2.2. Characterization
The concentration of Fe was obtained by inductively coupled
plasma emission spectrometry (ICP-MS) (Vistampxicp Varian,
USA). The morphology of NP was observed using a JEOLJEM-2010
transmission electron microscope. The hydrodynamic diameter of
NPs was obtained by dynamic light scattering (DLS) with a Malvern
Zetasizer Nano ZS model ZEN3600. FT-IR spectra were registered
using Nicolet Avatar 370 with KBr pellets. The UV–vis spectra were
obtained using a DU 730 UV–vis–NIR spectrophotometer. The value
of T2 was measured with a 0.5 T magnet NMI20-Analyst (Shanghai,
Niumag Corporation).