Environmental Engineering Reference
In-Depth Information
7.5
N,o-CoNtaiNiNg ligaNds
7.5.1
edta
A series of reports are dedicated to eDTA-based (Fig. 7.12) nanochelators due to commercial availability of this classic ligand.
Thus, separation of cerium ions from dilute cerium feed solution was carried [36] out by nanofiltration. Cerium rejection by
nanofiltration assisted by complexation with eDTA as chelating agent was markedly influenced by ph (2-10), where a higher
degree of cerium removal was achieved for the basic medium than the acidic medium. The maximum observed rejection of
Ce(III) was found to be 94.37 and 90.03% for an initial feed concentration of 10 and 80 mg/l, respectively. Attachment of
eDTA-like chelators to carbon-coated metal nanomagnets resulted in a magnetic reagent for the rapid removal of heavy metals
(Cd, Pb, Cu) from solutions or contaminated water by three orders of magnitude to concentrations as low as µg/l [37]. In
addition, eDTA was used as a precursor for metal complex formation and further to control the growth of NPs. Thus, monoclinic
scheelite-type BiVO
4
NPs with large surface area, synthesized using Bi(NO
3
)
3
and Nh
4
VO
3
as raw materials, through a hydro-
thermal process in the presence of eDTA [38], exhibited a good photocatalytic performance for degrading phenol solution as a
model organic pollutant under visible illumination. The key feature of this method was found to be the chelating role of the
eDTA group in the synthetic process, which can greatly control the concentration of Bi
3+
, leading to growth inhibition of BiVO
4
crystallites.
7.5.2
Chitosan-Based Nanomaterials
Chitosan (Fig. 7.13) has attracted considerable interest because of its unique combination of properties, such as biocompati-
bility, biodegradability, metal complexation, and antibacterial activity. Therefore, chitosan has a variety of current and potential
applications in various fields, for example, biotechnology, pharmaceutics, wastewater treatment, cosmetics, and food science.
O
O
OH
OH
N
N
HO
O
OH
O
figure 7.12
eDTA.
CH
2
OH
CH
2
OH
CH
2
OH
OH
O
O
O
OH
OH
O
OH
O
OH
NH
2
n
NH
2
NH
2
figure 7.13
Chitosan.
