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Nanoremediation: Information for Decision Makers from NanoRem

Thematic Page 2: Benefits of Using Nanoparticles in Remediation


1.  Aim
2.  Broad Benefits of In Situ Treatments in General
3.  Benefits of In Situ Nanoremediation using nZVI
4.  NanoRem Activities
5.  Additional Resources on the NanoRem Web Site
6.  References
7.  Feedback and Opinions

1 Aim 

This page summarises the benefits of using nano-scale zero valent iron particles (nZVI) in remediation, compared to the use of alternative in situ technologies. nZVI has been the most widely used nanoparticle type in practice. 

This thematic page summarises information provided by a chapter of the NanoRem report: 'A Risk/Benefit Appraisal for the Application of Nano-Scale Zero Valent Iron (nZVI) for the Remediation of Contaminated Sites'. The full report including additional information, detail and referencing can be downloaded from: 

2 Broad Benefits of In Situ Treatments in General

Over the last 30 years, approximately 80,000 sites have been remediated in European countries (European Commission 2014). Early efforts were largely based on containment, “pump and treat” and/or removal to landfill. However, treatment based approaches began to become widely available from the late-1980s (NATO / CCMS 2002). In the majority of remediation projects, the contaminated materials (solid or liquid) are removed to the surface prior to treatment (ex situ). However, in many cases the excavation of contaminated material may be neither desirable, nor even feasible; e.g. the contamination may be inaccessible: either at significant depth or below operational plant infrastructure or building footprints. In such cases the contamination can be addressed using in situ remediation technologies. 

A range of in situ technologies are in use that exploit biological, chemical, physical and/or thermal processes to treat soil and/or groundwater in the sub-surface. In situ remediation is now a significant remediation market segment (Nathanail et al. 2013), although it is still only employed on a minority of projects. These enable remediation to be undertaken with minimal disruption to site operations and with minimal exposure of site workers and others to the contaminants (e.g. in dust, gas or vapours). The “footprint” of an in situ remediation project tends to be much smaller than for an ex situ scheme, meaning that treatment can usually be carried out where access and available space are restricted.

The use of nanoparticles potentially extends the range of available in situ remediation technologies, and may offer particular benefits in some applications. Zero valent iron (essentially finely ground iron) has been used as a treatment reagent in in situ remediation for many years, in particular for permeable reactive barriers. Nano-scale zero valent iron (nZVI) is a type of iron nanoparticle that has been investigated for deployment for in situ remediation as a groundwater and aquifer treatment technology.

Proponents of the use of nZVI see it as a remediation intervention capable of delivering a substantial improvement in remediation performance for a wide range of problems. This view is based at least in part on projections from laboratory-scale performance (Tratnyek and Johnson 2006). However, like many remediation techniques, the transfer of use of nZVI from laboratory scale experiments to practical remediation applications has seen this potential constrained.

3 Benefits of In Situ Nanoremediation using nZVI

The broad potential benefits seen for using nZVI fall into a number of categories: improving the extent and rate of contaminant destruction; extending the treatable range of contaminants, in particular some persistent organic pollutants; providing source term treatment capability; limited longevity of action; and compatibility with other treatments. Each of these categories is described in more detail in the sections following.

Extending the Range of Treatable Contaminants

The nano-scale effects of nZVI have been shown to extend the range of treatable contaminants leading to the destruction of organic contaminants and the transformation and/or precipitation of inorganic contaminants such as the treatment of hexavalent chromium (Cr(VI)) (Singh et al. 2012). Additional studies have demonstrated the treatment of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), pentachlorophenol (PCPs), and the chlorinated benzenes. nZVI has also been considered as a treatment for radionuclides such as radium, uranium and pertechnetate.

A full overview of the known treatability of contaminant categories by nZVI based on bench scale work can be found in Annex 2 of the report “A Risk/Benefit Appraisal for the Application of Nano-Scale Zero Valent Iron (nZVI) for the Remediation of Contaminated Sites”
www.nanorem.eu/Displaynews.aspx?ID=525. However, the range of contaminants treated in the field is not as broad.

Improving the Extent and Speed of Contaminant Destruction

Due to their small particle size, nanoparticles have a very high specific surface area, which significantly increases their reactivity. In addition, the enhanced surface area allows the particles to be in more intimate contact with the contaminants. In theory, the combination of these two features should make nanoparticles more efficient compared with other solid chemical reactants, including microscale ZVI, in treating identical contaminant masses. This effect can be significantly enhanced by the use of catalytic bimetallic nanoparticles (BNP). In bench-scale tests, BNPs of iron combined with palladium showed contaminant degradation two orders of magnitude greater than microscale iron particles alone (Zhang 2006b). However, it should be noted that this claim has been difficult to verify in the field largely due to the heterogeneous nature of in situ conditions.

The most common usage of nZVI to date has been to degrade chlorinated solvents such as perchloroethene (PCE), trichloroethene (TCE), and other chlorinated aliphatic hydrocarbons. Bench scale studies indicate that in the presence of nZVI, PCE is degraded fully to ethane, ethene, or other light non-chlorinated hydrocarbons, without the build-up of toxic intermediates (Gavaskar et al. 2005). While the majority of published papers on field trials have supported these conclusions, it should be noted that some researchers investigating the use of nZVI have reported the
production of short lived toxic intermediates, including vinyl chloride (VC) (De Boer 2009).

3.3 Providing Source Term Treatment Capability

Generally, nZVI is highly reactive to contaminants in the dissolved phase and the sorbed phase, and technologies to enhance activity against the free phase have also been tested such as eZVI (emulsified nano-scale zero valent iron). The high reactivity of nZVI has led to suggestions that it could be injected as an in situ source management application in saturated zones, capable of destroying NAPL (Quinn et al. 2005). In practice, the ability of nZVI to reduce the amount of contamination as a source is limited by the accessibility and availability of the source contamination to the nZVI being supplied to treat it, and the physical amount of iron that is needed to treat the source term. Al-Shamsi et al. (2013) found treatment of NAPL using bimetallic Pd-Fe was constrained by a lack of effective injection technique. Likewise, Fagerlund et al. (2012) found that nZVI applied directly in the vicinity of a PCE NAPL source did not enhance NAPL dissolution and increase the speed for remediation. Moreover, the reaction rate was controlled by the dissolution rate of the NAPL. Similar results were found by Phenrat et al. (2011), who found poor treatment of high saturation pools of DNAPL.

3.4 Limited Activity

The active lifespan of nZVI particles has been shown to be limited, even when modified to improve their stability (<1-2 years) (See Thematic Page: Application of nZVI in Remediation). This can be beneficial for some remediation interventions where the treatment agent should not persist or where limited mobility is desired (i.e. source depletion). However, it can also be a drawback, for example, in cases where nZVI is being used as the active component within a PRB matrix, as it would need to be renewed on a regular basis. 

3.5 Compatibility with Other Treatments

A number of researchers have suggested that nZVI may be suitable for deployment
alongside other remediation technologies, with some studies demonstrating a synergistic effect. In particular, the combination of nZVI and biodegradation reduced the concentration of chlorinated solvents in an aquifer by 76%, compared to a reduction of only 48% when nZVI was applied in isolation (Lacinová et al. 2013). However, it should be noted that other researchers have reported that nano-scale iron-nickel BNPs are inhibitory to biological dechlorination.  

Jiamjitrpanich et al. (2012) examined the compatibility of nZVI with phytoremediation techniques for the removal of 2,4,6-trinitrotoluene (TNT) from soil, where TNT contaminated soil was treated with hyperaccumulator plants and nZVI applications, as both single and combined treatments. Results suggested TNT removal was highest where soils were treated with a combination of nZVI and hyperaccumulator plants.

4 NanoRem Activities

Bench scale test work and subsequent modelling indicate potential benefits for nZVI remediation, in particular relating to speed of action, range of treatable problems, extent of degradation and potential for source zone treatments. However, in practical applications this has not been demonstrated in the field where the use of nZVI has been restricted to a relatively narrow range of problems principally the destruction of chlorinated solvents (see FAQ: Where have nanoparticles been used in remediation?) Further, there has been an insufficient number of field demonstrations to collect the data necessary to adequately validate treatment performance. This is also considered to be part of the reason for the limited uptake of this technology.

The NanoRem project aims to investigate practical benefits of nanoremediation by:
  • Laboratory testing of nZVI on very persistent contaminants including additional chlorinated (and brominated or fluorinated) organic compounds (PCBs, lindane, TNT, chlorinated ethanes) and inorganic compounds (heavy metals, nitrates, sulphates, and radionuclides).
  • Close interactions between laboratory and field based project teams.
  • Undertaking a number of fully documented and costed field trials at a number of sites with differing hydro - chemical characteristics. These trials will include fully delineating the contamination sources, installing dedicated monitoring equipment to allow the continual monitoring of nanoparticle concentrations within the ground water, and a sampling programme to establish the fate of nanoparticles and their degradation products within the subsurface.
  • Carefully designed NR field trials using a range of iron-based NPs, which will be fully documented and incorporate costs, performance, and fate and transport information.
  • Integrated laboratory treatability studies and field trials.
  • Dissemination and dialogue with key stakeholders to ensure that the research, development and demonstration outputs meet end-user and regulatory requirements and that information and knowledge is shared widely across the EU.
  • Source zone treatments.

5 Additional Resources on the NanoRem Web Site

This thematic page summarises information provided by a chapter of the NanoRem report: 'A Risk/Benefit Appraisal for the Application of Nano-Scale Zero Valent Iron (nZVI) for the Remediation of Contaminated Sites'. The full report including additional information, detail and referencing can be downloaded from: 

Additional summary information is also available on the following online pages.


Currently we have the following FAQ pages:


6 References

AL-SHAMSI, M. A., AND THOMSON, N. R. 2013 ‘Treatment of a Trichloroethylene Source Zone using Persulfate Activated by an Emplaced Nano-Pd–Fe0 Zone’,
Water, Air, & Soil Pollution, 224, 11, 1-12. 


Singh R, Misra V, Singh RP Environ Monit Assess. 2012 Jun; 184(6):3643-51

LIEN, H., ELLIOTT, D.W., SUN, Y. AND ZHANG, W. 2006 ‘Recent progress in zero-valent iron nanoparticles for groundwater remediation’, Journal of Environmental Engineering and Management, 16, 6, 371-380.

European Commission – Life and Soil Protection, 2014 - ISBN 978-92-79-34664-4.

FAGERLUND, F., ILLANGASEKARE, T. H., PHENRAT, T., KIM, H. J., AND LOWRY, G. V. 2012 ‘PCE dissolution and simultaneous dechlorination by nanoscale zero-valent iron particles in a DNAPL source zone’, Journal of Contaminant Hydrology, 131(1), 9-28.


GAVASKAR, A., TATAR, L. AND CONDIT, W. 2005 Cost and Performance Report Nanoscale Zero-Valent Iron Technologies for Source Remediation, Contract Report CR-05-007-ENV. [Online] Available at:

JIAMJITRPANICH, W., PARKPIAN, P., POLPRASERT, C., AND KOSANLAVIT, R. 2012 ‘Enhanced Phytoremediation Efficiency of TNT-Contaminated Soil by Nanoscale Zero Valent Iron’ International Proceedings of Chemical, Biological & Environmental Engineering: Environment and Industrial Innovation, 35, 82-86.


LACINOVÁ, L., ČERNÍKOVÁ, M., HRABAL AND J., ČERNÍK, M. 2013 ‘In-Situ Combination of Bio and Abio Remediation of Chlorinated Ethenes’ Ecological Chemistry and Engineering, 20, 463–473.


NATO / Committee on the Challenges of Modern Society – 2002 overview report NATO/CCMS pilot study.

NATHANAIL, C. P. BARDOS, R. P., GILLETT, A., MCCAFFREY, C., OGDEN, R., SCOTT, D., NATHANAIL, J. 2013. “SP1004 International Processes for Identification and Remediation of Contaminated Land” [Online] Available at: http://randd.defra.gov.uk/Default.aspx?Menu=Menu&Module=More&Location=None&Completed=0&ProjectID=16289#Description

PHENRAT, T., FAGERLUND, F., ILLANGASEKARE, T., LOWRY, G. V., AND TILTON, R. D. 2011 ‘Polymer-modified Fe0 nanoparticles target entrapped NAPL in two dimensional porous media: effect of particle concentration, NAPL saturation, and injection strategy’ Environmental Science & Technology, 45, 14, 6102-6109.


TRATNYEK, P.G. AND JOHNSON, R.L. 2006 ‘Nanotechnologies for environmental cleanup’, Nano Today, 1, 2, 44-48.

DE BOER C., KLAAS N., AND BRAUN J. 2009 ‘Anwendung nanoskaliger
Eisenkolloide zur In-Situ-Sanierung anthropogener CKW-Kontaminationen im
Untergrund.’ Wissenschaftlicher Bericht Nr. VEG 36, 2009/05. University of Stuttgart


QUINN, J., GEIGER, C., CLAUSEN, C., BROOKS, K., COON, C., O’HARA, S., KRUG, T., MAJOR, D., YOON, W-S., GAVASKAR, A. AND HOLDSWORTH, T.  2005 ‘Field demonstration of DNAPL dehalogenation using emulsified zero-valent iron’, Environmental Science and Technology, 39, 5, 1309-1318


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Taking Nanotechnological Remediation Processes from Lab Scale to End User Applications for the Restoration of a Clean Environment.
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