Adsorption Behavior of Lysozyme on Carbon-Coated Fe3O4 Nanoparticles
Background: Recently, hydrophilic carbon-coated magnetite (Fe3O4/C) has been prepared
and applied in adsorption and separation sciences. Although there have been some works on preparation
and application of Fe3O4/C in adsorption and separation sciences, little work has been carried
out on protein adsorption and desorption on Fe3O4/C. Herein, the present work investigated the equilibrium
and kinetics of protein (lysozyme) adsorption on Fe3O4/C NPs.
Methods: Fe3O4/C NPs were prepared by hydrothermal method. Effects of pH, initial lysozyme concentrations,
and ionic strength on adsorption performance of Fe3O4/C NPs were investigated.
Desorption of lysozyme from the Fe3O4/C was examined using 0.5M NaH2PO4, 0.5M NaCl and
1.5M NaSCN, respectively.
Results: Fe3O4 and Fe3O4/C NPs with uniform particle size were of quasi-spherical shapes and the
dominant diameters of them were about 300 nm and 330 nm, respectively. A coating thickness of
carbon on surface of the Fe3O4/C NPs was about 15 nm. Fe3O4/C NPs exhibited typical superparamagnetic
characteristics with the maximal saturation magnetization of 73.8 emu/g. Fe3O4/C NPs
had a maximum adsorption of lysozyme at pH 9. The adsorption kinetics data fitted well into the
pseudo-second-order model while the adsorption equilibrium results were best described by the
Conclusion: Fe3O4/C NPs were prepared by hydrothermal reaction and applied to adsorb lysozyme.
The maximum adsorption of lysozyme on Fe3O4/C NPs arose at pH 9. Adsorption equilibria could be
reached within 40 min. Adsorption kinetics of lysozyme on Fe3O4/C NPs could be expressed by
pseudo-second order model. Langmuir isotherm fitted with experimental data best. The theoretical
maximum adsorption capacity of Fe3O4/C NPs for lysozyme was 76.34 mg/g. The best desorption
rate was about 32.7%.
Keywords: Adsorption, Carbon coated Fe3O4 nanoparticles, Isotherm, Kinetics, Lysozyme, Magnetic separation.
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