Magnetic chitosan nanoparticles: Studies on chitosan binding and adsorption of Co(II) ions

Yang Chuang Chang, Song Wen Chang, Dong Hwang Chen

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225 Citations (Scopus)


The magnetic chitosan nanoparticles of 13.5 nm were prepared as a magnetic nano-adsorbent by the carboxymethylation of chitosan and the followed binding on the surface of Fe3O4 nanoparticles via carbodiimide activation. Their saturation magnetization, remanent magnetization, coercivity, and squareness were 62 emu/g, 1.8 emu/g, 6.0 Oe, and 0.029, respectively, reflecting their superparamagnetic property. The binding reaction of carboxymethyl chitosan on the surface of Fe3O4 nanoparticles was much faster than the self-crosslinking of carboxymethyl chitosan, and the appropriate reaction time was 1 h. At low carboxymethyl chitosan concentrations, the binding efficiency could be as high as 100%. The maximum amount of chitosan bound on the Fe3O4 nanoparticles was 4.92 wt%. In addition, magnetic chitosan nano-adsorbent was shown to be quite efficient for the fast removal of Co(II) ions at pH 3-7 and 20-45 °C. The maximum adsorption capacity for Co(II) ions occurred at pH 5.5, and the adsorption process was exothermic in nature with an enthalpy change of -12.04 kJ/mol. The equilibrium was achieved within 1 min, and the adsorption data obeyed the Langmuir equation with a maximum adsorption capacity of 27.5 mg/g (557 mg/g based on the weight of chitosan) and a Langmuir adsorption equilibrium constant of 0.034 l/mg at 25 °C. Such fast adsorption rate and high adsorption capacity could be attributed to the absence of internal diffusion resistance and the high specific surface area.

Original languageEnglish
Pages (from-to)335-341
Number of pages7
JournalReactive and Functional Polymers
Issue number3
Publication statusPublished - 2006 Mar

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Environmental Chemistry
  • Biochemistry
  • Chemical Engineering(all)
  • Polymers and Plastics
  • Materials Chemistry


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