iron nanoparticle

Iron nanoparticles can be synthesized using two primary approaches: top-down and bottom-up methods.{{Cite journal |last1=Saif |first1=Sadia |last2=Tahir |first2=Arifa |last3=Chen |first3=Yongsheng |date=November 2016 |title=Green Synthesis of Iron Nanoparticles and Their Environmental Applications and Implications |journal=Nanomaterials |language=en |volume=6 |issue=11 |pages=209 |doi=10.3390/nano6110209 |doi-access=free |issn=2079-4991 |pmc=5245755 |pmid=28335338}}

Top-down approaches create nanoparticles by breaking down larger bulk materials into smaller particles, including laser ablation and mechanical grinding.

Bottom-up approaches involve the chemical and biological synthesis of iron nanoparticles from metal precursors (e.g., Fe(II) and Fe(III)). This method is widely regarded as the most effective and commonly used strategy for nanoparticle preparation. For example, iron nanoparticles can be chemically prepared by reducing Fe(II) or Fe(III) salts with sodium borohydride in an aqueous medium. This process can be described by the following equations:{{Cite journal |last1=Wang |first1=Chuan-Bao |last2=Zhang |first2=Wei-xian |date=1997-07-01 |title=Synthesizing Nanoscale Iron Particles for Rapid and Complete Dechlorination of TCE and PCBs |url=https://pubs.acs.org/doi/10.1021/es970039c |journal=Environmental Science & Technology |volume=31 |issue=7 |pages=2154–2156 |doi=10.1021/es970039c |bibcode=1997EnST...31.2154W |issn=0013-936X|url-access=subscription }}{{Cite journal |last1=Ponder |first1=Sherman M. |last2=Darab |first2=John G. |last3=Mallouk |first3=Thomas E. |date=2000-06-01 |title=Remediation of Cr(VI) and Pb(II) Aqueous Solutions Using Supported, Nanoscale Zero-valent Iron |url=https://pubs.acs.org/doi/10.1021/es9911420 |journal=Environmental Science & Technology |volume=34 |issue=12 |pages=2564–2569 |doi=10.1021/es9911420 |bibcode=2000EnST...34.2564P |issn=0013-936X|url-access=subscription }}

:4 Fe³⁺ + 3 BH₄⁻ + 9 H₂O → 4 Fe⁰↓ + 12 H⁺ + 6 H₂ + 3 H₂BO⁻{{spaces|6}}(1)

:4 Fe²⁺ + 3 BH₄⁻ + 9 H₂O → 4 Fe⁰↓ + 8 H⁺ + 8 H₂ + 3 H₂BO⁻{{spaces|6}}(2)

Iron nanoparticles are prone to oxidation when exposed to air and water. This redox process can occur under both acidic and neutral/basic conditions:{{Cite journal |last1=Dickinson |first1=Michelle |last2=Scott |first2=Thomas B. |date=2010-06-15 |title=The application of zero-valent iron nanoparticles for the remediation of a uranium-contaminated waste effluent |url=https://linkinghub.elsevier.com/retrieve/pii/S0304389410000932 |journal=Journal of Hazardous Materials |volume=178 |issue=1 |pages=171–179 |doi=10.1016/j.jhazmat.2010.01.060 |pmid=20129731 |bibcode=2010JHzM..178..171D |issn=0304-3894|url-access=subscription }}

:2 Fe⁰ + 4 H⁺ + O₂ → 2 Fe²⁺ + 2 H₂O{{spaces|6}}(3)

:Fe⁰ + 2 H₂O → Fe²⁺ + H₂ + 2 OH⁻{{spaces|6}}(4)

Research has shown that nanoscale iron particles can be effectively used to treat several forms of ground contamination, including grounds contaminated by polychlorinated biphenyls (PCBs), chlorinated organic solvents, and organochlorine pesticides. Nanoscale iron particles are easily transportable through ground water, allowing for in situ treatment. Additionally, the nanoparticle-water slurry can be injected into the contaminated area and stay there for long periods of time.{{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 }} 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 polyelectrolytes have been used as supports for the metallic iron nanoparticles. The hydrophobic contaminants adsorb to these supports, improving permeability in sand and soil.

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.

Iron oxide nanoparticles (IONPs) have widespread applications in biomedicine, including their use in magnetic resonance imaging and cancer therapy via magnetic hyperthermia{{Cite journal |last1=Espinosa |first1=Ana |last2=Di Corato |first2=Riccardo |last3=Kolosnjaj-Tabi |first3=Jelena |last4=Flaud |first4=Patrice |last5=Pellegrino |first5=Teresa |last6=Wilhelm |first6=Claire |date=2016-02-23 |title=Duality of Iron Oxide Nanoparticles in Cancer Therapy: Amplification of Heating Efficiency by Magnetic Hyperthermia and Photothermal Bimodal Treatment |url=https://pubs.acs.org/doi/full/10.1021/acsnano.5b07249 |journal=ACS Nano |volume=10 |issue=2 |pages=2436–2446 |doi=10.1021/acsnano.5b07249 |pmid=26766814 |issn=1936-0851|url-access=subscription }}{{Cite journal |last1=Liu |first1=Jia |last2=Xu |first2=Jie |last3=Zhou |first3=Jun |last4=Zhang |first4=Yu |last5=Guo |first5=Dajing |last6=Wang |first6=Zhigang |date=2017-02-09 |title=Fe3O4-based PLGA nanoparticles as MR contrast agents for the detection of thrombosis |journal=International Journal of Nanomedicine |language=English |volume=12 |pages=1113–1126 |doi=10.2147/IJN.S123228 |doi-access=free |pmc=5310639 |pmid=28223802}}

In addition to these applications, IONPs exhibit strong antibacterial activity and have been explored for drug and viral vector delivery to target cells.{{Cite journal |last1=V. |first1=Gudkov, Sergey |last2=E. |first2=Burmistrov, Dmitriy |last3=A. |first3=Serov, Dmitriy |last4=B. |first4=Rebezov, Maksim |last5=A. |first5=Semenova, Anastasia |last6=B. |first6=Lisitsyn, Andrey |date=July 2021 |title=Do Iron Oxide Nanoparticles Have Significant Antibacterial Properties? |url=https://www.mdpi.com/2079-6382/10/7/884 |journal=Antibiotics |language=en |volume=10 |issue=7 |doi=10.3390/antibiotic |doi-broken-date=12 April 2025 |doi-access=free |issn=2079-6382 |archive-url=http://web.archive.org/web/20250304223852/https://www.mdpi.com/2079-6382/10/7/884 |archive-date=2025-03-04}} Known microorganisms susceptible to the toxic effects of IONPs include Gram-negative bacteria (e.g., Escherichia coli and Klebsiella sp.) and Gram-positive bacteria (e.g., Bacillus sp. and Corynebacterium sp.) .

The antibacterial activity of IONPs is primarily attributed to the generation of reactive oxygen species (ROS), a mechanism similar to the Fenton reaction. Specifically, Fe²⁺ ions react with hydrogen peroxide (H₂O₂), producing Fe³⁺ ions and hydroxyl radicals.{{Cite journal |last1=Groiss |first1=Silvia |last2=Selvaraj |first2=Raja |last3=Varadavenkatesan |first3=Thivaharan |last4=Vinayagam |first4=Ramesh |date=2017-01-15 |title=Structural characterization, antibacterial and catalytic effect of iron oxide nanoparticles synthesised using the leaf extract of Cynometra ramiflora |url=https://www.sciencedirect.com/science/article/abs/pii/S0022286016309589 |journal=Journal of Molecular Structure |volume=1128 |pages=572–578 |doi=10.1016/j.molstruc.2016.09.031 |issn=0022-2860|url-access=subscription }} These highly reactive species induce oxidative damage to bacterial DNA, ultimately leading to cell death.

• Health and safety hazards of nanomaterials
• Environmental implications of nanotechnology

{{Reflist}}

• [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