Organic solvent nanofiltration(OSN) is an efficient,low-energy and environmentally friendly phase-free separation process.Obviously,the core of OSN lies in the fabrication of solvent-resistant nanofiltration membranes...Organic solvent nanofiltration(OSN) is an efficient,low-energy and environmentally friendly phase-free separation process.Obviously,the core of OSN lies in the fabrication of solvent-resistant nanofiltration membranes.Although membrane materials reported in the literature such as 2D membranes,porous organic cages,etc.have the potential for ultra-high performance,polymeric membranes provide key advantages in mass production and processability.Therefore,this review focuses on polymeric materials for OSN.This review summarizes the recent progress of polymeric materials,including emerging and traditional polymeric membranes.Then,a summary of recent progress about strategies developed for perm-selective nanofilms are presented,followed by a brief overview of commercial membrane technology for OSN.Finally,major challenges of OSN and future research directions are presented.Close interaction between the academic research and practical application would help improve greener and more sustainable manufacturing processes.展开更多
A PVC membrane electrode based on copper（II） bis（N-2-bromophenylsalicyldenaminato） as ionophor was prepared. The ion selective electrode was tested by inorganic anions and showed a good selectivity for iodide ion....A PVC membrane electrode based on copper（II） bis（N-2-bromophenylsalicyldenaminato） as ionophor was prepared. The ion selective electrode was tested by inorganic anions and showed a good selectivity for iodide ion. This sensor exhibited Nernstian behavior with a slope of -57.8 mV per decade at 25℃. The proposed electrode showed a linear range from 1.0 × 10 ^-5 to 1.0 × 10 ^-1 mol/L with a detection limit of 5.0 × 10 ^-6 mol/L. The electrode response was independent of pH in the range of 3.0- 10.0. The proposed sensor was applied to determine the iodide in water and antiseptic samples.展开更多
A review is presented of studies of polymeric membranes by applying positron annihilation lifetime spectroscopy （PALS）. PALS has been used to study subnanometer-sized holes, to determine their size distribution and ...A review is presented of studies of polymeric membranes by applying positron annihilation lifetime spectroscopy （PALS）. PALS has been used to study subnanometer-sized holes, to determine their size distribution and free-volume fractions, and to probe molecular-sized vacancies in glassy polymers. At present, PALS is believed to be a highly effective physical method for the examination of polymeric membranes.展开更多
The analytical technique of conductometric titration is used to characterize polymeric materials.This technique allows obtaining the polymer dry weight capacity(DWC)and the extent of reaction and establishing the opti...The analytical technique of conductometric titration is used to characterize polymeric materials.This technique allows obtaining the polymer dry weight capacity(DWC)and the extent of reaction and establishing the optimal number of water molecules per sulfonic groups.In this particular case the polymer material under study was Nafion?117.Two different reactions were made:Neutralization and exchange.Both of them allow obtaining the same result.Conductometric titrations could be considered as a good method to study the neutralization and exchange reactions for polymeric materials used in fuel cells or electrolyzers.The implementation of this analytical technique allows reducing operation time of those types of materials.The waiting time between determinations permits to say that the amount of reactant consumed and products obtained were the same after each addition of titrant.展开更多
A new solvent polymeric membrane (SPM)pH2sensor based on 4,4'-bis (N, N-didecylamino)methyl)azobenzene as neutral carricr has been reported. It has excellent pH response characteristics with the linear response ra...A new solvent polymeric membrane (SPM)pH2sensor based on 4,4'-bis (N, N-didecylamino)methyl)azobenzene as neutral carricr has been reported. It has excellent pH response characteristics with the linear response range (1.7—13.2)much wider than that of similar SPM pH sensors reported so far. The sensor has a theoretical Nernstian response of 57.4+0.2V/pH(at 20℃)without super—Nernstian response phenomenon.展开更多
Separation of refined soybean oil/n-hexane miscellas was studied using different commercial ultra- and nanofiltration membranes, with cut-oil＇s in the range of 1 to 5 kDa and salt rejection higher than 97% （MgSO4）....Separation of refined soybean oil/n-hexane miscellas was studied using different commercial ultra- and nanofiltration membranes, with cut-oil＇s in the range of 1 to 5 kDa and salt rejection higher than 97% （MgSO4）. Commercial soybean oil and n-hexane miscellas with 1：3 and 1：1 mass ratios were permeated in a dead-end module. The effects of the feed pressure （2-25 bar） on oil and n-hexane fluxes and rejection were investigated. Oil rejection ranged from negative values to 30.8%, soybean oil flux from 28.9 to 617.8 g/m2 hl and n-hexane flux from 8.5 to 1,078.5 g m2 hl. Membrane fouling was observed at all experimental conditions studied. The membrane separation process has proven to be a promising alternative to solvent recovery in soybean oil extraction.展开更多
For the last two decades polymeric membranes have been used in several gas separation processes. For the high selectivity and permeability various types of membranes have been developed. Thin layers to high dense and ...For the last two decades polymeric membranes have been used in several gas separation processes. For the high selectivity and permeability various types of membranes have been developed. Thin layers to high dense and hollow fiber to asymmetric wounded materials to determine the effective separation of CO2 from CH4 were used. Ideal membrane materials must have provisions of durability, chemical and thermal resistance, effective separation and economical production and operation. In this review it is observed that most of the polymeric materials face plasticization problem in the separation of CO2 from CH4. This is due to the condensable nature of carbon dioxide that causes swelling in most of the polymeric membranes due to which the efficiency of selectivity and permeability is affected. Most extensive works have been carried out in developing the chemical structure and compositions of polymeric materials to improve the separation properties. Cross-linking and blending of molecular sieving called ＂mixed-matrix＂ are the most useful approaches applied in this regard, but no where it is found to be fully effective and ideal polymeric membranes commercially fit to replace the existing systems of CO2 separation from the natural gas. Still area is open to work on to produce more worth full materials and switch towards liquid membranes and hybrid systems.展开更多
The efficiency,robustness and reliability of recent numerical methods for finding solutions to flow problems have given rise to the implementation of computational fluid dynamics(CFD) as a broadly used analysis method...The efficiency,robustness and reliability of recent numerical methods for finding solutions to flow problems have given rise to the implementation of computational fluid dynamics(CFD) as a broadly used analysis method for engineering problems like membrane separation system.The CFD modeling in this study observes steady and unsteady(transient) heat flux and temperature profiles in a polymeric(cellulose acetate) membrane.This study is novel due to the implementation of user defined scalar(UDS) diffusion equation by using user-defined functions(UDFs) infinite volume method(FVM).Some details of the FVM used by the solver are carefully discussed when implementing terms in the governing equation and boundary conditions(BC).The contours of temperature due to high-temperature gradient are reported for steady and unsteady problems.展开更多
Bio-nanochannels in living organisms participate in the physiological activities by selectively transporting ions through cell membranes.The structure and function of biological ion channels inspire the development of...Bio-nanochannels in living organisms participate in the physiological activities by selectively transporting ions through cell membranes.The structure and function of biological ion channels inspire the development of artificial ion nanochannels with practical applications.The bioinspired nanochannels based on polymer materials present good mechanical stability,high-performance ion transport and designability,which have attracted much attention.In this review,we mainly focus on the fabrication and application of polymer-based biomimetic nanochannels especially in environmentally responsive biosensor and energy conversion.We firstly introduce the basic understanding of nanochannels in ion regulation and osmotic energy conversion.Then,we discuss the fabrication methods of polymer-based nanochannels and highlight their advantages compared with other materials.The practical applications of polymer-based biomimetic nanochannels,especially in energy conversion and environmentally responsive biosensor,are detailedly discussed.Finally,we summarize the unsolved problems in bioinspired nanochannels and overview the further developing direction in this field.展开更多
Anion-selective electrodes based on dissociated ion-exchangers such as lipophilicquaternary ammonium or phosphonium species always display classical Hofmeister be-havior in the following order: ClO<sub>4</sub...Anion-selective electrodes based on dissociated ion-exchangers such as lipophilicquaternary ammonium or phosphonium species always display classical Hofmeister be-havior in the following order: ClO<sub>4</sub><sup>-</sup>】SCN<sup>-</sup>】I<sup>-</sup>】Br<sup>-</sup>】NO<sub>2</sub><sup>-</sup>】Cl<sup>-</sup>】SO<sub>4</sub><sup>2-</sup>.A new sol-vent polymeric membrane electrode based on Schiff base complexes of Co（Ⅱ）[Co（Ⅱ）S]and showing excellent selectivity toward iodide ion is for the first time prepared inour work. The resulting electrodes exhibit fairly low detection limits andpotentiometric anion-selectivity sequences deviated from the Hofmeister pattern.Bis（salicylaldehyde） ethylenediiminecobalt（Ⅱ） [Co（Ⅱ）（salen）], bis（salicylaldehyde）-phenyldiiminecobalt（Ⅱ） [Co（Ⅱ）（salophen）],展开更多
Phenol is extensively utilized in various industries involving paints,rubber,textiles,explosives,plastics,etc.Compared to the conventional distillation or extraction technologies,pervaporation(PV)membrane process can ...Phenol is extensively utilized in various industries involving paints,rubber,textiles,explosives,plastics,etc.Compared to the conventional distillation or extraction technologies,pervaporation(PV)membrane process can be operated at a low temperature and has a low energy consumption as well as a high separation efficiency for phenol recovery.Thus,to meet the high demand for phenol recovery,the application of PV has been encouraged,and reached a new level.The PV process is governed by the properties of the membrane materials that significantly influence the energy costs associated with the separation unit,and the membrane types include polymer membranes,inorganic membranes,and mixed matrix membranes.Although recent literatures show that PV membranes have been continuously updated,no review has reported the latest development about it.In this work,the material types,separation properties and preparation methods of hydrophobic PV membranes for phenol recovery are summarized.Furthermore,the key preparation methods and application challenges associated with membranes are summarized,along with an overview of the opportunities and challenges posed by hydrophobic PV membranes for phenol recovery.展开更多
Liquid phosphoric acid(PA),as the proton carrier for high temperature polymer electrolyte membrane fuel cells(HT-PEMFCs),presents challenges such as catalyst poisoning,high gas transport resistance and electrolyte los...Liquid phosphoric acid(PA),as the proton carrier for high temperature polymer electrolyte membrane fuel cells(HT-PEMFCs),presents challenges such as catalyst poisoning,high gas transport resistance and electrolyte loss.These issues significantly impede the performance and durability of HT-PEMFCs,thereby limiting their potential for further application.In this study,poly(2,3,5,6-tetrafluorostylene-4-phosphonic acid)(PWN)with intrinsic proton conduction ability was employed as catalyst layer binder to reveal the impacts of the ionomer's molecular structure on mass transport within the catalyst layer.Our findings demonstrated that increasing the phosphorylation degree of PWN could enhance both pore formation at the catalyst layer and electrode acidophilic capability while improving proton conduction ability and reducing cells'internal resistance.However,adverse effects included increased local oxygen transport resistance and decreased catalyst utilization resulting from electrode acidophilic capability.This research offers valuable insights for the relationships between micro-scale molecule structure,mesoscale electrode architecture,and membrane electrode assembly design in HT-PEMFCs.展开更多
Separation of organic mixture is an inevitable process in most modern industrial processes. In the quest for a more sustainable and efficient separation, solvent-resistant nanofiltration(SRNF) has emerged as a promisi...Separation of organic mixture is an inevitable process in most modern industrial processes. In the quest for a more sustainable and efficient separation, solvent-resistant nanofiltration(SRNF) has emerged as a promising answer. This is because SRNF is a membrane-based process which offers the key advantages of high efficacy and low energy intensity separation. In particular, polymer-based membranes can offer compelling opportunities for SRNF with unprecedented cost-effectiveness. As a result, intensive research efforts have been devoted into developing novel polymer-based membranes with solvent-resistant capacities as well as exploring potential applications in different types of industries. In this review, we aim to give an overview of the recent progress in the development of the state-of-the-art polymer-based membranes for SRNF in the first section. Emerging nanomaterials for mixed matrix and thin film nanocomposite membranes are also covered in this section. This is followed by a discussion on the current status of membrane engineering and SRNF membrane commercialization. In the third section, we highlight recent efforts in adopting SRNF for relevant industrial applications such as food, bio-refinery, petrochemical, fine chemical and pharmaceutical industries followed by separations of enantiomers in stereochemistry, homogeneous catalysis and ionic liquids. Finally, we offer a perspective and provide deeper insights to help shape future research direction in this very important field of SRNF.展开更多
Bioethanol, as a clean and renewable fuel, has gained increasing attention due to its major environmental benefits. Pervaporation(PV) is a promising and competitive technique for the recovery of ethanol from bioethano...Bioethanol, as a clean and renewable fuel, has gained increasing attention due to its major environmental benefits. Pervaporation(PV) is a promising and competitive technique for the recovery of ethanol from bioethanol fermentation systems due to the advantages of environmental friendliness, low energy consumption and easy coupling with fermentation process. The main challenge for the industrial application of ethanol perm-selective membranes is to break the trade-off effect between permeability and selectivity. As membrane is the heart of the pervaporation separation process, this article attempts to provide a comprehensive survey on the breakthroughs of ethanol perm-selective PV membranes from the perspectives of tailoring membrane materials to enhance PV separation performance. The research and development of polymeric and organic/inorganic hybrid membranes are reviewed to explore the fundamental structure-property-performance relationships. It is found that mixed matrix membranes with welldesigned membrane structures offer the hope of better control overphysi-/chemical microenvironment and cavity/pore size as well as size distribution, which may provide both high permeability and membrane selectivity to break the trade-off effect. The tentative perspective on the possible future directions of ethanol perm-selective membranes is also briefly discussed, which may provide some insights in developing a new generation of high-performance PV membranes for ethanol recovery.展开更多
The results of molecular dynamics （MD） simulations on transport process of CO2 and CH4 gases in poly（ether-b- amide） （PEBAX）/nanosilica membranes are discussed. The diffusion coefficients for CH4 and CO2 gases a...The results of molecular dynamics （MD） simulations on transport process of CO2 and CH4 gases in poly（ether-b- amide） （PEBAX）/nanosilica membranes are discussed. The diffusion coefficients for CH4 and CO2 gases at 6 cases with different amounts of nanosilica loading in the simulation boxes are presented. The results show that diffusion coefficients for CO2 gas in all cases are larger than those for the CH4 one. Moreover 10% nanosilica loading case shows maximum effects on diffusion coefficients and improves them by more than 68% and 157% for CO2 and CH4 gases, respectively. Additionally, the results of 3-D Cartesian trajectories and displacements curves are presented and the jumping attempt of CO2 is significantly more than that of CH4. Due to the rubbery state of PEBAX membranes in ambient temperature, the results confirm that channel lifetimes are very short and then back diffusion is not observed for this polymer.展开更多
Nanofiltration separation has become a popular technique for removing largeorganic molecules and inorganic substances from water. It is achieved by a combination of threemechanisms: electrostatic repulsion, sieving an...Nanofiltration separation has become a popular technique for removing largeorganic molecules and inorganic substances from water. It is achieved by a combination of threemechanisms: electrostatic repulsion, sieving and diffusion. In the present work, a model based onirreversible thermodynamics is extended and used to estimate rejection of inorganic salts andorganic substances. Binary systems are modeled, where the feed contains an ion that is much lesspermeable to the membrane as compared with the other ion. The two model parameters are estimated byfitting the model to the experimental data. Variation of these parameters with the composition ofthe feed is described by an empirical correlation. This work attempts to describe transport throughthe nanofiltration membranes by a simple model.展开更多
Magnesium(Mg)is a widely used and attractive metal,known for its unique physical and chemical properties,and it has been employed in the manufacture of many practical materials.Layered Double Hydroxides(LDHs),particul...Magnesium(Mg)is a widely used and attractive metal,known for its unique physical and chemical properties,and it has been employed in the manufacture of many practical materials.Layered Double Hydroxides(LDHs),particularly Mg-based LDHs,rank among the most prevalent two-dimensional materials utilized in separation processes,which include adsorption,extraction,and membrane technology.The high popularity of Mg-based LDHs in separation applications can be attributed to their properties,such as excellent hydrophilicity,high surface area,ion exchangeability,and adjustable interlayer space.Currently,polymer membranes play a pivotal role in semi-industrial and industrial separation processes.Consequently,the development of polymer membranes and the mitigation of their limitations have emerged as compelling topics for researchers.Several methods exist to enhance the separation performance and anti-fouling properties of polymer membranes.Among these,incorporating additives into the membrane polymer matrix stands out as a cost-effective,straightforward,readily available,and efficient approach.The use of Mg-based LDHs,either in combination with other materials or as a standalone additive in the polymer membrane matrix,represents a promising strategy to bolster the separation and anti-fouling efficacy of flat sheet mixed matrix polymer membranes.This review highlights Mg-based LDHs as high-potential additives designed to refine flat sheet mixed matrix polymer membranes for applications in wastewater treatment and brackish water desalination.展开更多
This article presents a new synergistic extraction system composed of Cyanex 272(C272,bis(2,4,4-trimethylpentyl)phosphinic acid)and iso-octanol for Sc_(3+) separation.The proposed synergistic system possessed an Sc^(3...This article presents a new synergistic extraction system composed of Cyanex 272(C272,bis(2,4,4-trimethylpentyl)phosphinic acid)and iso-octanol for Sc_(3+) separation.The proposed synergistic system possessed an Sc^(3+) extraction efficiency of 93.5%and a back-extraction efficiency of 82.7%,with selectivity coefficients of β_(Sc/Fe)=459 and β_(Sc/Al)=4241,which are considerably higher as compared to the current extraction systems.The extraction mechanism was studied and interpreted.The enhanced extraction efficiency is attributed to the increased hydrophobicity of the ternary complex,whereas the back-extraction efficiency can be ascribed to the attenuated stability of the complex.C272 and C272–iso-octanol systems also possess considerable surface activity,which is beneficial for the phase separation in solvent extraction.Based on the solvent extraction results,a preliminary study was conducted on polymer inclusion membranes(PIMs)using the binary system for Sc^(3+) separation to avoid the formation of the third phase,achieving an optimal initial flux of PIM of 6.71×10^(−4)mol·m^(−2)·h^(−1).Our results provide valuable information on highly efficient Sc^(3+) separation,and the study on PIM extraction has shown a green alternative to solvent extraction.展开更多
The main difficulty in the extensive commercial use of polymer electrolyte membrane fuel cells （PEMFCs） is the use of noble metals such as Pt-based electrocatalyst at the cathode, which is essential to ease the oxyg...The main difficulty in the extensive commercial use of polymer electrolyte membrane fuel cells （PEMFCs） is the use of noble metals such as Pt-based electrocatalyst at the cathode, which is essential to ease the oxygen reduction reaction （ORR） in fuel cells （FCs）. To eliminate the high loading of Pt-based electrocatalysts to minimize the cost, extensive study has been carried out over the previous decades on the non-noble metal catalysts. Development in enhancing the ORR performance of FCs is mainly due to the doped carbon materials, Fe and Co-based electrocatalysts, these materials could be considered as probable substitutes for Pt-based catalysts. But the stability of these non-noble metal electrocatalysts is low and the durability of these metals remains unclear. The three basic reasons of instability are： （i） oxidative occurrence by H2O2, （ii） leakage of the metal site and （iii） protonation by probable anion adsorption of the active site. Whereas leakage of the metal site has been almost solved, more work is required to understand and avoid losses from oxidative attack and protonation. The ORR performance such as stability tests are usually run at low current densities and the lifetime is much shorter than desired need. Therefore, improvement in the ORR activity and stability afe the key issues of the non-noble metal electrocatalyst. Based on the consequences obtained in this area, numerous future research directions are projected and discussed in this paper. Hence, this review is focused on improvement of stability and durability of the non-noble metal electrocatalyst.展开更多
Pervaporation(PV),as an environmental friendly and energy-saving separation technology,has been received increasing attention in recent years.This article reviews the preparation and application of macroporous ceramic...Pervaporation(PV),as an environmental friendly and energy-saving separation technology,has been received increasing attention in recent years.This article reviews the preparation and application of macroporous ceramic-supported polymer composite pervaporation membranes.The separation materials of polymer/ceramic composite membranes presented here include hydrophobic polydimethylsiloxane(PDMS) and hydrophilic poly(vinyl alcohol)(PVA),chitosan(CS) and polyelectrolytes.The effects of ceramic support treatment,polymer solution properties,interfacial adhesion and incorporating or blending modification on the membrane structure and PV performance are discussed.Two in-situ characterization methods developed for polymer/ceramic composite membranes are also covered in the discussion.The applications of these composite membranes in pervaporation process are summarized as well,which contain the bio-fuels recovery,gasoline desulfuration and PV coupled proc-ess using PDMS/ceramic composite membrane,and dehydration of alcohols and esters using ceramic-supported PVA or PVA-CS composite membrane.Finally,a brief conclusion remark on polymer/ceramic composite mem-branes is given and possible future research is outlined.展开更多
基金Knowledge Innovation Program of Wuhan-Basic Research(2022010801010321)Wuhan Limo Technology Limited Company(2022420111000256)。
文摘Organic solvent nanofiltration(OSN) is an efficient,low-energy and environmentally friendly phase-free separation process.Obviously,the core of OSN lies in the fabrication of solvent-resistant nanofiltration membranes.Although membrane materials reported in the literature such as 2D membranes,porous organic cages,etc.have the potential for ultra-high performance,polymeric membranes provide key advantages in mass production and processability.Therefore,this review focuses on polymeric materials for OSN.This review summarizes the recent progress of polymeric materials,including emerging and traditional polymeric membranes.Then,a summary of recent progress about strategies developed for perm-selective nanofilms are presented,followed by a brief overview of commercial membrane technology for OSN.Finally,major challenges of OSN and future research directions are presented.Close interaction between the academic research and practical application would help improve greener and more sustainable manufacturing processes.
文摘A PVC membrane electrode based on copper（II） bis（N-2-bromophenylsalicyldenaminato） as ionophor was prepared. The ion selective electrode was tested by inorganic anions and showed a good selectivity for iodide ion. This sensor exhibited Nernstian behavior with a slope of -57.8 mV per decade at 25℃. The proposed electrode showed a linear range from 1.0 × 10 ^-5 to 1.0 × 10 ^-1 mol/L with a detection limit of 5.0 × 10 ^-6 mol/L. The electrode response was independent of pH in the range of 3.0- 10.0. The proposed sensor was applied to determine the iodide in water and antiseptic samples.
基金The project supported by the Hundred-Persons Plan Foundation of Chinese Academy of Sciences in 2003
文摘A review is presented of studies of polymeric membranes by applying positron annihilation lifetime spectroscopy （PALS）. PALS has been used to study subnanometer-sized holes, to determine their size distribution and free-volume fractions, and to probe molecular-sized vacancies in glassy polymers. At present, PALS is believed to be a highly effective physical method for the examination of polymeric membranes.
基金supported by the Defense Ministry of Argentina under Grant PIDDEF No.22/11
文摘The analytical technique of conductometric titration is used to characterize polymeric materials.This technique allows obtaining the polymer dry weight capacity(DWC)and the extent of reaction and establishing the optimal number of water molecules per sulfonic groups.In this particular case the polymer material under study was Nafion?117.Two different reactions were made:Neutralization and exchange.Both of them allow obtaining the same result.Conductometric titrations could be considered as a good method to study the neutralization and exchange reactions for polymeric materials used in fuel cells or electrolyzers.The implementation of this analytical technique allows reducing operation time of those types of materials.The waiting time between determinations permits to say that the amount of reactant consumed and products obtained were the same after each addition of titrant.
基金Project supported by the National Natural Science Foundation of China partially by Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Academia Sinica.
文摘A new solvent polymeric membrane (SPM)pH2sensor based on 4,4'-bis (N, N-didecylamino)methyl)azobenzene as neutral carricr has been reported. It has excellent pH response characteristics with the linear response range (1.7—13.2)much wider than that of similar SPM pH sensors reported so far. The sensor has a theoretical Nernstian response of 57.4+0.2V/pH(at 20℃)without super—Nernstian response phenomenon.
文摘Separation of refined soybean oil/n-hexane miscellas was studied using different commercial ultra- and nanofiltration membranes, with cut-oil＇s in the range of 1 to 5 kDa and salt rejection higher than 97% （MgSO4）. Commercial soybean oil and n-hexane miscellas with 1：3 and 1：1 mass ratios were permeated in a dead-end module. The effects of the feed pressure （2-25 bar） on oil and n-hexane fluxes and rejection were investigated. Oil rejection ranged from negative values to 30.8%, soybean oil flux from 28.9 to 617.8 g/m2 hl and n-hexane flux from 8.5 to 1,078.5 g m2 hl. Membrane fouling was observed at all experimental conditions studied. The membrane separation process has proven to be a promising alternative to solvent recovery in soybean oil extraction.
文摘For the last two decades polymeric membranes have been used in several gas separation processes. For the high selectivity and permeability various types of membranes have been developed. Thin layers to high dense and hollow fiber to asymmetric wounded materials to determine the effective separation of CO2 from CH4 were used. Ideal membrane materials must have provisions of durability, chemical and thermal resistance, effective separation and economical production and operation. In this review it is observed that most of the polymeric materials face plasticization problem in the separation of CO2 from CH4. This is due to the condensable nature of carbon dioxide that causes swelling in most of the polymeric membranes due to which the efficiency of selectivity and permeability is affected. Most extensive works have been carried out in developing the chemical structure and compositions of polymeric materials to improve the separation properties. Cross-linking and blending of molecular sieving called ＂mixed-matrix＂ are the most useful approaches applied in this regard, but no where it is found to be fully effective and ideal polymeric membranes commercially fit to replace the existing systems of CO2 separation from the natural gas. Still area is open to work on to produce more worth full materials and switch towards liquid membranes and hybrid systems.
文摘The efficiency,robustness and reliability of recent numerical methods for finding solutions to flow problems have given rise to the implementation of computational fluid dynamics(CFD) as a broadly used analysis method for engineering problems like membrane separation system.The CFD modeling in this study observes steady and unsteady(transient) heat flux and temperature profiles in a polymeric(cellulose acetate) membrane.This study is novel due to the implementation of user defined scalar(UDS) diffusion equation by using user-defined functions(UDFs) infinite volume method(FVM).Some details of the FVM used by the solver are carefully discussed when implementing terms in the governing equation and boundary conditions(BC).The contours of temperature due to high-temperature gradient are reported for steady and unsteady problems.
基金supported by the National Natural Science Foundation of China (22005162, 21675091, 21874078 and 22074072)China Postdoctoral Science Foundation (2019M652319)+4 种基金the Special Financial Aid to Post-doctor Research Fellow (2020T130330)Taishan Young Scholar Program of Shandong Province (tsqn20161027)the Major Science and Technology Innovation Project of Shandong Province (2018CXGC1407)the Key Research and Development Project of Shandong Province (2016GGX102028, 2016GGX102039 and 2017GGX20111)the First Class Discipline Project of Shandong Province
文摘Bio-nanochannels in living organisms participate in the physiological activities by selectively transporting ions through cell membranes.The structure and function of biological ion channels inspire the development of artificial ion nanochannels with practical applications.The bioinspired nanochannels based on polymer materials present good mechanical stability,high-performance ion transport and designability,which have attracted much attention.In this review,we mainly focus on the fabrication and application of polymer-based biomimetic nanochannels especially in environmentally responsive biosensor and energy conversion.We firstly introduce the basic understanding of nanochannels in ion regulation and osmotic energy conversion.Then,we discuss the fabrication methods of polymer-based nanochannels and highlight their advantages compared with other materials.The practical applications of polymer-based biomimetic nanochannels,especially in energy conversion and environmentally responsive biosensor,are detailedly discussed.Finally,we summarize the unsolved problems in bioinspired nanochannels and overview the further developing direction in this field.
基金National Natural Science Foundation of ChinaElectroanalytical Chemistry Laboratory, Changchun Institute of Applied Chemistry, Academia Sinica.
文摘Anion-selective electrodes based on dissociated ion-exchangers such as lipophilicquaternary ammonium or phosphonium species always display classical Hofmeister be-havior in the following order: ClO<sub>4</sub><sup>-</sup>】SCN<sup>-</sup>】I<sup>-</sup>】Br<sup>-</sup>】NO<sub>2</sub><sup>-</sup>】Cl<sup>-</sup>】SO<sub>4</sub><sup>2-</sup>.A new sol-vent polymeric membrane electrode based on Schiff base complexes of Co（Ⅱ）[Co（Ⅱ）S]and showing excellent selectivity toward iodide ion is for the first time prepared inour work. The resulting electrodes exhibit fairly low detection limits andpotentiometric anion-selectivity sequences deviated from the Hofmeister pattern.Bis（salicylaldehyde） ethylenediiminecobalt（Ⅱ） [Co（Ⅱ）（salen）], bis（salicylaldehyde）-phenyldiiminecobalt（Ⅱ） [Co（Ⅱ）（salophen）],
基金funded by National Natural Science Foundation of China(22278023,22208010)S&T Program of Hebei(24464301D)SINOPEC Group(24-ZS-0447).
文摘Phenol is extensively utilized in various industries involving paints,rubber,textiles,explosives,plastics,etc.Compared to the conventional distillation or extraction technologies,pervaporation(PV)membrane process can be operated at a low temperature and has a low energy consumption as well as a high separation efficiency for phenol recovery.Thus,to meet the high demand for phenol recovery,the application of PV has been encouraged,and reached a new level.The PV process is governed by the properties of the membrane materials that significantly influence the energy costs associated with the separation unit,and the membrane types include polymer membranes,inorganic membranes,and mixed matrix membranes.Although recent literatures show that PV membranes have been continuously updated,no review has reported the latest development about it.In this work,the material types,separation properties and preparation methods of hydrophobic PV membranes for phenol recovery are summarized.Furthermore,the key preparation methods and application challenges associated with membranes are summarized,along with an overview of the opportunities and challenges posed by hydrophobic PV membranes for phenol recovery.
基金supported by The National Key Research and Development Program of China(2021YFB4001204)National Natural Science Foundation of China(22179130,22379143,22479145)。
文摘Liquid phosphoric acid(PA),as the proton carrier for high temperature polymer electrolyte membrane fuel cells(HT-PEMFCs),presents challenges such as catalyst poisoning,high gas transport resistance and electrolyte loss.These issues significantly impede the performance and durability of HT-PEMFCs,thereby limiting their potential for further application.In this study,poly(2,3,5,6-tetrafluorostylene-4-phosphonic acid)(PWN)with intrinsic proton conduction ability was employed as catalyst layer binder to reveal the impacts of the ionomer's molecular structure on mass transport within the catalyst layer.Our findings demonstrated that increasing the phosphorylation degree of PWN could enhance both pore formation at the catalyst layer and electrode acidophilic capability while improving proton conduction ability and reducing cells'internal resistance.However,adverse effects included increased local oxygen transport resistance and decreased catalyst utilization resulting from electrode acidophilic capability.This research offers valuable insights for the relationships between micro-scale molecule structure,mesoscale electrode architecture,and membrane electrode assembly design in HT-PEMFCs.
基金funding support from the Singapore Economic Development Board to Singapore Membrane Technology Center
文摘Separation of organic mixture is an inevitable process in most modern industrial processes. In the quest for a more sustainable and efficient separation, solvent-resistant nanofiltration(SRNF) has emerged as a promising answer. This is because SRNF is a membrane-based process which offers the key advantages of high efficacy and low energy intensity separation. In particular, polymer-based membranes can offer compelling opportunities for SRNF with unprecedented cost-effectiveness. As a result, intensive research efforts have been devoted into developing novel polymer-based membranes with solvent-resistant capacities as well as exploring potential applications in different types of industries. In this review, we aim to give an overview of the recent progress in the development of the state-of-the-art polymer-based membranes for SRNF in the first section. Emerging nanomaterials for mixed matrix and thin film nanocomposite membranes are also covered in this section. This is followed by a discussion on the current status of membrane engineering and SRNF membrane commercialization. In the third section, we highlight recent efforts in adopting SRNF for relevant industrial applications such as food, bio-refinery, petrochemical, fine chemical and pharmaceutical industries followed by separations of enantiomers in stereochemistry, homogeneous catalysis and ionic liquids. Finally, we offer a perspective and provide deeper insights to help shape future research direction in this very important field of SRNF.
基金financial support of Beijing Natural Science Foundation Commission-Beijing Municipal Education Commission Joint Foundation,China(KZ201910011012)National Natural Science Foundation of China(21736001,21776153,21206001)+1 种基金Open Research Fund Program of Key Laboratory of Cleaner Production and Integrated Resource Utilization of China National Light Industry(CP-2020-YB7)College Students Scientific Research and Undertaking Starting Action Project,China。
文摘Bioethanol, as a clean and renewable fuel, has gained increasing attention due to its major environmental benefits. Pervaporation(PV) is a promising and competitive technique for the recovery of ethanol from bioethanol fermentation systems due to the advantages of environmental friendliness, low energy consumption and easy coupling with fermentation process. The main challenge for the industrial application of ethanol perm-selective membranes is to break the trade-off effect between permeability and selectivity. As membrane is the heart of the pervaporation separation process, this article attempts to provide a comprehensive survey on the breakthroughs of ethanol perm-selective PV membranes from the perspectives of tailoring membrane materials to enhance PV separation performance. The research and development of polymeric and organic/inorganic hybrid membranes are reviewed to explore the fundamental structure-property-performance relationships. It is found that mixed matrix membranes with welldesigned membrane structures offer the hope of better control overphysi-/chemical microenvironment and cavity/pore size as well as size distribution, which may provide both high permeability and membrane selectivity to break the trade-off effect. The tentative perspective on the possible future directions of ethanol perm-selective membranes is also briefly discussed, which may provide some insights in developing a new generation of high-performance PV membranes for ethanol recovery.
文摘The results of molecular dynamics （MD） simulations on transport process of CO2 and CH4 gases in poly（ether-b- amide） （PEBAX）/nanosilica membranes are discussed. The diffusion coefficients for CH4 and CO2 gases at 6 cases with different amounts of nanosilica loading in the simulation boxes are presented. The results show that diffusion coefficients for CO2 gas in all cases are larger than those for the CH4 one. Moreover 10% nanosilica loading case shows maximum effects on diffusion coefficients and improves them by more than 68% and 157% for CO2 and CH4 gases, respectively. Additionally, the results of 3-D Cartesian trajectories and displacements curves are presented and the jumping attempt of CO2 is significantly more than that of CH4. Due to the rubbery state of PEBAX membranes in ambient temperature, the results confirm that channel lifetimes are very short and then back diffusion is not observed for this polymer.
文摘Nanofiltration separation has become a popular technique for removing largeorganic molecules and inorganic substances from water. It is achieved by a combination of threemechanisms: electrostatic repulsion, sieving and diffusion. In the present work, a model based onirreversible thermodynamics is extended and used to estimate rejection of inorganic salts andorganic substances. Binary systems are modeled, where the feed contains an ion that is much lesspermeable to the membrane as compared with the other ion. The two model parameters are estimated byfitting the model to the experimental data. Variation of these parameters with the composition ofthe feed is described by an empirical correlation. This work attempts to describe transport throughthe nanofiltration membranes by a simple model.
文摘Magnesium(Mg)is a widely used and attractive metal,known for its unique physical and chemical properties,and it has been employed in the manufacture of many practical materials.Layered Double Hydroxides(LDHs),particularly Mg-based LDHs,rank among the most prevalent two-dimensional materials utilized in separation processes,which include adsorption,extraction,and membrane technology.The high popularity of Mg-based LDHs in separation applications can be attributed to their properties,such as excellent hydrophilicity,high surface area,ion exchangeability,and adjustable interlayer space.Currently,polymer membranes play a pivotal role in semi-industrial and industrial separation processes.Consequently,the development of polymer membranes and the mitigation of their limitations have emerged as compelling topics for researchers.Several methods exist to enhance the separation performance and anti-fouling properties of polymer membranes.Among these,incorporating additives into the membrane polymer matrix stands out as a cost-effective,straightforward,readily available,and efficient approach.The use of Mg-based LDHs,either in combination with other materials or as a standalone additive in the polymer membrane matrix,represents a promising strategy to bolster the separation and anti-fouling efficacy of flat sheet mixed matrix polymer membranes.This review highlights Mg-based LDHs as high-potential additives designed to refine flat sheet mixed matrix polymer membranes for applications in wastewater treatment and brackish water desalination.
基金support from the National Natural Science Foundation of China Regional Innovation and Development Joint Fund(U24A20557)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDC0230403)+3 种基金the National Natural Science Foundation of China(22378393,22208356)“Hundred Talents Program”of the Chinese Academy of Sciencesthe Chinese Academy of Sciences stably supports the youth team plan in the field of basic research(YSBR 038)Key Research&Development projects in Qinghai Province(2023-HZ-805).
文摘This article presents a new synergistic extraction system composed of Cyanex 272(C272,bis(2,4,4-trimethylpentyl)phosphinic acid)and iso-octanol for Sc_(3+) separation.The proposed synergistic system possessed an Sc^(3+) extraction efficiency of 93.5%and a back-extraction efficiency of 82.7%,with selectivity coefficients of β_(Sc/Fe)=459 and β_(Sc/Al)=4241,which are considerably higher as compared to the current extraction systems.The extraction mechanism was studied and interpreted.The enhanced extraction efficiency is attributed to the increased hydrophobicity of the ternary complex,whereas the back-extraction efficiency can be ascribed to the attenuated stability of the complex.C272 and C272–iso-octanol systems also possess considerable surface activity,which is beneficial for the phase separation in solvent extraction.Based on the solvent extraction results,a preliminary study was conducted on polymer inclusion membranes(PIMs)using the binary system for Sc^(3+) separation to avoid the formation of the third phase,achieving an optimal initial flux of PIM of 6.71×10^(−4)mol·m^(−2)·h^(−1).Our results provide valuable information on highly efficient Sc^(3+) separation,and the study on PIM extraction has shown a green alternative to solvent extraction.
基金supported by the National Natural Science Foundation of China(21306119)the Key Research and Development Projects in Sichuan Province(2017GZ0397,2017CC0017)+1 种基金the Science and Technology Project of Chengdu(2015-HM01-00531-SF)the Outstanding Young Scientist Foundation of Sichuan University(2013SCU04A23)
文摘The main difficulty in the extensive commercial use of polymer electrolyte membrane fuel cells （PEMFCs） is the use of noble metals such as Pt-based electrocatalyst at the cathode, which is essential to ease the oxygen reduction reaction （ORR） in fuel cells （FCs）. To eliminate the high loading of Pt-based electrocatalysts to minimize the cost, extensive study has been carried out over the previous decades on the non-noble metal catalysts. Development in enhancing the ORR performance of FCs is mainly due to the doped carbon materials, Fe and Co-based electrocatalysts, these materials could be considered as probable substitutes for Pt-based catalysts. But the stability of these non-noble metal electrocatalysts is low and the durability of these metals remains unclear. The three basic reasons of instability are： （i） oxidative occurrence by H2O2, （ii） leakage of the metal site and （iii） protonation by probable anion adsorption of the active site. Whereas leakage of the metal site has been almost solved, more work is required to understand and avoid losses from oxidative attack and protonation. The ORR performance such as stability tests are usually run at low current densities and the lifetime is much shorter than desired need. Therefore, improvement in the ORR activity and stability afe the key issues of the non-noble metal electrocatalyst. Based on the consequences obtained in this area, numerous future research directions are projected and discussed in this paper. Hence, this review is focused on improvement of stability and durability of the non-noble metal electrocatalyst.
文摘Pervaporation(PV),as an environmental friendly and energy-saving separation technology,has been received increasing attention in recent years.This article reviews the preparation and application of macroporous ceramic-supported polymer composite pervaporation membranes.The separation materials of polymer/ceramic composite membranes presented here include hydrophobic polydimethylsiloxane(PDMS) and hydrophilic poly(vinyl alcohol)(PVA),chitosan(CS) and polyelectrolytes.The effects of ceramic support treatment,polymer solution properties,interfacial adhesion and incorporating or blending modification on the membrane structure and PV performance are discussed.Two in-situ characterization methods developed for polymer/ceramic composite membranes are also covered in the discussion.The applications of these composite membranes in pervaporation process are summarized as well,which contain the bio-fuels recovery,gasoline desulfuration and PV coupled proc-ess using PDMS/ceramic composite membrane,and dehydration of alcohols and esters using ceramic-supported PVA or PVA-CS composite membrane.Finally,a brief conclusion remark on polymer/ceramic composite mem-branes is given and possible future research is outlined.
