Tag Archives: oil spills

Cleaning up oil* spills with cellulose nanofibril aerogels

Given the ever-expanding scope of oil and gas production as previously impossible to reach sources are breached and previously unusable contaminated sources are purified for use while major pipelines and mega tankers are being built to transport all this product, it’s good to see that research into cleaning up oil spills is taking place. A Feb. 26, 2014 news item on Azonano features a project at the University of Wisconsin–Madison,

Cleaning up oil spills and metal contaminates in a low-impact, sustainable and inexpensive manner remains a challenge for companies and governments globally.

But a group of researchers at the University of Wisconsin–Madison is examining alternative materials that can be modified to absorb oil and chemicals without absorbing water. If further developed, the technology may offer a cheaper and “greener” method to absorb oil and heavy metals from water and other surfaces.

Shaoqin “Sarah” Gong, a researcher at the Wisconsin Institute for Discovery (WID) and associate professor of biomedical engineering, graduate student Qifeng Zheng, and Zhiyong Cai, a project leader at the USDA Forest Products Laboratory in Madison, have recently created and patented the new aerogel technology.

The Feb. 25, 2014 University of Wisconsin–Madison news release, which originated the news item, explains a little bit about aergels and about what makes these cellulose nanofibril-based aerogels special,

Aerogels, which are highly porous materials and the lightest solids in existence, are already used in a variety of applications, ranging from insulation and aerospace materials to thickening agents in paints. The aerogel prepared in Gong’s lab is made of cellulose nanofibrils (sustainable wood-based materials) and an environmentally friendly polymer. Furthermore, these cellulose-based aerogels are made using an environmentally friendly freeze-drying process without the use of organic solvents.

It’s the combination of this “greener” material and its high performance that got Gong’s attention.

“For this material, one unique property is that it has superior absorbing ability for organic solvents — up to nearly 100 times its own weight,” she says. “It also has strong absorbing ability for metal ions.”

Treating the cellulose-based aerogel with specific types of silane after it is made through the freeze-drying process is a key step that gives the aerogel its water-repelling and oil-absorbing properties.

The researchers have produced a video showing their aerogel in operation,

For those who don’t have the time for a video, the news release describes some of the action taking place,

“So if you had an oil spill, for example, the idea is you could throw this aerogel sheet in the water and it would start to absorb the oil very quickly and efficiently,” she says. “Once it’s fully saturated, you can take it out and squeeze out all the oil. Although its absorbing capacity reduces after each use, it can be reused for a couple of cycles.”

In addition, this cellulose-based aerogel exhibits excellent flexibility as demonstrated by compression mechanical testing.

Though much work needs to be done before the aerogel can be mass-produced, Gong says she’s eager to share the technology’s potential benefits beyond the scientific community.

“We are living in a time where pollution is a serious problem — especially for human health and for animals in the ocean,” she says. “We are passionate to develop technology to make a positive societal impact.”

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

Green synthesis of polyvinyl alcohol (PVA)–cellulose nanofibril (CNF) hybrid aerogels and their use as superabsorbents by Qifeng Zheng, Zhiyong Cai, and Shaoqin Gong.  J. Mater. Chem. A, 2014,2, 3110-3118 DOI: 10.1039/C3TA14642A First published online 16 Dec 2013

This paper is behind a paywall. I last wrote about oil-absorbing nanosponges in an April 17, 2012 posting. Those sponges were based on carbon nanotubes (CNTs).

* ‘oils’ in headline changed to ‘oil’ on May 6, 2014.

Mop up the oil spills with nanosheets from Deakin University and The Conversation

Researchers from Deakin University (Australia) have developed a new material, boron-based nanosheets, which can mop up oil spills more efficiently than current methods and are recyclable. From the May 1, 2013 news item on Nanowerk, (Note: A link has been removed)

In Nature Communications today (“Porous boron nitride nanosheets for effective water cleaning”), we showed how we produced, probably for the first time, nanosheets that could revolutionise oil spill clean ups and water purification.

Not only do our nanosheets absorb 33 times their weight in oil, they’re also recyclable.

Ordinarily there’d be a news release from Deakin University but these researchers appear to have taken a different approach posting on a website called The Conversation. This is a very interesting science communicaton initiative from Australia and I will be digressing for a moment. Here’s a description of the initiative from their Who We Are page,

The Conversation is an independent source of news and views, sourced from the academic and research community and delivered direct to the public.

Our team of professional editors work with university, CSIRO and research institute experts to unlock their knowledge for use by the wider public.

Access to independent, high-quality, authenticated, explanatory journalism underpins a functioning democracy. Our aim is to allow for better understanding of current affairs and complex issues. And hopefully allow for a better quality of public discourse and conversations.

We have introduced new protocols and controls to help rebuild trust in journalism. All authors and editors sign up to our Editorial Charter and Code of Ethics. And all contributors must abide by our Community Standards policy. We only allow authors to write on a subject on which they have proven expertise, which they must disclose alongside their article. Authors’ funding and potential conflicts of interest must be disclosed. Failure to do so carries a risk of being banned from contributing to the site.

Since our launch in March 2011, we’ve grown to become one of Australia’s largest independent news and commentary sites. Around 35% of our readers are from outside Australia.

We believe in open access and the free-flow of information. The Conversation is a free resource: free to read (we’ll never go behind a paywall), and free to share or republish under Creative Commons. All you need to do is follow our simple guidelines. We have also become an indispensable media resource: providing free content, ideas and talent to follow up for press, web, radio or TV.

They believe in open access and the free-flow of information as long as you don’t edit the article, etc. Here are five of the guidelines (from the Republishing guidelines page),

Republishing guidelines, for print and online

  1. Unless you have express permission from the author, you can’t edit our material, except to reflect relative changes in time, location and editorial style. (For example, “yesterday” can be changed to “last week,” and “Canberra, ACT.” to “Canberra” or “here”). If you need to materially edit our content, please contact our External Relations Manager.
  2. You have to credit our authors and partner institutions — ideally in the byline. We prefer “Author Name, Institution” (for example, Qing Wang, Warwick Business School).
  3. You have to credit The Conversation — ideally at the top of the article and include our logo — with a link back to either our home page, The Conversation, or (preferably) the specific article URL on The Conversation website.
  4. If space is tight, you can run the first few lines of the article and then say: “Read the full article at The Conversation” with a link back to the article page on our site.
  5. If you’re republishing online, you must use our page view counter, link to us, and include links from our story. Our page view counter is a small pixel-ping image (invisible to the eye) that allows us to know when our content is republished, and gives our authors sense of the size of audience and which publications they’re reaching. It is a condition of our guidelines that you include our counter. If you use the “republish” button that accompanies each article then you’ll capture our page counter.
  6. ….

Since I usually cut and paste parts of articles and news releases and often intersperse with my own comments and I don’t have the technical skills to use their page view counter, I won’t be using anything directly from The Conversation. I view my role as a curator (bringing together pieces of information from disparate sources) and a ‘connector’. To encourage connections, I don’t usually include a full news release or article as I suggest my readers look at the original or seek out the other sources I’ve included if they want more information.

Back to the boron nitride nanosheets and the news item on Nanowerk,

We found that porous boron nitride nanosheets have a couple of properties that make them particularly suitable for absorbing organic (carbon-based) contaminants, such as oil or dyes.

The nanosheets are made of a few layers of boron nitride atomic planes, and these sheets have a large number of holes.

It’s these holes that increase the surface area of the nanosheets to a huge 1,425m2 a gram.
This means one gram of porous boron nitride nanosheets has the same surface area as nearly 5.5 tennis courts – so plenty of surface for absorption.

Another advantage is that the saturated boron nitride nanosheets can be cleaned for reuse by simply heating in air for two hours.

The absorbed oil is burned off, leaving the nanosheets clean and free to absorb again.

To make our porous nanosheets, boron oxide powder and guanidine hydrochloride are mixed in methane and heated at 1,100C for several hours in nitrogen gas.

The news item on Nanowerk is illustrated with images and provides more detail as does the May 1, 2013 article (Don’t cry over spilled oil – use nanosheets) on The Conversation.

For those who’d like to read the published research, here’s a link to and a citation for it,

Porous boron nitride nanosheets for effective water cleaning by Weiwei Lei, David Portehault, Dan Liu, Si Qin, & Ying Chen. Nature Communications 4, Article number: 1777 doi:10.1038/ncomms2818 Published 30 April 2013

The article is behind a paywall.

Interestingly scientists in China have developed an entirely different material with similar properties for mopping up oil spills as per my Feb. 27, 2013 posting titled, Bacterial cellulose could suck up pollutants from oil spills.

ETA May 6, 2013: Dexter Johnson has commented on an outstanding issue with the Deakin University research and other such initiatives: a lack of commercialization efforts. From his May 4, 2013 posting on his Nanoclast blog (found on the IEEE [Institute of Electrical and Electronics Engineers] website), Note: A link has been removed,

In fact, there are a variety of nanomaterials for these applications [oil spill remediation and water purification]—so many of them that there are catalogues to guide you through them.  But not so fast. As yet, no one is bothering to commercialize them so that they are available for the next oil spill.

Dexter provides worthwhile context and some provocative comments on how to ‘encourage’ commercialization of nanotechnology-enabled oil spill remediation/water purification  products.

Bacterial cellulose could suck up pollutants from oil spills

Who doesn’t love a cellulose story, especially when it could involve cleaning up oil spills? The Feb. 26, 2013 news item on phys.org titled, Airy but thirsty: Ultralight, flexible, fire-resistant carbon nanotube aerogels from bacterial cellulose, highlights some work being done in China,

They can absorb vast amounts of oil or organic compounds, yet they are nearly as light as air: highly porous solids made of a three-dimensional network of carbon nanotubes. In the journal Angewandte Chemie, Chinese scientists have now introduced a simple technique for the production of these ultralight, flexible, fire-resistant aerogels. Their method begins with bacterial cellulose as an inexpensive starting material. Their fibrous lightweights can “suck” organic contaminants from polluted water and could possibly be used as pressure sensors.

The researchers [led by Shu-Hong Yu at the Hefei National Laboratory for Physical Sciences at Micrscale (HFNL), Univeristy of Science and Technology of China] trimmed off small pieces of the tangled cellulose nanofibers. These were freeze-dried and then pyrolyzed at 1300 °C under argon. This converts the cellulose into graphitic carbon. The density decreases but the network structure remains intact. The result is a black, ultralight, mechanically stable aerogel. Because it is porous and highly hydrophobic, it can adsorb organic solvents and oils—up to 106 to 312 times its own weight. It draws oil out of an oil/water mixture with high efficiency and selectivity, leaving behind pure water. This makes the new aerogel an ideal candidate for cleaning up oil spills or sucking up nonpolar industrial pollutants. The absorbed substances can easily be removed from the gel through distillation or combustion, allowing the gel to be used again.

There’s more about the work and its possible applications at physorg.com or, if you have access behind the paywall, here’s a citation and a link to the research article,

Ultralight, Flexible, and Fire-Resistant Carbon Nanofiber Aerogels from Bacterial Cellulose by Zhen-Yu Wu, Chao Li, Dr. Hai-Wei Liang, Prof. Dr. Jia-Fu Chen, Prof. Dr. Shu-Hong Yu. Angewandte Chemie International Edition, Volume 52, Issue 10, pages 2925–2929, March 4, 2013.

Here’s an image which illustrates the aerogels’ ability to suck up an organic solvent and explains some of the excitement,

Thirsty fibers: The aerogels described in the title can be fabricated in large scale by using a low-cost biomass, bacterial cellulose, as a precursor, which can be produced at industrial level in a microbial fermentation process. The carbon nanofiber aerogels (black pieces in picture) exhibit superior absorption capacity for organic solvents (red solution) and high potential for pressure sensing. [downloaded from http://onlinelibrary.wiley.com/doi/10.1002/anie.201209676/abstract;jsessionid=3EFB4241C0083135A6E657808F5410E5.d03t04]

Thirsty fibers: The aerogels described in the title can be fabricated in large scale by using a low-cost biomass, bacterial cellulose, as a precursor, which can be produced at industrial level in a microbial fermentation process. The carbon nanofiber aerogels (black pieces in picture) exhibit superior absorption capacity for organic solvents (red solution) and high potential for pressure sensing. [downloaded from http://onlinelibrary.wiley.com/doi/10.1002/anie.201209676/abstract;jsessionid=3EFB4241C0083135A6E657808F5410E5.d03t04]

Magnetically cleaning up oil spills

Researchers at the Massachusetts Institute of Technology (MIT) have developed a promising technique for cleaning up oil spills, using magnets, which is more efficient and more environmentally friendly.

ETA Sept. 14, 2012: For some reason the embedded video keeps disappearing, so here’s the link: http://youtu.be/ZaP7XOjsCHQ

The Sept. 12, 2012 news item on Nanowerk notes,

The researchers will present their work at the International Conference on Magnetic Fluids in January. Shahriar Khushrushahi, a postdoc in MIT’s Department of Electrical Engineering and Computer Science, is lead author on the paper, joined by Markus Zahn, the Thomas and Gerd Perkins Professor of Electrical Engineering, and T. Alan Hatton, the Ralph Landau Professor of Chemical Engineering. The team has also filed two patents on its work.

In the MIT researchers’ scheme, water-repellent ferrous nanoparticles would be mixed with the oil, which could then be separated from the water using magnets. The researchers envision that the process would take place aboard an oil-recovery vessel, to prevent the nanoparticles from contaminating the environment. Afterward, the nanoparticles could be magnetically removed from the oil and reused.

Larry Hardesty’s Sept. 12, 2012 MIT news release , which originated the news item, provides detail about the standard technique for  using magnetic nanoparticles and the new technique,

According to Zahn, there’s a good deal of previous research on separating water and so-called ferrofluids — fluids with magnetic nanoparticles suspended in them. Typically, these involve pumping a water-and-ferrofluid mixture through a channel, while magnets outside the channel direct the flow of the ferrofluid, perhaps diverting it down a side channel or pulling it through a perforated wall.

This approach can work if the concentration of the ferrofluid is known in advance and remains constant. But in water contaminated by an oil spill, the concentration can vary widely. Suppose that the separation system consists of a branching channel with magnets along one side. If the oil concentration were zero, the water would naturally flow down both branches. By the same token, if the oil concentration is low, a lot of the water will end up flowing down the branch intended for the oil; if the oil concentration is high, a lot of the oil will end up flowing down the branch intended for the water.


The MIT researchers vary the conventional approach in two major ways: They orient their magnets perpendicularly to the flow of the stream, not parallel to it; and they immerse the magnets in the stream, rather than positioning them outside of it.

The magnets are permanent magnets, and they’re cylindrical. Because a magnet’s magnetic field is strongest at its edges, the tips of each cylinder attract the oil much more powerfully than its sides do. In experiments the MIT researchers conducted in the lab, the bottoms of the magnets were embedded in the base of a reservoir that contained a mixture of water and magnetic oil; consequently, oil couldn’t collect around them. The tops of the magnets were above water level, and the oil shot up the sides of the magnets, forming beaded spheres around the magnets’ ends.

The design is simple, but it provides excellent separation between oil and water. Moreover, Khushrushahi says, simplicity is an advantage in a system that needs to be manufactured on a large scale and deployed at sea for days or weeks, where electrical power is scarce and maintenance facilities limited

. …

In their experiments, the MIT researchers used a special configuration of magnets, called a Halbach array, to extract the oil from the tops of the cylindrical magnets. When attached to the cylinders, the Halbach array looks kind of like a model-train boxcar mounted on pilings. The magnets in a Halbach array are arranged so that on one side of the array, the magnetic field is close to zero, but on the other side, it’s roughly doubled. In the researchers’ experiments, the oil in the reservoir wasn’t attracted to the bottom of the array, but the top of the array pulled the oil off of the cylindrical magnets.

While this work is promising, there are still a lot of issues to be addressed including how water will be removed from the recovered oil (oil and water can mix to some degree depending on their relative densities).

Oil spills, environmental remediation, and nanotechnology

Oil spills have been on my mind lately as I’ve caught some of the overage about the BP (British Petroleum) oil spill in the Gulf of Mexico. One  leak (the smallest) has been fixed according to a news item on physorg.com

Days of work off the coast of Louisiana with underwater submarines nearly a mile below the surface finally bore fruit as a valve was secured over the smallest of the three leaks and the flow shut off.

The feat does not alter the overall amount of crude spilling into the sea and threatening the fragile US Gulf coast, but is significant nonetheless as the focus can now narrow on just two remaining leaks.

“Working with two leaks is going to be a lot easier than working with three leaks. Progress is being made,” US Coast Guard Petty Officer Brandon Blackwell told AFP.

More than two weeks after the Deepwater Horizon rig exploded, the full impact of the disaster is being realized as a massive slick looms off the US Gulf coast, imperilling the livelihoods of shoreline communities.

The news item goes on to detail how much crude oil is still being lost, the oil slick’s progress, the probable impact on the shoreline and animals, and the other efforts being made to ameliorate the situation.

With all the talk there is about nanotechnology’s potential for helping us to clean up these messes, there’s been no mention of it in the current  efforts as Dexter Johnson over at the IEEE’s (Institute of Electrical and Electronics Engineers)  Nanoclast blog pointed out the other day. From Dexter’s posting which features both a  discussion about patents for nanotechnology-enabled clean up products and an interview with Tim Harper,

So to get a sense of where we really are I wanted to get the perspective of my colleague, Tim Harper (principal of Cientifica), who in addition to being a noted expert on the commercialization of nanotechnologies also has devoted his attention to the use of nanotechnologies in cleantech including its remediation capabilities, leading him to his presentation this week in Australia at the conference Cleantech Science and Solutions: mainstream and at the edge.

“If you are looking for a quick fix from nanotechnology, forget it,” says Harper. “Nanotech is already making an impact in reducing energy, and therefore oil use, it is also being used to create stronger lighter materials that can be used for pipelines, and enabling better sensors for early warning of damage, but in terms of cleaning up the mess, the contribution is minor at best.”

Clearly not the hopeful words that many would have hoped for, and the pity is that it might have been different, according to Harper.

“As with all technologies, the applications take a while to develop,” he says. “If someone had come up with some funding 10 years ago for this specific application then we may have had better tools to deal with it.”

Dexter’s posting about patents and Harper’s comments reminded me of an article by Mason Inman I saw two years ago on the New Scientist website titled, Nanotech ’tissue’ loves oil spills, hates water. From the article,

A material with remarkable oil-absorbing properties has been developed by US researchers. It could help develop high-tech “towels” able to soak up oil spills at sea faster, protecting wildlife and human health.

Almost 200,000 tonnes of oil have been spilled at sea in accidents since the start of the decade, according to the International Tanker Owners Pollution Federation. [This article was posted May 30, 2008]

Clean-up methods have improved in recent years, but separating oil from thousands of gallons of water is still difficult and perhaps the biggest barrier to faster clean ups.

The new water-repellent material is based on manganese oxide nanowires and could provide a blueprint for a new generation of oil-spill cleaners. It is able to absorb up to 20 times its own weight in oil, without sucking up a drop of water.

Unfortunately,

But [Joerg] Lahann [University of Michigan in Ann Arbor, US]  points out that manganese oxide may not be the best material for real-world applications because it could be toxic. He says, though, that the new material “clearly provides a blueprint that can guide the design of future nanomaterials for environmental applications.”

I wonder if they’ve done any research to determine if manganese oxide in the shape and size required to create this nanotech ’tissue’ is toxic. Intriguingly, there was a recent news item on Nanowerk about toxicology research in a marine environment being undertaken.

Led by Dr. Emilien Pelletier, the Institut des Sciences de la Mer de Rimouski at the Université du Québec à Rimouski has obtained an LVEM5 benchtop electron microscope to help them study the short-term and long-term effects of nano-materials on the marine environment.

Dr. Pelletier is the Canada Research Chair in Marine Ecotoxicology. The overall objective of the chair is to understand the impact of natural and anthropogenic stresses on the short-and long-term high-latitude coastal ecosystems to contribute to the conservation, protection and sustainable development of cold coastal marine resources.

Since the news release was written by the company supplying the microscope there is no word as to exactly what Emilien’s team will be researching and how the work might have an impact on other members of the community such as the researchers with the ‘oil-hungry nanotech tissue’ made of nanoscale manganese oxide.

There is as always a political element to all of this discussion about what we could or couldn’t do with nanotechnology-enabled means to clean up oil spills and/or reduce/eliminate our dependence on oil. This discussion is not new as Dr. J. Storrs Hall implies during a presentation being reported in a recent (May 4, 2010) Foresight Institute blog entry by Dave Cronz, PhD. From the posting,

Here I offer my reflections on some of the highlights of the presentation by Dr. J. Storrs Hall of the Foresight Institute, entitled “Feynman’s Pathway to Nanomanufacturing,” and the panel discussion that followed, “How Do We Get There from Here?” Discussions such as these are crucial opportunities to reflect on – and potentially shape – emerging technologies whose destinies are often left to be determined by “market forces.”

Dr. Hall began with an intriguing argument: Feynman’s top-down approach to reaching the nano scale in manufacturing, achieved through a step-down method of replicating and miniaturizing an entire, fully-equipped machine shop in 1:4 scale over and over would yield countless benefits to science, engineering, and manufacturing at each step. These microscopic, tele-manipulated master-slave “Waldos” (named after Heinlein’s 1942 story “Waldo F. Jones”) would get nanotechnology back on track by focusing on machines and manufacturing, since most of our current emphasis is on science at the nano scale. Feynman’s top-down approach to nanoscale manufacturing is missing from the Foresight Institute’s roadmap, according to Hall, “for political reasons.” This raises a fundamental point: science and technology cannot develop independent of the political and social spheres, which pose as many challenges as the technology. Many would argue that social and technological processes are inseparable and treating them otherwise borders on folly. I commend Dr. Hall for offering his argument. It soon became clear that the panelists who joined him after his presentation disagreed. [bolded emphases mine]

As Dr. Hall aptly noted it’s not dispassionate calculations but “serendipity: the way science always works.”

I’m in agreement with Dr. Hall, the political and social spheres are inseparable from the scientific and technological spheres. As for “emerging technologies whose destinies  are often left to be determined by market forces”, Dexter’s posting ends with this,

But foresight is not the strong suit of businesses built around short-term profit motives as evidenced by them [BP] not even investing in the remote systems that would have turned the oil well off and possibly avoided the entire problem.

I strongly recommend reading Dexter’s posting to get the nuances and to explore his links.

I’m going to finish on a faint note of hope. There is work being done on site remediation and it seems to be successful, i.e., nonpolluting, less disruptive to the environment, and cheaper.  The Project on Emerging Nanotechnologies (PEN) has a webcast of a presentation titled, Contaminated Site Remediation: Are Nanomaterials the Answer?. You can find my comments about the webcast here (scoll down a bit) and PEN’s Nanoremediation Map which lists projects around the world although most are in the US. It’s incomplete since there is no requirement to report a nanoremediation site to PEN but it does give you an idea of what’s going on. Canada has two sites on the map.