Category Archives: environment

From monitoring glucose in kidneys to climate change in trees

That headline is almost poetic but I admit It’s a bit of a stretch rhymewise, kidneys/trees. In any event, a Feb. 6, 2015 news item on Azonano describes research into monitoring the effects of climate change on trees,

Serving as a testament to the far-reaching impact of Governor Andrew M. Cuomo’s commitment to maintaining New York State’s global leadership in nanotechnology innovation, SUNY Polytechnic Institute’s Colleges of Nanoscale Science and Engineering (SUNY Poly CNSE) today announced the National Science Foundation (NSF) has awarded $837,000 to support development of a first of its kind nanoscale sensor to monitor the effects of climate change on trees.

A Feb. 5, 2015 SUNY Poly CNSE news release, which originated the news item, provides more details including information about the sensor’s link to measuring glucose in kidneys,

The NSF grant was generated through the Instrument Development for Biological Research (IDBR) program, which provides funds to develop new classes of devices for bio-related research. The NANAPHID, a novel aphid-like nanosensor, will provide real-time measurements of carbohydrates in live plant tissue. Carbohydrate levels in trees are directly connected to plant productivity, such as maple sap production and survival. The NANAPHID will enable researchers to determine the effects of a variety of environmental changes including temperature, precipitation, carbon dioxide, soil acidity, pests and pathogens. The nanosensor can also provide real-time monitoring of sugar concentration levels, which are of signficant importance in maple syrup production and apple and grape farming.

“The technology for the NANAPHID is rooted in a nanoscale sensor SUNY Poly CNSE developed to monitor glucose levels in human kidneys being prepared for transplant. Our team determined that certain adjustments would enable the sensor to provide similar monitoring for plants, and provide a critical insight to the effects of climate change on the environment,” said Dr. James Castracane, professor and head of the Nanobioscience Constellation at SUNY Polytechnic Institute. “This is a perfect example of the cycle of innovation made possible through the ongoing nanotechnology research and development at SUNY Poly CNSE’s NanoTech Complex.”

“This new sensor will be used in several field experiments on measuring sensitivity of boreal forest to climate warming. Questions about forest response to rising air and soil temperatures are extremely important for forecasting future atmospheric carbon dioxide levels, climate change and forest health,” said Dr. Andrei Lapenas, principal investigator and associate professor of climatology at the University at Albany. “At the same time, we already see some potential commercial application for NANAPHID-type sensors in agriculture, food industry and other fields. Our collaboration with SUNY Poly CNSE has been extremely productive and I look forward to continuing our work together.”

The NANAPHID project began in 2014 with a $135,000 SUNY Research Foundation Network of Excellence grant. SUNY Poly CNSE will receive $400,000 of the NSF award for the manufacturing aspects of the sensor array development and testing. The remaining funds will be shared between Dr. Lapenas and researchers Dr. Ruth Yanai (ESF), Dr. Thomas Horton (ESF), and Dr. Pamela Templer (Boston University) for data collection and analysis.

“With current technology, analyzing carbohydrates in plant tissues requires hours in the lab or more than $100 a sample if you want to send them out. And you can’t sample the same tissue twice, the sample is destroyed in the analysis,” said Dr. Yanai. “The implantable device will be cheap to produce and will provide continuous monitoring of sugar concentrations, which is orders of magnitude better in both cost and in the information provided. Research questions we never dreamed of asking before will become possible, like tracking changes in photosynthate over the course of a day or along the stem of a plant, because it’s a nondestructive assay.”

“I see incredible promise for the NANAPHID device in plant ecology. We can use the sensors at the root tip where plants give sugars to symbiotic fungi in exchange for soil nutrients,” said Dr. Horton. “Some fungi are believed to be significant carbon sinks because they produce extensive fungal networks in soils and we can use the sensors to compare the allocation of photosynthate to roots colonized by these fungi versus the allocation to less carbon demanding fungi. Further, the vast majority of these symbiotic fungi cannot be cultured in lab. These sensors will provide valuable insights into plant-microbe interactions under field conditions.”

“The creation of this new sensor will make understanding the effects of a variety of environmental changes, including climate change, on the health and productivity of forests much easier to measure,” said Dr. Templer. “For the first time, we will be able to measure concentrations of carbohydrates in living trees continuously and in real-time, expanding our ability to examine controls on photosynthesis, sap flow, carbon sequestration and other processes in forest ecosystems.”

Fascinating, eh? I wonder who made the connection between human kidneys and plants and how that person made the connection.

Poopy gold, silver, platinum, and more

In the future, gold rushes could occur in sewage plants. Precious metals have been found in large quantity by researchers investigating waste and the passage of nanoparticles (gold, silver, platinum, etc.) into our water. From a Jan. 29, 2015 news article by Adele Peters for Fast Company (Note: Links have been removed),

One unlikely potential source of gold, silver, platinum, and other metals: Sewage sludge. A new study estimates that in a city of a million people, $13 million of metals could be collecting in sewage every year, or $280 per ton of sludge. There’s gold (and silver, copper, and platinum) in them thar poop.

Funded in part by a grant for “nano-prospecting,” the researchers looked at a huge sample of sewage from cities across the U.S., and then studied several specific waste treatment plants. “Initially we thought gold was at just one or two hotspots, but we find it even in smaller wastewater treatment plants,” says Paul Westerhoff, an engineering professor at Arizona State University, who led the new study.

Some of the metals likely come from a variety of sources—we may ingest tiny particles of silver, for example, when we eat with silverware or when we drink water from pipes that have silver alloys. Medical diagnostic tools often use gold or silver. …

The metallic particles Peters is describing are nanoparticles some of which are naturally occurring  as she notes but, increasingly, we are dealing with engineered nanoparticles making their way into the environment.

Engineered or naturally occurring, a shocking quantity of these metallic nanoparticles can be found in our sewage. For example, a waste treatment centre in Japan recorded 1,890 grammes of gold per tonne of ash from incinerated sludge as compared to the 20 – 40 grammes of gold per tonne of ore recovered from one of the world’s top producing gold mines (Miho Yoshikawa’s Jan. 30, 2009 article for Reuters).

While finding it is one thing, extracting it is going to be something else as Paul Westerhoff notes in Peters’ article. For the curious, here’s a link to and a citation for the research paper,

Characterization, Recovery Opportunities, and Valuation of Metals in Municipal Sludges from U.S. Wastewater Treatment Plants Nationwide by Paul Westerhoff, Sungyun Lee, Yu Yang, Gwyneth W. Gordon, Kiril Hristovski, Rolf U. Halden, and Pierre Herckes. Environ. Sci. Technol., Article ASAP DOI: 10.1021/es505329q Publication Date (Web): January 12, 2015

Copyright © 2015 American Chemical Society

This paper is behind a paywall.

On a completely other topic, this is the first time I’ve noticed this type of note prepended to an abstract,

 Note

This article published January 26, 2015 with errors throughout the text. The corrected version published January 27, 2015.

Getting back to the topic at hand, I checked into nano-prospecting and found this Sept. 19, 2013 Arizona State University news release describing the project launch,

Growing use of nanomaterials in manufactured products is heightening concerns about their potential environmental impact – particularly in water resources.

Tiny amounts of materials such as silver, titanium, silica and platinum are being used in fabrics, clothing, shampoos, toothpastes, tennis racquets and even food products to provide antibacterial protection, self-cleaning capability, food texture and other benefits.

Nanomaterials are also put into industrial polishing agents and catalysts, and are released into the environment when used.

As more of these products are used and disposed of, increasing amounts of the nanomaterials are accumulating in soils, waterways and water-systems facilities. That’s prompting efforts to devise more effective ways of monitoring the movement of the materials and assessing their potential threat to environmental safety and human health.

Three Arizona State University faculty members will lead a research project to help improve methods of gathering accurate information about the fate of the materials and predicting when, where and how they may pose a hazard.

Their “nanoprospecting” endeavor is supported by a recently awarded $300,000 grant from the National Science Foundation.

You can find out more about Paul Westerhoff and his work here.

A hedgehog particle for safer paints and coatings?

The researchers did not extract particles from hedgehogs for this work but they are attempting to provide a description for a class of particles, which could make paints and coatings more environmentally friendly. From a Jan. 28, 2015 news item on phys.org,

A new process that can sprout microscopic spikes on nearly any type of particle may lead to more environmentally friendly paints and a variety of other innovations. Made by a team of University of Michigan engineers, the “hedgehog particles” are named for their bushy appearance under the microscope. …

A Jan. 28, 2015 University of Michigan news release (also EurekAlert), which originated the news item, describes the research,

The new process modifies oily, or hydrophobic, particles, enabling them to disperse easily in water. It can also modify water-soluble, or hydrophilic, particles, enabling them to dissolve in oil or other oily chemicals.

The unusual behavior of the hedgehog particles came as something of a surprise to the research team, says Nicholas Kotov, the Joseph B. and Florence V. Cejka Professor of Engineering.

“We thought we’d made a mistake,” Kotov said. “We saw these particles that are supposed to hate water dispersing in it and we thought maybe the particles weren’t hydrophobic, or maybe there was a chemical layer that was enabling them to disperse. But we double-checked everything and found that, in fact, these particles defy the conventional chemical wisdom that we all learned in high school.”

The team found that the tiny spikes made the particles repel each other more and attract each other less. The spikes also dramatically reduce the particles’ surface area, helping them to diffuse more easily.

One of the first applications for the particles is likely to be in paints and coatings, where toxic volatile organic compounds (VOCs) like toluene are now used to dissolve pigment. Pigments made from hedgehog particles could potentially be dissolved in nontoxic carriers like water, the researchers say.

This would result in fewer VOC emissions from paints and coatings, which the EPA [US Environmental Protection Agency] estimates at over eight million tons per year in the United States alone. VOCs can cause a variety of respiratory and other ailments and also contribute to smog and climate change. Reducing their use has become a priority for the Environmental Protection Agency and other regulatory bodies worldwide.

“VOC solvents are toxic, they’re flammable, they’re expensive to handle and dispose of safely,” Kotov said. “So if you can avoid using them, there’s a significant cost savings in addition to environmental benefits.”

While some low- and no-VOC coatings are already available, Kotov says hedgehog particles could provide a simpler, more versatile and less expensive way to manufacture them.

For the study, the team created hedgehog particles by growing zinc oxide spikes on polystyrene microbeads. The researchers say that a key advantage of the process is its flexibility; it can be performed on virtually any type of particle, and makers can vary the number and size of the spikes by adjusting the amount of time the particles sit in various solutions while the protrusions are growing. They can also make the spikes out of materials other than zinc oxide.

“I think one thing that’s really exciting about this is that we’re able to make such a wide variety of hedgehog particles,” said Joong Hwan Bahng, a chemical engineering doctoral student. “It’s very controllable and very versatile.”

The researchers say the process is also easily scalable, enabling hedgehog particles to be created “by the bucketful,” according to Kotov. Further down the road, Kotov envisions a variety of other applications, including better oil dispersants that could aid in the cleanup of oil spills and better ways to deliver non-water-soluble prescription medications.

As is becoming more common in news releases, there’s a reference to commercial partners, suggesting (to me) they might be open to offers,

“Anytime you need to dissolve an oily particle in water, there’s a potential application for hedgehog particles,” he said. “It’s really just a matter of finding the right commercial partners. We’re only just beginning to explore the uses for these particles, and I think we’re going to see a lot of applications in the future.”

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

Anomalous dispersions of ‘hedgehog’ particles by Joong Hwan Bahng, Bongjun Yeom, Yichun Wang, Siu On Tung, J. Damon Hoff, & Nicholas Kotov. Nature 517, 596–599 (29 January 2015) doi:10.1038/nature14092 Published online 28 January 2015

This paper is behind a paywall.

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.