To scrutinize the characteristics of wave-current loads on a bridge shuttle-shaped cap–pile foundation,a 1:125 test model was considered in a laboratory flume.The inline,transverse and vertical wave–current forces a...To scrutinize the characteristics of wave-current loads on a bridge shuttle-shaped cap–pile foundation,a 1:125 test model was considered in a laboratory flume.The inline,transverse and vertical wave–current forces acting on the shuttle-shaped cap-pile group model were measured considering both random waves and a combination of random waves with a current.The experimental results have shown that the wave-current forces can be well correlated with the wave height,the wavelength,the current velocity,the incident direction and the water level in the marine environment.An increase in the current velocity can lead to a sharp increase in the inline and transverse wave-current forces,while the vertical wave-current force decreases.Moreover,the wave-current forces are particularly strong when a combination of high tide,strong wave and strong current is considered.展开更多
In recent years,Remotely Operated Vehicles(ROVs)have played an increasingly important role in the construc-tion and monitoring of underwater pile foundations.However,due to the open frame structure of such vehicles,a ...In recent years,Remotely Operated Vehicles(ROVs)have played an increasingly important role in the construc-tion and monitoring of underwater pile foundations.However,due to the open frame structure of such vehicles,a gap of knowledge still exists with regard to their hydrodynamic behavior.In this study,the hydrodynamic stability of such vehicles is investigated numerically by means of a multiple reference frame method.The hydrodynamic characteristics of the ROV when it moves horizontally and upward in the vertical plane are examined.It is found that there is interference between the horizontal and vertical thrusters of the ROV.There is also interference between the propeller thrust and drag(or lift).The effect of the vertical thrusters can increase the horizontal thrust by about 5%.The horizontal thrusters create a low-pressure area below the body,which can make vertical drag experienced by the ROV significantly higher.展开更多
A novel molten salt extraction process consisting of chlorination roasting and molten salt electrolysis was proposed to develop a more efficient and environmental friendly technology for recovering lead from spent lea...A novel molten salt extraction process consisting of chlorination roasting and molten salt electrolysis was proposed to develop a more efficient and environmental friendly technology for recovering lead from spent lead acid batteries(LABs).The feasibility of this process was firstly assessed based on thermodynamics fundamentals.The electrochemical behavior of Pb(II)on a tungsten electrode in the eutectic NaCl−KCl melts at 700℃ was then investigated in detail by transient electrochemical techniques.The results indicated that the reduction reaction of Pb(II)in NaCl−KCl melts was a one-step process exchanging two electrons,and it was determined to be a quasi-reversible diffusion-controlled process.Finally,potentiostatic electrolysis was carried out at−0.6 V(vs Ag/AgCl)in the NaCl−KCl−PbCl2 melts,and the obtained cathodic product was identified as pure Pb by X-ray diffraction analysis.This investigation demonstrated that it is practically feasible to produce pure Pb metal by electrochemical reduction of PbCl2 in eutectic NaCl−KCl melts,and has provided important fundamental for the further study on lead recovery from spent LABs via molten salt extraction process.展开更多
This study aims to investigate the primary carbides precipitation in H13 steel solidified at relatively high cooling rates,ranging from 300 to 6,000℃·min^-1,based on in situ observations with a high temperature ...This study aims to investigate the primary carbides precipitation in H13 steel solidified at relatively high cooling rates,ranging from 300 to 6,000℃·min^-1,based on in situ observations with a high temperature confocal laser scanning microscope.In the cooling rate range investigated,the solidification microstructure becomes more refined as cooling rate increases and the relationship between the secondary dendrite arm spacing(SDAS),λ2,and cooling rate,.T,can be expressed asλ2=128.45.T-0.124.Regardless of cooling rates,two kinds of primary carbides,i.e.,the Mo-Cr-rich and V-rich carbides,are precipitated along the interdendritic region and most of them are the Mo-Cr-rich carbides.The morphology of Mo-Cr-rich carbide is not obviously influenced by the cooling rate,but that of V-rich carbide is obviously affected.The increasing cooling rate markedly refines the primary carbides and reduces their volume fractions,but their precipitations cannot be inhibited even when the cooling rate is increased to 6,000℃·min^-1.Besides,the segregation ratios(SRs)of the carbides forming elements are not obviously affected by the cooling rate.However,compared with the conventionally cast ingot,the SDAS and primary carbides in the steel solidified at the investigated cooling rates are much finer,morphologies of the carbides have changed significantly,and SRs of the carbides forming elements are markedly greater.The variation of primary carbide characteristics with cooling rate is mainly due to the change in SDAS.展开更多
It is a challenge to recover lithium from the leaching solution of spent lithium-ion batteries,and crown ethers are potential extractants due to their selectivity to alkali metal ions.The theoretical calculations for ...It is a challenge to recover lithium from the leaching solution of spent lithium-ion batteries,and crown ethers are potential extractants due to their selectivity to alkali metal ions.The theoretical calculations for the selectivity of crown ethers with different structures to Li ions in aqueous solutions were carried out based on the density functional theory.The calculated results of geometries,binding energies,and thermodynamic parameters show that 15C5 has the strongest selectivity to Li ions in the three crown ethers of 12C4,15C5,and 18C6.B15C5 has a smaller binding energy but more negative free energy than 15C5 when combined with Li^+,leading to that the lithium ions in aqueous solutions will combine with B15C5 rather than 15C5.The exchange reactions between B15C5 and hydrated Li^+,Co^2+,and Ni^2+were analyzed and the results show that B15C5 is more likely to capture Li^+from the hydrated ions in an aqueous solution containing Li^+,Co^2+,and Ni^2+.This study indicates that it is feasible to extract Li ions selectively using B15C5 as an extractant from the leaching solution of spent lithium-ion batteries.展开更多
An electrochemical study on the redox behavior of indium in the eutectic LiCl-KCl system at 450 ℃ was carried out with the transient techniques of cyclic voltammetry and chronopotentiometry on an inert molybdenum ele...An electrochemical study on the redox behavior of indium in the eutectic LiCl-KCl system at 450 ℃ was carried out with the transient techniques of cyclic voltammetry and chronopotentiometry on an inert molybdenum electrode. The reduction of In(Ⅲ) was found to be a two-step process involving In(Ⅲ)/In(Ⅰ) and In(Ⅰ)/In couples at the potentials of about-0.4 and-0.8 V versus Ag/AgCl, respectively. The redox mechanism was further confirmed by the theoretical evaluation of the number of transferred electrons based on cyclic voltammetry and characterizations of the precipitates generated by the potentiostatic electrolysis. The diffusion coefficients of indium ions in the eutectic LiCl-KCl melt at 450 ℃ were estimated by cyclic voltammetry and chronopotentiometry. The results obtained through the two methods are in fair agreement, delivering an average diffusion coefficient of approximately 1.8×10^(-5)cm^(2)/s for In(Ⅲ), and 1.4×10^(-4)cm^(2)/s for In(Ⅰ).展开更多
The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international partners.The complex comprises four accelerators:a 3...The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international partners.The complex comprises four accelerators:a 30 GeV Linac,a 1.1 GeV Damping Ring,a Booster capable of achieving energies up to 180 GeV,and a Collider operating at varying energy modes(Z,W,H,and tt).The Linac and Damping Ring are situated on the surface,while the subterranean Booster and Collider are housed in a 100 km circumference underground tunnel,strategically accommodating future expansion with provisions for a potential Super Proton Proton Collider(SPPC).The CEPC primarily serves as a Higgs factory.In its baseline design with synchrotron radiation(SR)power of 30 MW per beam,it can achieve a luminosity of 5×10^(34)cm^(-2)s^(-1)per interaction point(IP),resulting in an integrated luminosity of 13 ab^(-1)for two IPs over a decade,producing 2.6 million Higgs bosons.Increasing the SR power to 50 MW per beam expands the CEPC's capability to generate 4.3 million Higgs bosons,facilitating precise measurements of Higgs coupling at sub-percent levels,exceeding the precision expected from the HL-LHC by an order of magnitude.This Technical Design Report(TDR)follows the Preliminary Conceptual Design Report(Pre-CDR,2015)and the Conceptual Design Report(CDR,2018),comprehensively detailing the machine's layout,performance metrics,physical design and analysis,technical systems design,R&D and prototyping efforts,and associated civil engineering aspects.Additionally,it includes a cost estimate and a preliminary construction timeline,establishing a framework for forthcoming engineering design phase and site selection procedures.Construction is anticipated to begin around 2027-2028,pending government approval,with an estimated duration of 8 years.The commencement of experiments and data collection could potentially be initiated in the mid-2030s.展开更多
The present study has proposed a compact process for the production of high-purity β-Ga_(2)O_(3)powder by simply using gallium metal and water as the raw materials.The process basically consists of two essential step...The present study has proposed a compact process for the production of high-purity β-Ga_(2)O_(3)powder by simply using gallium metal and water as the raw materials.The process basically consists of two essential steps including hydrothermal synthesis of Ga OOH and calcination of Ga OOH for the production of the target product of β-Ga_(2)O_(3).Thermodynamic evaluation and systematic experiments were conducted for process parameter optimization.X-ray diffractometer(XRD),scanning electron microscopy(SEM),thermogravimetryDdifferential scanning calorimetry(TG-DSC)and X-ray photoelectron spectroscopy(XPS)were utilized to clarify the reaction mechanisms of the hydrothermal synthesis and transformation of Ga OOH to β-Ga_(2)O_(3)by calcination.Chemical analysis of the final product of β-Ga_(2)O_(3)obtained under the optimal conditions was carried out with inductively coupled plasma mass spectrometry(ICP-MS),and the results showed that the contents of the representative impurities such as Ni,Cu,In,Mn,Co,Zn and Cr are obviously lower than the requirement of 5N β-Ga_(2)O_(3)standard,exhibiting excellent application prospect of the proposed process to produce high-purity β-Ga_(2)O_(3).展开更多
Platinum(Pt)is a critical raw material for automotive catalytic converters due to its high-temperature stability,corrosion resistance and catalytic activity,whereas its limited primary resources and uneven distributio...Platinum(Pt)is a critical raw material for automotive catalytic converters due to its high-temperature stability,corrosion resistance and catalytic activity,whereas its limited primary resources and uneven distribution make it hard to meet the growing demand of platinum.Spent automotive catalyst(SAC)is currently the most important secondary resource of platinum,of which the platinum content is much higher than that of the primary platinum resources.The recovery process of platinum from spent automobile catalyst mainly consists of pretreatment followed by enrichment and refining,involving pyro-and hydrometallurgical techniques,among which enrichment and refining processes are extremely important for platinum recovery from spent automobile catalyst.This paper provides an overview of the technologies for platinum recovery from spent automotive catalyst.The emphasis is placed on the processes of enrichment and refining based on hydrometallurgical techniques.Future directions of research and development of platinum recovery from spent automobile catalyst are also proposed.展开更多
Lithium is critical for economic growth since it is the primary component of batteries.Na^(+)is one of the main impurity ions in solution during the separation and enrichment of Li^(+).According to the size-matching e...Lithium is critical for economic growth since it is the primary component of batteries.Na^(+)is one of the main impurity ions in solution during the separation and enrichment of Li^(+).According to the size-matching effect between the cavities of crown ethers and Li+,crown ethers can selectively adsorb Li^(+).Herein,1,8-dihydroxyl-4,4,5,5-tetramethylbenzo-14-crown-4 was synthesized and used to extract lithium from a Li^(+)/Na^(+)mixed solution.Density functional theory(DFT)was used to explore the properties of complexes with M062X.The results show that the interactions between crown ethers and metal ions are due to electrostatic attraction.Hydroxyl functional groups can synergistically extract Li^(+)/Na^(+)from solutions with the oxygen atom in the crown ether ring.The stability of the complex is also enhanced by van der Waals interactions between the butyrate acid root and crown ether.1,8-dihydroxyl-4,4,5,5-tetramethylbenzo-14-crown-4 has a stronger interaction with lithium butyrate than with sodium butyrate for most conformations.The adsorption selectivity for Li+is proportional to the number of ether oxygen atoms that interact with Li^(+).The Li^(+)extraction efficiency increases from 3.93%to 20.93%in lithium hydroxide solution with the presence of butyrate acid root.When the butyrate acid root is added to the mixed Li^(+)/Na^(+)solution,the Li^(+)extraction efficiency increases from 6.54%to 31.20%,while the Li^(+)/Na^(+)separation coefficient decreases from33.25 to 1.32.展开更多
The research and application of responsive materials have long been hampered by their complicated designs and tedious construction processes.Besides,many current responsive materials show retard or weak responsiveness...The research and application of responsive materials have long been hampered by their complicated designs and tedious construction processes.Besides,many current responsive materials show retard or weak responsiveness.In this study,responsive hybrid poly(vinyl alcohol)hydrogel membranes with embedded poly(N-isopropylacrylamide-acrylic acid)microgels as valves were constructed by simple mixing and subsequent freezing-thawing process.In the structure of the membranes,the matrix poly(vinyl alcohol)chains thread through and entangle with the microgels,and the microgels are firmly constrained within the hybrid hydrogel network.The fast and sharp temperature responsiveness of the embedded microgels was largely retained and endowed the hydrogel membrane with excellent temperature and pH responsiveness.Moreover,the hydrogel membrane showed excellent fatigue resistance in both temperature and pH-responsive flux examination.This study presented the great potential of these hybrid hydrogel membranes in biomedical applications and provided a new strategy for the future design and construction of responsive biomaterials.展开更多
基金the financial supports from the National Natural Science Foundation of China(Nos.51704011,51904003)the Joint Funds of the National Natural Science Foundation of China(No.U1703130)。
基金supported by the Major Special Science and Technology Project of“Ningbo Science and Technology Innovation 2025”(Grant No.2019B10076)Natural Science Foundation of Zhejiang Province(No.LY23E080001).
文摘To scrutinize the characteristics of wave-current loads on a bridge shuttle-shaped cap–pile foundation,a 1:125 test model was considered in a laboratory flume.The inline,transverse and vertical wave–current forces acting on the shuttle-shaped cap-pile group model were measured considering both random waves and a combination of random waves with a current.The experimental results have shown that the wave-current forces can be well correlated with the wave height,the wavelength,the current velocity,the incident direction and the water level in the marine environment.An increase in the current velocity can lead to a sharp increase in the inline and transverse wave-current forces,while the vertical wave-current force decreases.Moreover,the wave-current forces are particularly strong when a combination of high tide,strong wave and strong current is considered.
基金supported by the Major Special Science and Technology Project(2019B10076)of“Ningbo Science and Technology Innovation 2025”.
文摘In recent years,Remotely Operated Vehicles(ROVs)have played an increasingly important role in the construc-tion and monitoring of underwater pile foundations.However,due to the open frame structure of such vehicles,a gap of knowledge still exists with regard to their hydrodynamic behavior.In this study,the hydrodynamic stability of such vehicles is investigated numerically by means of a multiple reference frame method.The hydrodynamic characteristics of the ROV when it moves horizontally and upward in the vertical plane are examined.It is found that there is interference between the horizontal and vertical thrusters of the ROV.There is also interference between the propeller thrust and drag(or lift).The effect of the vertical thrusters can increase the horizontal thrust by about 5%.The horizontal thrusters create a low-pressure area below the body,which can make vertical drag experienced by the ROV significantly higher.
基金Project(gxyq2018012)supported by the Developing Program Foundation for the Excellent Youth Talents of Higher Education of Anhui Province,ChinaProject(SKF19-05)supported by Foundation of Anhui Province Key Laboratory of Metallurgical Engineering&Resources Recycling,ChinaProjects(51904003,U1703130)supported by the National Natural Science Foundation of China。
文摘A novel molten salt extraction process consisting of chlorination roasting and molten salt electrolysis was proposed to develop a more efficient and environmental friendly technology for recovering lead from spent lead acid batteries(LABs).The feasibility of this process was firstly assessed based on thermodynamics fundamentals.The electrochemical behavior of Pb(II)on a tungsten electrode in the eutectic NaCl−KCl melts at 700℃ was then investigated in detail by transient electrochemical techniques.The results indicated that the reduction reaction of Pb(II)in NaCl−KCl melts was a one-step process exchanging two electrons,and it was determined to be a quasi-reversible diffusion-controlled process.Finally,potentiostatic electrolysis was carried out at−0.6 V(vs Ag/AgCl)in the NaCl−KCl−PbCl2 melts,and the obtained cathodic product was identified as pure Pb by X-ray diffraction analysis.This investigation demonstrated that it is practically feasible to produce pure Pb metal by electrochemical reduction of PbCl2 in eutectic NaCl−KCl melts,and has provided important fundamental for the further study on lead recovery from spent LABs via molten salt extraction process.
基金the National Natural Science Foundation of China(Grant No.51904146)the Doctor Start-up Fund of Liaoning Province(Grant No.2019-BS-125)the National Key Laboratory of Marine Engineering of China(Grant No.SKLMEA-USTL-201707)。
文摘This study aims to investigate the primary carbides precipitation in H13 steel solidified at relatively high cooling rates,ranging from 300 to 6,000℃·min^-1,based on in situ observations with a high temperature confocal laser scanning microscope.In the cooling rate range investigated,the solidification microstructure becomes more refined as cooling rate increases and the relationship between the secondary dendrite arm spacing(SDAS),λ2,and cooling rate,.T,can be expressed asλ2=128.45.T-0.124.Regardless of cooling rates,two kinds of primary carbides,i.e.,the Mo-Cr-rich and V-rich carbides,are precipitated along the interdendritic region and most of them are the Mo-Cr-rich carbides.The morphology of Mo-Cr-rich carbide is not obviously influenced by the cooling rate,but that of V-rich carbide is obviously affected.The increasing cooling rate markedly refines the primary carbides and reduces their volume fractions,but their precipitations cannot be inhibited even when the cooling rate is increased to 6,000℃·min^-1.Besides,the segregation ratios(SRs)of the carbides forming elements are not obviously affected by the cooling rate.However,compared with the conventionally cast ingot,the SDAS and primary carbides in the steel solidified at the investigated cooling rates are much finer,morphologies of the carbides have changed significantly,and SRs of the carbides forming elements are markedly greater.The variation of primary carbide characteristics with cooling rate is mainly due to the change in SDAS.
基金supported by the National Natural Science Foundation of China(No.51604005,No.U1703130,and No.51574003)
文摘It is a challenge to recover lithium from the leaching solution of spent lithium-ion batteries,and crown ethers are potential extractants due to their selectivity to alkali metal ions.The theoretical calculations for the selectivity of crown ethers with different structures to Li ions in aqueous solutions were carried out based on the density functional theory.The calculated results of geometries,binding energies,and thermodynamic parameters show that 15C5 has the strongest selectivity to Li ions in the three crown ethers of 12C4,15C5,and 18C6.B15C5 has a smaller binding energy but more negative free energy than 15C5 when combined with Li^+,leading to that the lithium ions in aqueous solutions will combine with B15C5 rather than 15C5.The exchange reactions between B15C5 and hydrated Li^+,Co^2+,and Ni^2+were analyzed and the results show that B15C5 is more likely to capture Li^+from the hydrated ions in an aqueous solution containing Li^+,Co^2+,and Ni^2+.This study indicates that it is feasible to extract Li ions selectively using B15C5 as an extractant from the leaching solution of spent lithium-ion batteries.
基金the National Natural Science Foundation of China(Nos.51904003,U1703130,51704011)the China Postdoctoral Science Foundation(No.2019M651466)the Foundation of Anhui Province Key Laboratory of Metallurgical Engineering&Resources Recycling of China(Nos.SKF18-01,SKF19-05).
文摘An electrochemical study on the redox behavior of indium in the eutectic LiCl-KCl system at 450 ℃ was carried out with the transient techniques of cyclic voltammetry and chronopotentiometry on an inert molybdenum electrode. The reduction of In(Ⅲ) was found to be a two-step process involving In(Ⅲ)/In(Ⅰ) and In(Ⅰ)/In couples at the potentials of about-0.4 and-0.8 V versus Ag/AgCl, respectively. The redox mechanism was further confirmed by the theoretical evaluation of the number of transferred electrons based on cyclic voltammetry and characterizations of the precipitates generated by the potentiostatic electrolysis. The diffusion coefficients of indium ions in the eutectic LiCl-KCl melt at 450 ℃ were estimated by cyclic voltammetry and chronopotentiometry. The results obtained through the two methods are in fair agreement, delivering an average diffusion coefficient of approximately 1.8×10^(-5)cm^(2)/s for In(Ⅲ), and 1.4×10^(-4)cm^(2)/s for In(Ⅰ).
基金support from diverse funding sources,including the National Key Program for S&T Research and Development of the Ministry of Science and Technology(MOST),Yifang Wang's Science Studio of the Ten Thousand Talents Project,the CAS Key Foreign Cooperation Grant,the National Natural Science Foundation of China(NSFC)Beijing Municipal Science&Technology Commission,the CAS Focused Science Grant,the IHEP Innovation Grant,the CAS Lead Special Training Programthe CAS Center for Excellence in Particle Physics,the CAS International Partnership Program,and the CAS/SAFEA International Partnership Program for Creative Research Teams.
文摘The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international partners.The complex comprises four accelerators:a 30 GeV Linac,a 1.1 GeV Damping Ring,a Booster capable of achieving energies up to 180 GeV,and a Collider operating at varying energy modes(Z,W,H,and tt).The Linac and Damping Ring are situated on the surface,while the subterranean Booster and Collider are housed in a 100 km circumference underground tunnel,strategically accommodating future expansion with provisions for a potential Super Proton Proton Collider(SPPC).The CEPC primarily serves as a Higgs factory.In its baseline design with synchrotron radiation(SR)power of 30 MW per beam,it can achieve a luminosity of 5×10^(34)cm^(-2)s^(-1)per interaction point(IP),resulting in an integrated luminosity of 13 ab^(-1)for two IPs over a decade,producing 2.6 million Higgs bosons.Increasing the SR power to 50 MW per beam expands the CEPC's capability to generate 4.3 million Higgs bosons,facilitating precise measurements of Higgs coupling at sub-percent levels,exceeding the precision expected from the HL-LHC by an order of magnitude.This Technical Design Report(TDR)follows the Preliminary Conceptual Design Report(Pre-CDR,2015)and the Conceptual Design Report(CDR,2018),comprehensively detailing the machine's layout,performance metrics,physical design and analysis,technical systems design,R&D and prototyping efforts,and associated civil engineering aspects.Additionally,it includes a cost estimate and a preliminary construction timeline,establishing a framework for forthcoming engineering design phase and site selection procedures.Construction is anticipated to begin around 2027-2028,pending government approval,with an estimated duration of 8 years.The commencement of experiments and data collection could potentially be initiated in the mid-2030s.
基金supported by the National Natural Science Foundation of China(No.51904003)the Key Research and Development Plan of Anhui Province(No.2022n07020004)+1 种基金the Natural Science Foundation of Anhui Province(Nos.2308085ME156 and 2108085J26)Anhui Provincial Department of Education(No.2022AH050332)。
文摘The present study has proposed a compact process for the production of high-purity β-Ga_(2)O_(3)powder by simply using gallium metal and water as the raw materials.The process basically consists of two essential steps including hydrothermal synthesis of Ga OOH and calcination of Ga OOH for the production of the target product of β-Ga_(2)O_(3).Thermodynamic evaluation and systematic experiments were conducted for process parameter optimization.X-ray diffractometer(XRD),scanning electron microscopy(SEM),thermogravimetryDdifferential scanning calorimetry(TG-DSC)and X-ray photoelectron spectroscopy(XPS)were utilized to clarify the reaction mechanisms of the hydrothermal synthesis and transformation of Ga OOH to β-Ga_(2)O_(3)by calcination.Chemical analysis of the final product of β-Ga_(2)O_(3)obtained under the optimal conditions was carried out with inductively coupled plasma mass spectrometry(ICP-MS),and the results showed that the contents of the representative impurities such as Ni,Cu,In,Mn,Co,Zn and Cr are obviously lower than the requirement of 5N β-Ga_(2)O_(3)standard,exhibiting excellent application prospect of the proposed process to produce high-purity β-Ga_(2)O_(3).
基金financially supported by the Natural Science Foundation of Anhui Province(No.2108085J26)the National Natural Science Foundation of China(Nos.51904003 and U1703130)+1 种基金the Key Research and Development Plan of Anhui Province(No.2022n07020004)the Open Foundation of State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization(No.CNMRCUKF2208)。
文摘Platinum(Pt)is a critical raw material for automotive catalytic converters due to its high-temperature stability,corrosion resistance and catalytic activity,whereas its limited primary resources and uneven distribution make it hard to meet the growing demand of platinum.Spent automotive catalyst(SAC)is currently the most important secondary resource of platinum,of which the platinum content is much higher than that of the primary platinum resources.The recovery process of platinum from spent automobile catalyst mainly consists of pretreatment followed by enrichment and refining,involving pyro-and hydrometallurgical techniques,among which enrichment and refining processes are extremely important for platinum recovery from spent automobile catalyst.This paper provides an overview of the technologies for platinum recovery from spent automotive catalyst.The emphasis is placed on the processes of enrichment and refining based on hydrometallurgical techniques.Future directions of research and development of platinum recovery from spent automobile catalyst are also proposed.
基金financially supported by the National Natural Science Foundation of China(Nos.51704011,U1703130 and 51904003)。
文摘Lithium is critical for economic growth since it is the primary component of batteries.Na^(+)is one of the main impurity ions in solution during the separation and enrichment of Li^(+).According to the size-matching effect between the cavities of crown ethers and Li+,crown ethers can selectively adsorb Li^(+).Herein,1,8-dihydroxyl-4,4,5,5-tetramethylbenzo-14-crown-4 was synthesized and used to extract lithium from a Li^(+)/Na^(+)mixed solution.Density functional theory(DFT)was used to explore the properties of complexes with M062X.The results show that the interactions between crown ethers and metal ions are due to electrostatic attraction.Hydroxyl functional groups can synergistically extract Li^(+)/Na^(+)from solutions with the oxygen atom in the crown ether ring.The stability of the complex is also enhanced by van der Waals interactions between the butyrate acid root and crown ether.1,8-dihydroxyl-4,4,5,5-tetramethylbenzo-14-crown-4 has a stronger interaction with lithium butyrate than with sodium butyrate for most conformations.The adsorption selectivity for Li+is proportional to the number of ether oxygen atoms that interact with Li^(+).The Li^(+)extraction efficiency increases from 3.93%to 20.93%in lithium hydroxide solution with the presence of butyrate acid root.When the butyrate acid root is added to the mixed Li^(+)/Na^(+)solution,the Li^(+)extraction efficiency increases from 6.54%to 31.20%,while the Li^(+)/Na^(+)separation coefficient decreases from33.25 to 1.32.
基金supported by the National Natural Science Foundation of China(Nos.22275137 and 82202342)Natural Science Foundation of Tianjin Municipal Science and Technology Commission(No.21JCYBJC01810).
文摘The research and application of responsive materials have long been hampered by their complicated designs and tedious construction processes.Besides,many current responsive materials show retard or weak responsiveness.In this study,responsive hybrid poly(vinyl alcohol)hydrogel membranes with embedded poly(N-isopropylacrylamide-acrylic acid)microgels as valves were constructed by simple mixing and subsequent freezing-thawing process.In the structure of the membranes,the matrix poly(vinyl alcohol)chains thread through and entangle with the microgels,and the microgels are firmly constrained within the hybrid hydrogel network.The fast and sharp temperature responsiveness of the embedded microgels was largely retained and endowed the hydrogel membrane with excellent temperature and pH responsiveness.Moreover,the hydrogel membrane showed excellent fatigue resistance in both temperature and pH-responsive flux examination.This study presented the great potential of these hybrid hydrogel membranes in biomedical applications and provided a new strategy for the future design and construction of responsive biomaterials.
