report
6.5.5 Applications and perspectives

At the time the following applications are the most promising:

- in-situ remediation of chlorinated solvents in groundwater with nano iron

- on-site removal of metals, especially As, from groundwater with iron oxides

- on-site removal of pollutants (e.g. pesticides, nitrate) by nanofiltration

- on-site destruction of organic pollutants using nano TiO2-photocatalysis

As the following paragraphs illustrate, it is confirmed that there is mass production of nZVI particles and that nZVI is applied in field trials in different places in Europe. On commercial applications of nanofiltration and TiO2-photocatalysis, there are now information so far. It is thus to be assumed that these techniques are not yet ready for large scale applications.

A product called AC Nano (a JNJ Smart-Sorb product) which is supposed to remove heavy metals (lead, cadmium, nickel, zinc, copper, manganese and cobalt) from contaminated soils, groundwater and industrial wastewater was developed by AC Environmental. The composition of the remediation material though is not public. A similar product also addresses arsenic contamination and the company is working on a AC Nano-product that will remove mercury. AC Nano is claimed to be non-toxic.

(http://www.ac-environmental.com/products/acnano/removing-heavy-metals)

nZVI

A comprehensive review of nZVI for groundwater remediation is found in the focus report 2010 which can be downloaded from http://www.observatorynano.eu/project/catalogue/2EV.FO/

According to Richard Mach (Naval Facilities Engineering Command) nanoscale iron was not commercially available until 2003. But within the first year, the costs for the material dropped two times (Federal Remedial Technology Roundtable http://www.frtr.gov/pdf/meetings/l--mach_09jun04.pdf). The Czech company “Nanoiron” (www.nanoiron.cz) has informed in January 2009 that they have started the mass production of nZVI particles. They offer three products:

• NANOFER 25* -  Aqueous dispersion of Fe(0) nanoparticles stabilized solely by an inorganic modifier. The product exhibits an extremely high reactivity with preservation of long- term stability but is characterized by a higher degree of agglomeration and faster sedimentation.
• NANOFER 25S* -  Aqueous dispersion of Fe(0) nanoparticles with special patented surface modification which is based on combination of a biodegradable organic and inorganic stabilizer. The product exhibits not only a high reactivity with a large scale of pollutants, but also very low degree of agglomeration, which implies for excellent migration and sedimentation properties. It is destined especially for the application in the reduction technologies of treatments of contaminated underground waters.
• NANOFER 25N* -  Nanopowder, consisting of Fe(0) nanoparticles without surface modification, preserved in the inert nitrogen atmosphere. The product exhibits extremely high reactivity and is usable for any secondary stabilization in dependence on particular application of nanoparticles.

Verutek and the USEPA (U.S. Environmental Protection Agency) have developed a green synthesis method of nanometals using plant extracts (provisional patent obtained) (http://www.verutek.com/Nano%20Zero%20Valent%20Iron.htm) which is used for the treatment of soils and groundwater (http://www.verutek.com/Role%20of%20 Nanomaterials%20.htm).

Meisol Ltd., a company set up in February 2008, is developing a new composite material for the remediation of contaminated groundwater, soil and wastewater. The composite material is formed by bonding nano-sized zero-valent iron (nZVI) particles with metalloporphyrin catalysts onto a diatomite matrix that shows catalytic activity toward different contaminants, especially to halogenated organic compounds, that are common soil and groundwater pollutants. http://www.incubators.org.il/26064.htm

Golder Associates (www.golder.com), an international company specialized in environmental engineering, is working with nZVI and bimetallic nanoparticles for groundwater remediation. In Europe the company is present with about 25 offices in 13 countries. More than 40 projects with nZVI are managed. In Europe, pilot tests and field applications for remediation in the Czech Republic, Italy and Germany are carried out since 2004. The company describes remediation with nZVI to be very effective (within a short time period), less costly and easily ajustable to site-specific requirements. Further applications of nZVI in wastewater and drinking water treatment are planned.

Alenco Environmental Consult GmbH, a German company with 7 offices in Germany and Hungary, is also advertising nano iron for remedation. A project description of the first full-scale remediation with nano iron in Europe can be found on their website: http://www.fe4u.de

A report published by Lloyd’s in 2007 (http://www.nanet.nu/upload/centre/nanet/nyheder/lloydsemergingrisksteamreport_nanotechnology_report.pdf) claims that it is very unlikely that any companies are using

nanotechnology for remediation in the UK, even though there is no ban on using nanoparticles for environmental use.

A field test at a CHC contaminated site in Germany by the Federal Institute for Geosciences and Natural Resources (BGR) (Houben et al., 2006) indicated that injection of nZVI particles caused significant changes in redox chemistry while other physico-chemical and hydrochemical parameters of the groundwater were not negatively affected. The limited penetration depth and lateral dispersion prevented the clean-up of a larger part of the test site.

Information on different case studies (supervised by governmental bodies) and background information on nZVI is found in the report of the U.S. EPA Workshop on Nanotechnology for Site Remediation (http://es.epa.gov/ncer/publications/workshop/pdf/10_20_05_nanosummary.pdf)

as well as in the presentation of the Naval Facilities Engineering Command at the Federal Remedial Technology Roundtable (http://www.frtr.gov/pdf/meetings/l--mach_09jun04.pdf)