Category Archives: environment

Nanowaste or the end of the life cycle for nanoscale materials

A Jan. 27, 2015 Nanwerk spotlight article on nanowaste presents a comprehensive picture of possible issues (Note: Footnotes have been removed),

Based on their special chemical and physical properties, synthetically produced nanomaterials (engineered nanomaterials, ENMs) are currently being used in a wide range of products and applications. The Nanomaterial Databank of Nanowerk … currently lists nanomaterials composed of 28 different elements as well as of carbon (fullerenes, CNT, graphene), quantum dots consisting of several semi-conductor materials, a large number of simple nanoparticulate compounds (oxides, carbonates, nitrides) and those made up of complex compounds containing several components. On the one hand, the application of nanomaterials promises reduction potentials and sustainability effects for the environment, for example through resource and material savings ….

On the other hand, we know very little about the behavior of nanomaterials or about environmental and health risks when these products enter various waste streams at the end of their life cycles. A better understanding of the risks in the so-called End-of-Life-Phase (EOL) calls for considering the different disposal pathways and potential transformation processes that nanomaterials undergo in waste treatment plants. In the disposal phase no consideration is being given to either the special properties of nanomaterials or to potential recovery and re-use. …

There is no special legal framework in place for a separate treatment of nanomaterial containing wastes … or the monitoring of the processes. A prerequisite for such a framework would be exact knowledge about the nanomaterials being used, their form (species) and composition, potential transformation processes as well as about amounts and concentrations. Such information, however, is not available, and virtually no studies have been conducted on the EOL phase of products containing nanomaterials. Very little is known about how nanomaterial-containing wastes behave in thermal, biological or mechanical-biological waste treatment plants or in landfills. …

The spotlight article appears to be a reprint of an ITA (Institute of Technology Assessment) NanoTrust Dossier [“Nanowaste” – Nanomaterial-containing products at the end of their life cycle (NanoTrust Dossier No. 040en – August 2014)] by Sabine Greßler, Florian Part, and André Gazsó,

Abstract:
Based on their special chemical and physical properties, synthetically produced nanomaterials are currently being used in a wide range of products and applications. At the end of their product life cycle, nanomaterials can enter waste treatment plants and landfills via diverse waste streams. Little, however, is known about how nanomaterials behave in the disposal phase and whether potential environmental or health risks arise. There are no specific legal requirements for a separate treatment of nanomaterial-containing wastes. Virtually no information is available about the nanomaterials currently in use, their form and composition, or about their amounts and concentrations. The current assumption is that stable nanoparticles (e.g. metal oxides) are neither chemically nor physically altered in waste incineration plants and that they accumulate especially in the residues (e.g. slag). These residues are ultimately dumped. The disposal problem in the case of stable nanoparticles is therefore merely shifted to the subsequent steps in the waste treatment process. Carbon nanotubes (CNT) are almost completely combusted in incineration plants. Filter systems seem to be only partially efficient, and a release of nanoparticles into the environment cannot be excluded. Incinerating nanomaterials contained in products can also promote the development of organic pollutants as undesired by-products. Only few studies are available on the behavior of nanomaterials in landfills. Moreover, recycling such products could release nanomaterials, most likely when these are shredded and crushed.

This dossier offers a good review of the current state of affairs with regard to nanowaste. I haven’t read it exhaustively but it coincides with my understanding of the situation including the fact that there’s not much research on the topic.

BTW, NanoTrust is a project of the Austrian Academy of Sciences’ Institute of Technology Assessment (ITA). The nanowaste dossier is also available in German.

Government of Canada’s risk assessment for multi-walled carbon nanotubes

Lynn Bergeson’s Jan. 15, 2015 post on the Nanotechnology Now website mentions a newly issued Canadian risk assessment for multi-walled carbon nanotubes (MWCNTs),

Canada announced on January 9, 2015, that the New Substances Program has published six new risk assessment summaries for chemicals and polymers, including a summary for multi-wall carbon nanotubes.

… Environment Canada and Health Canada conduct risk assessments on new substances. These assessments include consideration of information on physical and chemical properties, hazards, uses, and exposure to determine whether a substance is or may become harmful to human health or environment as set out in Section 64 of the Canadian Environmental Protection Act, 1999 (CEPA 1999), and, if harm is suspected, to introduce any appropriate or required control measures. …

Here’s more information from the Summary of Risk Assessment Conducted Pursuant to subsection 83(1) of the Canadian Environmental Protection Act, 1999
Significant New Activity No. 17192: Multi-wall carbon nanotubes webpage,

Substance Identity

The substance is a short tangled multi-walled carbon nanotube that can be classified as a nanomaterial. [emphasis mine]

Notified Activities

The substance is proposed to be manufactured in or imported into Canada in quantities greater than 1000 kg/yr for use as an additive in plastics.

Environmental Fate and Behaviour

Based on its physical and chemical properties, if released to the environment, the substance will tend to partition to water, sediment, soil, and ambient air. The substance is expected to be persistent in these compartments because it is a stable inorganic chemical that will not degrade. Based on the limited understanding of uptake by organisms, more data is required to assess the bioaccumulation potential of this substance at the current schedule notification.

Ecological Assessment

Based on the available hazard information on the substance and surrogate data on structurally related nanomaterials, the substance has low to moderate (1-100 mg/L) acute toxicity in aquatic life (fish/daphnia/algae). The predicted no effect concentration was calculated to be less than 1 mg/L using the ErC50 from the most sensitive organism (P. subcapitata), which was used to estimate the environmental risk.

The notified and other potential activities in Canada were assessed to estimate the environmental exposure potential of the substance throughout its life cycle. Environmental exposure from the notified activities was determined through a conservative generic single point-source release blending scenario. The predicted environmental concentration for notified activities is estimated to be 2.1 µg/L.

Based on the current use profile in conjunction with low to moderate ecotoxicity endpoints, the substance is unlikely to cause ecological harm in Canada.

However, based on the current understanding of carbon nanotubes and nanomaterials in general, a change in the use profile of the substance (SNAc No. 17192) may significantly alter the exposure resulting in the substance becoming harmful to the environment.  Consequently, more information is necessary to better characterize potential environmental risks.

Human Health Assessment

Based on the available hazard information on the substance, the substance has a low potential for acute toxicity by the oral, dermal and inhalation routes of exposure (oral and dermal LD50 greater than 2000 mg/kg bw; inhalation LC50 greater than 1.3 mg/m3). It is a severe eye irritant (MAS score = 68), a mild skin irritant (PII = 1.08) and at most a weak sensitizer (because the positive control was tested at a concentration 10X higher than the test substance). It is not an in vitro mutagen (negative in a mammalian cell gene mutation test and in a mammalian chromosome aberration test).  Therefore the substance is unlikely to cause genetic damage.

Hazards related to substances used in the workplace should be classified accordingly under the Workplace Hazardous Materials Information System (WHMIS).

However, based on the available information on structurally related nanomaterials, the substance may cause respiratory toxicity, immunotoxicity, cardiovascular toxicity and carcinogenicity following oral and inhalation exposure.

When used as an additive in plastics, the substance is expected to be manufactured in or imported into Canada encapsulated in a solid polymer matrix. The potential site of exposure to the substance is expected to be within industrial facilities. Therefore, direct exposure of the general population is expected to be low. No significant environmental release is anticipated due to the specialized use under this notification and therefore indirect exposure of the general population from environmental media is also expected to be low. However, if the substance is produced in different forms (e.g. liquid polymer form), applied in different formulations or used in any other potential applications, an increased direct or indirect exposure potential may exist.

Based on the low potential for direct and indirect exposure of the general population under the industrial uses identified in this submission, the substance is not likely to pose a significant health risk to the general population, and is therefore unlikely to be harmful to human health.

However, based on the current understanding of carbon nanotubes and of nanomaterials in general, the risk arising from the use of the substance in consumer products is not known at this time.  The use of the substance in consumer products or in products intended for use by or for children may significantly alter the exposure of the general population resulting in the substance becoming harmful to human health.  Similarly, the import or manufacture of the substance in quantities greater than 10 000 kg/yr may significantly increase the exposure levels of the general population resulting in the substance becoming harmful to human health.  Consequently, more information is necessary to better characterize potential health risks.

I would like to see a definition for the word short as applied, in this risk assessment, to multi-walled carbon nanotubes. That said, this assessment is pretty much in line with current thinking about short, multi-walled carbon nanotubes. In short (wordplay noted), these carbon nanotubes are relatively safe (although some toxicological issues have been noted) as far as can be determined. However, the ‘relatively safe’ assessment may change as more of these carbon nanotubes enter the environment and as people are introduced to more products containing them.

One last comment, I find it surprising I can’t find any mention in the risk assessment of emergency situations such as fire, earthquake, explosions, etc. which could conceivably release short multi-walled carbon nanotubes into the air exposing emergency workers and people caught in a disaster. As well, those airborne materials might subsequently be found in greater quantity in the soil and water.

Quantum dots, televisions, and a counter-intuitive approach to environmental issues

There’s a very interesting Jan. 8, 2015 essay by Dr. Andrew Maynard, being hosted on Nanowerk, about the effects that quantum dot televisions could have on the environment (Note: A link has been removed),

Earlier this week, The Conversation reported that, “The future is bright, the future is … quantum dot televisions”. And judging by the buzz coming from this week’s annual Consumer Electronics Show (CES) that’s right – the technology is providing manufacturers with a cheap and efficient way of producing the next generation of brilliant, high-definition TV screens.

But the quantum dots in these displays also use materials and technologies – including engineered nanoparticles and the heavy metal cadmium – that have been a magnet for health and environmental concerns. Will the dazzling pictures this technology allow blind us to new health and environmental challenges, or do their benefits outweigh the potential risks?

If I understand things rightly, cadmium is toxic at both the macroscale and the nanoscale and Andrew goes on to describe quantum dots (cadmium at the nanoscale) and the problem they could present in his Jan. 7, 2015 essay on The Conversation,also hosted by Nanowerk, (Note: Link have been removed),

Quantum dots are a product of the emerging field of nanotechnology. They are made of nanometer-sized particles of a semiconducting material – often cadmium selenide. About 2,000 to 20,000 times smaller than the width of a single human hair, they’re designed to absorb light of one color and emit it as another color – to fluoresce. This property makes them particularly well-suited for use in products like tablets and TVs that need bright, white, uniform backlights.

… What is unique about quantum dots is that the color of the emitted light can be modified by simply changing the size of the quantum dot particles. And because this color-shifting is a physical phenomenon, quantum dots far outperform their chemical counterparts in brightness, color and durability.

Unfortunately, the heavy metal cadmium used in the production of many quantum dots is a health and environmental hazard.

On top of this, the potential health and environmental impacts of engineered nanoparticles like quantum dots have been raising concerns with toxicologists and regulators for over a decade now. Research has shown that the size, shape and surface properties of some particles influence the harm they are capable of causing in humans and the environment; smaller particles are often more toxic than their larger counterparts. That said, this is an area where scientific understanding is still developing.

Together, these factors would suggest caution is warranted in adopting quantum dot technologies. Yet taken in isolation they are misleading.

The essay describes the risk factors for various sectors (Note: A link has been removed),

The quantum dots currently being used in TVs are firmly embedded in the screens – usually enclosed behind multiple layers of glass and plastic. As a result, the chances of users being exposed to them during normal operation are pretty much nil.

The situation is potentially different during manufacturing, when there is a chance that someone could be inadvertently exposed to these nanoscopic particles. Scenarios like this have led to agencies like the US National Institute for Occupational Safety and Health taking a close look at safety when working with nanoparticles. While the potential risks are not negligible, good working practices are effective at reducing or eliminating potentially harmful exposures.

End-of-life disposal raises additional concerns. While the nanoparticles are likely to remain firmly embedded within a trashed TV’s screen, the toxic materials they contain, including cadmium, could well be released into the environment. Cadmium is certainly a health and environmental issue with poorly regulated e-waste disposal and recycling. However, when appropriate procedures are used, exposures should be negligible.

It seems quantum dot televisions impose a smaller burden than their cousins on the environment,

Although it seems counter-intuitive, analysis by the company that was made available to the EPA [US Environmental Protection Agency] showed QD Vision’s products lead to a net decrease in environmental cadmium releases compared to conventional TVs. Cadmium is one of the pollutants emitted from coal-fired electrical power plants. Because TVs using the company’s quantum dots use substantially less power than their non-quantum counterparts, the combined cadmium in QD Vision TVs and the power plant emissions associated with their use is actually lower than that associated with conventional flat screen TVs. In other words, using cadmium in quantum dots for production of more energy-efficient displays can actually results in a net reduction in cadmium emissions.

Not the conclusion one might have drawn at the outset, eh? You can read the essay in its entirety on either Nanowerk (Jan. 8, 2015 essay) or The Conversation (Jan. 7, 2015 essay). (Same essay just different publication dates.) Andrew has also posted his essay on the University of Michigan Risk Science Center website, Are quantum dot TVs – and their toxic ingredients – actually better for the environment? Note: Andrew Maynard is the center’s director.

Treating municipal wastewater and dirty industry byproducts with nanocellulose-based filters

Researchers at Sweden’s Luleå University of Technology have created nanocellulose-based filters in collaboration with researchers at the Imperial College of London (ICL) good enough for use as filters according to a Dec. 23, 2014 news item on Nanowerk,

Prototypes of nano-cellulose based filters with high purification capacity towards environmentally hazardous contaminants from industrial effluents e.g. process industries, have been developed by researchers at Luleå University of Technology. The research, conducted in collaboration with Imperial College in the UK has reached a breakthrough with the prototypes and they will now be tested on a few industries in Europe.

“The bio-based filter of nano-cellulose is to be used for the first time in real-life situations and tested within a process industry and in municipal wastewater treatment in Spain. Other industries have also shown interest in this technology and representatives of the mining industry have contacted me and I have even received requests from a large retail chain in the UK,” says Aji Mathew Associate Professor, Division of Materials Science at Luleå University.

A Dec. 22, 2014 Luleå University of Technology press release, which originated the news item, further describes the research,

Researchers have combined a cheap residue from the cellulose industry, with functional nano-cellulose to prepare adsorbent sheets with high filtration capacity. The sheets have since been constructed to different prototypes, called cartridges, to be tested. They have high capacity and can filter out heavy metal ions from industrial waters, dyes residues from the printing industry and nitrates from municipal water. Next year, larger sheets with a layer of nano-cellulose can be produced and formed into cartridges, with higher capacity.

– Each such membrane can be tailored to have different removal capability depending on the kind of pollutant, viz., copper, iron, silver, dyes, nitrates and the like, she says.

Behind the research, which is funded mainly by the EU, is a consortium of research institutes, universities, small businesses and process industries. It is coordinated by Luleå University led by Aji Mathew. She thinks that the next step is to seek more money from the EU to scale up this technology to industrial level.

– Alfa Laval is very interested in this and in the beginning of 2015, I go in with a second application to the EU framework program Horizon 2020 with goals for full-scale demonstrations of this technology, she says.

Two of Aji Mathews graduate student Peng Liu and Zoheb Karim is also deeply involved in research on nano-filters.

– I focus on how these membranes can filter out heavy metals by measuring different materials such as nanocrystals and nano-fibers to determine their capacity to absorb and my colleague focuses on how to produce membranes, says Peng Liu PhD student in the Department of Materials Science and Engineering at Luleå University of Technology.

I have been following the nanocellulose work at Luleå University of Technology for a few years now. The first piece was a Feb. 15, 2012 post titled, The Swedes, sludge, and nanocellulose fibres, and the next was a Sept. 19, 2013 post titled, Nanocellulose and forest residues at Luleå University of Technology (Sweden). It’s nice to mark the progress over time although I am curious as to the source for the nanocellulose, trees, carrots, bananas?

India, Lockheed Martin, and canal-top solar power plants

Apparently the state of Gujarat (India) has inspired at least one other state, Punjab, to build (they hope) a network of photovoltaic (solar energy) plants over top of their canal system (from a Nov. 16, 2014 article by Mridul Chadha for cleantechnica.com),

India’s northern state of Punjab plans to set up 1,000 MW of solar PV projects to cover several kilometres of canals over the next three years. The state government has announced a target to cover 5,000 km of canals across the state. Through this program, the government hopes to generate 15% of the state’s total electricity demand.

Understandably, the construction of canal-top power plants is technically and structurally very different from rooftop or ground-based solar PV projects. The mounting structures for the solar PV modules cannot be heavy, as it could adversely impact the structural integrity of the canal itself. The structures should be easy to work with, as they are to be set up over a slope.

This is where the Punjab government has asked Lockheed Martin for help. The US-based company has entered into an agreement with the Punjab government to develop lightweight mounting structures for solar panels using nanotechnology.

Canal and rooftop solar power projects are the only viable options for Punjab as it is an agricultural state and land availability for large-scale ground-mounted projects remains an issue. As a result, the state government has a relatively lower (compared to other states) capacity addition target of 2 GW.

There’s more about the Punjab and current plans to increase its investment in solar photovoltaics in the article.

Here’s an image of a canal-top solar plant near Kadi (Gujarat),

Canal_Top_Solar_Power_PlantImage Credit: Hitesh vip | CC BY-SA 3.0

A Nov. 15, 2014 news item by Kamya Kandhar for efytimes.com provides a few more details about this Memorandum of Understanding (MOU),

Punjab government had announced its tie up with U.S. aerospace giant Lockheed Martin to expand the solar power generation and overcome power problems in the State. As per the agreement, the state will put in 1,000 MW solar power within the next three years. Lockheed Martin has agreed to provide plastic structures for solar panels on canals by using nano technology.

While commenting upon the agreement, a spokesperson said, “The company would also provide state-of-the-art technology to convert paddy straw into energy, solving the lingering problem of paddy straw burning in the state. The Punjab government and Lockheed Martin would ink a MoU in this regard [on Friday, Nov. 14, 2014].”

The decision was taken during a meeting between three-member team from Lockheed Martin, involving the CEO Phil Shaw, Chief Innovation Officer Tushar Shah and Regional Director Jagmohan Singh along with Punjab Non-Conventional Energy Minister Bikram Singh Majithia and other senior Punjab officials.

As for paddy straw and its conversion into energy, there’s this from a Nov. 14, 2014 news item on India West.com,

Shaw [CEO Phil Shaw] said Lockheed has come out with waste-to-energy conversion solutions with successful conversion of waste products to electricity, heat and fuel by using gasification processes. He said it was an environmentally friendly green recycling technology, which requires little space and the plants are fully automated.

Getting back to the nanotechnology, I was not able to track down any information about nanotechnology-enabled plastics and Lockheed Martin. But, there is a Dec. 11, 2013 interview with Travis Earles, Lockheed Martin Advanced materials and nanotechnology innovation executive and policy leader, written up by Kris Walker for Azonano. Note: this is a general interview and focuses largely on applications for carbon nanotubes and graphene.

Graphene oxide-silver nanoparticle composite along with sunlight removes* endocrine disruptors from the environment

Removing pollutants from the environment with a combination of silver nanoparticles, graphene, and ordinary sunlight may be possible according to a Nov. 6, 2014 news item on Azonano,

Many pollutants with the potential to meddle with hormones — with bisphenol A (BPA) as a prime example — are already common in the environment. In an effort to clean up these pollutants found in the soil and waterways, scientists are now reporting a novel way to break them down by recruiting help from nanoparticles and light. The study appears in the journal ACS [American Chemical Society] Applied Materials & Interfaces.

A Nov. 5, 2014 ACS press pak news item (also on EurekAlert), which originated the Azonano piece, describes the work further,

Nikhil R. Jana and Susanta Kumar Bhunia explain that the class of pollutants known as endocrine disruptors has been shown to either mimic or block hormones in animals, including humans. That interference can cause reproductive and other health problems. The compounds are used to make many household and industrial products, and have been detected in soil, water and even human breast milk. Scientists have been working on ways to harness sunlight to break down endocrine disruptors to make them less of a health threat. But the approaches so far only work with ultraviolet light, which at a mere 6 percent of sunlight, means these methods are not very efficient. Jana and Bhunia wanted to find a simple way to take advantage of visible light, which comprises 52 percent of sunlight.

For inspiration, the researchers turned to an already-developed graphene composite that uses visible light to degrade dyes. They tweaked the composite and loaded it with silver nanoparticles that serve as an antenna for visible light. When they tested it, the new material successfully degraded three different kinds of endocrine disruptors: phenol, BPA and atrazine. They conclude that their composite is a promising way to harness visible light to break down these potentially harmful compounds and other organic pollutants.

The authors acknowledge funding from India’s Department of Science & Technology.

Here’s a link to and a citation for the paper,

Reduced Graphene Oxide-Silver Nanoparticle Composite as Visible Light Photocatalyst for Degradation of Colorless Endocrine Disruptors by Susanta Kumar Bhunia and Nikhil R. Jana. ACS Appl. Mater. Interfaces, Article ASAP DOI: 10.1021/am505677x Publication Date (Web): October 8, 2014

Copyright © 2014 American Chemical Society

This article is behind a paywall.

The authors have provided a diagram illustrating the effectiveness of a control material, graphene-oxide alone, silver nanoparticles alone, and a graphene-oxide silver nanoparticle composite at reducing organic pollutants when used in conjunction with sunlight,

[downloaded from http://pubs.acs.org/doi/abs/10.1021/am505677x]

[downloaded from http://pubs.acs.org/doi/abs/10.1021/am505677x]

* ‘Remove’ in head corrected to ‘removes’ on Nov. 7, 2014.

Carbon nanotube accumulation in Duke University’s (US) mesocosm

This Oct. 1, 2014 news item on ScienceDaily about carbon nanotubes accumulating in the wetlands is carefully worded,

A Duke University team has found that nanoparticles called single-walled carbon nanotubes accumulate quickly in the bottom sediments of an experimental wetland setting, an action they say could indirectly damage the aquatic food chain. [emphasis mine]

The results indicate little risk to humans ingesting the particles through drinking water, say scientists at Duke’s Center for the Environmental Implications of Nanotechnology (CEINT). But the researchers warn that, based on their previous research, the tendency for the nanotubes to accumulate in sediment could indirectly damage the aquatic food chain in the long term if the nanoparticles provide “Trojan horse” piggyback rides to other harmful molecules. [emphases mine]

There’s a lot of hedging (could, if) in the way this research is being described. I imagine the researchers are indicating they have concerns but have no wish to stimulate panic and worry.

An Oct. 1, 2014 Duke University news release (also on EurekAlert), which originated the news item, goes on to explain the interest in carbon nanotubes specifically,

Carbon nanotubes are rapidly becoming more common because of their usefulness in nanoelectric devices, composite materials and biomedicine.

The Duke study was done using small-scale replications of a wetland environment, called “mesocosms,” that include soil, sediments, microbes, insects, plants and fish. These ecosystems-in-a-box are “semi-closed,” meaning they get fresh air and rainwater but don’t drain to their surroundings. While not perfect representations of a natural environment, mesocosms provide a reasonable compromise between the laboratory and the real world.

“The wetland mesocosms we used are a much closer approximation of the natural processes constantly churning in the environment,” said Lee Ferguson, associate professor of civil and environmental engineering at Duke. “Although it’s impossible to know if our results are fully accurate to natural ecosystems, it is clear that the processes we’ve seen should be considered by regulators and manufacturers.”

Ferguson and his colleagues dosed the mesocosms with single-walled carbon nanotubes and measured their concentrations in the water, soil and living organisms during the course of a year. They found that the vast majority of the nanoparticles quickly accumulated in the sediment on the “pond” floor. However, they found no sign of nanoparticle buildup in any plants, insects or fish living in the mesocosms.

That sounds marvelous and then the researchers provide a few facts about carbon nanotubes,

While this is good news for humans or other animals drinking water after a potential spill or other contamination event, the accumulation in sediment does pose concerns for both sediment-dwelling organisms and the animals that eat them. Previous research has shown that carbon nanotubes take a long time to degrade through natural processes — if they do at all — and any chemical that binds to them cannot easily be degraded either.

“These nanoparticles are really good at latching onto other molecules, including many known organic contaminants,” said Ferguson. “Coupled with their quick accumulation in sediment, this may allow problematic chemicals to linger instead of degrading. The nanoparticle-pollutant package could then be eaten by sediment-dwelling organisms in a sort of ‘Trojan horse’ effect, allowing the adsorbed contaminants to accumulate up the food chain.

“The big question is whether or not these pollutants can be stripped away from the carbon nanotubes by these animals’ digestive systems after being ingested,” continued Ferguson. “That’s a question we’re working to answer now.”

It’s good to see this research is being followed up so quickly. I will keep an eye out for it and, in the meantime, wonder how the followup research will be conducted and what animals will be used for the tests.

Here’s a link to and a citation for the researchers’ most recent paper on possible ‘Trojan’ carbon nanotubes,

Fate of single walled carbon nanotubes in wetland ecosystems by Ariette Schierz, Benjamin Espinasse, Mark R. Wiesner, Joseph H. Bisesi, Tara Sabo-Attwood, and P. Lee Ferguson. Environ. Sci.: Nano, 2014, Advance Article DOI: 10.1039/C4EN00063C First published online 03 Sep 2014

This is an open access paper.

I have written about Duke University and its nanoparticle research in mesocosms before. Most recently, there was a Feb. 28, 2013 posting about work on silver nanoparticles which mentions research in the ‘mesocosm’ (scroll down about 50% of the way). There’s also an Aug. 15, 2011 posting which describes the ‘mesocosm’ project at some length.

For anyone unfamiliar with the Trojan horse story (from its Wikipedia entry; Note: Links have been removed),

The Trojan Horse is a tale from the Trojan War about the subterfuge that the Greeks used to enter the city of Troy and win the war. In the canonical version, after a fruitless 10-year siege, the Greeks constructed a huge wooden horse, and hid a select force of men inside. The Greeks pretended to sail away, and the Trojans pulled the horse into their city as a victory trophy. That night the Greek force crept out of the horse and opened the gates for the rest of the Greek army, which had sailed back under cover of night. The Greeks entered and destroyed the city of Troy, decisively ending the war.

Canadian nano business news: international subsidiary (Nanex) opens in Québec and NanoStruck’s latest results on recovering silver from mine tailings

The Canadian nano business sector is showing some signs of life. Following on my Sept. 3, 2014 posting about Nanotech Security Corp.’s plans to buy a subsidiary business, Fortress Optical Features, there’s an international subsidiary of Nanex (a Belgium-based business) planning to open in the province of Québec and NanoStruck (an Ontario-based company) has announced the results of its latest tests on cyanide-free recovery techniques.

In the order in which I stumbled across these items, I’m starting with the Nanex news item in a Sept. 3, 2014 posting on the Techvibes blog,

Nanex, a Belgian-based innovator and manufacturer of superhydrophobic nanotechnology products, announced last week the creation of its first international subsidiary.

Nanex Canada will be headquartered in Montreal.

For those unfamiliar with the term superhydrophobic, it means water repellent to a ‘super’ degree. For more information the properties of superhydrophobic coatings, the Techvibes post is hosting a video which demonstrates the coating’s properties (there’s a car which may never need washing again).

An Aug. 1, 2014 Nanex press release, which originated the news item, provides more details,

… Nanex Canada Incorporated will be starting operations on October 1st, 2014 and will be headquartered in Montreal, Quebec.

“Nanex’s expansion into Canada is a tremendous leap forward in our international operations, creating not only more efficient and direct channels into all of North America, but also providing access to a new top-notch intellectual pool for our R&D efforts,” Said Boyd Soussana, National Marketing Director at Nanex Canada. “We feel that Quebec and Canada have a great reputation as leaders in the field of advanced technologies, and we are proud to contribute to this scientific landscape.”

Upon launch, Nanex Canada Inc. will begin with retail and sales of its nanotechnology products, which have a wide range of consumer applications. Formal partnerships in B2B [business-to-business] further expanding these applications have been in place throughout Canada beginning in August of 2014. Through its Quebec laboratories Nanex Canada Inc. will also be pursuing R&D initiatives, in order to further develop safe and effective nano-polymers for consumer use, focusing entirely on ease of application and cost efficiency for the end consumer. In addition application of nano-coatings in green technologies will be a priority for North American R&D efforts.

Nanex Company currently manufactures three lines of products: Always Dry, Clean & Coat, and a self-cleaning coating for automotive bodies. These products contain proprietary nano-polymers that when sprayed upon a surface provide advanced abilities including super hydrophobic (extremely water-repellent), oleophobic (extremely oil repellent), and scratch resistance as well as self-cleaning properties.

 

The second piece of news is featured in a Sept. 5, 2014 news item on Azonano,

NanoStruck Technologies Inc. is pleased to announce positive results from test work carried out on silver mine tailings utilizing proprietary cyanide free recovery technologies that returned up to 87.6% of silver from samples grading 56 grams of silver per metric ton (g/t).

A Sept. 4, 2014 NanoStruck news release, which originated the news item, provides more details,

Three leach tests were conducted using the proprietary mixed acid leach process. Roasting was conducted on the sample for two of the leach tests, producing higher recoveries, although the un-roasted sample still produced a 71% recovery rate.

87.6% silver recoveries resulted from a 4 hour leach time at 95 degrees Celsius, with the standard feed grind size of D80 175 micron of roasted material.
84.3% recoveries resulted from a 4 hour leach at 95 degrees Celsius with the standard feed grind size of D80 175 micron with roasted material at a lower acid concentration.
71% recoveries resulted from a 4 hour leach at 95 degrees Celsius from received material, with the standard feed grind size of D80 175 micron with an altered acid mix concentration.

The average recovery for the roasted samples was 86% across the two leach tests performed using the proprietary process.

Bundeep Singh Rangar, Interim CEO and Chairman of the Board, said: “These results further underpin the effectiveness of our processing technology. With our patented process we are achieving excellent recoveries in not only silver tailings, but also gold tailings as well, both of which have vast global markets for us.”

The proprietary process combines a novel mixed acid leach with a solvent extraction stage, utilizing specific organic compounds. No cyanide is used in this environmentally friendly process. The flow sheet design is for a closed loop, sealed unit in which all chemicals are then recycled.

Previous test work undertaken on other gold mine tailings utilizing the proprietary process resulted in a maximum 96.1% recovery of gold. Previous test work undertaken on other silver tailings resulted in a maximum 86.4% recovery of silver.

The technical information contained in this news release has been verified and approved by Ernie Burga, a qualified person for the purpose of National Instrument 43-101, Standards of Disclosure for Mineral Projects, of the Canadian securities administrators.

Should you choose to read the news release in its entirety, you will find that no one is responsible for the information should anything turn out to be incorrect or just plain wrong but, like Nanotech Security Corp., (as I noted in my Sept. 4, 2014 posting), the company is very hopeful.

I have mentioned NanoStruck several times here:

March 14, 2014 posting

Feb. 19, 2014 posting

Feb. 10, 2014 posting

Dec. 27, 2013 posting

Don’t throw that cigarette butt away—use it to store energy!

I’ve read the news release and briefly skimmed the research paper and cannot find any discussion of how these scientists got the idea to ‘recycle’ used cigarette butts for energy storage (supercapacitors) although the inspiration seems to have its roots in a desire to create better supercapacitors from recycled materials. From an Aug. 5, 2014 news item on ScienceDaily,

A group of scientists from South Korea have converted used-cigarette butts into a high-performing material that could be integrated into computers, handheld devices, electrical vehicles and wind turbines to store energy.

Presenting their findings today, 5 August 2014, in IOP Publishing’s journal Nanotechnology, the researchers have demonstrated the material’s superior performance compared to commercially available carbon, graphene and carbon nanotubes.

It is hoped the material can be used to coat the electrodes of supercapacitors — electrochemical components that can store extremely large amounts of electrical energy — whilst also offering a solution to the growing environmental problem caused by used-cigarette filters.

An Aug. 5, 2014 Institute of Physics (IOP) news release (also on EurekAlert), which originated the news item, further describes the situation regarding used cigarette butts and the characteristics that could render them into supercapacitors

It is estimated that as many as 5.6 trillion cigarette butts (equivalent to 766 571 metric tons), are deposited into the environment worldwide every year.

Co-author of the study Professor Jongheop Yi, from Seoul National University, said: “Our study has shown that used cigarette filters can be transformed into a high-performing carbon-based material using a simple one-step process, which simultaneously offers a green solution to meeting the energy demands of society.

“Numerous countries are developing strict regulations to avoid the trillions of toxic and non-biodegradable used cigarette filters that are disposed of into the environment each year; our method is just one way of achieving this.”

Carbon is the most popular material that supercapacitors are composed of, due to its low cost, high surface area, high electrical conductivity and long-term stability.

Scientists around the world are currently working towards improving the characteristics of supercapacitors – such as energy density, power density and cycle stability – while also trying to reduce production costs.

In their study, the researchers demonstrated that the cellulose acetate fibres that cigarette filters are mostly composed of could be transformed into a carbon-based material using a simple, one-step burning technique called pyrolysis.

As a result of this burning process, the resulting carbon-based material contained a number of tiny pores, increasing its performance as a supercapacitive material.

“A high-performing supercapacitor material should have a large surface area, which can be achieved by incorporating a large number of small pores into the material,” continued Professor Yi.

“A combination of different pore sizes ensures that the material has high power densities, which is an essential property in a supercapacitor for the fast charging and discharging.”

Once fabricated, the carbon-based material was attached to an electrode and tested in a three-electrode system to see how well the material could adsorb electrolyte ions (charge) and then release them (discharge).

The material stored a higher amount of electrical energy than commercially available carbon and also had a higher amount of storage compared to graphene and carbon nanotubes, as reported in previous studies.

Here’s a link to and a citation for the research paper,

Preparation of energy storage material derived from a used cigarette filter for a supercapacitor electrode by Minzae Lee, Gil-Pyo Kim, Hyeon Don Song, Soomin Park, and Jongheop Yi. Nanotechnology 25 (34) 5601 doi:10.1088/0957-4484/25/34/345601

This is an open access paper.

Germany’s nano-supercapacitors for electric cars

Kudos to the writer for giving a dull topic, supercapacitors and electric cars, a jolt of life. From a July 24, 2014 news item on ScienceDaily,

Innovative nano-material based supercapacitors are set to bring mass market appeal a good step closer to the lukewarm public interest in Germany. [emphasis mine] This movement is currently being motivated by the advancements in the state-of-the-art of this device.

A July 1, 2014 Fraunhofer-Gesellschaft press release (also on EurekAlert), which originated the news item and, sadly, did not reveal the writer’s name, goes on in this refreshing fashion,

Electric cars are very much welcomed in Norway and they are a common sight on the roads of the Scandinavian country – so much so that electric cars topped the list of new vehicle registrations for the second time. This poses a stark contrast to the situation in Germany, where electric vehicles claim only a small portion of the market. Of the 43 million cars on the roads in Germany, only a mere 8000 are electric powered. The main factors discouraging motorists in Germany from switching to electric vehicles are the high investments cost, their short driving ranges and the lack of charging stations. Another major obstacle en route to the mass acceptance of electric cars is the charging time involved. The minutes involved in refueling conventional cars are so many folds shorter that it makes the situation almost incomparable. However, the charging durations could be dramatically shortened with the inclusion of supercapacitors. These alternative energy storage devices are fast charging and can therefore better support the use of economical energy in electric cars. Taking traditional gasoline-powered vehicles for instance, the action of braking converts the kinetic energy into heat which is dissipated and unused. Per contra, generators on electric vehicles are able to tap into the kinetic energy by converting it into electricity for further usage. This electricity often comes in jolts and requires storage devices that can withstand high amount of energy input within a short period of time. In this example, supercapacitors with their capability in capturing and storing this converted energy in an instant fits in the picture wholly. Unlike batteries that offer limited charging/discharging rates, supercapacitors require only seconds to charge and can feed the electric power back into the air-conditioning systems, defogger, radio, etc. as required.

So, the Norwegians have embraced electric cars while the Germans have remained reluctant. The writer offers a clear explanation of supercapacitors and mentions a solution for improving the electric vehicle acceptance rate in Germany (from the press release)

Rapid energy storage devices are distinguished by their energy and power density characteristics – in other words, the amount of electrical energy the device can deliver with respect to its mass and within a given period of time. Supercapacitors are known to possess high power density, whereby large amounts of electrical energy can be provided or captured within short durations, albeit at a short-coming of low energy density. The amount of energy in which supercapacitors are able to store is generally about 10% that of electrochemical batteries (when the two devices of same weight are being compared). This is precisely where the challenge lies and what the “ElectroGraph” project is attempting to address.

ElectroGraph is a project supported by the EU and its consortium consists of ten partners from both research institutes and industries. One of the main tasks of this project is to develop new types of supercapacitors with significantly improved energy storage capacities. As the project is approaches its closing phase in June, the project coordinator at Fraunhofer Institute for Manufacturing Engineering and Automation IPA in Stuttgart, Carsten Glanz explained the concept and approach taken en route to its successful conclusion: “during the storage process, the electrical energy is stored as charged particles attached on the electrode material.” “So to store more energy efficiently, we designed light weight electrodes with larger, usable surfaces.”

Next, the ‘nano’ aspect (graphene) of this particular project is explained,

In numerous tests, the researcher and his team investigated the nano-material graphene, whose extremely high specific surface area of up to 2,600 m2/g and high electrical conductivity practically cries out for use as an electrode material. It consists of an ultrathin monolayer lattice made of carbon atoms. When used as an electrode material, it greatly increases the surface area with the same amount of material. From this aspect, graphene is showing its potential in replacing activated carbon – the material that has been used in commercial supercapacitors to date – which has a specific surface area between 1000 and 1800 m2/g.

“The space between the electrodes is filled with a liquid electrolyte,” revealed Glanz. “We use ionic liquids for this purpose. Graphene-based electrodes together with ionic liquid electrolytes present an ideal material combination where we can operate at higher voltages.” “By arranging the graphene layers in a manner that there is a gap between the individual layers, the researchers were able to establish a manufacturing method that efficiently uses the intrinsic surface area available of this nano-material. This prevents the individual graphene layers from restacking into graphite, which would reduce the storage surface and consequently the amount of energy storage capacity. “Our electrodes have already surpassed commercially available one by 75 percent in terms of storage capacity,” emphasizes the engineer. “I imagine that the cars of the future will have a battery connected to many capacitors spread throughout the vehicle, which will take over energy supply during high-power demand phases during acceleration for example and ramming up of the air-conditioning system. These capacitors will ease the burden on the battery and cover voltage peaks when starting the car. As a result, the size of massive batteries can be reduced.”

Whether this effort has already been or, at some time in the future, will be demonstrated is not entirely clear to me,

In order to present the new technology, the ElectroGraph consortium developed a demonstrator consisting of supercapacitors installed in an automobile side-view mirror and charged by a solar cell in an energetically self-sufficient system. The demonstrator will be unveiled at the end of May [2015?] during the dissemination workshop at Fraunhofer IPA.

I imagine improved supercapacitors will be prove to be an enticement for more than one reluctant electric car purchaser no matter where they reside.