A high temperature resistant alumina with high specific surface area was prepared by sol-gel method. XRD,TEM,XPS and surface analysis method were used to study the effect of dopant lanthanum on the alumina.The results...A high temperature resistant alumina with high specific surface area was prepared by sol-gel method. XRD,TEM,XPS and surface analysis method were used to study the effect of dopant lanthanum on the alumina.The results showed that lanthanum ion could suppress alumina transition to α-phase and then inhibit alumina from sintering and the thermal stability of the Al 2O 3 was improved. Different ratios of La/Al had different effects on the specific surface area of Al 2O 3.The Al 2O 3 containing 1.0 mol/% lanthanum has a BET specific surface area of 71.8 m 2/g after calcination for 32 hours at 1*#100℃, whereas the undoped Al 2O 3 only had a BET specific surface area of 10 m 2/g under similar conditions.展开更多
The effect of surfacefactant(polyvinylalcohol,PVA) and lanthanum on the property of alumina was studied by XRD,XPS,TEM and surface analysis techniques.The results showed that addition of proper amount of PVA and lanth...The effect of surfacefactant(polyvinylalcohol,PVA) and lanthanum on the property of alumina was studied by XRD,XPS,TEM and surface analysis techniques.The results showed that addition of proper amount of PVA and lanthanum can prevent alumina crystal from growing at high temperature and inhibit alumina from transforming to α phase and improve its pore structure.PVA can also make lanthanum less rich at the surface of samples,so alumian can keep high surface area after calcination at high temperature,then its thermal stability was improved.When W(La)∶W(Al)=0.052∶1 and W(PVA)∶W(alumina)=0.4∶1,the alumina can maintain surface area of 102.7m 2g -1 after calcination at 1100℃ for 32h.展开更多
Surface roughness is an important factor that affects the wetting of molten metal on ceramics.The effect of surface roughness of the alumina substrate on the contact angle,contact diameter,drop height and surface tens...Surface roughness is an important factor that affects the wetting of molten metal on ceramics.The effect of surface roughness of the alumina substrate on the contact angle,contact diameter,drop height and surface tension of molten lead was investigated in the temperature range of 923-1123 K.The microstructure of the lead/substrate interface was observed by SEM.The surface free energy of alumina substrates was calculated by the geometrical average method.When the surface roughness of the substrate increased from 0.092 to 2.23μm,the surface free energy increased gradually,ranging from 13.356 to 39.998 mJ/m^(2).The contact diameter of lead droplets decreased from 9.111 to 7.19 mm.The lead drop height increased from 3.41 to 3.85 mm.The contact angle increased from 113.05°to 137.15°.Moreover,the surface depression of the alumina substrate was filled with lead,and no obvious change was observed.The results demonstrated that the wetting of lead drop on alumina substrates was consistent with the Wenzel state.展开更多
Through improving the aging process during synthesis of the support, γ-Al2O3 with large pore volume and high surface area was synthesized by a facile secondary reforming method. The synthesis parameters, such as the ...Through improving the aging process during synthesis of the support, γ-Al2O3 with large pore volume and high surface area was synthesized by a facile secondary reforming method. The synthesis parameters, such as the reaction temperature, the first aging temperature and the second aging temperature, were investigated. The textural properties of γ-Al2O3 were characterized by means of N2 adsorption-desorption isotherms, X-ray powder diffractometry （XRD）, scanning electron microscopy （SEM）, Fourier transform infrared （FTIR） spectroscopy and thermogravimetry （TG）. The experimental results indicated that AACH and amorphous A1OOH were the precursors of alumina, which were formed via precipitation from solutions after reaction of aluminum sulphate with ammonium hydrogen carbonate. The precursor nanocrystallites grew and re-assembled during the secondary reforming process, which resulted in an increased pore size and pore volume and a decreased bulk density. The as-synthesized γ-Al2O3 materials featured meso/macroporosity, large pore volume （2.175 cm^3/g）, high surface area （237.8 m^2/g）, and low bulk density （0.284 g/mL）.展开更多
The formation of metastable alumina phases due to the oxidation of commercial FeCralloy（R） rods （0.5 mm thickness） at various temperatures and time periods has been examined. This structured layer acts as an ancho...The formation of metastable alumina phases due to the oxidation of commercial FeCralloy（R） rods （0.5 mm thickness） at various temperatures and time periods has been examined. This structured layer acts as an anchor to bind additional coatings of alumina via wash-coat techniques, thereby improving the layer thickness and increasing adhesion of the catalytic surface. Optimisation of the layer thickness and catalytic properties were conducted, using a range of analytical systems [scanning electron microscope （SEM）, energy dispersive X-ray （EDX） and X-ray diffraction （XRD）]. The modified FeCralloy（R） rods were tested in a fixed bed reactor rig to assess the impact on yield for the dehydrogenation of methylcyclohexane.展开更多
Based on the deficiency of catalytic elements in methane sensors such as sintering,activity decrease and surface area reduction at high temperature, three differentnano vectors Ce-Zr-Al_2O_3, Ce-Al_2O_3, and Zr-Al_2O_...Based on the deficiency of catalytic elements in methane sensors such as sintering,activity decrease and surface area reduction at high temperature, three differentnano vectors Ce-Zr-Al_2O_3, Ce-Al_2O_3, and Zr-Al_2O_3 were prepared via sol-gel technique inthe experiment.BET surface area, catalytic activity and thermal stability were tested andcompared.It is found from the experiment that the Ce-doped Al_2O_3 vector possesseshigher catalytic activity than pure Al_2O_3 vector.Zr-doped Al_2O_3 vector can enhance thethermal stability of methane sensors.Ce-Zr-Al solid solution can be obtained by the presenceof Ce and Zr doped with Al_2O_3.The reaction activity and thermal stability of catalyticsensors were improved because of the unique synergy effect from Ce-Zr-O.Among themixed cocatalysts, Ce-Zr-O was reported to be an excellent cocatalyst material.The performanceof methane sensors can be improved significantly via the modification ofCe-Zr-Al_2O_3 vector.展开更多
Fibrous activated alumina is widely applied in catalysts,adsorbents,and composite materials.This work presents a green approach in preparing the fibrous activated Al_(2)O_(3) with high purity and specific surface area...Fibrous activated alumina is widely applied in catalysts,adsorbents,and composite materials.This work presents a green approach in preparing the fibrous activated Al_(2)O_(3) with high purity and specific surface area through multistep phase transformation of aluminum-bearing substances using intermediate dawsonite as a template.Thermodynamic calculations and experimental results show that increasing the concentration of Na_(2)CO_(3) and(NH_(4))_(2)CO_(3) is remarkably beneficial to the formation of dawsonite and ammonium aluminum carbonate hydroxide,respectively.Based on determination of dissolution and precipitation mechanism,the ultrafine granular gibbsite is converted to the uniform fibrous dawsonite with a ratio of length to diameter over 50,and the fibrous dawsonite changes into the long fibrous ammonium aluminum carbonate hydroxide with a ratio of length to diameter is about 80 in above 70 g/L(NH_(4))_(2)CO_(3) solution.Furthermore,the activated alumina remains fibrous morphology after roasting ammonium aluminum carbonate hydroxide at a slow heating rate,plentiful open mesopore and weak aggregation of particles,which contributes to the high specific surface area of 159.37 m^(2)/g at 1273 K for the activated alumina.The complete transformation of dawsonite to ammonium aluminum carbonate hydroxide and high specific surface area contribute to the purity of the activated fibrous alumina above 99.9%with low Na and Fe content.展开更多
A matrix of 96 Al2O3 ceramics was implanted with Ni ion of different dosages and energies using a MEVVA implanter. Then metallic structures of copper were made on the implanted ceramics, by using selective electroless...A matrix of 96 Al2O3 ceramics was implanted with Ni ion of different dosages and energies using a MEVVA implanter. Then metallic structures of copper were made on the implanted ceramics, by using selective electroless copper plating. In addition, the characteristics and microstructure of the implanted layer were studied by using the SEM, RBS and XPS. The results show that： 1） the implanted Ni exits as Ni^2, Ni^2＋, and Ni^3＋ in the surface of Al2O3 and metal Ni particles precipitate on ceramics during implantation; 2） the concentration of Ni submits to the Gauss distribution along the direction of implantation on the surface of Al2O3 and high Ni concentration on the surface can be obtained if the Ni is implanted with low energy and a high dosage and 3） Ni ion implantation can activate the surface of Al2O3 and induce electroless copper plating on the ceramics.展开更多
The surface modification of aluminum and its alloys using plasma technology is increasingly being investigated, Thick ceramic coatings with high hardness on aluminum alloys can be prepared successfully using a micro-p...The surface modification of aluminum and its alloys using plasma technology is increasingly being investigated, Thick ceramic coatings with high hardness on aluminum alloys can be prepared successfully using a micro-plasma oxidation （MPO） technique. In this work, the composition, microstructure and elemental distribution of ceramic coatings formed by MPO on LY 12 almnlnum alloy and its hardness are investigated using XRD, EPMA and microhardness instruments. The results show that the ceramic coatings consist of mullite,γ-Al2O3 and a lot of amorphous matter. The content of silicon in the coatings increases from interface to the coatings, however, the content of aluminum decreases along this direction. The maximum hardness of ceramic coatings is up to 9.2 GPa.展开更多
The evolution of the surface oxide film along the depth direction of typical aluminum alloy under mediumtemperature brazing was investigated by means of X-ray photoelectron spectroscopy(XPS). For the alloy with Mg con...The evolution of the surface oxide film along the depth direction of typical aluminum alloy under mediumtemperature brazing was investigated by means of X-ray photoelectron spectroscopy(XPS). For the alloy with Mg content below 2.0wt%, whether under cold rolling condition or during medium-temperature brazing process, the enrichment of Mg element on the surface was not detected and the oxide film was pure Al2O3. However, the oxide film grew obviously during medium-temperature brazing process, and the thickness was about 80 nm. For the alloy with Mg content above 2.0wt%, under cold rolling condition, the original surface oxide film was pure Al2O3. However, the Mg element was significantly enriched on the outermost surface during medium-temperature brazing process, and MgO-based oxide film mixed with small amount of MgAl2O4 was formed with a thickness of about 130 nm. The alloying elements of Mn and Si were not enriched on the surface neither under cold rolling condition nor during mediumtemperature brazing process for all the selected aluminum alloy, and the surface oxide film was similar to that of pure aluminum, which was almost entire Al2O3.展开更多
In order to obtain higher emission performance than that of a traditional M-type cathode, we have developed a new type impregnated dispenser cathode. The new cathode is impregnated with a new active substance with mol...In order to obtain higher emission performance than that of a traditional M-type cathode, we have developed a new type impregnated dispenser cathode. The new cathode is impregnated with a new active substance with molar ratio of 26BaO·29SrO·8Sc2O3 ·7CaO·Al2O3 . This paper introduces the emission performance, surface active material, and work function of the new cathode. At 1100℃B , the DC current density and pulse current density are 30.6±1.0 A/cm2 and 171.6±2.8 A/cm2 , respectively, 2.1 and 5.4 times of that of an M-type cathode. The work function of the new cathode is 1.668± 0.002 eV. High concentration O-Al-Sc-Sr-Ba and O-Al-Sc-Ba are found in the pores and at pore edges, respectively. By comparing the emission performances and surface characteristics of as-polished and as-cleaned cathodes, it is proposed that, the emission around pore ends forms the major part of the total emission for the new cathodes.展开更多
To contribute to the understanding of Eu(Ⅲ)interaction properties on hydrous alumina particles in the absence and presence of fulvic acid(FA),the complexation properties of Eu(Ⅲ)with hydrous alumina,FA and FA-alumin...To contribute to the understanding of Eu(Ⅲ)interaction properties on hydrous alumina particles in the absence and presence of fulvic acid(FA),the complexation properties of Eu(Ⅲ)with hydrous alumina,FA and FA-alumina hybrids are studied by batch and time-resolved laser fluorescence spectroscopy(TRLFS)techniques.The continuous increase in the fluorescence lifetime of Eu-alumina and Eu-FA with increasing pH indicates that the complexation is accompanied by decreasing number of hydration water in the first coordination sphere of Eu(Ⅲ).Eu(Ⅲ)is adsorbed onto alumina particles as outer-sphere surface complexes of≡(Al-O)-Eu·(OH)·7H_2O and≡(Al-O)-Eu·6H_2O at low pH values,and as inner-sphere surface complexes as≡(Al-O)_2-Eu^+·4H_2O at high pH.In FA solution,Eu(Ⅲ)forms complexes with FA as(COO)_2Eu^+(H_2O)_x and the hydration water number in the first coordination sphere decreases with pH increasing.The formation of≡COO-Eu-(O-Al≡)·4H_2O is observed on FA-alumina hybrids,suggesting the formation of strong inner-sphere surface complexes in the presence of FA.The surface complexes are also characterized by their emission spectra[the ratio of emission intensities of^5D_0→~7F_1(λ=594nm)and^5D_0→~7F_2(λ=619nm)transitions]and their fluorescence lifetime.The findings is important to understand the contribution of FA in the complexation properties of Eu(Ⅲ)on FA-alumina hybrids that the clarification of the environmental behavior of humic substances is necessary to understand fully the behavior of Eu(Ⅲ),or its analogue trivalent lanthanide and actinide ions in natural environment.展开更多
文摘A high temperature resistant alumina with high specific surface area was prepared by sol-gel method. XRD,TEM,XPS and surface analysis method were used to study the effect of dopant lanthanum on the alumina.The results showed that lanthanum ion could suppress alumina transition to α-phase and then inhibit alumina from sintering and the thermal stability of the Al 2O 3 was improved. Different ratios of La/Al had different effects on the specific surface area of Al 2O 3.The Al 2O 3 containing 1.0 mol/% lanthanum has a BET specific surface area of 71.8 m 2/g after calcination for 32 hours at 1*#100℃, whereas the undoped Al 2O 3 only had a BET specific surface area of 10 m 2/g under similar conditions.
文摘The effect of surfacefactant(polyvinylalcohol,PVA) and lanthanum on the property of alumina was studied by XRD,XPS,TEM and surface analysis techniques.The results showed that addition of proper amount of PVA and lanthanum can prevent alumina crystal from growing at high temperature and inhibit alumina from transforming to α phase and improve its pore structure.PVA can also make lanthanum less rich at the surface of samples,so alumian can keep high surface area after calcination at high temperature,then its thermal stability was improved.When W(La)∶W(Al)=0.052∶1 and W(PVA)∶W(alumina)=0.4∶1,the alumina can maintain surface area of 102.7m 2g -1 after calcination at 1100℃ for 32h.
基金financial supports from the National Natural Science Foundation of China(Nos.51974022,U1738101)Fundamental Research Funds for the Central Universities,China(No.FRF-MP-20-17)。
文摘Surface roughness is an important factor that affects the wetting of molten metal on ceramics.The effect of surface roughness of the alumina substrate on the contact angle,contact diameter,drop height and surface tension of molten lead was investigated in the temperature range of 923-1123 K.The microstructure of the lead/substrate interface was observed by SEM.The surface free energy of alumina substrates was calculated by the geometrical average method.When the surface roughness of the substrate increased from 0.092 to 2.23μm,the surface free energy increased gradually,ranging from 13.356 to 39.998 mJ/m^(2).The contact diameter of lead droplets decreased from 9.111 to 7.19 mm.The lead drop height increased from 3.41 to 3.85 mm.The contact angle increased from 113.05°to 137.15°.Moreover,the surface depression of the alumina substrate was filled with lead,and no obvious change was observed.The results demonstrated that the wetting of lead drop on alumina substrates was consistent with the Wenzel state.
基金the financial support by the Natural Science Foundation of Liaoning Province of China (Grant No. 2013020122)the National Natural Science Foundationof China (Grant No. 21076100 and 51308045)the financial support by the PetroChina Company Limited (Grant No. 10-01A-01-01-01)
文摘Through improving the aging process during synthesis of the support, γ-Al2O3 with large pore volume and high surface area was synthesized by a facile secondary reforming method. The synthesis parameters, such as the reaction temperature, the first aging temperature and the second aging temperature, were investigated. The textural properties of γ-Al2O3 were characterized by means of N2 adsorption-desorption isotherms, X-ray powder diffractometry （XRD）, scanning electron microscopy （SEM）, Fourier transform infrared （FTIR） spectroscopy and thermogravimetry （TG）. The experimental results indicated that AACH and amorphous A1OOH were the precursors of alumina, which were formed via precipitation from solutions after reaction of aluminum sulphate with ammonium hydrogen carbonate. The precursor nanocrystallites grew and re-assembled during the secondary reforming process, which resulted in an increased pore size and pore volume and a decreased bulk density. The as-synthesized γ-Al2O3 materials featured meso/macroporosity, large pore volume （2.175 cm^3/g）, high surface area （237.8 m^2/g）, and low bulk density （0.284 g/mL）.
文摘The formation of metastable alumina phases due to the oxidation of commercial FeCralloy（R） rods （0.5 mm thickness） at various temperatures and time periods has been examined. This structured layer acts as an anchor to bind additional coatings of alumina via wash-coat techniques, thereby improving the layer thickness and increasing adhesion of the catalytic surface. Optimisation of the layer thickness and catalytic properties were conducted, using a range of analytical systems [scanning electron microscope （SEM）, energy dispersive X-ray （EDX） and X-ray diffraction （XRD）]. The modified FeCralloy（R） rods were tested in a fixed bed reactor rig to assess the impact on yield for the dehydrogenation of methylcyclohexane.
基金Supported by the National Natural Science Foundation of China(60910005)
文摘Based on the deficiency of catalytic elements in methane sensors such as sintering,activity decrease and surface area reduction at high temperature, three differentnano vectors Ce-Zr-Al_2O_3, Ce-Al_2O_3, and Zr-Al_2O_3 were prepared via sol-gel technique inthe experiment.BET surface area, catalytic activity and thermal stability were tested andcompared.It is found from the experiment that the Ce-doped Al_2O_3 vector possesseshigher catalytic activity than pure Al_2O_3 vector.Zr-doped Al_2O_3 vector can enhance thethermal stability of methane sensors.Ce-Zr-Al solid solution can be obtained by the presenceof Ce and Zr doped with Al_2O_3.The reaction activity and thermal stability of catalyticsensors were improved because of the unique synergy effect from Ce-Zr-O.Among themixed cocatalysts, Ce-Zr-O was reported to be an excellent cocatalyst material.The performanceof methane sensors can be improved significantly via the modification ofCe-Zr-Al_2O_3 vector.
基金Project(51874372)supported by the National Natural Science Foundation of China。
文摘Fibrous activated alumina is widely applied in catalysts,adsorbents,and composite materials.This work presents a green approach in preparing the fibrous activated Al_(2)O_(3) with high purity and specific surface area through multistep phase transformation of aluminum-bearing substances using intermediate dawsonite as a template.Thermodynamic calculations and experimental results show that increasing the concentration of Na_(2)CO_(3) and(NH_(4))_(2)CO_(3) is remarkably beneficial to the formation of dawsonite and ammonium aluminum carbonate hydroxide,respectively.Based on determination of dissolution and precipitation mechanism,the ultrafine granular gibbsite is converted to the uniform fibrous dawsonite with a ratio of length to diameter over 50,and the fibrous dawsonite changes into the long fibrous ammonium aluminum carbonate hydroxide with a ratio of length to diameter is about 80 in above 70 g/L(NH_(4))_(2)CO_(3) solution.Furthermore,the activated alumina remains fibrous morphology after roasting ammonium aluminum carbonate hydroxide at a slow heating rate,plentiful open mesopore and weak aggregation of particles,which contributes to the high specific surface area of 159.37 m^(2)/g at 1273 K for the activated alumina.The complete transformation of dawsonite to ammonium aluminum carbonate hydroxide and high specific surface area contribute to the purity of the activated fibrous alumina above 99.9%with low Na and Fe content.
基金Project BK200403 supported by the Natural Science Foundation of Jiangsu Province Project 2005A046 supported by Youth Foundation of CUMT
文摘A matrix of 96 Al2O3 ceramics was implanted with Ni ion of different dosages and energies using a MEVVA implanter. Then metallic structures of copper were made on the implanted ceramics, by using selective electroless copper plating. In addition, the characteristics and microstructure of the implanted layer were studied by using the SEM, RBS and XPS. The results show that： 1） the implanted Ni exits as Ni^2, Ni^2＋, and Ni^3＋ in the surface of Al2O3 and metal Ni particles precipitate on ceramics during implantation; 2） the concentration of Ni submits to the Gauss distribution along the direction of implantation on the surface of Al2O3 and high Ni concentration on the surface can be obtained if the Ni is implanted with low energy and a high dosage and 3） Ni ion implantation can activate the surface of Al2O3 and induce electroless copper plating on the ceramics.
基金Sponsored by the National Natural Science Foundation of China (Grant No. 50171026) the Multidiscipline Scientific Research Foundations of HarbinInstitute of Technology (HIT.MD. 2001. 23).
文摘The surface modification of aluminum and its alloys using plasma technology is increasingly being investigated, Thick ceramic coatings with high hardness on aluminum alloys can be prepared successfully using a micro-plasma oxidation （MPO） technique. In this work, the composition, microstructure and elemental distribution of ceramic coatings formed by MPO on LY 12 almnlnum alloy and its hardness are investigated using XRD, EPMA and microhardness instruments. The results show that the ceramic coatings consist of mullite,γ-Al2O3 and a lot of amorphous matter. The content of silicon in the coatings increases from interface to the coatings, however, the content of aluminum decreases along this direction. The maximum hardness of ceramic coatings is up to 9.2 GPa.
基金Supported by National Natural Science Foundation of China(No.51005163 and No.51275351)Scientific Research Foundation for the Returned Overseas Chinese Scholars,Ministry of Education of China
文摘The evolution of the surface oxide film along the depth direction of typical aluminum alloy under mediumtemperature brazing was investigated by means of X-ray photoelectron spectroscopy(XPS). For the alloy with Mg content below 2.0wt%, whether under cold rolling condition or during medium-temperature brazing process, the enrichment of Mg element on the surface was not detected and the oxide film was pure Al2O3. However, the oxide film grew obviously during medium-temperature brazing process, and the thickness was about 80 nm. For the alloy with Mg content above 2.0wt%, under cold rolling condition, the original surface oxide film was pure Al2O3. However, the Mg element was significantly enriched on the outermost surface during medium-temperature brazing process, and MgO-based oxide film mixed with small amount of MgAl2O4 was formed with a thickness of about 130 nm. The alloying elements of Mn and Si were not enriched on the surface neither under cold rolling condition nor during mediumtemperature brazing process for all the selected aluminum alloy, and the surface oxide film was similar to that of pure aluminum, which was almost entire Al2O3.
基金Supported by the National Natural Science Foundation of China (No. 60871053)the Major State Basic Research Development Program of China (No. 2013CB328901)
文摘In order to obtain higher emission performance than that of a traditional M-type cathode, we have developed a new type impregnated dispenser cathode. The new cathode is impregnated with a new active substance with molar ratio of 26BaO·29SrO·8Sc2O3 ·7CaO·Al2O3 . This paper introduces the emission performance, surface active material, and work function of the new cathode. At 1100℃B , the DC current density and pulse current density are 30.6±1.0 A/cm2 and 171.6±2.8 A/cm2 , respectively, 2.1 and 5.4 times of that of an M-type cathode. The work function of the new cathode is 1.668± 0.002 eV. High concentration O-Al-Sc-Sr-Ba and O-Al-Sc-Ba are found in the pores and at pore edges, respectively. By comparing the emission performances and surface characteristics of as-polished and as-cleaned cathodes, it is proposed that, the emission around pore ends forms the major part of the total emission for the new cathodes.
基金Financial supports from the National Natural Science Foundation of China(21225730,91326202 and 21577032)the Fundamental Research Funds for the Central Universities(JB2015001)+1 种基金Kunlun scholarship of Qinghai province,the priority Academic program development of Jiangsu Higher Education Institutionsthe Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions are acknowledged
文摘To contribute to the understanding of Eu(Ⅲ)interaction properties on hydrous alumina particles in the absence and presence of fulvic acid(FA),the complexation properties of Eu(Ⅲ)with hydrous alumina,FA and FA-alumina hybrids are studied by batch and time-resolved laser fluorescence spectroscopy(TRLFS)techniques.The continuous increase in the fluorescence lifetime of Eu-alumina and Eu-FA with increasing pH indicates that the complexation is accompanied by decreasing number of hydration water in the first coordination sphere of Eu(Ⅲ).Eu(Ⅲ)is adsorbed onto alumina particles as outer-sphere surface complexes of≡(Al-O)-Eu·(OH)·7H_2O and≡(Al-O)-Eu·6H_2O at low pH values,and as inner-sphere surface complexes as≡(Al-O)_2-Eu^+·4H_2O at high pH.In FA solution,Eu(Ⅲ)forms complexes with FA as(COO)_2Eu^+(H_2O)_x and the hydration water number in the first coordination sphere decreases with pH increasing.The formation of≡COO-Eu-(O-Al≡)·4H_2O is observed on FA-alumina hybrids,suggesting the formation of strong inner-sphere surface complexes in the presence of FA.The surface complexes are also characterized by their emission spectra[the ratio of emission intensities of^5D_0→~7F_1(λ=594nm)and^5D_0→~7F_2(λ=619nm)transitions]and their fluorescence lifetime.The findings is important to understand the contribution of FA in the complexation properties of Eu(Ⅲ)on FA-alumina hybrids that the clarification of the environmental behavior of humic substances is necessary to understand fully the behavior of Eu(Ⅲ),or its analogue trivalent lanthanide and actinide ions in natural environment.
