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{{Nanomat}}

'''Nanoscale iron particles''' are sub-micrometer particles of [[iron]] metal. They are highly [[Chemical reaction|reactive]] because of their large surface area. In the presence of oxygen and water, they rapidly [[oxidize]] to form free iron [[ion]]s. They are widely used in medical and laboratory applications and have also been studied for remediation of industrial sites contaminated with chlorinated organic compounds.
== Synthesis ==
Iron nanoparticles can be synthesized by the reduction of Fe(II) or Fe(III) salt with [[sodium borohydride]] in an aqueous medium.


[[File:Reduction of Fe(III).gif]]

== Reactivity ==
When exposed to oxygen and water, iron oxidizes. This [[redox]] process can occur under either [[acid]]ic or neutral/[[Base (chemistry)|basic]] conditions:

:2 Fe<sup>0</sup>(s) + 4 H<sup>+</sup>(aq) + O<sub>2</sub>(aq) → 2 Fe<sup>2+</sup>(aq) + 2 H<sub>2</sub>O(l)

: Fe<sup>0</sup>(s) + 2 H<sub>2</sub>O (aq) → Fe<sup>2+</sup>(aq) + H<sub>2</sub>(g) + 2 OH<sup>−</sup>(aq)

==Research==
Research has shown that nanoscale iron particles can be effectively used to treat several forms of [[ground contamination]], including grounds contaminated by [[polychlorinated biphenyl]]s (PCBs), chlorinated organic solvents, and [[organochlorine]] pesticides.  Nanoscale iron particle are easily transportable through ground water, allowing for [[In_situ#Biology and biomedical engineering|in situ]] treatment.  Additionally, the nanoparticle-water slurry can be injected into the contaminated area and stay there for long periods of time.<ref name="Zhang">{{cite journal |last=Zhang |first=Wei-xian |year=2003 |title=Nanoscale iron particles for environmental remediation: an overview |journal=[[Journal of Nanoparticle Research]] |volume=5 |pages=323–332 |doi=10.1023/A:1025520116015 |issue=3/4|bibcode=2003JNR.....5..323Z }}</ref> These factors combine to make this method cheaper than the most currently used alternative.

Researchers have found that although metallic iron nanoparticles remediate contaminants well, they tend to agglomerate on the soil surfaces.  In response, [[carbon nanoparticles]] and water-soluble [[polyelectrolyte]]s have been used as supports to the metallic iron nanoparticles.  The [[hydrophobic]] contaminants adsorb to these supports, improving permeability in sand and soil.<ref name="Zhang"/>

In field tests have generally confirmed lab findings.  However, research is still ongoing and nanoscale iron particles are not yet commonly used for treating ground contamination.

==See also==
*[[Health and safety hazards of nanomaterials]]
*[[Environmental implications of nanotechnology]]

==References==
{{Reflist}} 
2.http://www.chalcogen.infim.ro/1771_Yuvakkaur.pdf

==External links==
*[http://www.nano.gov National Nanotechnology Initiative]
*[http://www.understandingnano.com/water.html Nanotechnology methods to clean up water pollution]
* [https://web.archive.org/web/20131029020046/http://nanoiron.cz/en/applications Largescale production and applications of zero-valent iron nanoparticles (nZVI)]

[[Category:Nanoparticles by composition]]
[[Category:Environmental science]]
[[Category:Pollution control technologies]]
[[Category:Iron]]


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