Tag Archives: nitrogen oxide

Less pollution from ships with nanofilter

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04.05.16 - Cargo ships are among the leading sources of pollution on the planet. Starting in 2020, however, stricter sulfur emission standards will take effect. A low-cost solution for reaching the new targets may come from an EPFL start-up, which is developing a nanostructured filter for use in a ship’s exhaust stacks. Courtesy EPFL

04.05.16 – Cargo ships are among the leading sources of pollution on the planet. Starting in 2020, however, stricter sulfur emission standards will take effect. A low-cost solution for reaching the new targets may come from an EPFL start-up, which is developing a nanostructured filter for use in a ship’s exhaust stacks. Copyright Alain Herzog Courtesy EPFL

A May 4, 2016 news item on Nanowerk describes a marine initiative from the École Polytechnique de Lausanne (EPFL) in Switzerland,

Around 55,000 cargo ships ply the oceans every day, powered by a fuel that is dirtier than diesel. And owing to lax standards, maritime transport has emerged as one of the leading emitters – alongside air transport – of nitrogen oxide and sulfur. But the International Maritime Organization has enacted tighter emission limits, with new standards set to take effect in 2020. In response, an EPFL start-up is developing a low-cost and eco-friendly solution: a filter that can be installed in the ships’ exhaust stacks. The start-up, Daphne Technology, could do well on this massive market.

Given that no oceans or seas border Switzerland, it’s a rather interesting initiative on their part. Here’s more from a May 4, 2015 EPFL press release, which originated the news item,

Lowering sulfur emissions to below 1%

Under laboratory conditions, the nanostructured filter is able to cut sulfur emissions to below 1% and nitrogen oxide emissions to 15% of the current standards. This is a major improvement, seeing as the new standards will require an approximately 14% reduction in sulfur emissions.

Manufacturing the filters is similar to manufacturing solar cells. A thin metal plate – titanium in this case – is nanostructured in order to increase its surface area, and a number of substances are deposited in extremely thin layers. The plates are then placed vertically and evenly spaced, creating channels through which the toxic gases travel. The gases are captured by the nanostructured surfaces. This approach is considered eco-friendly because the substances in the filter are designed to be recycled. And the exhaust gas itself becomes inert and could be used in a variety of products, such as fertilizer.

The main challenges now are to figure out a way to make these filters on large surfaces, and to bring down the cost. It was at EPFL’s Swiss Plasma Center that researcher Mario Michan found a machine that he could modify to meet his needs: it uses plasma to deposit thin layers of substances. The next step is to produce a prototype that can be tested under real-world conditions.

Michan came up with his solution for toxic gas emissions after he worked on merchant ships while completing his Master’s degree in microengineering. It took several years, some techniques he picked up in the various labs in which he worked, and a few patents for Michan to make headway on his project. It was while he was working in another field at CERN and observing the technologies used to coat the inside of particle accelerators that he discovered a process needed for his original concept. An EPFL patent tying together the various aspects of the technology and several manufacturing secrets should be filed this year.

According to the European Environment Agency, merchant ships give off 204 times more sulfur than the billion cars on the roads worldwide. Michan estimates that his nanostructured filters, if they were used by all cargo ships, would reduce these emissions to around twice the level given off by all cars, and the ships would not need to switch to another fuel. Other solutions exist, but his market research showed that they were all lacking in some way: “Marine diesel fuel is cleaner but much more expensive and would drive up fuel costs by 50% according to ship owners. And the other technologies that have been proposed cannot be used on boats or they only cut down on sulfur emissions without addressing the problem of nitrogen oxide.”

The Daphne Technology website is here.

Laundry detergents that clean clothes and pollution from the air

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Tony Ryan, as an individual (and with Helen Storey), knows how to provoke interest in a topic many of us find tired, air pollution. This time, Ryan and Storey have developed a laundry detergent additive through their Catalytic Clothing venture (mentioned previously in a Feb. 24, 2012 posting and in a July 8, 2011 posting). From Adele Peters’ July 22, 2014 article for Fast Company (Note: A link has been removed),

Here’s another reason cities need more pedestrians: If someone is wearing clothes that happened to be washed in the right detergent, just their walking down the street can suck smog out of the surrounding air.

For the last few years, researchers at the Catalytic Clothing project have been testing a pollution-fighting laundry detergent that coats clothing in nano-sized particles of titanium dioxide. The additive traps smog and converts it into a harmless byproduct. It’s the same principle that has been used smog-eating buildings and roads, but clothing has the advantage of actually taking up more space.

Kasey Lum in a June 25, 2014 article for Ecouterre describes the product as a “laundry additive [which] could turn clothing in mobile air purifiers,”

CatClo piggybacks the regular laundering process to deposit nanoparticles of titanium dioxide onto the fibers of the clothing. Exposure to light excites electrons on the particles’ surface, creating free radicals that react with water to make hydrogen peroxide. This, in turn, “bleaches out” volatile organic compounds and nitrogen oxides in the atmosphere, according to Storey, rendering them harmless.

Lum referenced a May 23, 2014 article written by Helen Storey and Tony Ryan for the UK’s Guardian, newspaper which gives a history of their venture, Catalytic Clothing, and an update on their laundry additive (Note: Links have been removed),

It was through a weird and wonderful coincidence on BBC [British Broadcasting Corporation] Radio 4 that we met to discuss quantum mechanics and plastic packaging, resulting in the Wonderland Project, where we created disappearing gowns and bottles as a metaphor for a planet that is going the same way.

Spurred by this collaborative way of working, Wonderland led to Catalytic Clothing, a liquid laundry additive. The idea came out of conversations about how we could harness the surface of our clothing and the power of fashion to communicate complex scientific ideas – and so began the campaign for clean air.

(When I first wrote about Catalytic Clothing I was under the impression that it was an art/science venture focused on clothing as a means of cleaning the air. I was unaware they were working on a laundry additive.)

Getting back to Storey’s and Ryan’s article (Note: A link has been removed),

Catalytic Clothing (CatClo) uses existing technology in a radical new way. Photocatalytic surface treatments that break down airborne pollutants are widely applied to urban spaces, in concrete, on buildings and self-cleaning glass. The efficacy is greatly increased when applied to clothing – not only is there a large surface area, but there is also a temperature gradient creating a constant flux of air, and movement through walking creates our own micro-wind, so catalysing ourselves makes us the most effective air purifiers of them all.

CatClo contains nanoparticles of titania (TiO2) a thousand times finer than a human hair. [generally nanoscale is described as between 1/60,000 to 1/100,000 of a hair’s width] When clothes are laundered through the washing process, particles are deposited onto the fibres of the fabric. When the catalysed clothes are worn, light shines on the titanium particles and it excites the electrons on the particle surface. These electrons cause oxygen molecules to split creating free-radicals that then react with water to make hydrogen peroxide. This then bleaches out the volatile organic compounds and nitrogen oxides (NOx) that are polluting the atmosphere.

The whole process is sped up when people, wearing the clothes, are walking down the street. The collective power of everyone wearing clothes treated with CatClo is extraordinary. If the whole population of a city such as Sheffield was to launder their clothes at home with a product containing CatClo technology they would have the power to remove three tonnes per day of harmful NOx pollution.

So, if the technology exists to clear the air, why isn’t it available? From Storey’s and Ryan’s article,

Altruism, is a hard concept to sell to big business. We have approached and worked with some of the world’s largest producers of laundry products but even though the technology exists and could be relatively cheap to add to existing products, it’s proved to be a tough sell. The fact that by catalysing your clothes the clean air you create will be breathed in by the person behind you is not seen as marketable.

A more serious issue is that photocatalysts can’t tell the difference between a bad pollutant and a “good” one; for example, it treats perfume as just another volatile organic compound like pollution. This is an untenable threat to an entire industry and existing products owned by those best able to take CatClo to market.

We’ve recently travelled to China to see whether CatClo could work there. China is a place where perfume isn’t culturally valued, but the common good is, so a country with one of the biggest pollution problems on the planet, and a government that isn’t hidebound by business as usual, might be the best place to start.

In the midst of developing their laundry additive, Storey and Ryan produced a pop-up exhibition, A Field of Jeans (first mentioned here in an Oct. 13, 2011 posting which lists events for the 2011 London Science Festival), to raise public awareness and support (from the article),

During the research period, we realised that there were more jeans on the planet than people. Knowing this, we launched a pop-up exhibition, A Field of Jeans. The jeans we catalysed are all recycled and as it turns out, because of the special nature of cotton denim, are the most efficacious fabric of all to support the catalysts.

The public have been overwhelmingly supportive; once fears about the “chemicals”, “nanotech” or becoming dirt magnets were dispelled, we captured people’s imagination and proved that CatClo could eventually be as normal as fluoride in toothpaste with enormous potential to increase wellbeing and clean up our polluted cities.

The pop-up exhibition is now at Thomas Tallis School in London (from the Catalytic Clothing homepage),

New 2013/2014
Field of Jeans is at Thomas Tallis school from December 2nd 2013 until further notice. Jeans can be viewed from Kidbrooke Park Road, London SE3 outside the main school entrance. This will inspire a piece of work across the school called Catalytic Learning. More will be posted here soon.
Click here for images
http://www.thomastallis.co.uk/

Here’s an image from the Field of Jeans,

Image can be found here at: https://www.flickr.com/photos/helenstoreyfoundation/sets/72157638346745735/

Image can be found here at: https://www.flickr.com/photos/helenstoreyfoundation/sets/72157638346745735/

I last featured Tony Ryan’s work here in a May 15, 2014 posting about a poem and a catalytic billboard at the University of Sheffield where Ryan is the Pro-Vice-Chancellor for Science.

Nanomaterial use in construction, in coatings, in site remediation, and on invisible planes

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Next to biomedical and electronics industries, the construction industry is expected to be the most affected by nanotechnology according to a study in ACS (American Chemical Society) Nano (journal). From the news item on Azonano,

Pedro Alvarez and colleagues note that nanomaterials likely will have a greater impact on the construction industry than any other sector of the economy, except biomedical and electronics applications. Certain nanomaterials can improve the strength of concrete, serve as self-cleaning and self-sanitizing coatings, and provide many other construction benefits. Concerns exist, however, about the potential adverse health and environmental effects of construction nanomaterials.

The scientists analyzed more than 140 studies on the benefits and risks of nanomaterials. …

The article in ACS Nano is titled, “Nanomaterials in the Construction Industry: A Review of Their Applications and Environmental Health and Safety Considerations.”

Still on the construction theme but this time more focused on site remediation, here’s a story about sulfur-rich drywall which corrodes pipes and wiring while possibly causing respiratory illness. From the news item on Nanowerk,

A nanomaterial originally developed to fight toxic waste is now helping reduce debilitating fumes in homes with corrosive drywall.

Developed by Kenneth Klabunde of Kansas State University, and improved over three decades with support from the National Science Foundation, the FAST-ACT material has been a tool of first responders since 2003.

Now, NanoScale Corporation of Manhattan, Kansas–the company Klabunde co-founded to market the technology–has incorporated FAST-ACT into a cartridge that breaks down the corrosive drywall chemicals.

Homeowners have reported that the chemicals–particularly sulfur compounds such as hydrogen sulfide and sulfur dioxide–have caused respiratory illnesses, wiring corrosion and pipe damage in thousands of U.S. homes with sulfur-rich, imported drywall.

“It is devastating to see what has happened to so many homeowners because of the corrosive drywall problem, but I am glad the technology is available to help,” said Klabunde. “We’ve now adapted the technology we developed through years of research for FAST-ACT for new uses by homeowners, contractors and remediators.”

The company has already tested its new product and found that corrosion was reduced and odor levels dropped to almost imperceptible. There are plans to use the company’s technology in the Gulf Coast and elsewhere there are airborne toxic substances.

In Europe, Germany has plans to introduce new concrete paving slabs that reduce the quantity of nitrogen oxide in the air. From the news item on Nanowerk,

In Germany, ambient air quality is not always as good as it might be – data from the federal environment ministry makes this all too clear. In 2009, the amounts of toxic nitrogen oxide in the atmosphere exceeded the maximum permitted levels at no fewer than 55 percent of air monitoring stations in urban areas. The ministry reports that road traffic is one of the primary sources of these emissions.

In light of this fact, the Baroque city of Fulda is currently embarking on new ways to combat air pollution. Special paving slabs that will clean the air are to be laid the length of Petersberger Strasse, where recorded pollution levels topped the annual mean limit of 40 micrograms per cubic meter (µg/m3) last year. These paving slabs are coated with titanium dioxide (TiO2), which converts harmful substances such as nitrogen oxides into nitrates. Titanium dioxide is a photocatalyst; it uses sunlight to accelerate a naturallyoccurring chemical reaction, the speed of which changes with exposure to light.

They’ve already had success with this approach in Italy but Germany has fewer hours of sunshine and lower intensities of light so the product had to be optimized and tested in Germany. Testing has shown that the effect for Germany’s optimized paving slabs does not wear off quickly (it was tested again at 14 months and 23 months). Finally, there don’t seem to be any environmentally unpleasant consequences. If you’re curious about the details, do click on the link.

One last item, this time it’s about a nano-enabled coating that’s a paint. An Israeli company has developed a paint for airplanes that can make them invisible to radar. From Dexter Johnson’s July 14, 2010 posting on Nanoclast,

No, we’re not talking about a Wonder Woman-type of invisible plane, but rather one that becomes very difficult to detect with radar.

The Israel-based Ynetnews is reporting that an Israeli company called Nanoflight has successfully run a test on dummy missiles that were painted with the nano-enabled coating and have shown that radar could not pick them up as missiles.

The YnetNews article rather brutally points out that painting an aircraft with this nanocoating is far cheaper than buying a $5 billion US-made stealth aircraft. Of course, it should also be noted that one sale of a $5 billion aircraft employs a large number of aeronautical engineers, and the high price tag also makes it far more difficult for others to purchase the technology and possess the ability to sneak up on an enemy as well.

You can read more and see a picture of Wonder Woman’s invisible plane by following the link to Dexter’s posting.