Iron-Based Magnetic Nanoparticles for Removal of Heavy Metals from Electroplating and Metal-Finishing Wastewater - Nanotechnologies for Water Environment Applications - page 253

freeze-dried for XPS investigation. It is found that there is no chromium peak present on
the XPS spectra, indicating that the remained chromium ions were thoroughly washed
out from nanoparticles.

3.0

2.5

Cu(II)
Ni(II)
Cr(VI)

2.0

1.5

1.0

0.5

0.0

0 20 40 60 80 100 120

Time (min)

Figure 9.26 Desorption kinetics of adsorbed and Cr(VI), Cu(II) and Ni(II).

30

25

20

15

10

5

Cr(VI) Cu(II) Ni(II)

0

1 2 3 4 5

Cycle number

Figure 9.27 Adsorption capacity of -Fe 2 O 3 nanoparticles in five cycles of a
regeneration study (Hu et al., 2006).