Tag Archives: nano zero valent iron

Nanoremediation to be combined with bioremediation for soil decontamination

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There’s a very interesting proposal to combine nanoremediation with bioremediatiion (also known as, phytoremediation) techniques to decontaminate soil. From a June 10, 2016 news item on Nanowerk,

The Basque Institute of Agricultural Research and Development Neiker-Tecnalia is currently exploring a strategy to remedy soils contaminated by organic compounds containing chlorine (organochlorine compounds). The innovative process consists of combining the application of zero-iron nanoparticles with bioremediation techniques. The companies Ekotek and Dinam, the UPV/EHU-University of the Basque Country and Gaiker-IK4 are also participating in this project known as NANOBIOR.

A June 10, 2016 Elhuyar Fundazioa news release, which originated the news item, provides more detail about the proposed integration of the two techniques,

Soils affected by organochlorine compounds are very difficult to decontaminate. Among these organochlorine compounds feature some insecticides mainly used to control insect pests, such as DDT, aldrin, dieldrin, endosulfan, hexachlorocyclohexane, toxaphene, chlordecone, mirex, etc. It is a well-known fact that the use of many of these insecticides is currently banned owing to their environmental impact and the risk they pose for human health.

To degrade organochlorine compounds (organic compounds whose molecules contain chlorine atoms) present in the soil, the organisations participating in the project are proposing a strategy based on the application, initially, of zero-iron nanoparticles [also known as nano zero valent iron] that help to eliminate the chlorine atoms in these compounds. Once these atoms have been eliminated, the bioremediation is carried out (a process in which microorganisms, fungi, plants or enzymes derived from them are used to restore an environment altered by contaminants to its natural state).

The bioremediation process being developed by Neiker-Tecnalia comprises two main strategies: biostimulation and bioaugmentation. The first consists of stimulating the bacteria already present in the soil by adding nutrients, humidity, oxygen, etc. Bioaugmentation is based on applying bacteria with the desired degrading capability to the soil. As part of this process, Neiker-Tecnalia collects samples of soils contaminated by organochlorine compounds and in the laboratory isolates the species of bacteria that display a greater capacity for degrading these contaminants. Once the most interesting strains have been isolated, the quantity of these bacteria are then augmented in the laboratory and the soil needing to be decontaminated is then inoculated with them.

Bank of effective strains to combat organochlorines

The first step for Neiker-Tecnalia is to identify bacterial species capable of degrading organochlorine compounds in order to have available a bank of species of interest for use in bioremediation. This bank will be gathering strains collected in the Basque Country and will allow bacteria that can be used as a decontaminating element of soils to be made available.

The combining of the application of zero-iron nanoparticles and bioremediation constitutes a significant step forward in the matter of soil decontamination; it offers the added advantage of potentially being able to apply them in situ. So this methodology, which is currently in the exploratory phase, could replace other processes such as the excavation of contaminated soils so that they can be contained and/or treated. What is more, the combination of the two techniques makes it possible to reduce the decontamination times, which would take much longer if bioremediation is used on its own.

There is a NANOBIOR webpage here.

For the curious I have two 2012 posts that provide some very nice explanations by Joe Martin, then a Master’s student in the University of Michigan’s Public Health program,: Phyto and nano soil remediation (part 1: phyto/plant) and Phyto and nano soil remediation (part 2: nano).

NanoRem: pollution, nanotechnology, and remediation

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According to a July 6, 2013 news item on Nanowerk, nanoremediation is not the right term for referring to pollution cleanup technologies that are nanotechnology-enabled,

In the remediation of pollutions in the soil and groundwater, minute nanoparticles are being increasingly used that are to convert resp. break down pollutants on site. The process, often somewhat mistakenly described as “nano-remediation”, can also be used with contaminations that have been hard to fight up to now, for example through heavy metals or the notorious, carcinogenic softener PCB. Yet how do the various nanoparticles behave in the earth, are they in turn harmless for humans and the environment and how can they be produced at a favourable price? These questions were investigated by scientists from the Research Facility for Subsurface Remediation (VEGAS) of the University of Stuttgart together with 27 partners from 13 countries in the framework of EU project “NanoRem”, planned to last four years. For this purpose the European Union is providing around 10.5 million Euros from the 7th research framework programme.

The July 6, 2013 news item on Nanotechnology Now (ordinarily, I’d quote from the University of Stuttgart press release which originated the Nanowerk and Nanotechnology Now news items but the university’s website seems to be experiencing technical problems) provides more details about treating pollution with ‘nanotechnology-enabled’ techniques and more information about NanoRem,

Nanotechnologies are particularly suited for treating groundwater aquifers but also contaminated soil at the site of the contamination (in situ). However, in remediation projects (reclamation of contaminated sites), they have only been used hesitantly since an effective and reliable application is not yet mature, the potential risks for the environment difficult to assess and nano-remediation in addition comparatively expensive due to the still high manufacturing costs of nanoparticles. The nanotechnology, however, offers advantages: compared to the classic remediation processes, such as “Pump & Treat” (pumping off contaminated groundwater and cleaning it in a treatment plant) or chemical, resp. microbiological in-situ remediation processes, the range of “treatable” contaminants is greater. In addition, a quick and targeted break down of pollutants can be achieved, for example also in industrial buildings without the production being interrupted. “Through nanotechnology we are expecting a significant improvement in the remediation service and the operational areas”, according to the Stuttgart coordinator Dr. Hans-Peter Koschitzky. This would not only be beneficial for the environment but would also be attractive from an economical point of view: the world market for the application of environmental nanotechnologies was estimated to be a total of six billion US Dollars in 2010.

Against this background the scientists involved in NanoRem want to develop practical, efficient, safe and economical nanotechnologies for in-situ remediation with the aim of enabling a commercial use as well as a spread of the application in Europe. The focus is on the best-suited nanotechnologies as well as favourably priced production techniques. For this purpose questions on the mobility and reactivity of nanoparticles in the subsoil as well as the possible risk potential for mankind and environment in particular are to be investigated. A further aim is the provision of a comprehensive “tool box” for the planning and monitoring of the remediation as well as success control.

The Stuttgart researchers will be focusing on the use of nanoscale iron particles (aka, nano zero valent iron nZVI?; you can find out more about zNVI in my Mar. 20, 2012 posting) as per the news items,

The researchers from the Stuttgart Research Facility for Subsurface Remediation, VEGAS, are concentrating on the large-scale implementation of nano-iron particles within the project. Initially three large-scale tests are conducted: artificial aquifers are established with defined sand layers of various properties in large stainless steel containers in the experimental hall and flooded with groundwater. In each of these large-scale tests a defined source of pollution is incorporated, then various nanoparticles are injected. Probes in the container provide information on the concentrations of pollutants and nanoparticles as well as on the remediation progress at many sites in the aquifer. These tests are validated by Dutch and Italian partners with the help of a numerical groundwater flow and transport model. Finally, field tests at sites in need of remediation with various requirement profiles are conducted in several countries in Europe in order to verify the efficiency and profitability of nano-remediation. In particular, however, they also serve the purpose of achieving acceptance through transparency Europe-wide with public authorities and the public.

There is more information about the NanoRem project on the CORDIS website. The NanoRem website is currently (July 8, 2013) under construction but does offer more overview information on its landing page.

Canadian soil remediation expert in Australia

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Back in my Nov. 4, 2011 posting where I reviewed the third episode in a limited series on nanotechnology, broadcast as a Nature of Things television science programme on  Canadian Broadcasting Corporation stations, I noted Dr. Dennis O’Carroll’s soil remediation work in southern Ontario.

There’s more news about professor O’Carroll, currently visiting Australia, in a June 4, 2012 news item on Nanowerk,

“Toxic contamination of soils is an historical problem,” says Dr Denis O’Carroll, a visiting academic at the University of New South Wales (UNSW) Water Research Lab. “Until the 1970s, people wrongly believed that if we put these toxins into the ground they would simply disappear – that the subsurface would act as a natural filtration unit.”

“The possibility of this waste polluting the environment, and potentially contaminating groundwater sources and remaining there for decades was ignored,” he says.

Far from magically disappearing, chemical contaminants from spilled gas and solvents, when not directly polluting surface waters, seep down into the earth, travelling through microscopic soil cracks, where they accumulate and can eventually reach the groundwater table.

Traditional clean-up methods have focussed on pumping out the contaminated water or flushing out toxins with a specially designed cleansing solution, but these are limited by difficulties in accurately pinpointing and accessing locations where contamination has occurred, says O’Carroll.

His approach is to tackle toxic contaminants with nanotechnology. O’Carroll, who is visiting UNSW from the University of Western Ontario in Canada, has been trialling an innovative new groundwater clean-up technology using metal nanoparticles 500 to 5,000 times narrower than a human hair.

There are more details about O’Carroll’s specific innovations in this field in the June 4, 2012 news item. As well, I published, in its entirety (and with permission), an excellent description of nanotechnology-enabled soil remediation by Joe Martin, a graduate student at the University of Michigan, in my March 30, 2012 posting. Here’s a tidbit from Joe’s article,

… The use of iron oxides to adsorb and immobilize metals and arsenic is not a new concept, but nano-particles offer new advantages. When I wrote “adsorb”, I was not making a spelling error; adsorption is a process by which particles adhere to the surface of another material, but do not penetrate into the interior. This makes surface area, not volume, the important characteristic. Nano-particles provide the maximum surface area-to-weight ratio, maximizing the adsorptive surfaces onto which these elements can attach. These adsorptive processes a very effective at binding and immobilizing metals and arsenic, but they do not allow for the removal of the toxic components. This may be less-than-ideal, but in places like Bangladesh, where arsenic contamination of groundwater poses major health risks, it may be just short of a miracle.

There’s an extensive list with links to further reading and videos on the topic of nanotechnology and site remediation at the end of the March 30, 2012 posting.

Phyto and nano soil remediation (part 2: nano)

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For Part 2, I’ve included part of my original introduction (sans the story about the neighbour’s soil and a picture of Joe Martin):

I’m pleased to repost a couple of pieces on soil remediation written by Joe Martin for the Mind the Science Gap (MTSG) blog.

I wrote about the MTSG blog in my Jan. 12, 2012 posting, which focussed on this University of Michigan project designed by Dr. Andrew Maynard for Master’s students in the university’s Public Health program. Very briefly here’s a description of Andrews and the program from the About page,

Mind the Science Gap is a science blog with a difference.  For ten weeks between January and April 2012, Masters of Public Health students from the University of Michigan will each be posting weekly articles as they learn how to translate complex science into something a broad audience can understand and appreciate.

Each week, ten students will take a recent scientific publication or emerging area of scientific interest, and write a post on it that is aimed at a non expert and non technical audience.  As the ten weeks progress, they will be encouraged to develop their own area of focus and their own style.

…

About the Instructor.  Andrew Maynard is Director of the University of Michigan Risk Science Center, and a Professor of Environmental Health Sciences in the School of Public Health.  He writes a regular blog on emerging technologies and societal implications at 2020science.org.

Here’s a bit more about Joe Martin,

I am a second year MPH student in Environmental Quality and Health, and after graduation from this program, I will pursue a Ph.D. in soil science.  My interests lie in soil science and chemistry, human health and how they interact, especially in regards to agricultural practice and productivity.

Here’s part 2: nano soil remediation or Joe’s Feb. 10, 2012 posting:

Last week I wrote about phytoremediation, and its potential to help us combat and undo soil contamination. But, like any good advanced society, we’re not pinning all our hopes on a single technique. A commenter, Maryse, alerted me to the existence of another promising set of techniques and technologies: nano-remediation.

For those who don’t know, nano-technology is a science which concerns itself with manipulating matter on a very small scale.  Nano-particles are commonly described as being between 100 nanometers (nm) to 1nm, though this is hardly a hard and fast rule. (For perspective, a nanometer is one one-millionth of a millimeter. If you aren’t inclined to the metric system, there are roughly four hundred million nanometers per inch.) On such micro-scales, the normal properties of compounds can be altered without changing the actual chemical composition. This allows for many new materials and products, (such as Ross Nanotechnology’s Neverwet Spray,) and for new applications for common materials, (using graphene to make the well-known carbon nanotubes).

When we apply the use of nano-scale particles to the remediation of contaminated soil, we are using nano-remediation. Unlike phytoremediation, this actually encompasses several different strategies which can be broadly classes as adsorptive or reactive. (Mueller and Nowack, 2010) The use of iron oxides to adsorb and immobilize metals and arsenic is not a new concept, but nano-particles offer new advantages. When I wrote “adsorb”, I was not making a spelling error; adsorption is a process by which particles adhere to the surface of another material, but do not penetrate into the interior. This makes surface area, not volume, the important characteristic. Nano-particles provide the maximum surface area-to-weight ratio, maximizing the adsorptive surfaces onto which these elements can attach. These adsorptive processes a very effective at binding and immobilizing metals and arsenic, but they do not allow for the removal of the toxic components. This may be less-than-ideal, but in places like Bangladesh, where arsenic contamination of groundwater poses major health risks, it may be just short of a miracle.

Reactive nano-remediation strategies focus on organic pollutants, and seem to work best for chlorinated solvents such as the infamous PCBs. Nano-scale zero valent iron, or nZVI, is the most widely explored and tested element used in these methods. The nZVI, or sometimes nZVI bound to various organic molecules like polysaccharides or protein chains, force redox reactions which rapidly disassemble the offending molecules.

There are other advantages to these nano-molecular techniques aside from the efficiency with which they bind or destroy the offending pollutants. In reactive remediation, the hyper reactivity nZVI causes it to react with other common and natural elements, such as dissolved oxygen in ground water, or nitrate and sulfate molecules, and in the process this inactivates the nZVI. While this forces multiple applications of the nano-particle (delivered in slurry form, through an injection well), it also prevents unused iron from drifting out of the treatment zone and becoming a pollutant itself. For adsorptive and reactive remediation techniques, that active nano-particles are injected into a well dug into or near the contaminated soil and/or groundwater. When injected as a slurry, the nano-particles can drift along with the flow of ground water, effectively creating an “anti-pollution” plume. In other formulations, the active mixture is made to flow less easily, effectively creating a barrier to filter spreading pollution or through which polluted ground water can be pulled.

There are health risks and concerns associated with the production and use of nano-particles, so some caution and validation is needed before its used everywhere. However, there has already been some successes with nano-remediation. The example of PCB remediation with nZVI is taken from great success the US Air Force has had. (PCB contamination is a legacy of their use as fire-suppressants). Beyond this, while nano-remediation has not been widely applied on surface or near-surface soils, it does enable remediation in deeper soils normally only accessed by “pump-and-treat” methods, (which are expensive and can have decades-long time frames). When coupled with other techniques, (like phytoremediation), it does fit nicely into an expanding tool bag, one with which we as a society and species can use to reverse our impact on the planet, (and our own health).

Further Reading: There was no way for me to represent the full sum of nano-remediation, nevertheless nanotechnology, in this post. It has such potential, and is developing at such a rate that the attention it deserves is better measured in blogs (or perhaps decablogs). So if you are interested in nano-technology or nano-remediation, click through some of the links below.

List of popular blogs: http://www.blogs.com/topten/10-popular-nanotechnology-blogs/, including some very important ones on the health risks of nano-technology.

A cool site listing sites currently using nano-remediation: http://www.nanotechproject.org/inventories/remediation_map/, and another post from the same site dealing with nano-remediation [PEN webcast on site remediation]: http://www.nanotechproject.org/events/archive/remediation/

An excellent peer-reviewed article: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2799454/

Citation: Mueller C and Nowack B. Nanoparticles for Remediation: Solving Big Problems with Little Particles. 2010. Elements, Vol. 6. pp 395-400.

You can read about the other MTSG contributors and find links to their work here.

I have mentioned remediation before on the blog,

soil remediation and Professor Dennis Carroll at the University of Western Ontario in my Nov. 4, 2011 posting

remediation and a patent for Green-nano zero valent iron (G-nZVI) in my June 17, 2011 posting

groundwater remediation and nano zero valent iron (nZVI) at the University of California at Santa Barbara in my March 30, 2011 posting

site remediation and drywall in my Aug. 2, 2010 posting

remediation technologies and oil spills my May 6, 2010 posting

my March 4, 2010 posting  (scroll down about 1/2 way) which is a commentary on the Project for Emerging Nanotechnologies (PEN) webcast about site remediation in Joe’s list of resources

Thank you Joe for giving me permission to repost your pieces. For more of Joe’s pieces,  Read his posts here –>

Green-nano zero valent iron (G-nZVI)

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I’m quite interested in patents and their possible impact on nanotechnology innovation so this item caught my attention. VeruTEK Technologies, Inc. just received notice of a patent allowance for the Green-nano zero valent iron (G-nZVI) product which was developed in collaboration with the US Environmental Protection Agency (EPA).

From the June 15, 2011 news item on Nanowerk,

The product is ideal for a broad range of remediation applications including treating produced water (wastewater) generated during oil and gas and other chemical production processes.

G-nZVI works more efficiently than conventional iron catalysts, significantly increasing the rate of oxidant activity and can be used under a wide range of conditions.  Unlike other catalysts which are typically sensitive to changes in pH, G-nZVI consistently delivers high performance over a wide pH range. G-nZVI is highly effective as an activator for VeruTEK’s patent-pending Surfactant-enhanced In Situ Chemical Oxidation (S-ISCO®) treatment of hydrocarbon and chlorinated solvent contamination. The product can also be used with conventional in situ chemical oxidation (ISCO) to improve the effectiveness of traditional remediation chemistry.

The EPA works with VeruTEK on a variety of projects, concentrating on new field-proven approaches to address difficult environmental issues. According to John Leazer, Director of the Sustainable Technology Division at EPA’s National Risk Management Research Laboratory in Cincinnati, “Patent awards are superb examples of what can be accomplished through collaborative research and development.” [emphases mine]

I have previously written about nano zero valent iron (nZVI) and site remediation in my March 30, 2011 posting which concerned a benchmarking study for nZVI and briefly in my March 4, 2010 posting (towards the end) where I summarized a Project on Emerging Nanotechnologies webcast (approximately 54 min.) on the topic.

As I understand it, the process (green or environmentally friendly) by which the nano zero valent iron is derived is the reason the VeruTek product has been awarded a patent and not because its remediation capabilities are superior to other nano zero valent iron products. From the VeruTEK’s G-nZVI product page,

GnZVI is a green synthesized nanoscale zero valent iron catalyst invented by VeruTEK and the US EPA. During the green synthesis process iron salts are exposed to naturally reductive plant material, the resultant nanoscale particles are coated in iron oxide and plant polyphenols which confer advantageous properties.  Research conducted by VeruTEK, the EPA and the University of Connecticut, published in peer reviewed journals, demonstrate the efficacy of the product and its unique chemical design.

So, in addition to being used to remove contamination, this product itself is manufactured in a relatively environmentally friendly fashion. Nice!

Of course, there’s a fair amount of discussion about how patenting impedes innovation. From Mike Masnick’s Feb. 17, 2011 article on Techdirt,

As with any “hot” technology area, it doesn’t take long for a massive, innovation hindering patent thicket to spring up. It effectively makes it impossible to bring anything to market unless you’ve got a huge patent portfolio yourself and deep pockets. Yet another example of patents harming the smaller players in the market. A new report is suggesting that the latest “hot” area to get patent crazy is nanotechnology.

However, the really worrying thing about the report is that it notes that the single largest “patent patron” in nanotechnology… is the federal government. [emphasis mine]

The report, The Big Downturn; Nanogeopolitics, that Masnick is referring to is from The ETC Group who released it on Dec. 17, 2010 so the material in it is relatively recent. They provide the only overview of the nanotechnology patent scene (Chapter 12, p. 43 PDF version and p. 36 print version) that I’ve come across so far. I find the reference to the federal government (US in this case) as being the largest patent patron interesting in light of the EPA’s collaborative relationship with VeruTEK.

One comment before you rush off to read The ETC Group’s report, the tone is very much ‘we are on the side of the angels; capitalists and governments and ‘anyone who disagrees with us in any way’ are not.”

Nano zero valent iron and groundwater remediation

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My interest in nano zero valent iron (nZVI) and site remediation was piqued by a webcast from the Project on Emerging Nanotechnologies (PEN). (I commented on the ‘cast in my March 4, 2010 posting [http://www.frogheart.ca/?p=792 {scroll down}]). Yesterday(March 29, 2011), I came across a news item on Business Wire (http://www.businesswire.com/news/home/20110329005424/en/AECOM-University-California-Santa-Barbara-UCSB-Continue) about a collaboration between AECOM and the University of California at Santa Barbara for benchmark testing of nZVI. From the news item,

The new AECOM and UCSB bench-scale studies will test use of several zero valent iron (ZVI) products, including nano zero valent iron (nZVI), on the remediation of chlorinated volatile organic compounds (CVOCs) a common contaminant at groundwater remediation sites. nZVI products were selected for the study because they have a much greater surface area than conventional iron powders, which make them more effective in certain site remediation scenarios.

The bench-scale studies will use samples of these new products on groundwater and geologic materials collected from a former manufacturing site to evaluate the morphology or structure of the products as well as their mobility, persistence, and toxicity to aquatic organisms.

According to Dr. Dora Chiang, P.E. Project Design Engineer with AECOM’s environmental practice in Atlanta, “We have had an in situ bioremediation system in place for several years and will be using an nZVI or other ZVI products to supplement biodegradation of the CVOCs. Enhanced non-biological degradation, coupled with ongoing biodegradation of CVOCs, will likely result in a reduction in treatment time by remediating CVOCs to below their respective federal drinking water maximum contaminant levels (MCLs). This new treatment technology may save significant life-cycle cleanup costs while ensuring protection of human health and the environment.”

…

Dr. Arturo A. Keller, Co-Director of UC Center for Environmental Implications of Nanotechnology, will direct the research at UCSB, in coordination with Prof. Hunter Lenihan. Prof. Keller states that “there is great potential in using nZVI and related technologies to solve a wide range of contamination issues. However, we need to determine the potential risks to achieve safe implementation of this important technology.”

Nano zero valent iron is currently being used in site remediation in the US and elsewhere in the world. PEN has an interactive nanoremediation map here (http://www.nanotechproject.org/inventories/remediation_map/). Just click on one of the ‘balloons’ to get a full description of where, which contaminant, and which type of nanomaterial (e.g. the site in Ontario, Canada lists nZVI) is being used for the cleanup operation.

You can find out more about AECOM here (http://www.aecom.com) from their About page,

AECOM (NYSE: ACM) is a global provider of professional technical and management support services to a broad range of markets, including transportation, facilities, environmental, energy, water and government.

With approximately 45,000 employees around the world, AECOM is a leader in all of the key markets that it serves. AECOM provides a blend of global reach, local knowledge, innovation, and technical excellence in delivering solutions that create, enhance and sustain the world’s built, natural, and social environments.

A Fortune 500 company, AECOM serves clients in more than 100 countries and had revenue of $7.0 billion during the 12 months ended Dec. 31, 2010.

AECOM is ranked by Ethisphere as one of the world’s 110 most ethical companies for 2011.

That’s a very big company. As for their ethics, I like to see what they do when the going gets tough. After all, BP Oil had a very good reputation at one point and then they had the oil spill in the Gulf of Mexico and destroyed that reputation with their subsequent actions.

California’s call for information about nanomaterials

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A little late but better than never, the US state of California has issued a call for information focused on analytical test methods, i.e., lab procedures for testing, nano silver, nano zero valent iron, nano titanium dioxide, nano zinc oxide, nano cerium oxide, and quantum dots. The deadline for a response is Dec. 21, 2011, one year from the date of the request. From the Dec. 27, 2010 news item on Nanowerk,

DTSC [Department of Toxic Substances Control] has conducted a search of known public sources for analytical test methods for these six nanomaterials. We have compiled our research in this bibliography. DTSC has also contacted and consulted with manufacturers, researchers, environmental laboratory experts, other governments, and stakeholders regarding analytical test methods for these nanomaterials in these matrices. We convened public workshops and symposia on nanotechnology and, in particular, these six nanomaterials.

From our research, consultations, and workshops, we have determined that little or no information on analytical test methods for these nanomaterials in the human body or the environment now exists. To better understand the behavior, fate and transport of the se six nanomaterials, appropriate analytical test methods are needed for manufacturers, for contract and reference laboratories, and for regulatory agencies.

You can get more information about the call from the DTSC site including a list of companies that received the ‘call for information’ letter.