Acta Chimica Sinica ›› 2009, Vol. 67 ›› Issue (11): 1211-1216. Previous Articles     Next Articles

Original Articles


王 冰a,b 张 锋a 邱建华c 张雪洪a 陈 洪b
杜 毅b 许 平*,a


  1. (a上海交通大学生命科学技术学院 上海 200240)
    (b上海爱普香料有限公司 上海 201809)
    (c山东大学生命科学学院 济南 250100)

  • 投稿日期:2008-09-12 修回日期:2009-01-04 发布日期:2009-06-14
  • 通讯作者: 许 平

Preparation of Fe3O4 Superparamagnetic Nanocrystals by Coprecipitation with Ultrasonic Enhancement and Their Characterization

Wang, Bing a,b Zhang, Feng a Qiu, Jianhua c Zhang, Xuehong a Chen, Hong b
Du, Yi b Xu, Ping *,a

  1. (a School of Life Science & Biotechnology, Shanghai Jiaotong University, Shanghai 200240)
    (b Shanghai Apple Flavor & Fragrance Co. Ltd., Shanghai 201809)
    (c School of Life Science, Shandong University, Jinan 250100)
  • Received:2008-09-12 Revised:2009-01-04 Published:2009-06-14
  • Contact: Xu, Ping

Fe3O4 magnetic nanocrystals were prepared by coprecipitating Fe2+ and Fe3+ ions in an ammonia solution with ultrasonic enhancement and modification by the anionic surfactant sodium dodecyl sulfate (SDS). The product was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), high resolution transmission electron microscopy (HRTEM), N2 absorption-desorption, and thermogravimetric-differential scanning calorimetry (TG-DSC), respectively. The surface electrical properties and magnetic properties of the Fe3O4 magnetic nanocrystals were systematically investigated. The growth mechanism of the Fe3O4 magnetic nanocrystals was discussed. The results show that the Fe3O4 magnetic nanoparticles obtained are well-crystallized particles, with an average size of 10 nm, which have good dispersivity. The specific surface area of particles can reach as much as 91.6 m2•g-1. The obtained nanoparticles also have good thermostability, and the isoelectric point (IEP) under water conditions is at pHpzc=5.7. Magnetic measurement reveals the magnetic nanoparticles are superparamagnetic with a saturation magnetization of 65.0 emu•g-1. The ultrasonic enhancement and the surfactant modification play an important role in the growth mechanism of the Fe3O4 superparamagnetic nanocrystals. These superparamagnetic nanocrystals might be applied to biological and medical fields such as cell or enzyme immobilization.

Key words: Fe3O4 superparamagnetic nanocrystal, ultrasonic enhancement, coprecipitation process, surface electrical property, magnetic property