排序方式: 共有21条查询结果,搜索用时 15 毫秒
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采用一种全新的快速萃取方法--磁性流体固定床萃取分离技术,该方法是将磁性Fe3O4纳米颗粒表面包覆油酸,溶于有机溶剂中,加入萃取剂三苯基氧化膦TPPO,制成磁性萃取剂。借助于高梯度磁性分离装置,对目标离子进行萃取分离。萃取完成后通过原子吸收光谱仪测定萃取后金溶液中Au3+的浓度。通过对铁磁导线直径、初始金溶液pH值、萃取剂体积分数和协同萃取等影响因素的考察,得出了对Au3+浓度为19.128 mg·L-1的氯金酸溶液进行萃取分离的最佳工艺:采用直径为2.34 mm的铁磁导线作为磁性填充介质时萃取率较其他优越。初始金溶液的pH值和萃取剂的体积分数对萃取率影响较大。在初始金溶液pH=1,萃取剂(TPPO)体积分数达到50%时萃取率最高。使用TPPO和TBP协同萃取也能提高萃取率。采用浓度为1 mol·L-1的硫脲进行反萃实验,振荡10 min,反萃率在90%以上。 相似文献
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Micron-size superparamagnetic poly(styrene-divinylbenzene-glycidyl methacrylate) (PSt-DVB-GMA)spheres were prepared via a modified suspension copolymerization method. Oleic acid coated magnetite (Fe_3O_4)nanoparticles made by co-precipitation were first mixed with monomers of St, DVB, GMA, and benzoyl peroxide(BPO) to form oil in water suspension with the presence of poly(vinyl pyrrolidone) (PVP-K30) as a stabilizer.Then the temperature of mixture was increased at a controlled rate to obtain small and relatively uniform droplets.Finally, the copolymerization reaction was initiated by the decomposition of BPO. The morphology and propertiesof magnetic PSt-DVB-GMA microspheres were examined by SEM, TEM, VSM, XRD and FT-IR. The magneticmicrospheres obtained have very small size (about 4-7μm) in diameter with narrow size distribution and super-paramagnetic characteristics. Powder X-ray diffraction measurements show the inverse cubic spinel structure forthe magnetite dispersed in polymer microspheres. FT-IR 相似文献
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论述了一种新型的磁性聚丙烯酸甲酯微球的制备方法,该方法制备的微球具有良好的磁性和单分散性,并且将其在磁性免疫分析技术中得以运用。首先用化学共沉淀法制备Fe3O4纳米颗粒,PMA种子颗粒由细乳液聚合方法合成,最后用单体溶胀聚合方法合成磁性PMA微球,也就是将PMA种子微球溶解于丙烯酸甲酯磁性流体中。利用氨解反应将氨基偶联在磁性PMA微球表面,进而将HCV抗体通过戊二醛共价偶联到磁性PMA微球表面。微球的单分散性、粒度分布、磁特性分别由扫描电镜、振动试样磁力计测定。实验结果表明:PMA磁性微球的平均尺寸为5.416μm,饱和磁化强度为5.839 Am2/kg,PMA磁性微球上的氨基和HCV抗体偶联量分别由原子吸收光谱仪以及紫外分光光度计测定,测定的氨基浓度为0.659 mmol/g。 相似文献
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采用共沉淀法合成油酸修饰的Fe3O4纳米颗粒,用其固定化Thioalkalivibrio versutus D301细胞,考察了盐碱环境下纳米颗粒固定化细胞的工艺条件,比较了固定化细胞和游离细胞的硫氧化活性,研究了固定化细胞的重复利用性能. 结果表明,最佳固定化条件为Na+浓度0.6 mol/L,pH值9.5,固定化温度20℃,吸附时间10 min. 固定化细胞硫氧化速率是游离细胞的81%. 固定化细胞具有很好的硫氧化活性,可重复使用至少6次. 相似文献
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Non-porous superparamagnetic polymer microspheres with epoxy groups were prepared by dispersion polymerization of glycidyl methacrylate (GMA) in the presence of magnetic iron oxide (Fe3O4) nanoparticles coated with oleic acid. The polymerization was carried out in the ethanol/water medium using polyvinylpyrrolidone (PVP) and 2,2'-azobisisobutyronitrile (AIBN) as stabilizer and initiator, respectively. The magnetic microspheres obtained were characterized with scanning electron microscopy (SEM), vibrating sample magnetometry (VSM) and Fourier transform infrared spectroscopy (FTIR). The results showed that the magnetic microspheres had an average size of 1μm with superparamagnetic characteristics. The saturation magnetization was found to be 4.5emu·g-1. There was abundance of epoxy groups with density of 0.028 mmol·g-1 in microspheres. The magnetic PGMA microspheres have extensive potential uses in magnetic bioseparation and biotechnology. 相似文献
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采用改进的悬浮聚合法制备磁性聚苯乙烯微球.利用扫描电子显微镜和振动样品磁强计对所合成磁性微球的尺寸和磁性能进行分析表征.采用巨磁阻生物传感器检测磁性微球的数量.结果表明:磁性微球粒径大小为0.5~50μm,比饱和磁化强度为4.56 A·m2·kg-1.巨磁阻生物传感器对磁性聚苯乙烯微球数量具有很好的可检测性.在一定的范围内,随着磁性微球数量的增多,传感器的输出信号增强.在磁性微球一定数量的情况下,随着磁性微球粒径的增大,传感器的电阻变化量先增大后减小. 相似文献