separation

摘要： Metal-organic frameworks(MOFs)have great potentials as adsorbents for natural gas purification.However,the trade-off between selectivity and adsorption capacity remains a challenge.Herein,we report a pillared-layer metal-organic framework Ni(HBTC)(bipy)for efficiently separating the C_(3)H_(8)/C_(2)H_(6)/CH_(4) mixture.The experimental results show that the adsorption capacity of C_(3)H_(8) and C_(2)H_(6) on Ni(HBTC)(bipy)are as high as 6.18 and 5.85 mmol·g^(-1),while only 0.93 mmol·g^(-1) for CH_(4) at 298 K and 100 kPa.Especially,the adsorption capacity of C_(3)H_(8) at 5 kPa can reach an unprecedented 4.52 mmol·g^(-1) and for C_(2)H_(6) it is 1.48 mmol·g^(-1) at 10 kPa.The ideal adsorbed solution theory predicted C_(3)H_(8)/CH_(4) selectivity is as high as 1857.0,superior to most of the reported materials.Breakthrough experiment results indicated that material could completely separate the C_(3)H_(8)/C_(2)H_(6)/CH_(4) mixture.Therefore,Ni(HBTC)(bipy)is a promising material for separation of natural gas.

摘要： The original version of this article,unfortunately,contained some mistakes and unintentional wrong description of Fig.6 and the caption of Figs.9,10.The correct version of Fig.6 is below.The mentioned figure name for the Fig.6 on the manuscript should be updated.In 2D vdW synaptic devices,the length of the tunneling barrier can be increased or decreased on the trapped or detrapped electrons.Kumar et al.reported memristive and neuromorphic devices composed of vertically grown WS2 layer and ZnO(Fig.6e)[149].The interlayer separation between WS2 and ZnO layers serves as an effective porous medium allowing the ZnO to grow with defects.The interfacial region of ZnO,the very contiguous to WS2 layer.

摘要： China has set the first batch of rare earth mining quota for 2022 at 100,800 tons, up about 20% compared with that in 2021, with the smelting & separation quota at 97,200 tons.Quotas for the first half of 2021 were set at 84,000 tons for mining and 81,000 tons for smelting & separation. An independent industrial analyst said that the 20% jump was mainly due to China’s surging demand for Nd Fe B magnets, amid the new energy push in China.

摘要： The separation of light hydrocarbon mixtures(C_(1)–C_(3))generated from petrochemical industry is vital and challenging process for obtaining valuable pure chemical feedstocks.In comparison to the energy intensive conventional separation technologies(cryogenic distillation,absorption and hydrogenation),the adsorptive separation is considered as a low energy cost and high efficiency process.Porous carbons have been demonstrated as excellent adsorbents for the separation of light hydrocarbons,owing to their designable structure and tailorable properties.This review summarizes the recent advances of using porous carbons as adsorbents for the separation of light hydrocarbons,including methane/nitrogen,methane/alkane,methane/carbon dioxide,ethylene/ethane and propylene/propane.We discuss the separation mechanisms and highlight the material features including pore structure,surface chemistry and target molecular properties that determine the separation performance.Furthermore,the challenges and development direction associated with carbonaceous adsorbents for light hydrocarbon separation are discussed,meanwhile the guidelines for the design of porous carbons are proposed.

摘要： It is difficult to separate the methanol and hydrocarbons in the propylene oxide(PO)purification process due to their forming azeotrope.As for this,a novel PO separation process,in that the deionized water is employed as extractant and 1,2-propylene glycol(MPG)that is formed from the PO hydrolysis reaction is recovered,is presented in this work.The salient feature of this process is that both the non-catalyzed reactions of PO hydrolysis to form MPG and dipropylene glycol(DPG)are simultaneously considered and MPG by-product with high purity is obtained in virtue of the deionized water as reflux liquid and side take-off in MPG column.In addition,the ionic liquid(IL)extractant is screened through the conductorlike screening model for segment activity coefficient(COSMO-SAC)and the comparisons of separation efficiency between the IL and normal octane(nC_(8))extractant for the separation of PO and 2-methylpentane are made.With the non-random two-liquid(NRTL)thermodynamic model,the simulation and optimization design for the full flow sheet are performed and the effects of the key operation parameters such as solvent ratio,theoretical stages,feeding stage etc.on separation efficiency are detailedly discussed.The results show that the mass purity and the mass yield of PO can be up to 99.99%and 99.0%,and the condenser duty,reboiler duty and PO loss in the process with IL extractant can be decreased by 69.66%,30.21%and 78.86%compared to ones with nC_(8).The total annual cost(TAC)calculation also suggests that the TAC would be significantly reduced if using IL in replace of nC_(8) for the investigated process.The presented results would provide a useful guide for improving the quality of PO product and the economic efficiency of industrial plant.

摘要： 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.

摘要： Recent years,membrane separation technology has attracted significant research attention because of the efficient and environmentally friendly operation.The selection of suitable materials to improve the membrane selectivity,permeability and other properties has become a topic of vital research relevance.Two-dimensional(2D)materials,a novel family of multifunctional materials,are widely used in membrane separation due to their unique structure and properties.In this respect,as a novel 2D material,graphitic carbon nitride(g-C_(3)N_(4))have found specific attention in membrane separation.This study reviews the application of carbon nitride in gas separation membranes,pervaporation membranes,nanofiltration membranes,reverse osmosis membranes,ion exchange membranes and catalytic membranes,along with describing the separation mechanisms.

摘要： Ca^(2+)/Na+separation is a common problem in industrial applications,biological and medical fields.However,Ca^(2+)and Na+have similar ionic radii and hydration radii,thus Ca^(2+)/Na+separation is challenging.Inspired by biological channels,group modification is one of the effective methods to improve the separation performance.In this work,molecular dynamics simulations were performed to investigate the effects of different functional groups(COO
,NH3+)on the separation performance of Ca^(2+)and Na+through graphene nanopores under an electric field.The pristine graphene nanopore was used for comparison.Results showed that three types of nanopores preferred Ca^(2+)to Na+,and Ca^(2+)/Na+selectivity followed the order of GE-COO
(4.06)>GE(1.85)>GE-NH3+(1.63).Detailed analysis of ionic hydration microstructure shows that different nanopores result in different hydration factors for the second hydration layer of Ca^(2+)and the first layer of Na+.Such different hydration factors corresponding to the dehydration ability can effectively evaluate the separation performance.In addition,the breaking of hydrogen bonds between water molecules due to electrostatic effects can directly affect the dehydration ability.Therefore,the electrostatic effect generated by group modification will affect the ionic hydration microstructure,thus reflecting the differences in dehydration ability.This in turn affects the permeable and separation performance of cations.The results of this work provide perceptive guidelines for the application of graphene-based membranes in ion separation.

摘要： Tight ceramic ultrafiltration membranes have been proven to exhibit good rejection performance for reactive dye wastewater at high temperatures because of their high thermal and chemical resistance.However,the application of ceramic membranes for the treatment of cationic dye wastewater is challenging because of their surface charge.In this study,a ceramic membrane is modified by grafting aminosilane(KH-551)to enhance the positive charge of the membrane surface.The rejection performance of the charged modified ceramic membrane toward the methylene blue solution is significantly improved.The modification substance is bonded to the ceramic membrane surface via covalent bonding,which imparts good thermal stability.The modified ceramic membrane exhibits stable separation performance toward the methylene blue solution.Overall,this study provides valuable guidance for the adjustment of the ceramic membrane surface charge for treating industrial cationic dye wastewater.

摘要： Membrane separation is a high-efficiency,energy-saving,and environment-friendly separation technology.Covalent organic framework(COF)-based mixed-matrix membranes(MMMs)have broad application prospects in gas separation and are expected to provide new solutions for coal-bed methane purification.Herein,a high-throughput screening method is used to calculate and evaluate COF-based MMMs for CH_(4)/N_(2) separation.General design rules are proposed from thermodynamic and kinetic points of view using the computation-ready,experimental COFs.From our database containing 471,671 generated COFs,5 COF membrane materials were screened with excellent membrane selectivities,which were then used as the filler of MMMs for separation performance evaluation.Among them,BAR-NAP-Benzene_CF_(3) combined with polydimethylsiloxane and styrene-b-butadiene-b-styrene show high CH_(4) permeability of 4.43×10^(-13) mol·m·s^(-1)·Pa^(-1)·m^(-2) and high CH_(4)/N_(2) selectivity of 9.54,respectively.The obtained results may provide reasonable information for the design of COF-based membranes for the efficient separation of CH_(4)/N_(2).

摘要： With the increased production of seawater desalination，issues about the drainage of brine．after seawater desalination have attracted extensive concern day by day．At present，the brine discharged from seawater desalination projects is almost poured into sea directly，which not only causes the marine environmental pollution，such as the unexpected rising of the seawater salt degree which brings on the death of fish，alga，and the worsens of ecological environment gradually；but also esults in a enormous waste of resource if drained directly not by utilizing．To herein，according to present research situation of seawater utilization all over the world，we propound the combined technology of seawater desalination coupled with extracting potassium，lithium and bromine from the discharged brine separately，and making use of brine as working medium for solar pond，which generates electricity to supply desalination system，thereby forms an effective cycle of whole seawater utilization．Through the above mentioned methods，it can not only improve the drainage of discharged brine，but also reduce costs of desalinization by assistant techniques．

摘要： With the increased production of seawater desalination，issues about the drainage of brine．after seawater desalination have attracted extensive concern day by day．At present，the brine discharged from seawater desalination projects is almost poured into sea directly，which not only causes the marine environmental pollution，such as the unexpected rising of the seawater salt degree which brings on the death of fish，alga，and the worsens of ecological environment gradually；but also esults in a enormous waste of resource if drained directly not by utilizing．To herein，according to present research situation of seawater utilization all over the world，we propound the combined technology of seawater desalination coupled with extracting potassium，lithium and bromine from the discharged brine separately，and making use of brine as working medium for solar pond，which generates electricity to supply desalination system，thereby forms an effective cycle of whole seawater utilization．Through the above mentioned methods，it can not only improve the drainage of discharged brine，but also reduce costs of desalinization by assistant techniques．

摘要： With the increased production of seawater desalination，issues about the drainage of brine．after seawater desalination have attracted extensive concern day by day．At present，the brine discharged from seawater desalination projects is almost poured into sea directly，which not only causes the marine environmental pollution，such as the unexpected rising of the seawater salt degree which brings on the death of fish，alga，and the worsens of ecological environment gradually；but also esults in a enormous waste of resource if drained directly not by utilizing．To herein，according to present research situation of seawater utilization all over the world，we propound the combined technology of seawater desalination coupled with extracting potassium，lithium and bromine from the discharged brine separately，and making use of brine as working medium for solar pond，which generates electricity to supply desalination system，thereby forms an effective cycle of whole seawater utilization．Through the above mentioned methods，it can not only improve the drainage of discharged brine，but also reduce costs of desalinization by assistant techniques．

摘要： With the increased production of seawater desalination，issues about the drainage of brine．after seawater desalination have attracted extensive concern day by day．At present，the brine discharged from seawater desalination projects is almost poured into sea directly，which not only causes the marine environmental pollution，such as the unexpected rising of the seawater salt degree which brings on the death of fish，alga，and the worsens of ecological environment gradually；but also esults in a enormous waste of resource if drained directly not by utilizing．To herein，according to present research situation of seawater utilization all over the world，we propound the combined technology of seawater desalination coupled with extracting potassium，lithium and bromine from the discharged brine separately，and making use of brine as working medium for solar pond，which generates electricity to supply desalination system，thereby forms an effective cycle of whole seawater utilization．Through the above mentioned methods，it can not only improve the drainage of discharged brine，but also reduce costs of desalinization by assistant techniques．