organic frameworks(COF...Membrane technology has become one of the most promising separation technologies for its energy saving, high separation efficiency, environmental friendliness, and economic feasibility. Covalent organic frameworks(COFs) with intrinsically high porosity, controllable pore size, uniform pore size distribution and long-range ordered channel structure, have emerged as next-generation materials to fabricate advanced separation membranes. This feature article summarizes some latest studies in the development of pure COF membranes in our lab, including their fabrication and applications in chemical separations. Finally, current challenges facing high-performance COF separation membranes are discussed.展开更多
DNA separation techniques have drawn attention because of their uses in applications such as gene analysis and manipulation. There have been many studies utilizing micro-fabricated devices for faster and more efficien...DNA separation techniques have drawn attention because of their uses in applications such as gene analysis and manipulation. There have been many studies utilizing micro-fabricated devices for faster and more efficient separations than traditional methods using gel electrophoresis. Although many experimental studies have presented various new devices and methods, computational studies have played a pivotal role in this development by identifying separation mechanisms and by finding optimal designs for efficient separation conditions. The simulation of DNA separation methods in micro-fabricated devices requires the correct capture of the dynamics and the structure of a single polymer molecule that is being affected by an applied flow field or an electric field in complex geometries. In this work, we summarize the polymer models (the bead-spring model, the bead-rod model, the slender-body model, and the touching-bead model) and the methods, focusing on Brownian dynamics simulation, used to calculate inhomogeneous fields taking into consideration complex boundaries (the finite element method, the boundary element method, the lattice-Boltzmann method, and the dissipative particle dynamics simulation). The worm-like chain model (adapted from the bead-spring model) combined with the finite element method has been most commonly used but other models have shown more efficient and accurate results. We also review the applications of these simulation approaches in various separation methods and devices: gel electrophoresis, post arrays, capillary electrophoresis, microchannel flows, entropic traps, nanopores, and rotational flows. As more complicated geometries are involved in new devices, more rigorous models (such as incorporating the hydrodynamic interactions of DNA with solid boundaries) that can correctly capture the dynamic behaviors of DNA in such devices are needed.展开更多
CONSPECTUS:Increasing demand for high-purity fine chemicals and a drive for process intensification of large-scale separations have driven significant work on the development of highly engineered porous materials with...CONSPECTUS:Increasing demand for high-purity fine chemicals and a drive for process intensification of large-scale separations have driven significant work on the development of highly engineered porous materials with promise for sorption-based separations.While sorptive separations in porous materials offer energy-efficient alternatives to longstanding thermal-based methods,the particulate nature of many of these sorbents has sometimes limited their large-scale deployment in high-throughput applications such as gas separations,for which the necessary high feed flow rates and gas velocities accrue prohibitive operational costs.These processability limitations have been historically addressed through powder shaping methods aimed at the fabrication of structured sorbent contactors based on pellets,beads or monoliths,commonly obtained as extrudates.These structures overcome limitations such as elevated pressure drops commonly recorded across powder adsorption beds but often accrue thermal limitations arising from elevated particle density and aggregation,which ultimately cap their maximum separation performance.Furthermore,the harsh mechanical strain to which powder particles are subjected during contactor fabrication,in the form of extrusion/compression forces,can result in partial pore occlusion and framework degradation,further limiting their performance.Here,we present the development of porous fiber sorbents as an alternative sorbent contactor design capable of addressing sorbent processability limitations while enabling an array of performance-maximizing heat integration capabilities.This new sorbent form factor leverages pre-existing know-how from hollow fiber spinning to produce fiber-shaped sorbent contactors through the phase inversion of known polymers in a process known as dry-jet/wet quenching.The process of phase inversion allows microporous sorbent particles to be latched onto a macroporous polymer matrix under mild processing conditions,thus making it compatible with soft porous materials prone to amorphization under traditional pelletization conditions.Sorbent fibers can be created with different geometries through control of the spinning apparatus and process,offering the possibility to produce monolithic and hollow fibers alike,the latter of which can be integrated with thermalization fluid flows.In this Account,we summarize our progress in the field of fiber sorbents from both design and application standpoints.We further guide the reader through the evolution of this field from the early inceptive work on zeolite hollow fibers to recent developments on MOF fibers.We highlight the versatile nature of fiber sorbents,both from the composition,fabrication and structure points of view,and further demonstrate how fiber sorbents offer alternative paths in tackling new and challenging chemical separation challenges like direct air capture(DAC),with a final perspective on the future of the field.展开更多
Separations of mixtures in fixed-bed adsorbers are influenced by factors such as(1)selectivity of adsorption,Sads,(2)diffusional time constants,Đi/rc 2,and(3)diffusion selectivity,Đ1/Đ2.In synergistic separations,intr...Separations of mixtures in fixed-bed adsorbers are influenced by factors such as(1)selectivity of adsorption,Sads,(2)diffusional time constants,Đi/rc 2,and(3)diffusion selectivity,Đ1/Đ2.In synergistic separations,intracrystalline diffusion of vip molecules serves to enhance the selectivities dictated by thermodynamics of mixture adsorption.In antisynergistic separations,intracrystalline diffusion serves to reverse the hierarchy of selectivities dictated by adsorption equilibrium.For both scenarios,the productivities of the desired product in fixed-bed operations are crucially dependent on diffusional time constants,Đi/rc 2;these need to be sufficiently low in order for diffusional influences to be effective.Also,the ratioĐ1/Đ2 should be large enough for manifestation of synergistic or antisynergistic influence.Both synergistic and antisynergistic separations have two common,distinguishing characteristics.Firstly,for transient uptake within crystals,the more mobile component attains supraequilibrium loadings during the initial stages of the transience.Such overshoots,signifying uphill diffusion,are engendered by the cross-coefficientsΓij(i≠j)of thermodynamic correction factors.Secondly,the component molar loadings,plotted in composition space,follow serpentine equilibration paths.If cross-coefficients are neglected,no overshoots in the loadings of the more mobile component are experienced,and the component loadings follow monotonous equilibration paths.The important takeaway message is that the modeling of mixture separations in fixed-bed adsorbers requires the use of the Maxwell−Stefan equations describing mixture diffusion employing chemical potential gradients as driving forces.展开更多
In this study,a straightforward one-step hydrothermal method was successfully utilized to synthesize the solid solution Na_(0.9)Mg_(0.45)Ti_(3.55)O_(8)-Na_(2)Ni_(2)Ti_(6)O_(16)(NNMTO-x),where x denotes the molar perce...In this study,a straightforward one-step hydrothermal method was successfully utilized to synthesize the solid solution Na_(0.9)Mg_(0.45)Ti_(3.55)O_(8)-Na_(2)Ni_(2)Ti_(6)O_(16)(NNMTO-x),where x denotes the molar percentage of Na_(2)Ni_(2)Ti_(6)O_(16)(NNTO)within Na_(0.9)Mg_(0.45)Ti_(3.55)O_(8)(NMTO),with x values of 10,20,30,40,and 50.Both XPS(X-ray Photoelectron Spectroscopy)and EDX(Energy Dispersive X-ray Spectroscopy)analyses unequivocally validated the formation of the NNMTO-x solid solutions.It was observed that when x is below 40,the NNMTO-x solid solution retains the structural characteristics of the original NMTO.However,beyond this threshold,significant alterations in crystal morphology were noted,accompanied by a noticeable decline in photocatalytic activity.Notably,the absorption edge of NNMTO-x(x<40)exhibited a shift towards the visible-light spectrum,thereby substantially broadening the absorption range.The findings highlight that NNMTO-30 possesses the most pronounced photocatalytic activity for the reduction of CO_(2).Specifically,after a 6 h irradiation period,the production rates of CO and CH_(4)were recorded at 42.38 and 1.47μmol/g,respectively.This investigation provides pivotal insights that are instrumental in the advancement of highly efficient and stable photocatalysts tailored for CO_(2)reduction processes.展开更多
Zn-I_(2) batteries have emerged as promising next-generation energy storage systems owing to their inherent safety,environmental compatibility,rapid reaction kinetics,and small voltage hysteresis.Nevertheless,two crit...Zn-I_(2) batteries have emerged as promising next-generation energy storage systems owing to their inherent safety,environmental compatibility,rapid reaction kinetics,and small voltage hysteresis.Nevertheless,two critical challenges,i.e.,zinc dendrite growth and polyiodide shuttle effect,severely impede their commercial viability.To conquer these limitations,this study develops a multifunctional separator fabricated from straw-derived carboxylated nanocellulose,with its negative charge density further reinforced by anionic polyacrylamide incorporation.This modification simultaneously improves the separator’s mechanical properties,ionic conductivity,and Zn^(2+)ion transfer number.Remarkably,despite its ultrathin 20μm profile,the engineered separator demonstrates exceptional dendrite suppression and parasitic reaction inhibition,enabling Zn//Zn symmetric cells to achieve impressive cycle life(>1800 h at 2 m A cm^(-2)/2 m Ah cm^(-2))while maintaining robust performance even at ultrahigh areal capacities(25 m Ah cm^(-2)).Additionally,the separator’s anionic characteristic effectively blocks polyiodide migration through electrostatic repulsion,yielding Zn-I_(2) batteries with outstanding rate capability(120.7 m Ah g^(-1)at 5 A g^(-1))and excellent cyclability(94.2%capacity retention after 10,000 cycles).And superior cycling stability can still be achieved under zinc-deficient condition and pouch cell configuration.This work establishes a new paradigm for designing high-performance zinc-based energy storage systems through rational separator engineering.展开更多
Electrospinning is regarded as an efficient method for directly and continuously fabricating nanofibers.The electrospinning process is relatively simple and convenient to operate and can be used to prepare polymer nan...Electrospinning is regarded as an efficient method for directly and continuously fabricating nanofibers.The electrospinning process is relatively simple and convenient to operate and can be used to prepare polymer nanofibers for almost all polymer solutions,melts,emulsions,and suspensions with sufficient viscosity.In addition,inorganic nanofibers can also be prepared via electrospinning by adding small amounts of polymers into the inorganic precursors,which are generally regarded as nonspinnable.The diameter of the electrospun nanofibers can be tuned from tens of nanometers to submicrons by changing the spinning parameters.The nonwoven fabric stacked with electrospun fibers is a porous material with interconnected submicron pores,providing a porosity above 80%.However,limited by the unstable rheological properties of the electrospinning fluid,it is difficult to obtain nanofibers stably and continuously with an average diameter of<100 nm,which narrows the separation applications of the electrospun nanofibrous membranes to only microfiltration,air filtration,or use as membrane substrates.Therefore,to fully take advantage of electrospun nanofibrous membranes in other separation applications,electrospun nanofibrous composite(ENC)membranes were developed to improve and optimize their selectivity,permeability,and other separation performances.The composite membranes not only have all the advantages of single-layered or single-component membranes,but also have more flexibility in the choice of functional components.In this account,we summarize the two combination strategies to design and fabricate ENC membranes.One is based on the component combination,in which functional components are homogeneously or heterogeneously mixed in the fiber matrix or modified on the nanofiber surface.The other one is termed as the interfacial combination,in which functional skin layers are fabricated on the top of the electrospun membranes via interfacial deposition or interfacial polymerization,to construct selective barriers.The specific preparation approaches in the two combination strategies are discussed systematically.Additionally,the structural characteristics and separation performances of ENC membranes fabricated via these approaches are also compared and analyzed to clarify their advantages and range of utilization.Subsequently,the six applications of ENC membranes we focus on are demonstrated,including adsorption,membrane distillation,oil/water emulsion separation,nanofiltration,hemodialysis,and pervaporation.To meet their different requirements for separations,our consideration about the choice of combination strategies,related preparation methods,and functional components are discussed based on typical research cases.In the end,we conclude this account with an overview of the challenges in industrial manufacturing,mechanical strength,and interfacial attachment of ENC membranes and prospect their future developments.展开更多
基金financial support by the National Key R&D Program of China (2016YFE0203500)National Science Foundation of China (No. U1510122)
文摘Asphaltenes, complex aromatic compounds from various carbonaceous sources, could be obtained by solvent dissolution, filtration and adsorption. It was difficult to clarify the molecular structures and chemical properties of asphaltene due to its structural similarity, composition complexity and source dependences. Many techniques, like Mass spectrometry, Chromatography, Nuclear magnetic resonance spectroscopy, Infrared spectroscopy, Roman spectroscopy, Fluorescence spectroscopy, X-ray diffraction analysis and Small-angle scattering techniques and so on, have revealed some valuable descriptions of asphaltenes chemical compositions and fundamental structures. Moreover, advanced Mass spectrometry,Atomic force microscopy and Scanning tunneling microscopy could provide more clear and essential molecular compounds and structures in asphaltenes. In addition, several asphaltenes models have succeeded to illustrate aggregation properties asphaltene. In this work, the progress on asphaltene separation, characterization and application was summarized, and the similarities and differences between coal-derived asphaltenes and petroleum asphaltenes were compared. Furthermore, the reactivity of asphaltenes has been discussed in the aspect of hydroprocessing, pyrolysis and gasification. Asphaltene was excellent carbon precursor for functional carbon material due to its high aromaticity and carbon yield;several porous carbon nanosheets from asphaltenes that would be prospective electrode materials after being graphitized were shown. Pitch-based carbon fiber derived from coal-derived asphaltenes displayed a tensile strength of 1.0 GPa and elastic modulus of 350 MPa, respectively. These powerful advances will provide asphaltenes promising developments.
文摘IBC Advanced Technologies’ Molecular Recognition Technology(MRT) SuperLig products selectively and rapidly bind with target species enabling their selective removal from solutions.The MRT process can produce a high purity separation product of maximum added value at a competitive cost.SuperLig products have high selectivity for many target species which can include metal ions,anions,and neutral molecules.In operation,the SuperLig product is first placed in a packed column.A solution containing a mixture of the target species and other chemical species is then passed through the column.The target species is removed selectively by the SuperLig product,the column is washed to remove residual feed solution,and the target species is recovered by a minimal quantity of eluent.The result is a pure and concentrated species that can be kept for its value or disposed of safely.The process is environmentally and ecologically friendly with no organic solvents being used.This paper provides a review of some examples of applications of MRT to separations of interest to the Chinese metallurgical industry.Included are several applications of MRT,including Pd separations from Pt metal refinery streams and low-grade spent catalyst wastes,Rh recovery from spent auto catalyst and other feeds,Re removal from selected impurity ions,Cd removal from Co electrolyte,Bi removal from Cu electrolyte,In and Ge separations from difficult matrices,and removal of bivalent first transition series and other metal ions from acid mine drainage(Berkeley Pit,Montana).Finally,the potential application of MRT to separations involving the recovery of rare earth metals and Li from low-level waste solutions and end-of-life products is discussed.
基金The project is supported by National Nature science Foundation of China.
文摘Enantiomers of a-substituted-(2-pyridyl)-methylarfdnes uere separated on SC -7 gas chromatograph with a 20m×0.25mm Chirasil-Val capIlary column,Carrier gas was nitro- gen or hydrogen.The resolution factors(ri.s) were 1.02 to 1.06.Enantiomers of pyridyl anines were separated to and near to base line.
基金The National Natural Science Funds Committee(50174035)
文摘A new experiment was made on the developing of bed separations and mining subsidence from Tangshan T2192 working face by equivalent materials simulation.The overburden deformation and the developing of bed separations with working face advanc- ing was simulated by a new model.The results show that the maximum value of bed separations moved forward gradually along with the working face advancing;the maxi- mum value of bed separations is 0.31～0.50 times of mining thickness.The key strata have a great influence upon surface subsidence during the overburden movement process.The mechanics parameters of new experiment are fitted with results in fields perfectly.
基金Supported by the National Natural Science Foundation of China(No.20206027)and the Natural Science Foundation of Zhejiang Province(No.202046).
文摘A non-linear non-ideal model, taking into account non-linear competitive isotherms, axial dispersion, film mass transfer, intraparticle diffusion, and port periodic switching, was developed to simulate the dynamics of simulated moving bed chromatography (SMBC). The model equations were solved by a new efficient numerical technique of orthogonal collocation on finite elements with periodical movement of concentration vector. The simulated SMBC performance is in accordance with the experimental results reported in the literature for separation of l,1'-bi-2-naphthol enantiomers using SMBC. This model is useful for design, operation, optimization and scale-up of non-linear SMBC for chiral separations with significant non-ideal effects, especially for high solute concentration and small intraparticle diffusion coefficient or large chiral stationary phase particle.
基金financial supports from the National Natural Science Foundation of China(Nos.51908485 and 51608468)the China Postdoctoral Science Foundation(No.2019T120194)the University Science and Technology Program Project of Hebei Provincial Department of Education(No.QN2018258)。
文摘Constructing a Z-scheme is a significant approach to improve the separation of photogene rated carriers for effective organic pollutant degradation.Herein,a BiVO4/ZnIn2S4(BZ) Z-scheme composite was successfully synthesized,and applied to photodegrade methyl orange(MO) irradiated by a LED lamp.Anchoring the BiVO4 on the ZnIn2S4 nanoparticles promoted the separation of photogenerated electronholes and broadened the light response range.The detailed characterizations,including surface morphology,elements valence state,and photocurrent performance,demonstrated that the enhanced separation of photogenerated carriers was the pivotal reason for the enhanced photocatalysis reaction.Benefiting from the excellent photocatalytic characteristics,the 5% mass ratio of BZ composite presented the highest MO degradation rate of 0.00997 min^-1,which was 1.9 and 10.3 times greater than the virgin ZnIn2S4 and BiVO4,respectively.Furthermore,the BZ hybrid materials indicated a well photo-stability in the four recycling tests.
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 King Abdullah University of Science and Technology,Saudi Arabia,under the competitive research grant URF/1/3769-01。
文摘Conjugated microporous polymers(CMPs) are a unique class of porous organic materials, which are constructed with π-conjugation structures leading to intrinsic micropores. The CMPs properties such as high surface area, intrinsic and rich micropores, interlocking and rigid structure, extensive π-conjugation and tunable band-gap, chemical and thermal stability, together with tailored functionalities, contribute to its abundant potential for application in fields such as photocatalysis, optoelectronics, energy storage, and chemical sensors. Recently, CMPs have gained importance in the field of membranes for chemical separation. In this review, we briefly discuss the historical development of CMPs, followed by a detailed description of the progress in state-of-the-art design, preparation, and application of CMPs in membranes. Additionally, we provide inference on the future prospects of CMPs as membranes.
基金supported by the National Science and Technology Special Projects(Nos.2012ZX 09301-002-001 and 2012 ZX09301-002-006)the Research and Application of New Efficient Analytical Technologies and Methods in Drug Quality Control and Drug Safety(No.2011IM030200)the State Key Laboratory of Bioactive Substances and Functions of Natural Medicines Open Project(No.GTZK201310)
文摘The chiral separations of four pharmaceutical racemates which contain N-alkyl groups were satisfactorily resolved using SBE-β-CD as a chiral mobile phase additive （CMPA） in a RP-HPLC system （the resolution is 2.701 for ondansetron hydrochloride, 1.996 for sulpiride, 1.293 for clenbuterol hydrochloride and 0.816 for omeprazole）. In addition, the effects of different parameters such as CD type and CD concentration were investigated. The separation mechanism arises through the combination of several potential interactions, including electrostatic interactions as well as hydrogen bonding interactions and hydrophobic inclusion interactions, which allow for the SBE-β-CD-drug complexation with strong stereoselectivity and stability. The resolution also relates to the number and location of N atoms in the enantiomers. This method will be applicable to the isolation of various types of biologically imoortant enantiomers containing N-alkyl groups.
基金the financial support by the National Natural Science Foundation of China(No.21575013)Analysis & Testing Center, Beijing Institute of Technology
文摘Favorable physicochemical properties and unique molecular recognition capability endow triptycenebased materials with good potential as stationary phases for gas chromatography (GC). This work reports a new type of triptycene-based materials functionalized by three benzimidazolium cations with different peripheral alkyl lengths (denoted as TP-3Bim-5C and TP-3Bim-12C) and their GC separation performance. As a result, they shared high resolving performance for the naphthalene isomers but differed for the benzene derivatives with varying polarity. Moreover, their capillary columns exhibited good repeatability and thermal stability. This work presents a facile strategy for tailoring the selectivity of the TP-based stationary phases and demonstrates their promising future for chromatographic analysis.
文摘We use a LaCoste-Romberg model D gravimeter to measure the gravitational forces at fixed positions when a large cylindrical reservoir is full and when it is empty.The differences determine the intermediate-range force at various separations around 50m to about 0.5%accuracy.
文摘Using two b-cyclodextrin derivatives (CDs) with long chain of acyl groups as chiral stationary phases (CSPs) of capillary gas chromatography (CGC), the enantiomers of racemic allethrone and propargyllone were well resolved after derived with acetyl chloride. The enantiomer excess values (e.e.%) of 1S-allethrone and 1S-propargyllone were also determined successfully using these CDs.
基金financially supported by the National Natural Science Foundation of China (Nos. 22378300 and 21878215)National Key Research and Development Program of China (No.2022YFB3805202)+3 种基金Key Research and Development Program of Zhejiang Province (No. 2021C03173)Ningbo Key Research and Development Project (No. 2022Z121)Program of Introducing Talents of Discipline to Universities (No.BP0618007)Haihe Laboratory of Sustainable Chemical Transformations for financial support。
文摘Membrane technology has become one of the most promising separation technologies for its energy saving, high separation efficiency, environmental friendliness, and economic feasibility. Covalent organic frameworks(COFs) with intrinsically high porosity, controllable pore size, uniform pore size distribution and long-range ordered channel structure, have emerged as next-generation materials to fabricate advanced separation membranes. This feature article summarizes some latest studies in the development of pure COF membranes in our lab, including their fabrication and applications in chemical separations. Finally, current challenges facing high-performance COF separation membranes are discussed.
文摘DNA separation techniques have drawn attention because of their uses in applications such as gene analysis and manipulation. There have been many studies utilizing micro-fabricated devices for faster and more efficient separations than traditional methods using gel electrophoresis. Although many experimental studies have presented various new devices and methods, computational studies have played a pivotal role in this development by identifying separation mechanisms and by finding optimal designs for efficient separation conditions. The simulation of DNA separation methods in micro-fabricated devices requires the correct capture of the dynamics and the structure of a single polymer molecule that is being affected by an applied flow field or an electric field in complex geometries. In this work, we summarize the polymer models (the bead-spring model, the bead-rod model, the slender-body model, and the touching-bead model) and the methods, focusing on Brownian dynamics simulation, used to calculate inhomogeneous fields taking into consideration complex boundaries (the finite element method, the boundary element method, the lattice-Boltzmann method, and the dissipative particle dynamics simulation). The worm-like chain model (adapted from the bead-spring model) combined with the finite element method has been most commonly used but other models have shown more efficient and accurate results. We also review the applications of these simulation approaches in various separation methods and devices: gel electrophoresis, post arrays, capillary electrophoresis, microchannel flows, entropic traps, nanopores, and rotational flows. As more complicated geometries are involved in new devices, more rigorous models (such as incorporating the hydrodynamic interactions of DNA with solid boundaries) that can correctly capture the dynamic behaviors of DNA in such devices are needed.
基金funded by the National Energy Technology Laboratory of the U.S.Department of Energy under Award No.DE FE0032129Advanced Research Projects Agency-Energy(ARPA-E),U.S.Department of Energy,under Award No.DE-AR0001309.
文摘CONSPECTUS:Increasing demand for high-purity fine chemicals and a drive for process intensification of large-scale separations have driven significant work on the development of highly engineered porous materials with promise for sorption-based separations.While sorptive separations in porous materials offer energy-efficient alternatives to longstanding thermal-based methods,the particulate nature of many of these sorbents has sometimes limited their large-scale deployment in high-throughput applications such as gas separations,for which the necessary high feed flow rates and gas velocities accrue prohibitive operational costs.These processability limitations have been historically addressed through powder shaping methods aimed at the fabrication of structured sorbent contactors based on pellets,beads or monoliths,commonly obtained as extrudates.These structures overcome limitations such as elevated pressure drops commonly recorded across powder adsorption beds but often accrue thermal limitations arising from elevated particle density and aggregation,which ultimately cap their maximum separation performance.Furthermore,the harsh mechanical strain to which powder particles are subjected during contactor fabrication,in the form of extrusion/compression forces,can result in partial pore occlusion and framework degradation,further limiting their performance.Here,we present the development of porous fiber sorbents as an alternative sorbent contactor design capable of addressing sorbent processability limitations while enabling an array of performance-maximizing heat integration capabilities.This new sorbent form factor leverages pre-existing know-how from hollow fiber spinning to produce fiber-shaped sorbent contactors through the phase inversion of known polymers in a process known as dry-jet/wet quenching.The process of phase inversion allows microporous sorbent particles to be latched onto a macroporous polymer matrix under mild processing conditions,thus making it compatible with soft porous materials prone to amorphization under traditional pelletization conditions.Sorbent fibers can be created with different geometries through control of the spinning apparatus and process,offering the possibility to produce monolithic and hollow fibers alike,the latter of which can be integrated with thermalization fluid flows.In this Account,we summarize our progress in the field of fiber sorbents from both design and application standpoints.We further guide the reader through the evolution of this field from the early inceptive work on zeolite hollow fibers to recent developments on MOF fibers.We highlight the versatile nature of fiber sorbents,both from the composition,fabrication and structure points of view,and further demonstrate how fiber sorbents offer alternative paths in tackling new and challenging chemical separation challenges like direct air capture(DAC),with a final perspective on the future of the field.
文摘Separations of mixtures in fixed-bed adsorbers are influenced by factors such as(1)selectivity of adsorption,Sads,(2)diffusional time constants,Đi/rc 2,and(3)diffusion selectivity,Đ1/Đ2.In synergistic separations,intracrystalline diffusion of vip molecules serves to enhance the selectivities dictated by thermodynamics of mixture adsorption.In antisynergistic separations,intracrystalline diffusion serves to reverse the hierarchy of selectivities dictated by adsorption equilibrium.For both scenarios,the productivities of the desired product in fixed-bed operations are crucially dependent on diffusional time constants,Đi/rc 2;these need to be sufficiently low in order for diffusional influences to be effective.Also,the ratioĐ1/Đ2 should be large enough for manifestation of synergistic or antisynergistic influence.Both synergistic and antisynergistic separations have two common,distinguishing characteristics.Firstly,for transient uptake within crystals,the more mobile component attains supraequilibrium loadings during the initial stages of the transience.Such overshoots,signifying uphill diffusion,are engendered by the cross-coefficientsΓij(i≠j)of thermodynamic correction factors.Secondly,the component molar loadings,plotted in composition space,follow serpentine equilibration paths.If cross-coefficients are neglected,no overshoots in the loadings of the more mobile component are experienced,and the component loadings follow monotonous equilibration paths.The important takeaway message is that the modeling of mixture separations in fixed-bed adsorbers requires the use of the Maxwell−Stefan equations describing mixture diffusion employing chemical potential gradients as driving forces.
基金Supported by the Doctoral Research Start-up Project of Yuncheng University(YQ-2023067)Project of Shanxi Natural Science Foundation(202303021211189)+1 种基金Fund Program for the Scientific Activities of Selected Returned Overseas Professionals in Shanxi Provinces(20220036)Shanxi ProvinceIntelligent Optoelectronic Sensing Application Technology Innovation Center and Shanxi Province Optoelectronic Information Science and TechnologyLaboratory,Yuncheng University.
文摘In this study,a straightforward one-step hydrothermal method was successfully utilized to synthesize the solid solution Na_(0.9)Mg_(0.45)Ti_(3.55)O_(8)-Na_(2)Ni_(2)Ti_(6)O_(16)(NNMTO-x),where x denotes the molar percentage of Na_(2)Ni_(2)Ti_(6)O_(16)(NNTO)within Na_(0.9)Mg_(0.45)Ti_(3.55)O_(8)(NMTO),with x values of 10,20,30,40,and 50.Both XPS(X-ray Photoelectron Spectroscopy)and EDX(Energy Dispersive X-ray Spectroscopy)analyses unequivocally validated the formation of the NNMTO-x solid solutions.It was observed that when x is below 40,the NNMTO-x solid solution retains the structural characteristics of the original NMTO.However,beyond this threshold,significant alterations in crystal morphology were noted,accompanied by a noticeable decline in photocatalytic activity.Notably,the absorption edge of NNMTO-x(x<40)exhibited a shift towards the visible-light spectrum,thereby substantially broadening the absorption range.The findings highlight that NNMTO-30 possesses the most pronounced photocatalytic activity for the reduction of CO_(2).Specifically,after a 6 h irradiation period,the production rates of CO and CH_(4)were recorded at 42.38 and 1.47μmol/g,respectively.This investigation provides pivotal insights that are instrumental in the advancement of highly efficient and stable photocatalysts tailored for CO_(2)reduction processes.
基金the financial support from the Natural Science Foundation of Jiangsu Province(BK20231292)the Jiangsu Agricultural Science and Technology Innovation Fund(CX(24)3091)+6 种基金the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX25_1429)the National Key R&D Program of China(2024YFE0109200)the Fundamental Research Funds for the Central Universities(No.2024300440)Guangdong Basic and Applied Basic Research Foundation(2025A1515011098)the National Natural Science Foundation of China(12464032)the Natural Science Foundation of Jiangxi Province(20232BAB201032)Ji'an Science and Technology Plan Project(2024H-100301)。
文摘Zn-I_(2) batteries have emerged as promising next-generation energy storage systems owing to their inherent safety,environmental compatibility,rapid reaction kinetics,and small voltage hysteresis.Nevertheless,two critical challenges,i.e.,zinc dendrite growth and polyiodide shuttle effect,severely impede their commercial viability.To conquer these limitations,this study develops a multifunctional separator fabricated from straw-derived carboxylated nanocellulose,with its negative charge density further reinforced by anionic polyacrylamide incorporation.This modification simultaneously improves the separator’s mechanical properties,ionic conductivity,and Zn^(2+)ion transfer number.Remarkably,despite its ultrathin 20μm profile,the engineered separator demonstrates exceptional dendrite suppression and parasitic reaction inhibition,enabling Zn//Zn symmetric cells to achieve impressive cycle life(>1800 h at 2 m A cm^(-2)/2 m Ah cm^(-2))while maintaining robust performance even at ultrahigh areal capacities(25 m Ah cm^(-2)).Additionally,the separator’s anionic characteristic effectively blocks polyiodide migration through electrostatic repulsion,yielding Zn-I_(2) batteries with outstanding rate capability(120.7 m Ah g^(-1)at 5 A g^(-1))and excellent cyclability(94.2%capacity retention after 10,000 cycles).And superior cycling stability can still be achieved under zinc-deficient condition and pouch cell configuration.This work establishes a new paradigm for designing high-performance zinc-based energy storage systems through rational separator engineering.
基金funded by the National Key Research and Development Program of China(2022YFB3804901,2022YFB3804900)the National Natural Science Foundation of China(51903044)the Major Program of Qingyuan Innovation Laboratory(00122006).
文摘Electrospinning is regarded as an efficient method for directly and continuously fabricating nanofibers.The electrospinning process is relatively simple and convenient to operate and can be used to prepare polymer nanofibers for almost all polymer solutions,melts,emulsions,and suspensions with sufficient viscosity.In addition,inorganic nanofibers can also be prepared via electrospinning by adding small amounts of polymers into the inorganic precursors,which are generally regarded as nonspinnable.The diameter of the electrospun nanofibers can be tuned from tens of nanometers to submicrons by changing the spinning parameters.The nonwoven fabric stacked with electrospun fibers is a porous material with interconnected submicron pores,providing a porosity above 80%.However,limited by the unstable rheological properties of the electrospinning fluid,it is difficult to obtain nanofibers stably and continuously with an average diameter of<100 nm,which narrows the separation applications of the electrospun nanofibrous membranes to only microfiltration,air filtration,or use as membrane substrates.Therefore,to fully take advantage of electrospun nanofibrous membranes in other separation applications,electrospun nanofibrous composite(ENC)membranes were developed to improve and optimize their selectivity,permeability,and other separation performances.The composite membranes not only have all the advantages of single-layered or single-component membranes,but also have more flexibility in the choice of functional components.In this account,we summarize the two combination strategies to design and fabricate ENC membranes.One is based on the component combination,in which functional components are homogeneously or heterogeneously mixed in the fiber matrix or modified on the nanofiber surface.The other one is termed as the interfacial combination,in which functional skin layers are fabricated on the top of the electrospun membranes via interfacial deposition or interfacial polymerization,to construct selective barriers.The specific preparation approaches in the two combination strategies are discussed systematically.Additionally,the structural characteristics and separation performances of ENC membranes fabricated via these approaches are also compared and analyzed to clarify their advantages and range of utilization.Subsequently,the six applications of ENC membranes we focus on are demonstrated,including adsorption,membrane distillation,oil/water emulsion separation,nanofiltration,hemodialysis,and pervaporation.To meet their different requirements for separations,our consideration about the choice of combination strategies,related preparation methods,and functional components are discussed based on typical research cases.In the end,we conclude this account with an overview of the challenges in industrial manufacturing,mechanical strength,and interfacial attachment of ENC membranes and prospect their future developments.
