Nanoparticles as Sorbents for Removal of Heavy Metal Ions from Aqueous Solutions - Nanotechnologies for Water Environment Applications - page 145

Table 6.3 Survey of literatures on nanoparticles and their applications for heavy metal removal.
Type of
Nanoparticles

Particle
Size (nm)

Target Heavy
Metals Ion

Major Binding Sites or Functional Groups
for Heavy Metal Removal

Reference

Zero-Valent Iron Nanoparticles
Nanoscale Zero-Valent Iron
(NZVIs)

1-120 As(III), As(V) Initially the sites are amorphous Fe(II)/Fe(III), magnetite

(maghemite). As treatment proceeds, initial reactive sites
gradually transform into lepidocrocite and more crystalline
magnetite.

Kanel et al . , 2005;
Kanel et al . , 2006.

~10 Cr(VI) Maghemite Nanoparticles The major binding site is hydroxyl groups of iron oxide. Hu et al., 2006.

10-200 Zn(II), Cd(II),

Pb(II), Ni(II),
Cu(II), Ag(I),
Cr(VI), Hg(II)

Core/Shell Nanoscale Zero-
Valent Iron (Fe(0)/Fe(III))

Simultaneous adsorption and co-precipitation may occur,
depending on the standard redox potential difference between the
Fe 0 and the incoming heavy metal. Major binding site is Fe-
OH.

Li and Zhang, 2006;
Li and Zhang, 2007.

Modified Iron-Based Nanoparticles
Modified Jacobsite
(MnFe 2 O 4 )

~10 Cr(VI) The major adsorptive components are MnO 2 and Fe 2 O 3 . Hu et al., 2005.

~20 Cr(VI)

Nanoscale Ferrites, MeFe 2 O 4
(Me = Mn, Co, Cu, Mg, Zn,
Ni)

For MnFe 2 O 4 , the major driving force for adsorption is chemical
redox reaction between Mn(II) and incoming Cr(VI).

Hu et al., 2007.

Magnetic Nanoparticles
Encapsulated by Poly(3,4-
ethylenedioxythiophene)
(PEDOT)

~11 Ag(I), Hg(II),

Pb(II)

The major binding sites are the O-donor-atoms and S-donor-
atoms of the PEDOT.

Shih and Jang, 2007.

Magnetite Nanoparticles
Modified with
Dimercaptosuccinic acid

~6 Hg(II), Co(II),

Cu(II), As(V),
Ag(I), Cd(II),
Tl(III), Pb(II)

The major binding site responsible for remarkable heavy metal
binding is thiol groups originated from the dimercaptosuccinic
acid added.

Yantasee et al . , 2007.

Poly(N-Isopropylacrylamide)-Based Nanoparticles
Poly(N-isopropylacrylamide)
Nanoparticles (PNIPAAm)

~550 Pb(II), Cd(II) The electrostatic interactions conferred to the microgel are from

the thermal initiators which possess the sulfate, carboxylic, and
amidine group, respectively.

Snowden et al . , 1993.