Environmental Engineering Reference
In-Depth Information
11.6
Magnetic Nanoparticles in Wastewater
Treatment
Magnetic nanoparticles such as Fe
3
O
4
and α-Fe
2
O
3
have been investigated
to resolve various environmental problems, such as removing toxic metal
ions and radioactive elements, capturing microbial pathogens and organic
dyes, accelerating the coagulation of sewage, and remediation of contami-
nated soils [84, 85, 86]. h e magnetic nanoparticles possess high surface
area, high chemical stability and optimal magnetic properties, which lead
to high adsorption ei ciency, highly ei cient removal of contaminants,
and easy and rapid separation of adsorbent from solution via external
magnetic i eld.
Magnetism of the nanomaterials is a unique property that autono-
mously assists in water/wastewater purii cation by inl uencing the physical
properties of contaminants in aqueous solutions. h us, magnetic separa-
tions of pollutants have been used extensively in wastewater treatment and
environmental cleanup. Magnetic iron oxide nanomaterials are promising
candidates for larger scale wastewater treatment due to their easy func-
tionalization, low cost, high adsorption capacity, strong physicochemical
stability, and easy separations. h us, these nanomaterials can be ei ciently
utilized for the treatment of wastewater containing hazardous dyes and
toxic metal ions. In the following sections we have described the appli-
cation of magnetic nanoparticles for rapid removal of heavy metals from
aqueous environments.
11.6.1
Magnetic Nanoparticles as Nanosorbents for Heavy
Metals
Heavy metal contamination of aqueous environments is an increasing
worldwide problem. Heavy metals are well known to cause serious envi-
ronmental and health problems due to their bioaccumulation through the
food chain, and cause serious damage to the nervous and endocrine sys-
tems of human beings. h erefore, the development of selective and ei cient
methodologies for detecting and removing heavy metals from aqueous
media is in great demand.
During the past few years, the majority of scientii c research and large-
scale i eld applications of materials for treatment of wastewater containing
heavy metals have focused on magnetic nanoparticles, activated carbon,
carbon nanotubes, biosorbents, zero-valent iron, and photocatalysts [87,
88, 89, 90, 91, 92, 93]. Among all these materials, magnetic nanoparticles
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