Bare and polymer coated iron oxide superparamagnetic nanoparticles for effective removal of U (VI) from acidic and neutral aqueous medium

Shan Zhu, Yangchun Leng, Minhao Yan, Xianguo Tuo, Jianbo Yang, László Almásy, Qiang Tian, Guangai Sun, Lin Zou, Qintang Li, Jérémie Courtois, Hong Zhang

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6 Citations (Scopus)


Superparamagnetic γ-Fe 2 O 3 nanoparticles (5 nm diameter) were synthesized in water. The bare particles exhibit good colloidal stability at ∼pH 2 because of the strong electrostatic repulsion with a surface charge of +25 mV. The polyacrylic acid (PAA)-coated particles exhibit remarkable colloidal stability at ∼pH 7 with abundant free carboxyl groups as reactive sites for subsequent functionalization. In this work, we used zeta potential analysis, transmission electron microscopy, small angle X-ray scattering, and Inductively coupled plasma mass spectrometry to investigate the adsorption behavior of U (VI) on bare and coated colloidal superparamagnetic nanoparticles at pH 2 and pH 7. At pH 2, uranyl ion (UO 2 2+ ) absorbed on the surface of the bare particles with decreasing particle surface charge. This induced particle agglomeration. At pH 7, uranyl ion (UO 2 2+ ) hydrolyzed and formed plate-like particles of uranium hydroxide that were ∼50 nm in diameter. The PAA-coated iron oxide nanoparticles absorbed on the surface of these U (VI) hydroxide plates to form large aggregates that precipitate to the bottom of the dispersion. At both pH 2 and pH 7, the resulting U (VI)/nanoparticle complex can be easily collected and extracted from the aqueous environment via an external magnetic field. The results show that both bare and polymer-coated superparamagnetic γ-Fe 2 O 3 nanoparticles are potential absorbents for removing U (VI) from water.

Original languageEnglish
Pages (from-to)381-387
Number of pages7
JournalApplied Surface Science
Publication statusPublished - Jul 31 2018



  • Effective removal
  • Small-angle X-ray scattering
  • Superparamagnetic nanoparticles
  • Uranium (VI)

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Physics and Astronomy(all)
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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