The removal of tungsten(W)and vanadium(V)from molybdate solutions was studied using the poly hydroxyl chelating resin D403in batch and column experiments.The batch experiments indicated that tungsten and vanadium coul...The removal of tungsten(W)and vanadium(V)from molybdate solutions was studied using the poly hydroxyl chelating resin D403in batch and column experiments.The batch experiments indicated that tungsten and vanadium could be preferentially adsorbed by the D403resin for4h in molybdate solution at a pH of approximately9.25.Separation factors,αVMo andαWMo,wereabove45and18,respectively,when the molar ratios of Mo/V and Mo/W in the solution exceeded40.Elution tests illustrated that vanadium and tungsten could be easily eluted from the resin with1mol/L sodium hydroxide solution in only1h.To further explore the sorption mechanism of the resin,the experimental equilibrium isotherm data of the three metals fitted well with the Freundlich model.The column experiments confirmed the adaptability of the D403resin in the production of sodium molybdate with a removal rate of tungsten surpassing90%and that of vanadium of99.4%.展开更多
Thin films of tungsten （W）-doped thermochromic vanadium dioxide （VO2） were deposited onto soda-lime glass and fused silica by radio frequency magnetron sputtering. The doped VO2 films were characterized by X-ray d...Thin films of tungsten （W）-doped thermochromic vanadium dioxide （VO2） were deposited onto soda-lime glass and fused silica by radio frequency magnetron sputtering. The doped VO2 films were characterized by X-ray diffraction, optical transmittance measurement, and near field optical microscopy with Raman spectroscopy. X-ray diffraction patterns show that the （011） peak of W-doped thermochromic VO2 film shifts to a lower diffraction angle with the increase of W concentration. The optical measurements indicated that the transmittance change （AT） at wavelength of 2500 nm drops from 65% （AT at 35 ℃ and 80 ℃ for undoped VO2 film） to 38% （AT at 30 ℃ and 42 ℃ for the doped VO2 film）. At the same time, phase transition temperature drops from 65 ℃ to room temperature or lower with the increase of W concentration. Near field optical microscopy image shows that the surface of W-doped VO2 film is smooth. Raman results show that the main Raman modes of W-doped VO2 are centered at 614 cm 1, the same as that of undoped VO2, suggesting no Raman mode changes for lightly W-doped VO2 at room temperature, due to no phase transition appearing under this condition.展开更多
A new niobate crystal Ba4Na2 VNb9O30 was synthesized in BaO-Na2O-V2O5-Nb2O5 system for the first time. Its shape, optical properties , melting point and chemical stability were studied. X - ray powder diffraction stud...A new niobate crystal Ba4Na2 VNb9O30 was synthesized in BaO-Na2O-V2O5-Nb2O5 system for the first time. Its shape, optical properties , melting point and chemical stability were studied. X - ray powder diffraction study determined that this compound assumes a tetragonal tungsten bronze structure with space group P4bm(100) and lattice parameters a = b= 12.4275(2),e=3.970(3). The new compound may be one kind of photorefractive crystals.展开更多
The ternary germanic heteropoly acids H_5GeW_(11)O_(40) centre dot 22H_2O andH_5GeMo_(11)VO_(40) centre dot 24H_2O were synthesized for the first time by the stepwiseacidification and the stepwise addition of solution...The ternary germanic heteropoly acids H_5GeW_(11)O_(40) centre dot 22H_2O andH_5GeMo_(11)VO_(40) centre dot 24H_2O were synthesized for the first time by the stepwiseacidification and the stepwise addition of solution of the component elements. The products werecharacterized by ICP, IR, UV, XRD and TG-DTA. The proton conductibility and the activation energy ofproton conduction of the heteropoly acids were investigated.展开更多
Selective separation of dissolved tungsten and vanadium is of great significance for the utilization of the secondary resources of these elements.In this work,selective removal of vanadium from tungstate solutions via...Selective separation of dissolved tungsten and vanadium is of great significance for the utilization of the secondary resources of these elements.In this work,selective removal of vanadium from tungstate solutions via microbubble floating-extraction was systematically investigated.The results indicated that vanadium can be more easily mineralized over tungsten from tungstate solutions using methyl trioctyl ammonium chloride as mineralization reagent under weak alkaline conditions.Owing to the higher bubble and interface mass transfer rates,high-efficiency enrichment and deep separation of vanadium could be achieved easily.Additionally,the deep recovery of tungsten and vanadium from the floated organic phase could be easily realized using a mixed solution of sodium hydroxide and sodium chloride as stripping agents.The separation mechanism mainly included the formation of hydrophobic complexes,their attachment on the surface of rising bubbles,and their mass transfer at the oil–water interface.Under the optimal conditions,the removal efficiency of vanadium reached 98.5%with tungsten loss below 8%after two-stage microbubble floating-extraction.Therefore,the microbubble floating-extraction could be an efficient approach for separating selectively vanadium from tungstate solutions,exhibiting outstanding advantages of high separation efficiency and low consumption of organic solvents.展开更多
基金Project(2014CB643405)supported by the National Basic Research Program of China
文摘The removal of tungsten(W)and vanadium(V)from molybdate solutions was studied using the poly hydroxyl chelating resin D403in batch and column experiments.The batch experiments indicated that tungsten and vanadium could be preferentially adsorbed by the D403resin for4h in molybdate solution at a pH of approximately9.25.Separation factors,αVMo andαWMo,wereabove45and18,respectively,when the molar ratios of Mo/V and Mo/W in the solution exceeded40.Elution tests illustrated that vanadium and tungsten could be easily eluted from the resin with1mol/L sodium hydroxide solution in only1h.To further explore the sorption mechanism of the resin,the experimental equilibrium isotherm data of the three metals fitted well with the Freundlich model.The column experiments confirmed the adaptability of the D403resin in the production of sodium molybdate with a removal rate of tungsten surpassing90%and that of vanadium of99.4%.
基金supported by the Chinese Universities Scientific Fund (Grant No. 2013QJ007)the Science Fund of China Agricultural University (Grant No. 2007037)the Major Project Foundation of Science and Technology Innovation in Advanced Education (Grant No. 21010112)
文摘Thin films of tungsten （W）-doped thermochromic vanadium dioxide （VO2） were deposited onto soda-lime glass and fused silica by radio frequency magnetron sputtering. The doped VO2 films were characterized by X-ray diffraction, optical transmittance measurement, and near field optical microscopy with Raman spectroscopy. X-ray diffraction patterns show that the （011） peak of W-doped thermochromic VO2 film shifts to a lower diffraction angle with the increase of W concentration. The optical measurements indicated that the transmittance change （AT） at wavelength of 2500 nm drops from 65% （AT at 35 ℃ and 80 ℃ for undoped VO2 film） to 38% （AT at 30 ℃ and 42 ℃ for the doped VO2 film）. At the same time, phase transition temperature drops from 65 ℃ to room temperature or lower with the increase of W concentration. Near field optical microscopy image shows that the surface of W-doped VO2 film is smooth. Raman results show that the main Raman modes of W-doped VO2 are centered at 614 cm 1, the same as that of undoped VO2, suggesting no Raman mode changes for lightly W-doped VO2 at room temperature, due to no phase transition appearing under this condition.
基金The work was supported by the Excellent Youth Foundation of Wuhan Science and Technology Commission (20005004035 ).
文摘A new niobate crystal Ba4Na2 VNb9O30 was synthesized in BaO-Na2O-V2O5-Nb2O5 system for the first time. Its shape, optical properties , melting point and chemical stability were studied. X - ray powder diffraction study determined that this compound assumes a tetragonal tungsten bronze structure with space group P4bm(100) and lattice parameters a = b= 12.4275(2),e=3.970(3). The new compound may be one kind of photorefractive crystals.
文摘The ternary germanic heteropoly acids H_5GeW_(11)O_(40) centre dot 22H_2O andH_5GeMo_(11)VO_(40) centre dot 24H_2O were synthesized for the first time by the stepwiseacidification and the stepwise addition of solution of the component elements. The products werecharacterized by ICP, IR, UV, XRD and TG-DTA. The proton conductibility and the activation energy ofproton conduction of the heteropoly acids were investigated.
基金supported by the Original Exploration Project of China(Grant No.52150079)the National Natural Science Foundation of China(Grant Nos.U2004215,51974280,51774252)the Educational Commission Fund of Henan Province of China(Grant Nos.20HASTIT012,18A450001,17A450001).
文摘Selective separation of dissolved tungsten and vanadium is of great significance for the utilization of the secondary resources of these elements.In this work,selective removal of vanadium from tungstate solutions via microbubble floating-extraction was systematically investigated.The results indicated that vanadium can be more easily mineralized over tungsten from tungstate solutions using methyl trioctyl ammonium chloride as mineralization reagent under weak alkaline conditions.Owing to the higher bubble and interface mass transfer rates,high-efficiency enrichment and deep separation of vanadium could be achieved easily.Additionally,the deep recovery of tungsten and vanadium from the floated organic phase could be easily realized using a mixed solution of sodium hydroxide and sodium chloride as stripping agents.The separation mechanism mainly included the formation of hydrophobic complexes,their attachment on the surface of rising bubbles,and their mass transfer at the oil–water interface.Under the optimal conditions,the removal efficiency of vanadium reached 98.5%with tungsten loss below 8%after two-stage microbubble floating-extraction.Therefore,the microbubble floating-extraction could be an efficient approach for separating selectively vanadium from tungstate solutions,exhibiting outstanding advantages of high separation efficiency and low consumption of organic solvents.
