In order to study the influence of cerium ion implantation on the aqueous corrosion behavior of zirconium, specimens were implanted by cerium ions with a dosage range from 1×1016 to 1×1017 ions/cm2 at about ...In order to study the influence of cerium ion implantation on the aqueous corrosion behavior of zirconium, specimens were implanted by cerium ions with a dosage range from 1×1016 to 1×1017 ions/cm2 at about 150℃, using MEVVA source at an acceler ative voltage of 40kV. The valence of the surface layer was analyzed by X-ray photo- electron spectroscopy (XPS); Three-sweep potentiodynamic polarization measurement was employed to value the aqueous corrosion resistance of zirconium in a 0.5mol/L H2SO4 solution. It was found that a remarkable decline in the aqueous corrosion behavior of zirconium implanted with cerium ions compared with that of the as-received zirconium. Finally, the mechanism of the corrosion resistance decline of the cerium-implanted zirconium is discussed.展开更多
The effects of cerium ion(Ce3+) on the proliferation,differentiation,adipocytic transdifferentiation and mineralization function of primary mouse osteoblasts(OBs) were investigated.The results indicated that Ce3+ at a...The effects of cerium ion(Ce3+) on the proliferation,differentiation,adipocytic transdifferentiation and mineralization function of primary mouse osteoblasts(OBs) were investigated.The results indicated that Ce3+ at all concentrations(1×10-9,1×10-8,1×10-7,1×10-6,1×10-5,and 1×10-4 mol/L) promoted the proliferation of osteoblasts(OBs).On day 1 and 3,Ce3+ promoted the differentiation of OBs at concentrations of 1×10-9,1×10-7,and 1×10-6 mol/L,but inhibited the differentiation of OBs at higher concentrations.On ...展开更多
The mechanism of cerium ions scavenging superoxide radical(O÷2) has been studied. The results show that (1) Ce^3+ can reduce O÷2 to H_2O_2 while it is oxidized to Ce^4+; (2) Ce^4+ can oxidize O÷2 to O_2...The mechanism of cerium ions scavenging superoxide radical(O÷2) has been studied. The results show that (1) Ce^3+ can reduce O÷2 to H_2O_2 while it is oxidized to Ce^4+; (2) Ce^4+ can oxidize O÷2 to O_2 while it is reduced to Ce^3+.展开更多
For wound healing,wound infection caused by bacteria is one of the important reasons that delay wound healing process.Therefore,it is very meaningful to develop a multifunctional wound dressing with antibacterial capa...For wound healing,wound infection caused by bacteria is one of the important reasons that delay wound healing process.Therefore,it is very meaningful to develop a multifunctional wound dressing with antibacterial capability to accelerate wound healing.Sodium alginate(SA)and carboxymethyl chitosan(CMCS)are the most commonly used compositions in wound dressing,but their poor stability inhibits the further applications.Introducing CMCS and using cerium ions(Ce^(3+))to crosslink CMCS and SA to form SA-CMCS hybrid spheres by electrostatic spray method,can not only improve the stability of SA hydrogels,but also endow the spheres with excelle nt antibacterial properties due to the characteristics of Ce^(3+).The gradual release of Ce^(3+)from the SA-CMCS spheres can effectively inhibit the growth of Staphylococcus aureus(S.aureus)and Escherichia coli(E.coli).Combining the wound healing promotion ability of SA and CMCS,this kind of wound dressing can not only avoid wound infection caused by bacteria effectively,but also accelerate wound healing,thus it is an easily prepared material with potential applications in skin defect repair.展开更多
An alkaline precipitation method was introduced to produce hydrous cerium oxides.The prepared powder was characterized by Brunauer-Emmett-Teller(BET) nitrogen adsorption-desorption,X-ray diffraction(XRD),Fourier t...An alkaline precipitation method was introduced to produce hydrous cerium oxides.The prepared powder was characterized by Brunauer-Emmett-Teller(BET) nitrogen adsorption-desorption,X-ray diffraction(XRD),Fourier transform infrared(FTIR) spectrometry,and thermal gravimetry(TG) approaches.The adsorbent has a chemical formula of CeO2·nH2O(n 2) and a cubic fluorite-type structure after high temperature treatment.Adsorption capacity of different temperature treated hydrous cerium oxides does not directly correlate with BET specific surface area.Phosphate adsorption isotherms follow the Langmuir equation below the treatment temperature of 800°C.Phosphate adsorption causes no change on the structure of a hydrous cerium oxides,and no signs of CePO4 precipitates are found.The ion-exchanging structure of hydrous cerium oxide plays a fundamental role in phosphate adsorption.The structure is highly temperature resistant and forms adsorption sites which adsorb both water and some anions.Complete loss of adsorption ability cannot be achieved unless the treatment temperature is higher than 1200°C.Mechanism study shows that the adsorption of phosphates is mainly an anion-exchange process.展开更多
In this study, the kinetics and mechanism of the iridium( Ⅲ ) -catalyzed oxidation of ethanol amine(EAN) by cerium(Ⅳ) in a sulfuric acid medium was investigated using titrimetric technique of redox in a temper...In this study, the kinetics and mechanism of the iridium( Ⅲ ) -catalyzed oxidation of ethanol amine(EAN) by cerium(Ⅳ) in a sulfuric acid medium was investigated using titrimetric technique of redox in a temperature range of 298--313 K. It was found that the reaction is of first order with respect to Ce( Ⅳ ) and It( Ⅲ ), and a positive fractional order with respect to EAN. It was also found that the pseudo-first-order ( [EAN ] 〉〉 [ Ce ( Ⅳ) ] ) rate constant koba decreases with the increase of [ H^+ ] and [ HSO^-4 ]. Under the protection of nitrogen gas, the reaction system can initiate the polymerization of acrylonitrile, indicating the generation of free radicals. On the basis of the experimental results, a suitable mechanism was proposed. From the dependence of koba on the concentration of hydrogen sulfate, Ce(SO4)2 was found to be the kinetically active species. The rate constants of the rote-determining step together with the activation parameters were evaluated.展开更多
As bearing parts, 12 Cr2 Ni4 A is expected to have high hardness and excellent fatigue strength, so carburizing is employed to improve the inherit properties of 12 Cr2 Ni4 A. However, the traditional carburizing is li...As bearing parts, 12 Cr2 Ni4 A is expected to have high hardness and excellent fatigue strength, so carburizing is employed to improve the inherit properties of 12 Cr2 Ni4 A. However, the traditional carburizing is limited by poor microstructure distribution and low rate of carburizing. The rare earth ion implantation is known to help improving the properties of tribology, corrosion resistance and oxidation resistance of metal. In this article, the RE implantation is employed to assist the carburizing. Lanthanum and cerium ion implantations are initially used to assist 12 Cr2 Ni4 A low pressure vacuum carburization.The microstructure, content of retained austenite, hardness, thickness of layer and carbon diffusion were analyzed by optical microscopy(OM), scanning electron microscopy(SEM), X-ray diffraction(XRD) and Rockwell/Vickers hardness tester, respectively. It was shown that lanthanum and cerium implantations can improve structure of the vacuum carburizing layer, and enhance the uniformity of carbon element distribution on the carburized surface. Meanwhile the RE implantation plays a positive role in promoting the surface hardness and carburized rate. The lanthanum element has more significant effect on surface hardness and content of retained austenite than cerium element. The surface hardness of lanthanum element implanted layer was 62.9 HRC with 9.6% content of retained austenite, while the carburizing rate of cerium implanted layer increased by 12.4%.展开更多
In hydrated NaY、NaX and NaA zeolites,the covalent nature of Ce-O bond is weakened progressively,and this causes the centroid of 5 d band raising.Further,the emission peak of Ce3+ ion shifts to a shorter wavelength.Th...In hydrated NaY、NaX and NaA zeolites,the covalent nature of Ce-O bond is weakened progressively,and this causes the centroid of 5 d band raising.Further,the emission peak of Ce3+ ion shifts to a shorter wavelength.There are two Ce3+ emission centers in calcined NaX and NaA zeolites.The strength of the crystal field at the two kinds of Ce3+ centers are much different,so the positions of their transition emission peaks vary quite considerably.There is only one kind of Ce3+ center in calcined NaY zeolite.展开更多
TiO2/V2O5 catalyst doped with rare earth ions was prepared by sol-gel method. Titanium tetrapropoxide and vanadium pentoxide were used as precursor of the composite catalyst and rare earth ions were used as dopant. Th...TiO2/V2O5 catalyst doped with rare earth ions was prepared by sol-gel method. Titanium tetrapropoxide and vanadium pentoxide were used as precursor of the composite catalyst and rare earth ions were used as dopant. The crystal phases, crystalline sizes, microstructure, absorption spectra of doped composite catalyst were studied by XRD, EDS, FT-IR and UV-Vis. Photoactivity of the prepared catalyst under ultraviolet irradiation were evaluated by degradation of methyl orange (MO) in aqueous solution. It is shown that the prepared catalyst is composed of anatase and futile. The rare earth ions are highly dispersed in composite catalyst. All the doped catalysts appear higher photocatalytic activity than TiO2/V2O5 catalyst and catalyst doped with Ce^4+ present the best activity to MO.展开更多
Ce (Ⅳ) nitrato complexes were adsorbed on two anion exchangers based on polyvinyl pyridine (PVP) and quatemized PVP incorporated into porous silica matrix. The effect of nitric acid concentration (0.5~6 mol...Ce (Ⅳ) nitrato complexes were adsorbed on two anion exchangers based on polyvinyl pyridine (PVP) and quatemized PVP incorporated into porous silica matrix. The effect of nitric acid concentration (0.5~6 mol·L^-1) and temperature (278 ~318 K) on Ce( Ⅳ ) sorption efficiency was investigated. Sorption increased with increasing nitric acid concentration, indicating that [Ce(NO3)6]^2- complex is the main adsorbed Ce(Ⅳ) species. Oxidation of sorbents by adsorbed Ce ( Ⅳ ) species resulting in Ce ( Ⅲ ) release to the solution was observed. Pyridine based anion exchangers exhibited higher oxidation stability compared to the commercial strong base anion exchanger. Ce( Ⅳ ) reduction was temperature dependent and obeyed pseudo-first-order reaction kinetics. Column separation of Ce ( Ⅳ ) from La ( Ⅲ ) and Y ( Ⅲ ) was carried out from 6 mol·L^-1 nitric acid with PVP based anion exchanger. Reasonable Ce (Ⅳ) breakthrough capacity (0.7 mol·kg^-1 PVP) was achieved. No remarkable decrease of capacity was observed within 3 consequent runs. In contrast, Ce (Ⅲ) leakage due to reduction decreased and breakthrough capacity slightly increased. This effect was more pronounced with increasing temperature. Regeneration with 0.1 mol·L^- 1 nitric acid was successful (recovery 100% ± 4% ) and Ce solution of high purity ( 〉 99.97% ) with respect to La and Y content was gained.展开更多
Polycrystalline Ce_(0.95)Ca_(0.05)F_(2.95) was prepared by a conventional solid-state reaction. The heat stability and ion conductivity of Ce_(0.95)Ca_(0.05)F_(2.95) were investigated by a high temperature calorimeter...Polycrystalline Ce_(0.95)Ca_(0.05)F_(2.95) was prepared by a conventional solid-state reaction. The heat stability and ion conductivity of Ce_(0.95)Ca_(0.05)F_(2.95) were investigated by a high temperature calorimeter and an ac impedance technique. Experimental results indicate that Ce_(0.95)Ca_(0.05)F_(2.95) is stable at temperatures below 1000 K and represents the ionic conductivity of 1×10^(-3) to 10^(-1) Ω^(-1)·cm^(-1) in temperature range of 660 to 1180 K.展开更多
The CeO 2 TiO 2/SiO 2 surface composites were prepared by sol gel method using SiO 2 as substrate and CeO 2 TiO 2 as coating film. The removal capabilities of the composities for fluoride ion and the influenc...The CeO 2 TiO 2/SiO 2 surface composites were prepared by sol gel method using SiO 2 as substrate and CeO 2 TiO 2 as coating film. The removal capabilities of the composities for fluoride ion and the influences of environment conditions of the preparation on the coating quality and removal capacities of F - were studied by experiments. SEM was used to study the surface morphologies of the films obtained. It is proved that n Ti(OC 4H 9) 4 / n CeCl 3·7H 2O =1, n CH 3COOH / n Ti(OC 4H 9) 4 =4 5, n C 3H 8O 3 / n Ti(OC 4H 9) 4 =0 3, R H=95% and t 110 ℃ are the acceptable conditions to get the surface composite whose adsorbent capacity( q ) and removal ratio( E ) for F - are 21 4 mg/g and 85 6% respectively.展开更多
Influence of doping and oxygen vacancy concentrations on oxygen ion or oxygen vacancy(V)migration energies of SmxCe1-xO2-δ(x=0.0625,0.125,0.25 andδ=0.0625,0.125)systems using a GGA+U method are studied.Calculated re...Influence of doping and oxygen vacancy concentrations on oxygen ion or oxygen vacancy(V)migration energies of SmxCe1-xO2-δ(x=0.0625,0.125,0.25 andδ=0.0625,0.125)systems using a GGA+U method are studied.Calculated results show that advantage migration types change from V→O2-to O2-→as x andδincrease.For V→O2-migrations of the Sm0.0625Ce0.9375O1.9375 and Sm0.125Ce0.875O1.9375 systems,electrostatic attractions between Sm"and V,defect associations between Ce3 and V,and steric hindrances of Sm3+affect the migration energies.For O2→V migrations of the Sm0.125Ce0.875O1.875 and Sm0.25Ce0.75O1.875 systems,migration energies of O2-are affected by electrostatic repulsions between Sm3+and O2-and defect associations between Ce3+and V.Increases of the oxygen vacancy and Sm3+doping concentrations benefit the oxygen ion and vacancy migrations,respectively.展开更多
基金the Ministry of Science and Technology of China forresearch funding(MSTC No.G 2000067207-1)Analysis Center of Tsinghua University for partial financial support.
文摘In order to study the influence of cerium ion implantation on the aqueous corrosion behavior of zirconium, specimens were implanted by cerium ions with a dosage range from 1×1016 to 1×1017 ions/cm2 at about 150℃, using MEVVA source at an acceler ative voltage of 40kV. The valence of the surface layer was analyzed by X-ray photo- electron spectroscopy (XPS); Three-sweep potentiodynamic polarization measurement was employed to value the aqueous corrosion resistance of zirconium in a 0.5mol/L H2SO4 solution. It was found that a remarkable decline in the aqueous corrosion behavior of zirconium implanted with cerium ions compared with that of the as-received zirconium. Finally, the mechanism of the corrosion resistance decline of the cerium-implanted zirconium is discussed.
基金supported by the Natural Science Foundation of China (20971034)Foundation for Key Program of Ministry of Education of China (208018)+2 种基金Returned Scholars of Hebei Province (207041)Natural Science Foundation of Hebei Province (B2009000161)Natural Science Foundation of Hebei University
文摘The effects of cerium ion(Ce3+) on the proliferation,differentiation,adipocytic transdifferentiation and mineralization function of primary mouse osteoblasts(OBs) were investigated.The results indicated that Ce3+ at all concentrations(1×10-9,1×10-8,1×10-7,1×10-6,1×10-5,and 1×10-4 mol/L) promoted the proliferation of osteoblasts(OBs).On day 1 and 3,Ce3+ promoted the differentiation of OBs at concentrations of 1×10-9,1×10-7,and 1×10-6 mol/L,but inhibited the differentiation of OBs at higher concentrations.On ...
文摘The mechanism of cerium ions scavenging superoxide radical(O÷2) has been studied. The results show that (1) Ce^3+ can reduce O÷2 to H_2O_2 while it is oxidized to Ce^4+; (2) Ce^4+ can oxidize O÷2 to O_2 while it is reduced to Ce^3+.
基金Project supported by the National Natural Science Foundation of China(52003124,21971117)China Postdoctoral Science Foundation(2020M680862)+10 种基金the Fundamental Research Funds for the Central UniversitiesNankai University(63211029,63186005,63211042)Tianjin Key Lab for Rare Earth Materials and Applications(ZB 19500202)the Open Funds(RERU2019001)of the State Key Laboratory of Rare Earth Resource Utilizationthe National Key R&D Program of China(2017YFA0208000)the 111 Project(B18030)from ChinaBeijing-Tianjin-Hebei Collaborative Innovation Project(19YFSLQY00030)the Outstanding Youth Project of Tianjin Natural Science Foundation(20JCJQJC00130)the Key Project of Tianjin Natural Science Foundation(20JCZDJC00650)the Basic Scientific Research Business Expenses of the Central UniversityOpen Project of Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education,Lanzhou University(LZUMMM2021009)。
文摘For wound healing,wound infection caused by bacteria is one of the important reasons that delay wound healing process.Therefore,it is very meaningful to develop a multifunctional wound dressing with antibacterial capability to accelerate wound healing.Sodium alginate(SA)and carboxymethyl chitosan(CMCS)are the most commonly used compositions in wound dressing,but their poor stability inhibits the further applications.Introducing CMCS and using cerium ions(Ce^(3+))to crosslink CMCS and SA to form SA-CMCS hybrid spheres by electrostatic spray method,can not only improve the stability of SA hydrogels,but also endow the spheres with excelle nt antibacterial properties due to the characteristics of Ce^(3+).The gradual release of Ce^(3+)from the SA-CMCS spheres can effectively inhibit the growth of Staphylococcus aureus(S.aureus)and Escherichia coli(E.coli).Combining the wound healing promotion ability of SA and CMCS,this kind of wound dressing can not only avoid wound infection caused by bacteria effectively,but also accelerate wound healing,thus it is an easily prepared material with potential applications in skin defect repair.
基金support from the National Natural Science Foundation of China (No.20876157)
文摘An alkaline precipitation method was introduced to produce hydrous cerium oxides.The prepared powder was characterized by Brunauer-Emmett-Teller(BET) nitrogen adsorption-desorption,X-ray diffraction(XRD),Fourier transform infrared(FTIR) spectrometry,and thermal gravimetry(TG) approaches.The adsorbent has a chemical formula of CeO2·nH2O(n 2) and a cubic fluorite-type structure after high temperature treatment.Adsorption capacity of different temperature treated hydrous cerium oxides does not directly correlate with BET specific surface area.Phosphate adsorption isotherms follow the Langmuir equation below the treatment temperature of 800°C.Phosphate adsorption causes no change on the structure of a hydrous cerium oxides,and no signs of CePO4 precipitates are found.The ion-exchanging structure of hydrous cerium oxide plays a fundamental role in phosphate adsorption.The structure is highly temperature resistant and forms adsorption sites which adsorb both water and some anions.Complete loss of adsorption ability cannot be achieved unless the treatment temperature is higher than 1200°C.Mechanism study shows that the adsorption of phosphates is mainly an anion-exchange process.
基金Supported by the Doctoral Foundation of Education Department of Hebei Province(NoB2004205) Hebei University Re-search Foundation(No2003Z09)
文摘In this study, the kinetics and mechanism of the iridium( Ⅲ ) -catalyzed oxidation of ethanol amine(EAN) by cerium(Ⅳ) in a sulfuric acid medium was investigated using titrimetric technique of redox in a temperature range of 298--313 K. It was found that the reaction is of first order with respect to Ce( Ⅳ ) and It( Ⅲ ), and a positive fractional order with respect to EAN. It was also found that the pseudo-first-order ( [EAN ] 〉〉 [ Ce ( Ⅳ) ] ) rate constant koba decreases with the increase of [ H^+ ] and [ HSO^-4 ]. Under the protection of nitrogen gas, the reaction system can initiate the polymerization of acrylonitrile, indicating the generation of free radicals. On the basis of the experimental results, a suitable mechanism was proposed. From the dependence of koba on the concentration of hydrogen sulfate, Ce(SO4)2 was found to be the kinetically active species. The rate constants of the rote-determining step together with the activation parameters were evaluated.
基金The National Natural Science Foundation of China(51575118,51375106)National Basic Research Program of China(973 Program)(No.61328303)+1 种基金China Postdoctoral Science Foundation(2017T100225)Fundamental Research Funds for the Central Universities(No.HEUCFP201608)
文摘As bearing parts, 12 Cr2 Ni4 A is expected to have high hardness and excellent fatigue strength, so carburizing is employed to improve the inherit properties of 12 Cr2 Ni4 A. However, the traditional carburizing is limited by poor microstructure distribution and low rate of carburizing. The rare earth ion implantation is known to help improving the properties of tribology, corrosion resistance and oxidation resistance of metal. In this article, the RE implantation is employed to assist the carburizing. Lanthanum and cerium ion implantations are initially used to assist 12 Cr2 Ni4 A low pressure vacuum carburization.The microstructure, content of retained austenite, hardness, thickness of layer and carbon diffusion were analyzed by optical microscopy(OM), scanning electron microscopy(SEM), X-ray diffraction(XRD) and Rockwell/Vickers hardness tester, respectively. It was shown that lanthanum and cerium implantations can improve structure of the vacuum carburizing layer, and enhance the uniformity of carbon element distribution on the carburized surface. Meanwhile the RE implantation plays a positive role in promoting the surface hardness and carburized rate. The lanthanum element has more significant effect on surface hardness and content of retained austenite than cerium element. The surface hardness of lanthanum element implanted layer was 62.9 HRC with 9.6% content of retained austenite, while the carburizing rate of cerium implanted layer increased by 12.4%.
文摘In hydrated NaY、NaX and NaA zeolites,the covalent nature of Ce-O bond is weakened progressively,and this causes the centroid of 5 d band raising.Further,the emission peak of Ce3+ ion shifts to a shorter wavelength.There are two Ce3+ emission centers in calcined NaX and NaA zeolites.The strength of the crystal field at the two kinds of Ce3+ centers are much different,so the positions of their transition emission peaks vary quite considerably.There is only one kind of Ce3+ center in calcined NaY zeolite.
基金Project supported by the National Natural Science Foundation of China (50571003)
文摘TiO2/V2O5 catalyst doped with rare earth ions was prepared by sol-gel method. Titanium tetrapropoxide and vanadium pentoxide were used as precursor of the composite catalyst and rare earth ions were used as dopant. The crystal phases, crystalline sizes, microstructure, absorption spectra of doped composite catalyst were studied by XRD, EDS, FT-IR and UV-Vis. Photoactivity of the prepared catalyst under ultraviolet irradiation were evaluated by degradation of methyl orange (MO) in aqueous solution. It is shown that the prepared catalyst is composed of anatase and futile. The rare earth ions are highly dispersed in composite catalyst. All the doped catalysts appear higher photocatalytic activity than TiO2/V2O5 catalyst and catalyst doped with Ce^4+ present the best activity to MO.
基金Project supported bythe Japan Societyfor the Promotion of Science (JSPS)
文摘Ce (Ⅳ) nitrato complexes were adsorbed on two anion exchangers based on polyvinyl pyridine (PVP) and quatemized PVP incorporated into porous silica matrix. The effect of nitric acid concentration (0.5~6 mol·L^-1) and temperature (278 ~318 K) on Ce( Ⅳ ) sorption efficiency was investigated. Sorption increased with increasing nitric acid concentration, indicating that [Ce(NO3)6]^2- complex is the main adsorbed Ce(Ⅳ) species. Oxidation of sorbents by adsorbed Ce ( Ⅳ ) species resulting in Ce ( Ⅲ ) release to the solution was observed. Pyridine based anion exchangers exhibited higher oxidation stability compared to the commercial strong base anion exchanger. Ce( Ⅳ ) reduction was temperature dependent and obeyed pseudo-first-order reaction kinetics. Column separation of Ce ( Ⅳ ) from La ( Ⅲ ) and Y ( Ⅲ ) was carried out from 6 mol·L^-1 nitric acid with PVP based anion exchanger. Reasonable Ce (Ⅳ) breakthrough capacity (0.7 mol·kg^-1 PVP) was achieved. No remarkable decrease of capacity was observed within 3 consequent runs. In contrast, Ce (Ⅲ) leakage due to reduction decreased and breakthrough capacity slightly increased. This effect was more pronounced with increasing temperature. Regeneration with 0.1 mol·L^- 1 nitric acid was successful (recovery 100% ± 4% ) and Ce solution of high purity ( 〉 99.97% ) with respect to La and Y content was gained.
文摘Polycrystalline Ce_(0.95)Ca_(0.05)F_(2.95) was prepared by a conventional solid-state reaction. The heat stability and ion conductivity of Ce_(0.95)Ca_(0.05)F_(2.95) were investigated by a high temperature calorimeter and an ac impedance technique. Experimental results indicate that Ce_(0.95)Ca_(0.05)F_(2.95) is stable at temperatures below 1000 K and represents the ionic conductivity of 1×10^(-3) to 10^(-1) Ω^(-1)·cm^(-1) in temperature range of 660 to 1180 K.
文摘The CeO 2 TiO 2/SiO 2 surface composites were prepared by sol gel method using SiO 2 as substrate and CeO 2 TiO 2 as coating film. The removal capabilities of the composities for fluoride ion and the influences of environment conditions of the preparation on the coating quality and removal capacities of F - were studied by experiments. SEM was used to study the surface morphologies of the films obtained. It is proved that n Ti(OC 4H 9) 4 / n CeCl 3·7H 2O =1, n CH 3COOH / n Ti(OC 4H 9) 4 =4 5, n C 3H 8O 3 / n Ti(OC 4H 9) 4 =0 3, R H=95% and t 110 ℃ are the acceptable conditions to get the surface composite whose adsorbent capacity( q ) and removal ratio( E ) for F - are 21 4 mg/g and 85 6% respectively.
基金Supported by the National Natural Science Foundation of China(No.51474133)Inner Mongolia Natural Science Foundation(No.2016MS0513)
文摘Influence of doping and oxygen vacancy concentrations on oxygen ion or oxygen vacancy(V)migration energies of SmxCe1-xO2-δ(x=0.0625,0.125,0.25 andδ=0.0625,0.125)systems using a GGA+U method are studied.Calculated results show that advantage migration types change from V→O2-to O2-→as x andδincrease.For V→O2-migrations of the Sm0.0625Ce0.9375O1.9375 and Sm0.125Ce0.875O1.9375 systems,electrostatic attractions between Sm"and V,defect associations between Ce3 and V,and steric hindrances of Sm3+affect the migration energies.For O2→V migrations of the Sm0.125Ce0.875O1.875 and Sm0.25Ce0.75O1.875 systems,migration energies of O2-are affected by electrostatic repulsions between Sm3+and O2-and defect associations between Ce3+and V.Increases of the oxygen vacancy and Sm3+doping concentrations benefit the oxygen ion and vacancy migrations,respectively.