Nanostructured γ-Fe2O3/SiO2 complex oxide was prepared by sol-gel method with tetraethoxysilane and iron nitrate as precursors. The particle size distribution, thermal and phase stabilities and gas sensing properties...Nanostructured γ-Fe2O3/SiO2 complex oxide was prepared by sol-gel method with tetraethoxysilane and iron nitrate as precursors. The particle size distribution, thermal and phase stabilities and gas sensing properties were systematically characterized by TEM, granularity distribution, TG-DTA, XRD and gas sensitivity measurements. The particle size is about 10 nm and size distribution is very narrow. The sensitivity of the sensing element to CO, H2, C2H4, C6H6 and the effects of calcination temperature on the sensitivity and conductance of gases were examined. The combination of excellent thermal stability and tunable gas sensing properties through careful control of the preparation and judicious selection of material compositions gives rise to novel nanocomposites, which is attractive for the sensitive and selective detection of reducing gases and some hydrocarbon gases.展开更多
Magnetic alumina composite microspheres with γ-Fe 2 O 3 core/Al 2 O 3 shell structure were prepared by the oil column method. A dense silica layer was deposited on the surface of γ-Fe 2 O 3 particles (denoted as γ...Magnetic alumina composite microspheres with γ-Fe 2 O 3 core/Al 2 O 3 shell structure were prepared by the oil column method. A dense silica layer was deposited on the surface of γ-Fe 2 O 3 particles (denoted as γ-Fe 2 O 3 /SiO 2 ) with a desired thickness to protect the iron oxide core against acidic or high temperature conditions. γ-Fe 2 O 3 /SiO 2 /Al 2 O 3 particles with about 85 wt% Al 2 O 3 were obtained and showed to be suitable for practical applications as a magnetic catalyst or catalyst support due to their magnetic properties and pore structure. The products were characterized with scanning electron microscope (SEM) and transmission electron microscope (TEM), nitrogen adsorption-desorption, and vibrating sample magnetometer (VSM). The specific surface area and pore volume of the γ-Fe 2 O 3 /SiO 2 /Al 2 O 3 composite microspheres calcined at 500 ? C were 200 m 2 /g and 0.77 cm 3 /g, respectively.展开更多
Hierachically porous(HP)CuO/α-Fe2O3/SiO2 composite material was fabricated by sol-gel method and multi-hydrothermal processes using HP-SiO2 as support.The resulting material was characterized by N2 adsorption-desorpt...Hierachically porous(HP)CuO/α-Fe2O3/SiO2 composite material was fabricated by sol-gel method and multi-hydrothermal processes using HP-SiO2 as support.The resulting material was characterized by N2 adsorption-desorption,X-ray diffraction and scanning electron microscopy.The as-prepared CuO/Fe2O3/HP-SiO2 sample,withα-Fe2O3 and CuO nanocrystals,possessed a co-continuous skeleton,through-macroporous and mesoporous structure.Its catalytic behavior for CO and o-DCB oxidation was investigated.The result showed that CuO/Fe2O3/HP-SiO2 catalyst exhibited high catalytic activity for both CO and o-DCB oxidation,indicating its potential application in combined abatement of CO and chlorinated volatile organic compounds.展开更多
In order to explore synthetic method of pure sodium pyroxene,the pure chemical reagents of Na2CO3,Fe(OH)3 and H2SiO3were used as raw materials,and the possible solid phase reactions for Na2CO3-Fe(OH)3-H2SiO3system...In order to explore synthetic method of pure sodium pyroxene,the pure chemical reagents of Na2CO3,Fe(OH)3 and H2SiO3were used as raw materials,and the possible solid phase reactions for Na2CO3-Fe(OH)3-H2SiO3system in heating process had been studied by means of differential thermal analysis(DTA)and X-ray diffraction(XRD). The influencing factors of sodium pyroxene(NaFeSi2O6)synthetic reaction,such as sintering temperature and holding time,had also been studied.The results show that sodium pyroxene can be largely synthesized at 737℃;it is helpful for synthesis of sodium pyroxene to increase sintering temperature appropriately,and the best temperature should be controlled at 900℃or so,because it will melt and decompose at temperatures higher than 900℃.In those influencing factors of sodium pyroxene synthesis the most important is temperature.The results will be helpful for providing pure NaFeSi2O6for further research on the formation of SFCA for NaFeSi2O6-KAlSi2O3-CaO-Fe2O3-CaF2 system in the sintering process of Bayan-obo iron ore.展开更多
Two-step steam reforming of methane (SRM) is a novel chemical looping process towards the production of pure hydrogen and syngas (synthesis gas), consisting of a syngas production step and a water-splitting step. Rene...Two-step steam reforming of methane (SRM) is a novel chemical looping process towards the production of pure hydrogen and syngas (synthesis gas), consisting of a syngas production step and a water-splitting step. Renewable energy can be used to drive this process for hydrogen production, especially solar energy. CeO2-Fe2O3 complex oxide oxygen carrier was prepared by the impregnation method and characterized by means of X-ray diffractometer (XRD), Raman spectroscopy (Raman) and hydrogen programmed reduction (H2-TPR). CH4 temperature programmed and isothermal reactions were adopted to test syngas production reactivity, and water splitting reaction was employed to investigate water-splitting activity. Moreover, two-step SRM performance was evaluated by a successive redox cycle. The results showed that CO-uncontaminated H2 and highly selective syngas (with H2/CO ratio close to 2) could be respectively obtained from two steps, and CeFeO3 formation was found in the first redox cycle and proved to be enhanced by the redox treatment. After 10 successive cycles, obvious CeFeO3 phase was detected, which may be responsible for favorable successive redox cycle performances.展开更多
A ternary composite of TiO2 and a SiO2-Al2O3 aerogel with good photocatalytic activity was prepared by a simple sol-gel method with TiO2 nanoparticles and SiO2-Al2O3 aerogels derived from industrial fly ash.The struct...A ternary composite of TiO2 and a SiO2-Al2O3 aerogel with good photocatalytic activity was prepared by a simple sol-gel method with TiO2 nanoparticles and SiO2-Al2O3 aerogels derived from industrial fly ash.The structural features of the TiO2/SiO2-Al2O3 aerogel composite were investigated by X-ray powder diffraction,Fourier transform infrared spectroscopy,transmission electron microscopy,gas adsorption measurements and diffuse reflectance UV-visible spectroscopy.The optimal conditions for photocatalytic degradation of 2-sec-butyl-4,6-dinitrophenol(DNBP],included an initial DNBP concentration of 0.167 mmol/L at pH = 4.86 with a catalyst concentration of 6 g/L,under visible light irradiation for 5 h.A plausible mechanism is proposed for the photocatalytic degradation of DNBP.Our composite showed higher photocatalytic activity for DNBP degradation than that of pure TiO2.This indicates that this material can serve as an efficient photocatalyst for degradation of hazardous organic pollutants in wastewater.展开更多
A facile hydrothermal method was developed for the preparation of Fe_2O_3@C nanocomposites using FeCl_3·6H_2O as iron source and glucose as carbon source under alkaline condition. The morphology and structure of ...A facile hydrothermal method was developed for the preparation of Fe_2O_3@C nanocomposites using FeCl_3·6H_2O as iron source and glucose as carbon source under alkaline condition. The morphology and structure of the as-prepared product were identified by transmission electron microscopy(TEM), high resolution transmission electron microscopy(HRTEM), field-emission scanning electron microscopy(FESEM),X-ray diffraction(XRD), Raman spectroscopy, Fourier Transform infrared spectroscopy(FTIR), and thermogravimetric analysis(TGA). The as-prepare α-Fe_2O_3@C nanocomposites were employed for supercapacitor electrode material. The synergistic combination of carbon electrical double-layer capacitance and α-Fe_2O_3 pseudo-capacitance established such nanocomposites as versatile platform for high performance supercapacitors. The synthesis method developed here is expected to obtain other metal oxide/carbon composite.展开更多
Fluorite is widely employed as fluxing agent in metallurgy flux , which inevitably leads to serious fluorine pollution.B2O3 is employed as fluxing agent of CaO-SiO2-Fe2O3steelmaking fluxes to substitute for CaF2.The e...Fluorite is widely employed as fluxing agent in metallurgy flux , which inevitably leads to serious fluorine pollution.B2O3 is employed as fluxing agent of CaO-SiO2-Fe2O3steelmaking fluxes to substitute for CaF2.The effects of B2O3 and CaF2 on the melting properties of this system were investigated.The melting temperatures of fluxes including softening temperature (Ts), hemispherical temperature (Th), and flow temperature (Tf) were measured using the hemisphere method.The results indicate that the fluxing effect of B2O3is more significant than that of CaF2 .When the addition amount of B2O3 (mass percent) exceeds 6% , the melting temperatures of fluxes including Ts , Th and Tf are decreased lower than 1 300℃.The basicity of fluxes has a significant effect on the melting temperature , and the melting temperatures of the fluxes increase with the increase of fluxes basicity.However , when B2O3 is used as fluxing agent , the melting temperature changes little with the basicity increasing from 2.5 to 5.0. These characteristics are suitable for steelmaking process.Moreover , Fe2O3 has an important fluxing effect on this CaO-based steelmaking fluxes.This indicates that the fluxes system is suitable for steelmaking process.展开更多
目的:检测γ-Fe2O3纳米粒表面油酸的残留量,考察油酸残留量对纳米粒磁共振T1造影效果的影响。方法:采用热分解法制备γ-Fe2O3纳米粒,使用mPEG-P取代γ-Fe2O3纳米粒表面的油酸,得到水溶性的γ-Fe2O3-PEG纳米粒,采用高效液相色谱法测定纳...目的:检测γ-Fe2O3纳米粒表面油酸的残留量,考察油酸残留量对纳米粒磁共振T1造影效果的影响。方法:采用热分解法制备γ-Fe2O3纳米粒,使用mPEG-P取代γ-Fe2O3纳米粒表面的油酸,得到水溶性的γ-Fe2O3-PEG纳米粒,采用高效液相色谱法测定纳米粒表面残留的油酸,并在7T磁共振成像仪下考察油酸残留量与纳米粒T1造影效果的关联。最后,对体外造影效果最优的样品进行了体内磁共振成像测试。结果:建立了油酸的高效液相色谱检测方法,油酸在10~400 μg/mL浓度范围内具有良好的线性关系(r2 = 1),平均回收率为99.86%。通过改变γ-Fe2O3与mPEG-P的投料比,得到γ-Fe2O3-PEG纳米粒表面油酸残留个数分别为100、83、56、33的样品。体外磁共振成像结果表明,油酸残留量较少的纳米粒拥有更好的T1加权成像性能。小鼠体内血管造影显示,本研究制备的γ-Fe2O3-PEG纳米粒与临床使用的钆类造影剂相比,拥有更好的血管成像效果。结论:本研究成果为热分解法制备的氧化铁纳米粒表面油酸的定量分析提供了一种有效的检测方法,以促进该类纳米粒在生物医学领域的应用。Objective: Detection of residual oleic acid on the surface of γ-Fe2O3 nanoparticles and investigation of its impact on magnetic resonance T1 imaging. Method: We prepared γ-Fe2O3 nanoparticles via thermal decomposition, with mPEG-P replacing the oleic acid on the surface of the nanoparticles to yield water-soluble γ-Fe2O3-PEG nanoparticles. The residual oleic acid on the surface of the nanoparticles was quantified using High-Performance Liquid Chromatography, and the relationship between the amount of residual oleic acid and the T1 contrast effect of the nanoparticles was investigated using a 7T magnetic resonance imaging system. Finally, the vivo magnetic resonance imaging of the sample exhibiting the optimal in vitro contrast effect was conducted. Results: We developed a High-Performance Liquid Chromatography method for the detection of oleic acid, demonstrating a strong linear correlation in the concentration range of 10~400 μg/mL (r² = 1) with an average recovery rate of 99.86%. By varying the ratio of γ-Fe2O3 to mPEG-P, samples with oleic acid on the surface of γ-Fe2O3-PEG nanoparticles were obtained, with respective counts of 100, 83, 56, and 33. In vitro magnetic resonance imaging demonstrated that nanoparticles with lower residual oleic acid exhibited enhanced T1-weighted imaging performance. In vivo vascular imaging in mice demonstrated that the γ-Fe2O3-PEG nanoparticles prepared in this study provided better imaging results compared to commercially available gadolinium-based contrast agents. Conclusions: This study presents an effective detection method for the quantitative analysis of oleic acid on the surface of iron oxide nanoparticles synthesized via a thermolytic approach, thereby facilitating the application of such nanoparticles in the biomedical field.展开更多
In this study, silicone-oil-based γ-Fe2O3 mag- netic fluid was successfully prepared by thermal oxidizing of Fe3O4 magnetic nanoparticles, which were prepared by chemical co-precipitation with FeSO4-7H2O and FeCl3- 6...In this study, silicone-oil-based γ-Fe2O3 mag- netic fluid was successfully prepared by thermal oxidizing of Fe3O4 magnetic nanoparticles, which were prepared by chemical co-precipitation with FeSO4-7H2O and FeCl3- 6H2O, and their surface was modified by oleate ligands. Silicone oil was used as carrier liquid and oleic acid was as surfactant for preparing γ-Fe2O3 magnetic fluid. It is found that the Fe3O4 nanoparticles surrounded by oleate ligands are not damaged during the thermal oxidizing. The shape of γ-Fe2O3 magnetic nanoparticles prepared is similar to spherical, and their mean size is about 10-20 nm, which has nothing obvious difference compared with Fe3O4. Thesaturation magnetization of γ-Fe2O3 magnetic fluid pre-pared is 14.25 A.me.kg-1 and that of γ-Fe2O3 nanoparti-cles is 57.56 A.m2.kg-1. The needle of γ-Fe2O3 magneticfluid is much bigger than that of Fe3O4 magnetic fluidunder the same magnetic field, which shows better mag-netic properties.展开更多
基金Supported by the National Natural Science Foundation of China (No. 20377004) and Beijing Natural Science Foundation (No. 2032014, No. 8032007).
摘要Nanostructured γ-Fe2O3/SiO2 complex oxide was prepared by sol-gel method with tetraethoxysilane and iron nitrate as precursors. The particle size distribution, thermal and phase stabilities and gas sensing properties were systematically characterized by TEM, granularity distribution, TG-DTA, XRD and gas sensitivity measurements. The particle size is about 10 nm and size distribution is very narrow. The sensitivity of the sensing element to CO, H2, C2H4, C6H6 and the effects of calcination temperature on the sensitivity and conductance of gases were examined. The combination of excellent thermal stability and tunable gas sensing properties through careful control of the preparation and judicious selection of material compositions gives rise to novel nanocomposites, which is attractive for the sensitive and selective detection of reducing gases and some hydrocarbon gases.
基金supported by the State Key Basic Research Program of PRC (2006CB202505)the National Natural Science Foundation of China (20806093)
摘要Magnetic alumina composite microspheres with γ-Fe 2 O 3 core/Al 2 O 3 shell structure were prepared by the oil column method. A dense silica layer was deposited on the surface of γ-Fe 2 O 3 particles (denoted as γ-Fe 2 O 3 /SiO 2 ) with a desired thickness to protect the iron oxide core against acidic or high temperature conditions. γ-Fe 2 O 3 /SiO 2 /Al 2 O 3 particles with about 85 wt% Al 2 O 3 were obtained and showed to be suitable for practical applications as a magnetic catalyst or catalyst support due to their magnetic properties and pore structure. The products were characterized with scanning electron microscope (SEM) and transmission electron microscope (TEM), nitrogen adsorption-desorption, and vibrating sample magnetometer (VSM). The specific surface area and pore volume of the γ-Fe 2 O 3 /SiO 2 /Al 2 O 3 composite microspheres calcined at 500 ? C were 200 m 2 /g and 0.77 cm 3 /g, respectively.
基金supported by the National Natural Science Foundation of China(No.20977052 and 21177066)the Science and Technology Commission Foundation of Tianjin(No.11JCYBJC05100)+1 种基金the Chinese Academy of Sciences(No.KZCX2-YW-420)the National 973 program(No.2009CB421606)
摘要Hierachically porous(HP)CuO/α-Fe2O3/SiO2 composite material was fabricated by sol-gel method and multi-hydrothermal processes using HP-SiO2 as support.The resulting material was characterized by N2 adsorption-desorption,X-ray diffraction and scanning electron microscopy.The as-prepared CuO/Fe2O3/HP-SiO2 sample,withα-Fe2O3 and CuO nanocrystals,possessed a co-continuous skeleton,through-macroporous and mesoporous structure.Its catalytic behavior for CO and o-DCB oxidation was investigated.The result showed that CuO/Fe2O3/HP-SiO2 catalyst exhibited high catalytic activity for both CO and o-DCB oxidation,indicating its potential application in combined abatement of CO and chlorinated volatile organic compounds.
基金Item Sponsored by National Natural Science Foundation of China (50944049)
摘要In order to explore synthetic method of pure sodium pyroxene,the pure chemical reagents of Na2CO3,Fe(OH)3 and H2SiO3were used as raw materials,and the possible solid phase reactions for Na2CO3-Fe(OH)3-H2SiO3system in heating process had been studied by means of differential thermal analysis(DTA)and X-ray diffraction(XRD). The influencing factors of sodium pyroxene(NaFeSi2O6)synthetic reaction,such as sintering temperature and holding time,had also been studied.The results show that sodium pyroxene can be largely synthesized at 737℃;it is helpful for synthesis of sodium pyroxene to increase sintering temperature appropriately,and the best temperature should be controlled at 900℃or so,because it will melt and decompose at temperatures higher than 900℃.In those influencing factors of sodium pyroxene synthesis the most important is temperature.The results will be helpful for providing pure NaFeSi2O6for further research on the formation of SFCA for NaFeSi2O6-KAlSi2O3-CaO-Fe2O3-CaF2 system in the sintering process of Bayan-obo iron ore.
基金Project support by the National Natural Science Foundation of China (50574046, 50774038)the Natural Science Foundation of Yunnan Prov-ince (2008E030M)+1 种基金the Research Fund for the Doctoral Program of Higher Education of China (20095314120005)2010 Innovation Fund of Kunming University of Science and Technology
摘要Two-step steam reforming of methane (SRM) is a novel chemical looping process towards the production of pure hydrogen and syngas (synthesis gas), consisting of a syngas production step and a water-splitting step. Renewable energy can be used to drive this process for hydrogen production, especially solar energy. CeO2-Fe2O3 complex oxide oxygen carrier was prepared by the impregnation method and characterized by means of X-ray diffractometer (XRD), Raman spectroscopy (Raman) and hydrogen programmed reduction (H2-TPR). CH4 temperature programmed and isothermal reactions were adopted to test syngas production reactivity, and water splitting reaction was employed to investigate water-splitting activity. Moreover, two-step SRM performance was evaluated by a successive redox cycle. The results showed that CO-uncontaminated H2 and highly selective syngas (with H2/CO ratio close to 2) could be respectively obtained from two steps, and CeFeO3 formation was found in the first redox cycle and proved to be enhanced by the redox treatment. After 10 successive cycles, obvious CeFeO3 phase was detected, which may be responsible for favorable successive redox cycle performances.
基金supported by the National Natural Science Foundation of China(21377018)the Natural Science Foundation of Liaoning Province of China(2013020116)the Fundamental Research Funds for the Central Universities(DUT15ZD240)~~
摘要A ternary composite of TiO2 and a SiO2-Al2O3 aerogel with good photocatalytic activity was prepared by a simple sol-gel method with TiO2 nanoparticles and SiO2-Al2O3 aerogels derived from industrial fly ash.The structural features of the TiO2/SiO2-Al2O3 aerogel composite were investigated by X-ray powder diffraction,Fourier transform infrared spectroscopy,transmission electron microscopy,gas adsorption measurements and diffuse reflectance UV-visible spectroscopy.The optimal conditions for photocatalytic degradation of 2-sec-butyl-4,6-dinitrophenol(DNBP],included an initial DNBP concentration of 0.167 mmol/L at pH = 4.86 with a catalyst concentration of 6 g/L,under visible light irradiation for 5 h.A plausible mechanism is proposed for the photocatalytic degradation of DNBP.Our composite showed higher photocatalytic activity for DNBP degradation than that of pure TiO2.This indicates that this material can serve as an efficient photocatalyst for degradation of hazardous organic pollutants in wastewater.
基金the National Natural Science Foundation of China (nos. 21403091 and 51473070)the Natural Science Foundation of Jiangsu Province (no. BK20140557)+1 种基金a project funded by Jiangsu University for Senior Intellectuals (grant no. 12JDG093)the Jiangsu Province for support under the innovation/entrepreneurship program (Suzutong [2012]19)
摘要A facile hydrothermal method was developed for the preparation of Fe_2O_3@C nanocomposites using FeCl_3·6H_2O as iron source and glucose as carbon source under alkaline condition. The morphology and structure of the as-prepared product were identified by transmission electron microscopy(TEM), high resolution transmission electron microscopy(HRTEM), field-emission scanning electron microscopy(FESEM),X-ray diffraction(XRD), Raman spectroscopy, Fourier Transform infrared spectroscopy(FTIR), and thermogravimetric analysis(TGA). The as-prepare α-Fe_2O_3@C nanocomposites were employed for supercapacitor electrode material. The synergistic combination of carbon electrical double-layer capacitance and α-Fe_2O_3 pseudo-capacitance established such nanocomposites as versatile platform for high performance supercapacitors. The synthesis method developed here is expected to obtain other metal oxide/carbon composite.
基金Item Sponsored by National Natural Science Foundation of China ( 51174099 )Natural Science Foundation of Jiangsu Province of China ( BK2010355 )National Science Foundation for Post-Doctoral Scientists of China ( 20100471382 )
摘要Fluorite is widely employed as fluxing agent in metallurgy flux , which inevitably leads to serious fluorine pollution.B2O3 is employed as fluxing agent of CaO-SiO2-Fe2O3steelmaking fluxes to substitute for CaF2.The effects of B2O3 and CaF2 on the melting properties of this system were investigated.The melting temperatures of fluxes including softening temperature (Ts), hemispherical temperature (Th), and flow temperature (Tf) were measured using the hemisphere method.The results indicate that the fluxing effect of B2O3is more significant than that of CaF2 .When the addition amount of B2O3 (mass percent) exceeds 6% , the melting temperatures of fluxes including Ts , Th and Tf are decreased lower than 1 300℃.The basicity of fluxes has a significant effect on the melting temperature , and the melting temperatures of the fluxes increase with the increase of fluxes basicity.However , when B2O3 is used as fluxing agent , the melting temperature changes little with the basicity increasing from 2.5 to 5.0. These characteristics are suitable for steelmaking process.Moreover , Fe2O3 has an important fluxing effect on this CaO-based steelmaking fluxes.This indicates that the fluxes system is suitable for steelmaking process.
摘要目的:检测γ-Fe2O3纳米粒表面油酸的残留量,考察油酸残留量对纳米粒磁共振T1造影效果的影响。方法:采用热分解法制备γ-Fe2O3纳米粒,使用mPEG-P取代γ-Fe2O3纳米粒表面的油酸,得到水溶性的γ-Fe2O3-PEG纳米粒,采用高效液相色谱法测定纳米粒表面残留的油酸,并在7T磁共振成像仪下考察油酸残留量与纳米粒T1造影效果的关联。最后,对体外造影效果最优的样品进行了体内磁共振成像测试。结果:建立了油酸的高效液相色谱检测方法,油酸在10~400 μg/mL浓度范围内具有良好的线性关系(r2 = 1),平均回收率为99.86%。通过改变γ-Fe2O3与mPEG-P的投料比,得到γ-Fe2O3-PEG纳米粒表面油酸残留个数分别为100、83、56、33的样品。体外磁共振成像结果表明,油酸残留量较少的纳米粒拥有更好的T1加权成像性能。小鼠体内血管造影显示,本研究制备的γ-Fe2O3-PEG纳米粒与临床使用的钆类造影剂相比,拥有更好的血管成像效果。结论:本研究成果为热分解法制备的氧化铁纳米粒表面油酸的定量分析提供了一种有效的检测方法,以促进该类纳米粒在生物医学领域的应用。Objective: Detection of residual oleic acid on the surface of γ-Fe2O3 nanoparticles and investigation of its impact on magnetic resonance T1 imaging. Method: We prepared γ-Fe2O3 nanoparticles via thermal decomposition, with mPEG-P replacing the oleic acid on the surface of the nanoparticles to yield water-soluble γ-Fe2O3-PEG nanoparticles. The residual oleic acid on the surface of the nanoparticles was quantified using High-Performance Liquid Chromatography, and the relationship between the amount of residual oleic acid and the T1 contrast effect of the nanoparticles was investigated using a 7T magnetic resonance imaging system. Finally, the vivo magnetic resonance imaging of the sample exhibiting the optimal in vitro contrast effect was conducted. Results: We developed a High-Performance Liquid Chromatography method for the detection of oleic acid, demonstrating a strong linear correlation in the concentration range of 10~400 μg/mL (r² = 1) with an average recovery rate of 99.86%. By varying the ratio of γ-Fe2O3 to mPEG-P, samples with oleic acid on the surface of γ-Fe2O3-PEG nanoparticles were obtained, with respective counts of 100, 83, 56, and 33. In vitro magnetic resonance imaging demonstrated that nanoparticles with lower residual oleic acid exhibited enhanced T1-weighted imaging performance. In vivo vascular imaging in mice demonstrated that the γ-Fe2O3-PEG nanoparticles prepared in this study provided better imaging results compared to commercially available gadolinium-based contrast agents. Conclusions: This study presents an effective detection method for the quantitative analysis of oleic acid on the surface of iron oxide nanoparticles synthesized via a thermolytic approach, thereby facilitating the application of such nanoparticles in the biomedical field.
基金financially supported by the National Natural Science Foundation of China (No.51274039)
摘要In this study, silicone-oil-based γ-Fe2O3 mag- netic fluid was successfully prepared by thermal oxidizing of Fe3O4 magnetic nanoparticles, which were prepared by chemical co-precipitation with FeSO4-7H2O and FeCl3- 6H2O, and their surface was modified by oleate ligands. Silicone oil was used as carrier liquid and oleic acid was as surfactant for preparing γ-Fe2O3 magnetic fluid. It is found that the Fe3O4 nanoparticles surrounded by oleate ligands are not damaged during the thermal oxidizing. The shape of γ-Fe2O3 magnetic nanoparticles prepared is similar to spherical, and their mean size is about 10-20 nm, which has nothing obvious difference compared with Fe3O4. Thesaturation magnetization of γ-Fe2O3 magnetic fluid pre-pared is 14.25 A.me.kg-1 and that of γ-Fe2O3 nanoparti-cles is 57.56 A.m2.kg-1. The needle of γ-Fe2O3 magneticfluid is much bigger than that of Fe3O4 magnetic fluidunder the same magnetic field, which shows better mag-netic properties.