The palladium/kieselguhr composites(Pd/K)were prepared by the PdCl_(2) dipping-reducing method.The effects of the preparation conditions on the Pd/K were studied,such as the heat treatment,dipping time,palladium conce...The palladium/kieselguhr composites(Pd/K)were prepared by the PdCl_(2) dipping-reducing method.The effects of the preparation conditions on the Pd/K were studied,such as the heat treatment,dipping time,palladium concentration in solution and number of loading cycles.The pore structure and palladium content of the Pd/K were measured by the Brunauer-Emmett-Teller method and an inductively coupled plasma mass spectrometry.The appearance and palladium element distribution were measured by a scanning electron microscope.It is found that the palladium element is more densely distributed in the irregular and porous parts of the kieselguhr particles,so the kieselguhr is superior to Al_(2)O_(3) as the carrier material.The heat treatment can improve the pore permeability and increase the palladium content for the Pd/K.Increasing the dipping time,palladium concentration in solution and number of loading cycles is beneficial to increase the palladium content of the Pd/K,but more loading cycles may lead to the pore collapse,which obstructs the interaction with the hydrogen isotope gases.A kind of Pd/K was prepared under a set of optimized conditions and was packed in a separation column.This Pd/K was proved to be of high performance and durable by some hydrogen-deuterium separation experiments.展开更多
Deuterium(D_(2)) is one of the important fuel sources that power nuclear fusion reactors. The existing D_(2)/H_(2) separation technologies that obtain high-purity D_(2) are cost-intensive. Recent research has shown th...Deuterium(D_(2)) is one of the important fuel sources that power nuclear fusion reactors. The existing D_(2)/H_(2) separation technologies that obtain high-purity D_(2) are cost-intensive. Recent research has shown that metal-organic frameworks(MOFs) are of good potential for D_(2)/H_(2) separation application. In this work, a high-throughput computational screening of 12020 computation-ready experimental MOFs is carried out to determine the best MOFs for hydrogen isotope separation application. Meanwhile, the detailed structure-performance correlation is systematically investigated with the aid of machine learning. The results indicate that the ideal D_(2)/H_(2) adsorption selectivity calculated based on Henry coefficient is strongly correlated with the 1/ΔAD feature descriptor;that is, inverse of the adsorbility difference of the two adsorbates. Meanwhile, the machine learning(ML) results show that the prediction accuracy of all the four ML methods is significantly improved after the addition of this feature descriptor. In addition, the ML results based on extreme gradient boosting model also revealed that the 1/ΔAD descriptor has the highest relative importance compared to other commonly-used descriptors. To further explore the effect of hydrogen isotope separation in binary mixture, 1548 MOFs with ideal adsorption selectivity greater than 1.5 are simulated at equimolar conditions. The structure-performance relationship shows that high adsorption selectivity MOFs generally have smaller pore size(0.3-0.5 nm) and lower surface area. Among the top 200 performers, the materials mainly have the sql, pcu, cds, hxl, and ins topologies.Finally, three MOFs with high D_(2)/H_(2) selectivity and good D_(2) uptake are identified as the best candidates,of all which had one-dimensional channel pore. The findings obtained in this work may be helpful for the identification of potentially promising candidates for hydrogen isotope separation.展开更多
Isotope separation by laser deflecting an atomic beam is analyzed theoretically. Interacting with a tilted one- dimensional optical molasses, an ytterbium atomic beam is split into multi-beams with different isotopes ...Isotope separation by laser deflecting an atomic beam is analyzed theoretically. Interacting with a tilted one- dimensional optical molasses, an ytterbium atomic beam is split into multi-beams with different isotopes like 172yb, Jv3yb, and J74yb. By using the numerical calculation, the dependences of the splitting angle on the molasses laser intensity and detuning are studied, and the optimal parameters for the isotope separation are also investigated. Furthermore, the isotope separation efficiency and purity are estimated. Finally a new scheme for the efficient isotope separation is proposed. These findings will give a guideline for simply obtaining pure isotopes of various elements.展开更多
Stable isotopes have been routinely used in chemical sciences,medical treatment and agricultural research.Conventional technologies to produce high-purity isotopes entail lengthy separation processes that often suffer...Stable isotopes have been routinely used in chemical sciences,medical treatment and agricultural research.Conventional technologies to produce high-purity isotopes entail lengthy separation processes that often suffer from low selectivity and poor energy efficiency.Recent advances in nanoporous materials open up new opportunities for more efficient isotope enrichment and separation as the pore size and local chemical environment of such materials can be engineered with atomic precision.In this work,we demonstrate the unique capability of nanoporous membranes for the separation of stable carbon isotopes by computational screening a materials database consisting of 12,478 computation-ready,experimental metal-organic frameworks(MOFs).Nanoporous materials with the highest selectivity and membrane performance scores have been identified for separation of^(12)CH_4/^(13)CH_4 at the ambient condition(300 K).Analyzing the structural features and metal sites of the promising MOF candidates offers useful insights into membrane design to further improve the performance.An upper limit of the efficiency has been identified for the separation of^(12)CH_4/^(13)CH_4 with the existing MOFs and those variations by replacement of the metal sites.展开更多
Separating high-purity hydrogen isotopes from their mixture still remains a huge challenge due to almost the identical physicochemical properties.Much importance has been attached to tune microstructure of porous mate...Separating high-purity hydrogen isotopes from their mixture still remains a huge challenge due to almost the identical physicochemical properties.Much importance has been attached to tune microstructure of porous materials,while heat management during hydrogen isotope separation tends to be ignored.Herein,a porous material 5 A molecular sieve(5 A)is mixed with graphene(GE)under ball grinding to enhance its thermal conductivity for hydrogen isotope separation.The thermal conductivity increases from 0.19 W m^(-1)K^(-1)of neat 5 A,0.75 W m^(-1)K^(-1)of 5 A/GE2(2 wt%GE)to 1.23 W m^(-1)K^(-1)of 5 A/GE8.In addition,introducing GE into 5 A promotes hydrogen adsorption and D_(2)/H_(2)adsorption ratio.5 A/GE2 shows the highest D_(2)adsorption capacity(5.40 mmol/g)and the largest D_(2)/H_(2)adsorption ratio(1.07)among the composites.It also displays a high efficiency of heat transfer that contributes to a low energy consumption due to the shortened cycle time during hydrogen isotope separation.This work offers new insights into material design for improved hydrogen isotope separation,which is greatly crucial to scientific and industrial applications,such as fuel self-sustaining in fusion reactors.展开更多
Hydrogen isotope separation is a challenging task due to their similar properties.Herein,based on the chemical affinity quantum sieve(CAQS)effect,the D_(2)/H_(2)separation performance of M_(2)(m-dobdc)(M=Co,Ni,Mg,Mn;m...Hydrogen isotope separation is a challenging task due to their similar properties.Herein,based on the chemical affinity quantum sieve(CAQS)effect,the D_(2)/H_(2)separation performance of M_(2)(m-dobdc)(M=Co,Ni,Mg,Mn;m-dobdc^(4-)=4,6-dioxido-1,3-benzenedicarboxylate),a series of honeycomb-shaped MOFs with high stability and abundant open metal sites,are studied by gases sorption and breakthrough experiments,in which two critical factors,gas uptake and adsorption enthalpy,are taken into consideration.Among these MOFs,Co_(2)(m-dobdc)exhibits the longest D_(2)retention time of 180 min/g(H_(2)/D_(2)/Ne:1/1/98)at 77 K because of its second-highest adsorption enthalpy(10.7 kJ/mol for H_(2)and 11.8 kJ/mol for D_(2))and the best sorption capacity(5.22 mmol/g for H_(2)and 5.49 mmol/g for D_(2))under low pressure of 1 kPa and 77 K,which make it a promising material for industrial hydrogen isotope separation.Moreover,the results indicate that H_(2)and D_(2)capacities under low pressure(about 1 kPa)dominate the final D_(2)/H_(2)separation property of MOFs.展开更多
A new operation policy--quasi-batch distillation for recovering infinitesimal amounts species existing in a mixture is presented. In quasi-batch distillation operation, feed is introduced with a constant flow rate ont...A new operation policy--quasi-batch distillation for recovering infinitesimal amounts species existing in a mixture is presented. In quasi-batch distillation operation, feed is introduced with a constant flow rate onto the feed stage of the column, and the flow rate of the distillate is the same as that of the feed, whereas the bottom product is withdrawn periodically. The behavior of quasi-batch distillation is simulated and analyzed through an example on heavy water separation. Comparing with continuous or batch distillation, the new operation policy is more reliable and efficient to achieve higher recovery of dilute component. This is especially suitable for separating small amount of precious species from large amount of raw material.展开更多
Hydrograph separation is a fundamental catchment descriptor,revealing information about sources of water in runoff generation processes. The water isotopes are ideal tracers in studying hydrological processes since th...Hydrograph separation is a fundamental catchment descriptor,revealing information about sources of water in runoff generation processes. The water isotopes are ideal tracers in studying hydrological processes since the isotope fractionation produces a natural labeling effect within the hydrologic cycle. The water isotope technique has become one of effective means for investigating complex hydrologic system on a catchment scale. This paper reviews the progress on the use of stable water isotope techniques in catchment hydrograph separation in last decades. Also,the isotope mixing model for hydrograph separation and its uncertainties are explained in detail. In future research,there are three hot issues in the use of isotopic hydrograph separation（ IHS） ： integrating new approaches into IHS,calibration and verification of IHS model and IHS application in large river basins.展开更多
Experiments, prqiects and patents, concerning practical usage of a separation method, based on ICR （ion cyclotron resonance） in plasma, carried out in the 2000s in USA, EU and in Russia, are discussed in this articl...Experiments, prqiects and patents, concerning practical usage of a separation method, based on ICR （ion cyclotron resonance） in plasma, carried out in the 2000s in USA, EU and in Russia, are discussed in this article. It was planned to use ICR method for production of isotopically enriched burnable poisons for nuclear reactor fuel, and also to use this method for extraction of neutron-excess isotopes for the purpose of observation of neutrinoless double beta decay （ββ0v）. One more application of this method can be a nuclear waste treatment technology. Current situation with realization of these plans is considered.展开更多
To understand the source and nature of the ore-forming fluids of the Edmond hydrothermal field on the Central Indian Ridge, we studied the He-Ar isotope composition and fluid inclusions of the hydrothermal precipitate...To understand the source and nature of the ore-forming fluids of the Edmond hydrothermal field on the Central Indian Ridge, we studied the He-Ar isotope composition and fluid inclusions of the hydrothermal precipitates.Our results show that the sulfide samples contain noble gases He, Ne, Kr, and Xe with their abundances in between those of air-saturated water（ASW） and mid-ocean ridge basalt（MORB）. The ^3He/^4He ratio varies from1.3 to 8.7 Ra（n=10, average： 5.1 Ra）, whereas the ^40Ar/^36Ar ratio is from 285.3 to 314.7（n=10, average： 294.8）. These results suggest that the He was derived from a mixture of MORB with variable amounts of seawater, but the Ar in the ore-forming fluids trapped in the sulfides is predominantly derived from seawater. The fluid inclusions of barite have a wide range of homogenization temperatures and salinities varying from 163℃ to 260℃ and 2.6 wt%to 8.5 wt% Na Cl equiv., respectively. It is suggested that the ore-forming fluids were produced by phase separation, which agreed with the present-day vent fluid study.展开更多
A synergistic solvent extraction system comprising trioctylamine(TOA)and ligands with hydroxyl and carboxyl groups can efficiently recover boric acid(H_(3)BO_(3))and separate boron isotopes.However,the structure of li...A synergistic solvent extraction system comprising trioctylamine(TOA)and ligands with hydroxyl and carboxyl groups can efficiently recover boric acid(H_(3)BO_(3))and separate boron isotopes.However,the structure of ligands might impact H_(3)BO_(3) extraction,boron isotope separation,and solvent loss,which has not been thoroughly investigated.This study initially evaluated the influence of ligand's type,pKa,and substituents on H_(3)BO_(3) extraction efficiency,as well as the impact of the B_((4))-O structure(boron is bound to four oxygen atoms)in the organic phase on isotope separation efficiency.Subsequently,by synthesizing the highly hydrophobic 2-hydroxydodecanoic acid(HYA),the extraction performance and mechanism of the TOA/HYA system were investigated.The findings highlight the superior extraction efficiency when employing di-phenolic hydroxyl,phenolic hydroxyl + carbinol hydroxyl,and alcoholic hydroxyl + carboxyl ligands compared to phenolic hydroxyl + carboxyl,phenolic hydroxyl + ethanol hydroxyl,diol hydroxyl,and dicarboxylic ligands.The organic phase anion complex,exclusively comprising the B_((4))-O structure,enhances isotope separation effectiveness.The TOA/HYA system achieves an 80%single-stage extraction efficiency for H_(3)BO_(3).H_(3)BO_(3) and HYA are extracted into the organic phase at a ratio of 1:2,with the anion complex solely containing the B_((4))-O structure.This study paves the way for the construction of novel boric acid extraction and boron isotope separation systems.展开更多
Ti-Ni porous alloy was made from titanium and nickel powder mixture in equiatomic composition by combustion synthesis technique (self-propagation high temperature synthesis). The result analyzed by SEM and XRD shows t...Ti-Ni porous alloy was made from titanium and nickel powder mixture in equiatomic composition by combustion synthesis technique (self-propagation high temperature synthesis). The result analyzed by SEM and XRD shows that the alloy possesses high porosity (50%～70%), and mainly consists of TiNi phase as well as rare Ti_2Ni and TiNi_3 transition phase. Then it was activated, cracked and used as sorbent for hydrogen isotope separation. Through experiment investigation, it was discovered that the alloy is able to absorb hydrogen in very large quantities in the lattice thereof, but deuterium only very slightly or not at all, at temperatures up to 623 K, especially at temperatures from about 323 to 423 K. According to this characteristic, the Ti-Ni porous alloys may replace noble metal palladium(Pd) as used for hydrogen isotope separation and purification. Study illustrated that the technology would have a promising engineering application, such as being used for reprocessing Tokamak exhaust gases and producing high purity deuterium.展开更多
In this study, life cycle assessment of oxygen-18 by using cryogenic distillation of oxygen is performed using SimaPro 8.3 software. Life cycle assessment is performed to understand the environmental profile and hotsp...In this study, life cycle assessment of oxygen-18 by using cryogenic distillation of oxygen is performed using SimaPro 8.3 software. Life cycle assessment is performed to understand the environmental profile and hotspots of this process in order to be used in design and development. Simulation of oxygen-18 process is executed by Hysys software, and the required inputs and outputs for inventory of life cycle were acquired. By doing life cycle assessment and considering achieved results after characterization and normalization of inventory data it has been investigated that in the majority of environmental impacts electricity consumption has a huge contribution relative to other parts of the system like liquefied oxygen production from air separation unit,required facilities for air separation and oxygen-18 units, and needed transportation. Also, among 17 impact categories investigated in ReCiPe impact assessment method, fossil depletion, climate change(human health),particulate matter formation, climate change(ecosystem), human toxicity, and metal depletion have the most contribution in entire environmental loads respectively. Furthermore, sensitivity analysis showed that changing life cycle impact assessment method from ReCiPe to IMPACT 2002+ has no significant effect on acquired results and results are confident. In addition, assumption of market for depleted oxygen from heavy isotopes which is withdrawn from top of distillation columns showed some positive effects compared to first case and environmental impacts resulted from liquefied oxygen production(feed) reduced but because of huge contribution of electricity consumption compared to other sections, this positive effect has no remarkable influence on entire environmental loads of product system.展开更多
Electrolysis of water is widely used for hydrogen isotope separation and the development of hydrogen evolution reaction(HER)catalysts with high selectivity and activity is of key importance.Herein,we propose single at...Electrolysis of water is widely used for hydrogen isotope separation and the development of hydrogen evolution reaction(HER)catalysts with high selectivity and activity is of key importance.Herein,we propose single atom catalysts(SACs)as promising catalysts for efficient hydrogen isotope separation.Pt SACs and Pt nanoparticles(NPs)have been fabricated on nanoarray-structured nitrogen-doped graphite foil(NGF)substrate by a polyol reduction method.The as prepared Pt1/NGF electrode exhibits high activity and selectivity toward HER with a low overpotential of 0.022 V at 10 mA·cm^(-2) and a high separation factor of 6.83 for hydrogen and deuterium separation,much better than Pt NPs counterpart.Density functional theory(DFT)calculations ascribe the high activity and selectivity to the constructed Pt-N_(2)C_(2) structure.This work develops a new opportunity for the design and application of high-efficiency and stable SACs toward hydrogen isotope separation by electrolysis of water.展开更多
γ-ray radiation-induced grafting strategy was first employed to immobilize 4-aminobenzo-15-crown-5 onto a covalent organic framework(COF).This endeavor culminated in the successful synthesis of a class of two-dimensi...γ-ray radiation-induced grafting strategy was first employed to immobilize 4-aminobenzo-15-crown-5 onto a covalent organic framework(COF).This endeavor culminated in the successful synthesis of a class of two-dimensional crown ether-modified COFs(named[15C5]n%-(TzDa-G-x%)),marking the maiden utilization of COFs in the realm of^(6)Li/^(7)Li isotope separation.These COFs exhibited swifter adsorption kinetics than alternative adsorbents.Among them,[15C5]_(57%)-(TzDa-G-50%)with its excellent crystallinity,porosity,and stability exhibited the best performance in Li+adsorption and^(6)Li/^(7)Li isotope separation.The Li+adsorption in acetonitrile achieved a capacity of 3.6 mg·g^(−1)within 30 min and a saturation capacity of 7.3 mg·g^(−1).The single-stage separation factor of^(6)Li/^(7)Li isotopes was 1.014±0.001.The results of dynamic adsorption column experiments showed that the packed column made of[15C5]_(57%)-(TzDa-G-50%)maintained stable performance during four cycles of Li+adsorptionelution,with over 99%Li+removal rate in acetonitrile.This crown ether-modified COF has potential application in^(6)Li/^(7)Li isotope separation,and this radiation-assisted synthesis strategy is expected to become universal in the modification of COFs for diverse applications.展开更多
Due to the similar physical and chemical properties, isotopes are usually hard to separate. On the other hand, the isotope shifts are very well separated in a high-resolution spectrum, making them possible to be addre...Due to the similar physical and chemical properties, isotopes are usually hard to separate. On the other hand, the isotope shifts are very well separated in a high-resolution spectrum, making them possible to be addressed individually by lasers, thus separated. Here we report such an isotope separation experiment with Potassium atoms. The isotopes are independently optical pumped to the desired spin states, and then separated with a Stern–Gerlach scheme. A micro-capillary oven is used to collimate the atomic beam, and a Halbach-type magnet array is used to deflect the desired atoms. Finally, the 40K is enriched by two orders of magnitude. This magneto–optical combined method provides an effective way to separate isotopes and can be extended to other elements if the relevant optical pumping scheme is feasible.展开更多
A well designed continuous annular chromatograph （CAC） column was set to stndy the enrichment of Boron isotopes. The column is 820 mm high and consists of a rotational annulus with an outer diameter of 246 mm and a ...A well designed continuous annular chromatograph （CAC） column was set to stndy the enrichment of Boron isotopes. The column is 820 mm high and consists of a rotational annulus with an outer diameter of 246 mm and a width of 15 mm. The weak basic resin （Diaion WA21J）, the boric acid and water were used as the absorbent, the feed and the eluent respectively. The effects of CAC rotating speed, concentration of boric acid and flow ratio of eluent to feed on the enrichment of 10B were investigated. The concentration of boron isotope was determined by a Thermal Elemental X7 ICP-MS （Thermo Electron Co., USA）. It is shown from the experimental results that 10B and 11B can be separated effectively by this CAC column. By fitting the experimental elution profiles based on reliable mathematic models and software the mass transfer coefficient k and adsorp- tion equilibrium constant K values of 10B and 11B in CAC column were estimated. It is clear from this study that the CAC has practical continuous operational capabilities in comparison with fixed batch chromatography and is an effective technology for seoarating boron isotones.展开更多
The synthesis of nanoporous materials that display a combination of molecular sieving(MS)and quantum sieving(QS)effects is still a challenging task.In this work,we have demonstrated the synthesis of a nanocaged metal...The synthesis of nanoporous materials that display a combination of molecular sieving(MS)and quantum sieving(QS)effects is still a challenging task.In this work,we have demonstrated the synthesis of a nanocaged metal–organic framework(MOF),ECUT-8,that has a dual-sieving capability.ECUT-8 afforded H_(2)/D_(2) isotope separation due to its extremely narrow window size(3.0Å),resulting in QS.Further,the framework flexibility of ECUT-8 was exploited for the separation of butane and hexane isomers due to its MS effect.Other desirable features of ECUT-8 include high thermal,water,and chemical stability,making it suitable for practical application.Herein,these results open up an avenue to design the effects of coexistence of multiple sieving in one material.展开更多
Isotope shifts among different isotopes can be effectively addressed using narrow-linewidth lasers,facilitating laser isotope separation and achieving significant enrichment at a single stage.The separation of potassi...Isotope shifts among different isotopes can be effectively addressed using narrow-linewidth lasers,facilitating laser isotope separation and achieving significant enrichment at a single stage.The separation of potassium isotopes,employing optical pumping and magnetic deflection,has proven to be efficient.To further improve the enrichment of ^(40)K,we introduce 2D transverse cooling to minimize the divergence angle.Through this modification,we demonstrate enrichment of ^(40)K,elevating it from 0.012%to 12%–20%.This represents an enrichment increase by three orders of magnitude,surpassing our previous result by one order.Our method is particularly well-suited for isotope enrichment of elements with extremely low abundance.展开更多
基金financially supported by the National Natural Science Foundation of China(22109145)the Foundation of Science and Technology on Surface Physics and Chemistry Laboratory(WDZC202202)the Natural Science Foundation of Sichuan Province(2024NSFTD0018)。
文摘The palladium/kieselguhr composites(Pd/K)were prepared by the PdCl_(2) dipping-reducing method.The effects of the preparation conditions on the Pd/K were studied,such as the heat treatment,dipping time,palladium concentration in solution and number of loading cycles.The pore structure and palladium content of the Pd/K were measured by the Brunauer-Emmett-Teller method and an inductively coupled plasma mass spectrometry.The appearance and palladium element distribution were measured by a scanning electron microscope.It is found that the palladium element is more densely distributed in the irregular and porous parts of the kieselguhr particles,so the kieselguhr is superior to Al_(2)O_(3) as the carrier material.The heat treatment can improve the pore permeability and increase the palladium content for the Pd/K.Increasing the dipping time,palladium concentration in solution and number of loading cycles is beneficial to increase the palladium content of the Pd/K,but more loading cycles may lead to the pore collapse,which obstructs the interaction with the hydrogen isotope gases.A kind of Pd/K was prepared under a set of optimized conditions and was packed in a separation column.This Pd/K was proved to be of high performance and durable by some hydrogen-deuterium separation experiments.
基金supported by the National Natural Science Foundation of China (22078004)the Research Development Fund from Xi’an Jiaotong-Liverpool University (RDF-16-02-03 and RDF15-01-23)key program special fund (KSF-E-03)。
文摘Deuterium(D_(2)) is one of the important fuel sources that power nuclear fusion reactors. The existing D_(2)/H_(2) separation technologies that obtain high-purity D_(2) are cost-intensive. Recent research has shown that metal-organic frameworks(MOFs) are of good potential for D_(2)/H_(2) separation application. In this work, a high-throughput computational screening of 12020 computation-ready experimental MOFs is carried out to determine the best MOFs for hydrogen isotope separation application. Meanwhile, the detailed structure-performance correlation is systematically investigated with the aid of machine learning. The results indicate that the ideal D_(2)/H_(2) adsorption selectivity calculated based on Henry coefficient is strongly correlated with the 1/ΔAD feature descriptor;that is, inverse of the adsorbility difference of the two adsorbates. Meanwhile, the machine learning(ML) results show that the prediction accuracy of all the four ML methods is significantly improved after the addition of this feature descriptor. In addition, the ML results based on extreme gradient boosting model also revealed that the 1/ΔAD descriptor has the highest relative importance compared to other commonly-used descriptors. To further explore the effect of hydrogen isotope separation in binary mixture, 1548 MOFs with ideal adsorption selectivity greater than 1.5 are simulated at equimolar conditions. The structure-performance relationship shows that high adsorption selectivity MOFs generally have smaller pore size(0.3-0.5 nm) and lower surface area. Among the top 200 performers, the materials mainly have the sql, pcu, cds, hxl, and ins topologies.Finally, three MOFs with high D_(2)/H_(2) selectivity and good D_(2) uptake are identified as the best candidates,of all which had one-dimensional channel pore. The findings obtained in this work may be helpful for the identification of potentially promising candidates for hydrogen isotope separation.
基金Project supported by the National Basic Research Program of China （Grant No. 2012CB821302）, the National Natural Science Foundation of China （Grant Nos. 11134003 and 10774044）, and the Shanghai Excellent Academic Leaders Program, China （Grant No. 12XD1402400）.
文摘Isotope separation by laser deflecting an atomic beam is analyzed theoretically. Interacting with a tilted one- dimensional optical molasses, an ytterbium atomic beam is split into multi-beams with different isotopes like 172yb, Jv3yb, and J74yb. By using the numerical calculation, the dependences of the splitting angle on the molasses laser intensity and detuning are studied, and the optimal parameters for the isotope separation are also investigated. Furthermore, the isotope separation efficiency and purity are estimated. Finally a new scheme for the efficient isotope separation is proposed. These findings will give a guideline for simply obtaining pure isotopes of various elements.
基金financially supported by the National Science Foundation Harnessing the Data Revolution Big Idea under Grant No.NSF 1940118supported by the State Key Laboratory of Chemical Engineering(SKL-CHE20)。
文摘Stable isotopes have been routinely used in chemical sciences,medical treatment and agricultural research.Conventional technologies to produce high-purity isotopes entail lengthy separation processes that often suffer from low selectivity and poor energy efficiency.Recent advances in nanoporous materials open up new opportunities for more efficient isotope enrichment and separation as the pore size and local chemical environment of such materials can be engineered with atomic precision.In this work,we demonstrate the unique capability of nanoporous membranes for the separation of stable carbon isotopes by computational screening a materials database consisting of 12,478 computation-ready,experimental metal-organic frameworks(MOFs).Nanoporous materials with the highest selectivity and membrane performance scores have been identified for separation of^(12)CH_4/^(13)CH_4 at the ambient condition(300 K).Analyzing the structural features and metal sites of the promising MOF candidates offers useful insights into membrane design to further improve the performance.An upper limit of the efficiency has been identified for the separation of^(12)CH_4/^(13)CH_4 with the existing MOFs and those variations by replacement of the metal sites.
基金the National Magnetic Confinement Fusion Science Program(2013GB108002,2014GB112005)National Natural Science Foundation of China(11747042)+2 种基金Science and Technology Development Foundation of China Academy of Engineering Physics(xk201701)Sichuan Science and Technology Program(2019YJ0445)Project of State Key Laboratory of Environment-friendly Energy Materials,Southwest University of Science and Technology(17FKSY0105)。
文摘Separating high-purity hydrogen isotopes from their mixture still remains a huge challenge due to almost the identical physicochemical properties.Much importance has been attached to tune microstructure of porous materials,while heat management during hydrogen isotope separation tends to be ignored.Herein,a porous material 5 A molecular sieve(5 A)is mixed with graphene(GE)under ball grinding to enhance its thermal conductivity for hydrogen isotope separation.The thermal conductivity increases from 0.19 W m^(-1)K^(-1)of neat 5 A,0.75 W m^(-1)K^(-1)of 5 A/GE2(2 wt%GE)to 1.23 W m^(-1)K^(-1)of 5 A/GE8.In addition,introducing GE into 5 A promotes hydrogen adsorption and D_(2)/H_(2)adsorption ratio.5 A/GE2 shows the highest D_(2)adsorption capacity(5.40 mmol/g)and the largest D_(2)/H_(2)adsorption ratio(1.07)among the composites.It also displays a high efficiency of heat transfer that contributes to a low energy consumption due to the shortened cycle time during hydrogen isotope separation.This work offers new insights into material design for improved hydrogen isotope separation,which is greatly crucial to scientific and industrial applications,such as fuel self-sustaining in fusion reactors.
基金financially supported by the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB20000000)the Key Research Program of Frontier Sciences,Chinese Academy of Sciences(No.QYZDB-SSW-SLH019)the National Natural Science Foundation of China(Nos.21771177,51603206 and 21203117).
文摘Hydrogen isotope separation is a challenging task due to their similar properties.Herein,based on the chemical affinity quantum sieve(CAQS)effect,the D_(2)/H_(2)separation performance of M_(2)(m-dobdc)(M=Co,Ni,Mg,Mn;m-dobdc^(4-)=4,6-dioxido-1,3-benzenedicarboxylate),a series of honeycomb-shaped MOFs with high stability and abundant open metal sites,are studied by gases sorption and breakthrough experiments,in which two critical factors,gas uptake and adsorption enthalpy,are taken into consideration.Among these MOFs,Co_(2)(m-dobdc)exhibits the longest D_(2)retention time of 180 min/g(H_(2)/D_(2)/Ne:1/1/98)at 77 K because of its second-highest adsorption enthalpy(10.7 kJ/mol for H_(2)and 11.8 kJ/mol for D_(2))and the best sorption capacity(5.22 mmol/g for H_(2)and 5.49 mmol/g for D_(2))under low pressure of 1 kPa and 77 K,which make it a promising material for industrial hydrogen isotope separation.Moreover,the results indicate that H_(2)and D_(2)capacities under low pressure(about 1 kPa)dominate the final D_(2)/H_(2)separation property of MOFs.
基金Supported by the National Natural Science Foundation of China (No. 20136010).
文摘A new operation policy--quasi-batch distillation for recovering infinitesimal amounts species existing in a mixture is presented. In quasi-batch distillation operation, feed is introduced with a constant flow rate onto the feed stage of the column, and the flow rate of the distillate is the same as that of the feed, whereas the bottom product is withdrawn periodically. The behavior of quasi-batch distillation is simulated and analyzed through an example on heavy water separation. Comparing with continuous or batch distillation, the new operation policy is more reliable and efficient to achieve higher recovery of dilute component. This is especially suitable for separating small amount of precious species from large amount of raw material.
基金Supported by the National Natural Science Foundation of China(41101066)the China Postdoctoral Science Foundation Funded Project(2013M532094)
文摘Hydrograph separation is a fundamental catchment descriptor,revealing information about sources of water in runoff generation processes. The water isotopes are ideal tracers in studying hydrological processes since the isotope fractionation produces a natural labeling effect within the hydrologic cycle. The water isotope technique has become one of effective means for investigating complex hydrologic system on a catchment scale. This paper reviews the progress on the use of stable water isotope techniques in catchment hydrograph separation in last decades. Also,the isotope mixing model for hydrograph separation and its uncertainties are explained in detail. In future research,there are three hot issues in the use of isotopic hydrograph separation（ IHS） ： integrating new approaches into IHS,calibration and verification of IHS model and IHS application in large river basins.
文摘Experiments, prqiects and patents, concerning practical usage of a separation method, based on ICR （ion cyclotron resonance） in plasma, carried out in the 2000s in USA, EU and in Russia, are discussed in this article. It was planned to use ICR method for production of isotopically enriched burnable poisons for nuclear reactor fuel, and also to use this method for extraction of neutron-excess isotopes for the purpose of observation of neutrinoless double beta decay （ββ0v）. One more application of this method can be a nuclear waste treatment technology. Current situation with realization of these plans is considered.
基金The National Natural Science Foundation of China under contract No.41306056the China Ocean Mineral Resources R&D Association Project under contract No.DY125-12-R-03the Scientific Research Fund of the Second Institute of Oceanography,SOA under contract No.JG1308
文摘To understand the source and nature of the ore-forming fluids of the Edmond hydrothermal field on the Central Indian Ridge, we studied the He-Ar isotope composition and fluid inclusions of the hydrothermal precipitates.Our results show that the sulfide samples contain noble gases He, Ne, Kr, and Xe with their abundances in between those of air-saturated water（ASW） and mid-ocean ridge basalt（MORB）. The ^3He/^4He ratio varies from1.3 to 8.7 Ra（n=10, average： 5.1 Ra）, whereas the ^40Ar/^36Ar ratio is from 285.3 to 314.7（n=10, average： 294.8）. These results suggest that the He was derived from a mixture of MORB with variable amounts of seawater, but the Ar in the ore-forming fluids trapped in the sulfides is predominantly derived from seawater. The fluid inclusions of barite have a wide range of homogenization temperatures and salinities varying from 163℃ to 260℃ and 2.6 wt%to 8.5 wt% Na Cl equiv., respectively. It is suggested that the ore-forming fluids were produced by phase separation, which agreed with the present-day vent fluid study.
基金supported by the National Natural Science Foundation of China(22278407,21922814,22138012,22178349)CAS Project for Young Scientists in Basic Research(YSBR-038)+1 种基金National Key Research and Development Program of China(2021YFC2901500,2022YFC2105302)Shandong Energy Institute(SEI U202306).
文摘A synergistic solvent extraction system comprising trioctylamine(TOA)and ligands with hydroxyl and carboxyl groups can efficiently recover boric acid(H_(3)BO_(3))and separate boron isotopes.However,the structure of ligands might impact H_(3)BO_(3) extraction,boron isotope separation,and solvent loss,which has not been thoroughly investigated.This study initially evaluated the influence of ligand's type,pKa,and substituents on H_(3)BO_(3) extraction efficiency,as well as the impact of the B_((4))-O structure(boron is bound to four oxygen atoms)in the organic phase on isotope separation efficiency.Subsequently,by synthesizing the highly hydrophobic 2-hydroxydodecanoic acid(HYA),the extraction performance and mechanism of the TOA/HYA system were investigated.The findings highlight the superior extraction efficiency when employing di-phenolic hydroxyl,phenolic hydroxyl + carbinol hydroxyl,and alcoholic hydroxyl + carboxyl ligands compared to phenolic hydroxyl + carboxyl,phenolic hydroxyl + ethanol hydroxyl,diol hydroxyl,and dicarboxylic ligands.The organic phase anion complex,exclusively comprising the B_((4))-O structure,enhances isotope separation effectiveness.The TOA/HYA system achieves an 80%single-stage extraction efficiency for H_(3)BO_(3).H_(3)BO_(3) and HYA are extracted into the organic phase at a ratio of 1:2,with the anion complex solely containing the B_((4))-O structure.This study paves the way for the construction of novel boric acid extraction and boron isotope separation systems.
文摘Ti-Ni porous alloy was made from titanium and nickel powder mixture in equiatomic composition by combustion synthesis technique (self-propagation high temperature synthesis). The result analyzed by SEM and XRD shows that the alloy possesses high porosity (50%～70%), and mainly consists of TiNi phase as well as rare Ti_2Ni and TiNi_3 transition phase. Then it was activated, cracked and used as sorbent for hydrogen isotope separation. Through experiment investigation, it was discovered that the alloy is able to absorb hydrogen in very large quantities in the lattice thereof, but deuterium only very slightly or not at all, at temperatures up to 623 K, especially at temperatures from about 323 to 423 K. According to this characteristic, the Ti-Ni porous alloys may replace noble metal palladium(Pd) as used for hydrogen isotope separation and purification. Study illustrated that the technology would have a promising engineering application, such as being used for reprocessing Tokamak exhaust gases and producing high purity deuterium.
文摘In this study, life cycle assessment of oxygen-18 by using cryogenic distillation of oxygen is performed using SimaPro 8.3 software. Life cycle assessment is performed to understand the environmental profile and hotspots of this process in order to be used in design and development. Simulation of oxygen-18 process is executed by Hysys software, and the required inputs and outputs for inventory of life cycle were acquired. By doing life cycle assessment and considering achieved results after characterization and normalization of inventory data it has been investigated that in the majority of environmental impacts electricity consumption has a huge contribution relative to other parts of the system like liquefied oxygen production from air separation unit,required facilities for air separation and oxygen-18 units, and needed transportation. Also, among 17 impact categories investigated in ReCiPe impact assessment method, fossil depletion, climate change(human health),particulate matter formation, climate change(ecosystem), human toxicity, and metal depletion have the most contribution in entire environmental loads respectively. Furthermore, sensitivity analysis showed that changing life cycle impact assessment method from ReCiPe to IMPACT 2002+ has no significant effect on acquired results and results are confident. In addition, assumption of market for depleted oxygen from heavy isotopes which is withdrawn from top of distillation columns showed some positive effects compared to first case and environmental impacts resulted from liquefied oxygen production(feed) reduced but because of huge contribution of electricity consumption compared to other sections, this positive effect has no remarkable influence on entire environmental loads of product system.
基金This work was financially supported by the National Natural Science Foundation of China(No.22109146)Institute of Materials CAEP(Nos.TP03201703,TP03201802,CX2019018,and WDZC202105).
文摘Electrolysis of water is widely used for hydrogen isotope separation and the development of hydrogen evolution reaction(HER)catalysts with high selectivity and activity is of key importance.Herein,we propose single atom catalysts(SACs)as promising catalysts for efficient hydrogen isotope separation.Pt SACs and Pt nanoparticles(NPs)have been fabricated on nanoarray-structured nitrogen-doped graphite foil(NGF)substrate by a polyol reduction method.The as prepared Pt1/NGF electrode exhibits high activity and selectivity toward HER with a low overpotential of 0.022 V at 10 mA·cm^(-2) and a high separation factor of 6.83 for hydrogen and deuterium separation,much better than Pt NPs counterpart.Density functional theory(DFT)calculations ascribe the high activity and selectivity to the constructed Pt-N_(2)C_(2) structure.This work develops a new opportunity for the design and application of high-efficiency and stable SACs toward hydrogen isotope separation by electrolysis of water.
基金the National Natural Science Foundation of China(grant no.U2067212)the National Science Fund for Distinguished Young Scholars(grant no.21925603).
文摘γ-ray radiation-induced grafting strategy was first employed to immobilize 4-aminobenzo-15-crown-5 onto a covalent organic framework(COF).This endeavor culminated in the successful synthesis of a class of two-dimensional crown ether-modified COFs(named[15C5]n%-(TzDa-G-x%)),marking the maiden utilization of COFs in the realm of^(6)Li/^(7)Li isotope separation.These COFs exhibited swifter adsorption kinetics than alternative adsorbents.Among them,[15C5]_(57%)-(TzDa-G-50%)with its excellent crystallinity,porosity,and stability exhibited the best performance in Li+adsorption and^(6)Li/^(7)Li isotope separation.The Li+adsorption in acetonitrile achieved a capacity of 3.6 mg·g^(−1)within 30 min and a saturation capacity of 7.3 mg·g^(−1).The single-stage separation factor of^(6)Li/^(7)Li isotopes was 1.014±0.001.The results of dynamic adsorption column experiments showed that the packed column made of[15C5]_(57%)-(TzDa-G-50%)maintained stable performance during four cycles of Li+adsorptionelution,with over 99%Li+removal rate in acetonitrile.This crown ether-modified COF has potential application in^(6)Li/^(7)Li isotope separation,and this radiation-assisted synthesis strategy is expected to become universal in the modification of COFs for diverse applications.
基金We acknowledge the support from the National Key R&D Program of China under Grant No.2018YFA0307200the National Natural Science Foundation of China under Grant No.12074337+2 种基金the Natural Science Foundation of Zhejiang Province under Grant Nos.LR21A040002 and LZ18A040001Zhejiang Province Plan for Science and Technology No.2020C01019the Fundamental Research Funds for the Central Universities under Grant Nos.2020XZZX002-05 and 2021FZZX001-02.
文摘Due to the similar physical and chemical properties, isotopes are usually hard to separate. On the other hand, the isotope shifts are very well separated in a high-resolution spectrum, making them possible to be addressed individually by lasers, thus separated. Here we report such an isotope separation experiment with Potassium atoms. The isotopes are independently optical pumped to the desired spin states, and then separated with a Stern–Gerlach scheme. A micro-capillary oven is used to collimate the atomic beam, and a Halbach-type magnet array is used to deflect the desired atoms. Finally, the 40K is enriched by two orders of magnitude. This magneto–optical combined method provides an effective way to separate isotopes and can be extended to other elements if the relevant optical pumping scheme is feasible.
基金supported by the Scientific and Technological Innovation Capacity Promotion Plan Project of Qinghai Province of China(2010-J-749)
文摘A well designed continuous annular chromatograph （CAC） column was set to stndy the enrichment of Boron isotopes. The column is 820 mm high and consists of a rotational annulus with an outer diameter of 246 mm and a width of 15 mm. The weak basic resin （Diaion WA21J）, the boric acid and water were used as the absorbent, the feed and the eluent respectively. The effects of CAC rotating speed, concentration of boric acid and flow ratio of eluent to feed on the enrichment of 10B were investigated. The concentration of boron isotope was determined by a Thermal Elemental X7 ICP-MS （Thermo Electron Co., USA）. It is shown from the experimental results that 10B and 11B can be separated effectively by this CAC column. By fitting the experimental elution profiles based on reliable mathematic models and software the mass transfer coefficient k and adsorp- tion equilibrium constant K values of 10B and 11B in CAC column were estimated. It is clear from this study that the CAC has practical continuous operational capabilities in comparison with fixed batch chromatography and is an effective technology for seoarating boron isotones.
基金supported financially by the National Natural Science Foundations of China(nos.21966002,21871047,and 21861017)the Natural Science Foundation of Jiangxi Province of China(no.20181ACB20003)the Training Program for Academic and Technical Leaders of Major Disciplines in Jiangxi Province(no.20194BCJ22010).
文摘The synthesis of nanoporous materials that display a combination of molecular sieving(MS)and quantum sieving(QS)effects is still a challenging task.In this work,we have demonstrated the synthesis of a nanocaged metal–organic framework(MOF),ECUT-8,that has a dual-sieving capability.ECUT-8 afforded H_(2)/D_(2) isotope separation due to its extremely narrow window size(3.0Å),resulting in QS.Further,the framework flexibility of ECUT-8 was exploited for the separation of butane and hexane isomers due to its MS effect.Other desirable features of ECUT-8 include high thermal,water,and chemical stability,making it suitable for practical application.Herein,these results open up an avenue to design the effects of coexistence of multiple sieving in one material.
基金supported by the National Natural Science Foundation of China(Nos.U21A20437 and 12074337)the National Key R&D Program of China(No.2022YFA1404203)+2 种基金the Natural Science Foundation of Zhejiang Province(No.LR21A040002)the Zhejiang Province Plan for Science and Technology(No.2020C01019)the Fundamental Research Funds for the Central Universities(No.2021FZZX001-02).
文摘Isotope shifts among different isotopes can be effectively addressed using narrow-linewidth lasers,facilitating laser isotope separation and achieving significant enrichment at a single stage.The separation of potassium isotopes,employing optical pumping and magnetic deflection,has proven to be efficient.To further improve the enrichment of ^(40)K,we introduce 2D transverse cooling to minimize the divergence angle.Through this modification,we demonstrate enrichment of ^(40)K,elevating it from 0.012%to 12%–20%.This represents an enrichment increase by three orders of magnitude,surpassing our previous result by one order.Our method is particularly well-suited for isotope enrichment of elements with extremely low abundance.
