Environmental Engineering Reference
In-Depth Information
photosynthetic aquatic micro- and macro-organisms occurs and ulti-
mately becomes a major cause of eutrophication, or extensive algae
growth. All parameters being equal, HAIX containing hydrated iron oxide
nanoparticles was compared with a granular ferric hydroxide (GFH) with-
out any ion exchange material. h e HAIX provided signii cantly greater
phosphate removal capacity [52]. Phosphate breakthrough with HAIX
occurred at er nearly four thousand bed volumes, while the commercially
available GFH column from the US Filter Corp. showed a breakthrough
at er one thousand bed volumes. Iron nanoparticles have been encapsu-
lated with silica in order to increase stability and prevent aggregation.
Iron oxide has been shown to retard the proliferation of bacteria. h e
incorporation of iron oxide catalyzed ozonation technology increases the
retention of bacteria to the surface of membranes, resulting in improved
remediation of water. Iron oxide catalyzed ozonation and membrane i l-
tration combine to improve inactivation and/or removal of bacteria [53].
h ere is fast adsorption of methylene blue on polyacrylic acid-bound iron
oxide magnetic nanoparticles [54].
7.5
Silicon Oxide Nanoparticles for Nanoremediation
Silica nanoparticles are promising materials as a solid-phase extract-
ant because of their large surface area, high adsorption capacity, low
temperature modification, lesser degree of unsaturation and low elec-
trophilicity (Figure 7.3). The sequence of reactivity is expressed as
follows:
Zr(OR)
4
, Al(OR)
4
> Ti(OR)
4
> Sn(OR)
4
>> Si(OR)
4
(7.15)
OH
OH
OH
SiO
2
OH
OH
OH
OH
OH
Figure 7.3
Silica nanoparticle.
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