The research of magnetic separation starts from magnetic solid particles to nanoparticles, and in the research progress,particles become smaller gradually with the development of application of magnetic separation tec...The research of magnetic separation starts from magnetic solid particles to nanoparticles, and in the research progress,particles become smaller gradually with the development of application of magnetic separation technology. Nevertheless,little experimental study of magnetic separation of molecules and ions under continuous flowing conditions has been reported. In this work, we designed a magnetic device and a ＂layered＂ flow channel to study the magnetic separation at the ionic level in continuous flowing solution. A segregation model was built to discuss the segregation behavior as well as the factors that may affect the separation. The magnetic force was proved to be the driving force which plays an indispensable role leading to the segregation and separation. The flow velocity has an effect on the segregation behavior of magnetic ions,which determines the separation result. On the other hand, the optimum flow velocity which makes maximum separation is related to the initial concentration of solution.展开更多
The chloridizing segregation and magnetic separation of low-grade nickel laterites from Yunnan province of China was investigated.The nickel laterites were characterized by microscopic investigations,using X-ray diffr...The chloridizing segregation and magnetic separation of low-grade nickel laterites from Yunnan province of China was investigated.The nickel laterites were characterized by microscopic investigations,using X-ray diffractometry(XRD)and energy dispersive spectrometry(EDS)techniques.The pellets,which were prepared with magnesium chloride and coke as chloride agent and reductant respectively,were heated to a high temperature,and the pellets after cooling were crushed for magnetic separation.A series of experiments were conducted to examine the effect of chlorinating agent dosage,reductant dosage,chloridizing temperature and chloridizing time on enrichment grade of Ni and Co.The results indicate that the four factors have significant effects on the extractions of Ni and Co.The optimum conditions are as follows:the amounts of magnesium chloride and coke are 6%and 2%,respectively,chloridizing temperature is 1 253 K,and chloridizing time is 90 min.Under the conditions,extractions of Ni and Co reach 91.5%and 82.3%,respectively.展开更多
Magnetic starch microspheres(AAM-MSM)were synthesized via an inverse emulsion graft copolymerization by using mechanically activated cassava starch(MS)as a crude material,acrylic acid(AA)and acrylamide(AM)as graft cop...Magnetic starch microspheres(AAM-MSM)were synthesized via an inverse emulsion graft copolymerization by using mechanically activated cassava starch(MS)as a crude material,acrylic acid(AA)and acrylamide(AM)as graft copolymer monomers,and methyl methacrylate(MMA)as the dispersing agent and used as an adsorbent for the removal of Cd(Ⅱ)ions from aqueous solution.Fourier-transform infrared spectroscopy(FT-IR),X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM),and vibrating sample magnetometry(VSM)were used to characterize the AAM-MSM adsorbent.The results indicated that AA,AM,and MMA were grafted to the MS,and the Fe_(3)O_(4) nanoparticles were encapsulated in the AAM-MSM adsorbent microspheres.The adsorbent exhibited a smooth surface,uniform size,and good sphericity because of the addition of the MMA and provided more adsorption sites for the Cd(Ⅱ)ions.The maximum adsorption capacity of Cd(Ⅱ)on the AAM-MSM was 39.98 mg·g^(-1).The adsorbents were superparamagnetic,and the saturation magnetization was 16.7 A·m^(2)·kg^(-1).Additionally,the adsorption isotherms and kinetics of the adsorption process were further investigated.The process of Cd(Ⅱ)ions adsorbed onto the AAM-MSM could be described more favorably by the pseudo-second-order kinetic and Langmuir isothermal adsorption models,which suggested that the chemical reaction process dominated the adsorption process for the Cd(Ⅱ)and chemisorption was the rate-controlling step during the Cd(Ⅱ)removal process.展开更多
The recovery of iron and enrichment of rare earths from Bayan Obo railings were investigated using Coal Ca（OH） 2 NaOH roasting followed by magnetic separation. The influences of roasting temperature, roasting time, ...The recovery of iron and enrichment of rare earths from Bayan Obo railings were investigated using Coal Ca（OH） 2 NaOH roasting followed by magnetic separation. The influences of roasting temperature, roasting time, coal content, milling time, Ca（OH）2 dosage and NaOH dosage on the iron and rare earths recovery were explored. The results showed that the magnetic concentrate containing 70.01 wt. % Fe with the iron recovery of 94.34G and the tailings of magnetic separation containing 11.46 wt. % rare earth oxides （REO） with the REO recovery of 98. 19% were obtained under the optimum conditions （i. e. , roasting temperature of 650℃, roasting time of 60 min, coal content of 2.0%, milling time of 5 min, and NaOH dosage of 2.0%）. The Ca（OH）2 dosage had no effect on the separation of iron and rare earths. According to the mineralogical and morphologic analysis, the iron and rare earths of Bayan Obo tailings could be utilized in subsequent ironmaking process and hydrometallurgy process.展开更多
A novel oxygen-enriched method is presented. Using two opposite magnetic poles of two magnets with certain distance forms a magnetic space having a field intensity gradient near its borders. When air injected into the...A novel oxygen-enriched method is presented. Using two opposite magnetic poles of two magnets with certain distance forms a magnetic space having a field intensity gradient near its borders. When air injected into the magnetic space outflows from the magnetic space via its borders, oxygen molecules in air will experience the interception effect of the gradient magnetic field, but nitrogen molecules will outflow without hindrance. Thereby the continuous oxygen enrichment is realized. The results show that the maximum increment of oxygen concentration reaches 0.49% at 298 K when the maximum product of magnetic flux density and field intensity gradient is 563T^2/m. The enrichment level is significantly influenced by the gas temperature and the magnetic field. The maximum increment of oxygen concentration drops to 0.16% when the gas temperature rises to 343 K, and drops to 0.09% when the maximum product of magnetic flux density and gradient is reduced to 101 T^2/m from 563 T^2/m.展开更多
The analysis of endogenous glycoproteins and glycopeptides in human body fluids is of great importance for screening and discovering disease biomarkers with clinical significance.However,the presence of interfering su...The analysis of endogenous glycoproteins and glycopeptides in human body fluids is of great importance for screening and discovering disease biomarkers with clinical significance.However,the presence of interfering substances makes the direct quantitative detection of low-abundance glycoproteins and glycopeptides in human body fluids one of the great challenges in analytical chemistry.Magnetic solid phase extraction(MSPE)has the advantages of easy preparation,low cost and good magnetic responsiveness.Magnetic adsorbents are the core of MSPE technology,and magnetic adsorbents based on different functional materials are widely used in the quantitative analysis of glycoproteins and glycopeptides in human body fluids,making it possible to analyze glycoproteins and glycopeptides with low abundance as well as multiple types,which provides a technical platform for screening and evaluating glycoproteins and glycopeptides in body fluids as disease biomarkers.In this paper,we focus on the recent advances in the application of MSPE technology and magnetic adsorbents for the separation and enrichment of glycoproteins and glycopeptides in human body fluids,and the future trends and application prospects in this field are also presented.展开更多
Efficient extraction and recycling methods are an important issue for rare earth elements(REE). The significant differences in their magnetic moments make magnetic separation a promising step. Although the magnetic fi...Efficient extraction and recycling methods are an important issue for rare earth elements(REE). The significant differences in their magnetic moments make magnetic separation a promising step. Although the magnetic field gradient manipulation of ions seemed to be impossible, the robust enrichment of some paramagnetic RE ions was found in the vicinity of the magnet. The studies in recent years resolved the physical paradox of why, despite the Brownian motion of the ions, there is a reproducible enrichment of RE ions in magnetic field gradients. The existence of trigger process and energy barrier was proved.However, these studies usually used only high paramagnetic ions, e.g., Dy(Ⅲ) or Ho(Ⅲ). This work verifies the theory of the possible magnetic separation for 8 different rare earth ions, respectively. For this purpose, concentration distribution in rare earth chloride solutions were measured using a MachZehnder interferometer. The magnetic field was assured by a Halbach configuration to enhance the effect. The results show the classification of RE solutions into 2 classes: Class I contains the REs with low magnetic moment, whereas Class II includes the REs of high magnetic moment. Only the latter group shows the enrichment of ions in the vicinity of the magnet which encourages the implementation of magnetic separation into existing hydrometallurgical technology to enhance the selectivity of REE.展开更多
A magnetic mesoporous expanded perlite-based(EPd-APTES@Fe3 O_(4))composite was designed and synthesized as a novel adsorbent for enrichment of rare earth ions in aqueous solution.Effect of various factors including th...A magnetic mesoporous expanded perlite-based(EPd-APTES@Fe3 O_(4))composite was designed and synthesized as a novel adsorbent for enrichment of rare earth ions in aqueous solution.Effect of various factors including the pH of solution,contact time and adsorbent dosage on the adsorption behaviors of yttrium(Ⅲ)by the EPd-APTES@Fe3 O_(4) nano-material composites from aqueous solution was investigated.The maximum adsorption capacity of the as-prepared materials for yttrium(Ⅲ)ions was 383.2 mg/g.Among the various isotherm models,the Freundlich isotherm model could well described for the adsorption of the rare ea rth ions at pH 5.5 and 298.15 K.The kinetic analysis indicated that the adsorption process followed the pseudo-second order kinetics model,and the rate-determining step might be chemical adsorption.Thermodynamic parameters declared that the adsorption process was endothermic.In addition,Fourier transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS)and the quantum chemical calculation indicated that the yttrium(Ⅲ)ions were captured on the EPd-APTES@Fe3 O_(4) surface mainly by coordination with functional group of-NH2.More importantly,the adsorption-desorption studies indicated that the EPd-APTES@Fe3 O_(4) nano-material composites had a high stability and good recyclability.展开更多
Magnetically separated and N, S co-doped mesoporous carbon microspheres （NIS-MCMs/Fe304） are fabricated by encapsulating Si02 nanoparticles within N, S-containing polymer microspheres which were prepared using resor...Magnetically separated and N, S co-doped mesoporous carbon microspheres （NIS-MCMs/Fe304） are fabricated by encapsulating Si02 nanoparticles within N, S-containing polymer microspheres which were prepared using resorcinol/formaldehyde as the carbon source and cysteine as the nitrogen and sulfur co-precursors, followed by the carbonization process, silica template removal, and the introduction of Fe3O4 into the carbon mesopores. N/S-MCMs/Fe3O4 exhibits an enhanced Hg2＋ adsorption capacity of 74.5 rag/g, and the adsorbent can be conveniently and rapidly separated from wastewater using an external magnetic field. This study opens up new opportunities to synthesize well- developed, carbon-based materials as an adsorbent for potential applications in the removal of mercury ions from wastewater.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.51276016)
文摘The research of magnetic separation starts from magnetic solid particles to nanoparticles, and in the research progress,particles become smaller gradually with the development of application of magnetic separation technology. Nevertheless,little experimental study of magnetic separation of molecules and ions under continuous flowing conditions has been reported. In this work, we designed a magnetic device and a ＂layered＂ flow channel to study the magnetic separation at the ionic level in continuous flowing solution. A segregation model was built to discuss the segregation behavior as well as the factors that may affect the separation. The magnetic force was proved to be the driving force which plays an indispensable role leading to the segregation and separation. The flow velocity has an effect on the segregation behavior of magnetic ions,which determines the separation result. On the other hand, the optimum flow velocity which makes maximum separation is related to the initial concentration of solution.
基金Project(2007CB613607)supported by National Basic Research Program of China
文摘The chloridizing segregation and magnetic separation of low-grade nickel laterites from Yunnan province of China was investigated.The nickel laterites were characterized by microscopic investigations,using X-ray diffractometry(XRD)and energy dispersive spectrometry(EDS)techniques.The pellets,which were prepared with magnesium chloride and coke as chloride agent and reductant respectively,were heated to a high temperature,and the pellets after cooling were crushed for magnetic separation.A series of experiments were conducted to examine the effect of chlorinating agent dosage,reductant dosage,chloridizing temperature and chloridizing time on enrichment grade of Ni and Co.The results indicate that the four factors have significant effects on the extractions of Ni and Co.The optimum conditions are as follows:the amounts of magnesium chloride and coke are 6%and 2%,respectively,chloridizing temperature is 1 253 K,and chloridizing time is 90 min.Under the conditions,extractions of Ni and Co reach 91.5%and 82.3%,respectively.
基金This work was supported by the National Natural Science Foundation of China(21766001,21961160741)Guangxi Natural Science Foundation of China(2018GXNSFAA281342)+1 种基金the Dean Project of Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology(2018Z009)Special funding for"Guangxi Bagui Scholars".
文摘Magnetic starch microspheres(AAM-MSM)were synthesized via an inverse emulsion graft copolymerization by using mechanically activated cassava starch(MS)as a crude material,acrylic acid(AA)and acrylamide(AM)as graft copolymer monomers,and methyl methacrylate(MMA)as the dispersing agent and used as an adsorbent for the removal of Cd(Ⅱ)ions from aqueous solution.Fourier-transform infrared spectroscopy(FT-IR),X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM),and vibrating sample magnetometry(VSM)were used to characterize the AAM-MSM adsorbent.The results indicated that AA,AM,and MMA were grafted to the MS,and the Fe_(3)O_(4) nanoparticles were encapsulated in the AAM-MSM adsorbent microspheres.The adsorbent exhibited a smooth surface,uniform size,and good sphericity because of the addition of the MMA and provided more adsorption sites for the Cd(Ⅱ)ions.The maximum adsorption capacity of Cd(Ⅱ)on the AAM-MSM was 39.98 mg·g^(-1).The adsorbents were superparamagnetic,and the saturation magnetization was 16.7 A·m^(2)·kg^(-1).Additionally,the adsorption isotherms and kinetics of the adsorption process were further investigated.The process of Cd(Ⅱ)ions adsorbed onto the AAM-MSM could be described more favorably by the pseudo-second-order kinetic and Langmuir isothermal adsorption models,which suggested that the chemical reaction process dominated the adsorption process for the Cd(Ⅱ)and chemisorption was the rate-controlling step during the Cd(Ⅱ)removal process.
基金supports by the National Key Basic Research Program of China (No.2012CBA01205)
文摘The recovery of iron and enrichment of rare earths from Bayan Obo railings were investigated using Coal Ca（OH） 2 NaOH roasting followed by magnetic separation. The influences of roasting temperature, roasting time, coal content, milling time, Ca（OH）2 dosage and NaOH dosage on the iron and rare earths recovery were explored. The results showed that the magnetic concentrate containing 70.01 wt. % Fe with the iron recovery of 94.34G and the tailings of magnetic separation containing 11.46 wt. % rare earth oxides （REO） with the REO recovery of 98. 19% were obtained under the optimum conditions （i. e. , roasting temperature of 650℃, roasting time of 60 min, coal content of 2.0%, milling time of 5 min, and NaOH dosage of 2.0%）. The Ca（OH）2 dosage had no effect on the separation of iron and rare earths. According to the mineralogical and morphologic analysis, the iron and rare earths of Bayan Obo tailings could be utilized in subsequent ironmaking process and hydrometallurgy process.
文摘A novel oxygen-enriched method is presented. Using two opposite magnetic poles of two magnets with certain distance forms a magnetic space having a field intensity gradient near its borders. When air injected into the magnetic space outflows from the magnetic space via its borders, oxygen molecules in air will experience the interception effect of the gradient magnetic field, but nitrogen molecules will outflow without hindrance. Thereby the continuous oxygen enrichment is realized. The results show that the maximum increment of oxygen concentration reaches 0.49% at 298 K when the maximum product of magnetic flux density and field intensity gradient is 563T^2/m. The enrichment level is significantly influenced by the gas temperature and the magnetic field. The maximum increment of oxygen concentration drops to 0.16% when the gas temperature rises to 343 K, and drops to 0.09% when the maximum product of magnetic flux density and gradient is reduced to 101 T^2/m from 563 T^2/m.
基金supported by the Natural Science Foundation of Jilin Provincial Science&Technology Department(No.20190201079JC)。
文摘The analysis of endogenous glycoproteins and glycopeptides in human body fluids is of great importance for screening and discovering disease biomarkers with clinical significance.However,the presence of interfering substances makes the direct quantitative detection of low-abundance glycoproteins and glycopeptides in human body fluids one of the great challenges in analytical chemistry.Magnetic solid phase extraction(MSPE)has the advantages of easy preparation,low cost and good magnetic responsiveness.Magnetic adsorbents are the core of MSPE technology,and magnetic adsorbents based on different functional materials are widely used in the quantitative analysis of glycoproteins and glycopeptides in human body fluids,making it possible to analyze glycoproteins and glycopeptides with low abundance as well as multiple types,which provides a technical platform for screening and evaluating glycoproteins and glycopeptides in body fluids as disease biomarkers.In this paper,we focus on the recent advances in the application of MSPE technology and magnetic adsorbents for the separation and enrichment of glycoproteins and glycopeptides in human body fluids,and the future trends and application prospects in this field are also presented.
基金Project supported by the German Aerospace Center(DLR)with funds provided by The Federal Ministry for Economic Affairs and Climate Action(BMWi)due to an enactment of the German Bundestag under grant number 50WM1741(project SESIMAG II)。
文摘Efficient extraction and recycling methods are an important issue for rare earth elements(REE). The significant differences in their magnetic moments make magnetic separation a promising step. Although the magnetic field gradient manipulation of ions seemed to be impossible, the robust enrichment of some paramagnetic RE ions was found in the vicinity of the magnet. The studies in recent years resolved the physical paradox of why, despite the Brownian motion of the ions, there is a reproducible enrichment of RE ions in magnetic field gradients. The existence of trigger process and energy barrier was proved.However, these studies usually used only high paramagnetic ions, e.g., Dy(Ⅲ) or Ho(Ⅲ). This work verifies the theory of the possible magnetic separation for 8 different rare earth ions, respectively. For this purpose, concentration distribution in rare earth chloride solutions were measured using a MachZehnder interferometer. The magnetic field was assured by a Halbach configuration to enhance the effect. The results show the classification of RE solutions into 2 classes: Class I contains the REs with low magnetic moment, whereas Class II includes the REs of high magnetic moment. Only the latter group shows the enrichment of ions in the vicinity of the magnet which encourages the implementation of magnetic separation into existing hydrometallurgical technology to enhance the selectivity of REE.
基金the National Natural Science Foundation of China(No.51704042)National Key Research and Development Program(No.2018YFC1903401)+3 种基金Project of jiangxi Provincial Department of Science and Technology(No.20202BABL204018)Project of Education Commission of Jiangxi Province of China(No.GJJ170488)Ganzhou Innovative Talents Plane,Natural Science Foundation ofJiangxi University of Science and Technology(No.jxxjbs17042)National College Students’Innovation and Entrepreneurship Training Program(Nos.201810407001,201810407003)。
文摘A magnetic mesoporous expanded perlite-based(EPd-APTES@Fe3 O_(4))composite was designed and synthesized as a novel adsorbent for enrichment of rare earth ions in aqueous solution.Effect of various factors including the pH of solution,contact time and adsorbent dosage on the adsorption behaviors of yttrium(Ⅲ)by the EPd-APTES@Fe3 O_(4) nano-material composites from aqueous solution was investigated.The maximum adsorption capacity of the as-prepared materials for yttrium(Ⅲ)ions was 383.2 mg/g.Among the various isotherm models,the Freundlich isotherm model could well described for the adsorption of the rare ea rth ions at pH 5.5 and 298.15 K.The kinetic analysis indicated that the adsorption process followed the pseudo-second order kinetics model,and the rate-determining step might be chemical adsorption.Thermodynamic parameters declared that the adsorption process was endothermic.In addition,Fourier transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS)and the quantum chemical calculation indicated that the yttrium(Ⅲ)ions were captured on the EPd-APTES@Fe3 O_(4) surface mainly by coordination with functional group of-NH2.More importantly,the adsorption-desorption studies indicated that the EPd-APTES@Fe3 O_(4) nano-material composites had a high stability and good recyclability.
基金financially supported by the National Natural Science Foundation of China (Nos. 21207099, 21273162, and 21473122)the Science and Technology Commission of Shanghai Municipality, China (No. 14DZ2261100)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Large Equipment Test Foundation of Tongji University
文摘Magnetically separated and N, S co-doped mesoporous carbon microspheres （NIS-MCMs/Fe304） are fabricated by encapsulating Si02 nanoparticles within N, S-containing polymer microspheres which were prepared using resorcinol/formaldehyde as the carbon source and cysteine as the nitrogen and sulfur co-precursors, followed by the carbonization process, silica template removal, and the introduction of Fe3O4 into the carbon mesopores. N/S-MCMs/Fe3O4 exhibits an enhanced Hg2＋ adsorption capacity of 74.5 rag/g, and the adsorbent can be conveniently and rapidly separated from wastewater using an external magnetic field. This study opens up new opportunities to synthesize well- developed, carbon-based materials as an adsorbent for potential applications in the removal of mercury ions from wastewater.
