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磁性Fe3O4纳米颗粒制备方法的比较 总被引:1,自引:0,他引:1
使用醇-水法、氢氧化钠共沉淀法和氨水共沉淀法制备磁性Fe3O4纳米颗粒.制得的纳米Fe3O4用饱和油酸钠的醇溶液进行改性.采用XRD,SEM,TEM,IR和振动样品磁强计等手段对制备的样品进行了表征研究.实验结果表明三种方法中,醇-水法和氨水共沉淀法所制备的纳米Fe3O4表面改性效果良好;氨水共沉淀法制备的颗粒磁性最强,但实验时间长;醇-水法制备的粉体粒径最小,但颗粒分散情况相对较差;氢氧化钠共沉淀法最简单,实验时间最短,收率也较高,但粉体性能不如其它两种. 相似文献
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磁性介孔二氧化硅复合材料作为酶固定化载体具有优异的酶固定化性能和良好的磁分离性能,受到国内外学术界广泛关注。本文在自制的β-FeOOH空心微球表面上包覆致密的SiO2保护层,在酸性条件下以P123为模板剂,十六烷基三甲基溴化铵(CTAB)为辅助导向剂成功制备出了磁性β-FeOOH@SiO2@介孔SiO2空心复合微球,最后在还原气氛下煅烧得到Fe3O4@SiO2@介孔SiO2空心微球。结果表明,所制备的Fe3O4@SiO2@介孔SiO2微球空心结构未坍塌,具有规整的球形结构,介孔SiO2壳层(平均厚度约为11nm)均匀地包覆在β-FeOOH@SiO2中空微球表面。伴随着CTAB量的增加,微球的最可几孔径由4.30nm减小到3.19nm,比表面积从376m2/g升高到640m2/g,孔容从0.36cm3/g升高到0.56cm3/g。复合微球的饱和磁化强度为11.3emu/g,矫顽力为111.5Oe,外加磁场作用下可以实现样品的快速分离,且样品的再分散性良好。当介孔孔径为4.30nm时,Fe3O4@SiO2@介孔SiO2空心复合微球漆酶固定量高达234mg/g。固定化漆酶在不同pH、温度下的活性显著优于游离酶。 相似文献
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Fe3O4@SiO2的表面改性 总被引:1,自引:0,他引:1
采用溶胶凝胶法在磁性Fe3O4纳米粒子的表面包覆SiO2,采用正交试验法,以表面Si-OH含量为指标,考察温度、时间和醇/水三因素对表面Si-OH含量的影响,利用X射线光电子能谱分析(XPS)测试Fe3O4@SiO2复合粒子表面Si-OH含量,结果表明在80%、回流时间为1h、醇/水为6∶1是改性Fe3O4@SiO2的... 相似文献
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Magnetite (Fe3O4) nanoparticles were prepared by solvothermal method and its composites with reduced graphene oxide namely FG1, FG2, and FG3 (changing magnetite precursor loading 0.1, 0.5, and 1 respectively) were used as adsorbents for the removal of methyl violet (MV) dye. The structural and morphological results confirm that rGO sheets were decorated with Fe3O4 and it ensures the variation of active sites toward dye removal property. The maximum adsorption capacity obtained for FG2 was 196 mg/g. The adsorption isotherms and kinetics better fit Langmuir and pseudo-second-order kinetic model for FG1 and FG2. Increasing of Fe3O4 loading on rGO reduces the dye adsorption sites and too low Fe3O4 loading affects the magnetic separation. The optimal loading of Fe3O4 on rGO is important parameter for the adsorption process and fast separation of adsorbent. 相似文献
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Core-shell Fe3O4@SiO2 nanoparticles synthesized with well-dispersed hydrophilic Fe3O4 seeds 总被引:1,自引:0,他引:1
Silica coated magnetite (Fe3O4@SiO2) core-shell nanoparticles (NPs) with controlled silica shell thicknesses were prepared by a modified St?ber method using 20 nm hydrophilic Fe3O4 NPs as seeds. The core-shell NPs were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), selected area electron diffraction (SAED), and UV-Vis adsorption spectra (UV-Vis). The results imply that NPs consist of a crystalline magnetite core and an amorphous silica shell. The silica shell thickness can be controlled from 12.5 nm to 45 nm by varying the experimental parameters. The reaction time, the ratio of TEOS/Fe3O4, and the concentration of hydrophilic Fe3O4 seeds were found to be very influential in the control of silica shell thickness. These well-dispersed core-shell Fe3O4@SiO2 NPs show superparamagnetic properties at room temperature. 相似文献
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采用浸渍法和共沉淀法制备了一系列不同Cu含量的超顺磁CuO-Bi2O3/Fe3O4-SiO2-MgO催化剂。使用电感耦合等离子体发射光谱仪(ICP-AES)、低温N2物理吸-脱附、X射线衍射(XRD)、H2程序升温还原(H2-TPR)、振动样品磁强计(VSM)对催化剂的组成、结构、织构及磁性能进行表征, 评价了该催化剂催化甲醛乙炔化合成1, 4-丁炔二醇的催化活性。结果表明, 制备方法对催化剂中活性组分CuO的存在状态及炔化性能有较大影响, 采用共沉淀法较浸渍法制备的催化剂具有更高的比表面积、CuO分散度与较好的还原能力, 表现出较高的炔化性能;Cu含量是影响催化剂炔化性能的另一重要因素, 随Cu含量的增加, 催化剂活性逐渐增加, 在本研究考察范围内, 以共沉淀法制备的Cu质量分数为30%的催化剂表现出最佳的甲醛乙炔化性能。同时, 该催化剂具有良好的超顺磁性, 可以在外加磁场的作用下迅速分离回收, 循环使用6次后, 其催化活性明显高于非磁性催化剂。 相似文献
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以硝酸铁和十二烷基三甲基溴化铵为原料,采用固相法制备了γ-氧化铁纳米粒子。通过X射线衍射、氮气吸附-脱附、磁性测试等手段对γ-氧化铁样品进行了表征。研究了γ-氧化铁对有机染料直接耐酸大红4BS的吸附性能。结果表明,制备的γ-氧化铁样品为γ-氧化铁纳米粒子,平均晶粒尺寸为18.5 nm;γ-氧化铁的比表面积为83.2 m 2/g,孔容为0.25 cm 3/g,最可几孔径为3.8 nm,属于介孔范围;γ-氧化铁的最大饱和磁化强度为63.7 A·m 2/kg;介孔γ-氧化铁对直接耐酸大红4BS的吸附过程符合准二级吸附动力学模型;γ-氧化铁对直接耐酸大红4BS的吸附符合Langmuir吸附等温式,极限吸附量为113.3 mg/g;将γ-氧化铁脱附处理后可重复使用。 相似文献
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合成了一种琥珀酸酐改性果胶-四氧化三铁(Fe3O4)磁性微球吸附剂,分别采用扫描电镜(SEM)、红外光谱(FT-IR)、X射线衍射(XRD)等手段对样品进行了表征,并研究了其吸附铅离子(Pb 2+)的性能。研究结果表明:成功制备了琥珀酸酐改性果胶-Fe3O4磁性微球,改性果胶包覆四氧化三铁几乎没有改变Fe3O4的尖晶石结构,其表面疏松多孔;改性果胶-Fe3O4磁性微球对铅离子的吸附符合准二级动力学方程、Langmuir等温吸附方程,吸附过程主要为化学吸附。最佳吸附条件:吸附时间为600 min,吸附温度为40 ℃,溶液pH为5,吸附剂添加量为20 mg,溶液中Pb 2+质量浓度为800 mg/L。改性果胶-Fe3O4磁性微球吸附剂用于脱除毛蚶子、扇贝酶解液中的Pb 2+,Pb 2+去除率分别为76.47%和80.34%,效果良好。 相似文献
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采用改进Stöber法制备超顺磁Fe3O4@SiO2复合粒子作为催化剂载体,再通过浸渍法将H3PW12O40(HPW)负载在Fe3O4@SiO2载体上,制备了一系列超顺磁负载型催化剂HPW/Fe3O4@SiO2。并使用X射线衍射(XRD)、傅里叶红外(FT-IR)、氨的程序升温脱附(NH3-TPD)、扫描电镜(SEM)、N2吸附-脱附和振动样品强磁计(VSM)对催化剂进行表征。结果表明,HPW固定并均匀分散在Fe3O4@SiO2载体上,40% HPW/Fe3O4@SiO2催化剂具有较高的饱和磁强度 (30.1 emu·g-1)和较大的比表面积 (303.6 m2·g-1),并可用外加磁场进行分离。采用40% HPW/Fe3O4@SiO2催化噻吩与1-辛烯组成的模拟汽油的烷基化脱硫反应,在160℃下反应2 h,噻吩转化率达到85.5%,有较好的催化脱硫性能,且可以多次循环利用。 相似文献
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为脱除油田采出水中的Fe(Ⅱ)合成磁性吸附剂,本文以溶剂热法制得亲水性Fe3O4纳米颗粒,使用盐酸多巴胺(DA)进行包覆得到Fe3O4@PDA,再以甲基丙烯酸缩水甘油酯(GMA)在其表面聚合接枝得到Fe3O4@PGMA,后经精氨酸(Arg)修饰后得到功能化的Fe3O4@PGMA-Arg。通过红外光谱、X射线光电子能谱、X射线衍射和磁化强度对制备的纳米颗粒进行表征,结果表明Fe3O4@PGMA-Arg中具有伯胺、亚胺双键、羟基和羧基官能团,其中伯胺基团和亚胺双键上的N可与Fe(Ⅱ)形成配位键,羟基和羧基的O可与Fe(Ⅱ)形成配位键,从而达到吸附Fe(Ⅱ)的目的。合成产物仍保持了Fe3O4的反尖晶石结构,具有好的磁响应性能。通过静态吸附实验探究吸附条件对Fe3O4@PGMA-Arg吸附Fe(Ⅱ)的影响因素,结果表明,Fe(Ⅱ)的吸附量随着温度和初始浓度的增加而增加,适宜的pH为4。动力学和热力学研究表明,吸附Fe(Ⅱ)过程符合准二级反应动力学模型,吸附等温线符合Langmuir模型,吸附过程活化能为45.60kJ/mol,为化学吸附。Fe3O4@PGMA-Arg经5次再生后,对亚铁离子仍保持较高的脱除率。 相似文献
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以Fe_3O_4纳米粒子为核、丙烯酸酯为壳,通过溶剂热法制备了Fe_3O_4@SiO_2@IPDI-HEA纳米粒子。通过IR、TEM和XRD对其结构进行了表征,通过光差热扫描(photo-DSC)和TGA考察了该纳米粒子对水性有机硅聚氨酯光固化体系性能的影响。结果表明:Fe_3O_4@SiO_2@IPDI-HEA粒子的加入,对体系的光聚合性能没有明显影响,但可明显提高固化膜的耐热性和拉伸强度,当Fe_3O_4@SiO_2@IPDI-HEA的质量分数为1.5%时,固化膜的初始分解温度(T5%)增加了21.9℃,拉伸强度增加了6.9MPa。并且,Fe_3O_4@SiO_2@IPDI-HEA可以赋予光固化膜一定的电磁性能,当频率在0~(1×10~7) Hz内时,其介电常数均在4以上。 相似文献
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B.V. Neamţu M. Pszola H. Vermeşan G. Stoian M. Grigoraş A. Opriş L. Cotojman T.F. Marinca N. Lupu I. Chicinaş 《Ceramics International》2021,47(1):581-589
Soft magnetic composites (FSMCs) have been prepared by using Fe fibres coated with a layer of Fe3O4, this layer playing the role of insulating material. The coating was made via blackening method by simply immersing the fibres in the blackening bath for 5, 10 and 15 min. The formation of the Fe3O4 coating on the surface of the fibres was confirmed by X-ray diffraction. The SEM investigation, used to evaluate the thickness of the coatings, has proved that increasing the coating duration leads to the increase of the coating thickness and complete coverage of the surface of the fibres. Differential scanning calorimetry and thermomagnetic measurements were used to investigate the thermal stability of the composite fibres. The fibres coated with Fe3O4 were compacted at a compaction pressure of 700 MPa to obtain toroidal magnetic cores. The obtained cores were characterised in DC and AC magnetisation regime. The analysis of the quasi-static hysteresis loops evidenced that increasing the thickness of the Fe3O4 leads to a slight deterioration of the compact's magnetic properties. However, as the thickness of the Fe3O4 layer increases, the development of eddy currents at a larger scale is hindered as proved by the AC magnetic investigations. A model for analytic separation of the core losses is proposed. By applying this model to the prepared samples, we are now able to discriminate between the occurring losses and adjust the preparation process of new samples to the targeted characteristics. 相似文献