Category Archives: water

Cleaning water with palladium nanoparticle catalysts

A Jan. 16, 2015 news item on Nanowerk describes research into using palladium as a catalyst for water remediation efforts,

One way of removing harmful nitrate from drinking water is to catalyse its conversion to nitrogen. This process suffers from the drawback that it often produces ammonia. By using palladium nanoparticles as a catalyst, and by carefully controlling their size, this drawback can be partially eliminated. It was research conducted by Yingnan Zhao of the University of Twente’s MESA+ Institute for Nanotechnology that led to this discovery.

A Jan. 14, 2015 University of Twente press release, which originated the news item, describes the problem and suggested solution; this was research for a PhD thesis,

Due to the excessive use of fertilizers, our groundwater is contaminated with nitrates, which pose a problem if they enter the mains water supply. Levels have fallen significantly in recent years, as a result of various European directives. In addition, the Integrated Approach to Nitrogen programme was launched in various Dutch nature reserves at the start of January. Tackling the problem at source is one thing, but it will still be necessary to treat the mains water supply. While this can be achieved through biological conversion – bacteria convert the nitrate to nitrogen gas-, this is a slow process. Using palladium to catalyse the conversion of nitrate to nitrogen speeds up the process enormously. However, this reaction suffers from the drawback that it produces a harmful by-product – ammonia.

Exposed surface

The amount of ammonia produced appears to depend on the method used to prepare the palladium and on the catalyst’s physical structure. Yingnan Zhao decided to use nanometre-sized colloidal palladium particles, as their dimensions can be easily controlled. These particles are fixed to a surface, so they do not end up in the mains water supply. However, it is important to stop them clumping together, so stabilizers such as polyvinyl alcohol are added. Unfortunately, these stabilizers tend to shield the surface of the palladium particles, which reduces their effectiveness as a catalyst. By introducing additional treatments, Yingnan Zhao has managed to fully expose the catalytic surface once again or to manipulate it in a controlled manner. This has resulted in palladium nanoparticles that can catalyse the conversion to nitrogen, while producing very little ammonia. This has brought the further development of catalytic water treatment (in compact devices for home use, for example) one step closer.

Yingnan Zhao, who is from Heze, Shandong, China, conducted his research in Prof. Leon Lefferts’ Catalytic Processes and Materials group. He defended his thesis, which is entitled “Colloidal Nanoparticles as Catalysts and Catalyst Precursors for Nitrite Hydrogenation” on Thursday 15 January [2015].

I trust Zhao successfully defended this thesis and perhaps more importantly helped to develop a new and better method for water remediation made necessary by the effects of fertilizers.

Egypt steps it up nanowise with a Center for Nanotechnology

Dec. 16, 2014 Egypt’s Prime Minister Ibrahim Mahlab along with other ministers and Dr. Ahmed Zewail, Chairman of the board of Zewail City of Science and Technology (this seems to be a campus with a university and a number of research institutes), announced Egypt’s Center for Nanotechnology (from a Zewail City of Science and Technology Dec. 16, 2014 press release),

The Center, funded by the National Bank of Egypt, cost over $ 100 Million and is, till this moment, the biggest research Center Egypt has seen. This center is hailed as a turning point in the development of scientific research in Egypt as it will allow researchers to develop nanoparticles and nanostructured applications that will improve, even revolutionize, many technology and industry sectors including: information technology, energy, environmental science, medicine, and food safety among many others.

During the visit, Dr. Zewail gave Mahlab and the Cabinet members a brief introduction about the City’s constituents, achievements, and how it is going to improve Egypt’s economic development.

Impressed by the magnitude of Zewail City, Mahalab expressed his excitement about the effect this project is going to have on the future of scientific research in Egypt.

Following the opening ceremony, they all moved to the construction site of the soon-to-be Zewail City new premises, in Hadayk October, to evaluate the progress of the construction process. This construction work is the result of the presidential decree issued on April 9, 2014 to allocate 200 acres for Zewail City in 6th of October City. The construction work is expected to be done by the end of 2015, and will approximately cost $ 1.5 billion.

The end of 2015 is a very ambitious goal for completion of this center but these projects can sometimes inspire people to extraordinary efforts and there seems to be quite a bit of excitement about this one if the video is any indication. From a Dec. 22, 2014 posting by Makula Dunbar, which features a CCTV Africa clip, on AFKInsider,

I was interested to learn from the clip that Egypt’s new constitution mandates at least 1% of the GDP (gross domestic product) must be earmarked for scientific research.

As for Ahmed Zewail, in addition to being Chairman of the board of Zewail City of Science and Technology, he is also a professor at the California Institute of Technology (CalTech). From his CalTech biography page (Note: A link has been removed),

Ahmed Zewail is the Linus Pauling Chair professor of chemistry and professor of physics at the California Institute of Technology (Caltech). For ten years, he served as the Director of the National Science Foundation’s Laboratory for Molecular Sciences (LMS), and is currently the Director of the Moore Foundation’s Center for Physical Biology at Caltech.

On April 27, 2009, President Barack Obama appointed him to the President’s Council of Advisors on Science and Technology, and in November of the same year, he was named the First United States Science Envoy to the Middle East.

The CalTech bio page is a bit modest, Zewail’s Wikipedia entry gives a better sense of this researcher’s eminence (Note: Links have been removed),

Ahmed Hassan Zewail (Arabic: أحمد حسن زويل‎, IPA: [ˈæħmæd ˈħæsæn zeˈweːl]; born February 26, 1946) is an Egyptian- American scientist, known as the “father of femtochemistry”, he won the 1999 Nobel Prize in Chemistry for his work on femtochemistry and became the first Egyptian scientist to win a Nobel Prize in a scientific field. …

If you watched the video, you may have heard a reference to ‘other universities’. The comment comes into better focus after reading about the dispute between Nile University and Zewail City (from the Wikipedia entry),

Nile University has been fighting with Zewail City of Science and Technology, established by Nobel laureate Ahmed Zewail, for more than two years over a piece of land that both universities claim to be their own.

A March 22, 2014 ruling turned down challenges to a verdict issued in April 2013 submitted by Zewail City. The court also ruled in favour of the return of Nile University students to the contested buildings.

In a statement released by Nile University’s Student Union before Saturday’s decision, the students stated that the verdict would test the current government’s respect to the judiciary and its rulings.

Zewail City, meanwhile, stressed in a statement released on Saturday that the recent verdict rules on an urgent level; the substantive level of the case is yet to be ruled on. Sherif Fouad, Zewail City’s spokesman and media adviser, said the verdict “adds nothing new.” It is impossible for Zewail City to implement Saturday’s verdict and take Nile University students into the buildings currently occupied by Zewail City students, he said.

If I understand things rightly, the government has pushed forward with this Zewail City initiative (Center for Nanotechnology) while the ‘City’ is still in a dispute over students and buildings with Nile University. This should make for some interesting dynamics (tension) for students, instructors, and administrators of both the institutions and may not result in those dearly hoped for scientific advances that the government is promoting. Hopefully, the institutions will resolve their conflict in the interest of promoting good research.

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?

Gold nanoparticles as catalysts for clear water and hydrogen production

The research was published online May 2014 and in a July 2014 print version,  which seems a long time ago now but there’s a renewed interest in attracting attention for this work. A Dec. 17, 2014 news item on phys.org describes this proposed water purification technology from Singapore’s A*STAR (Agency for Science Technology and Research), Note: Links have been removed,

A new catalyst could have dramatic environmental benefits if it can live up to its potential, suggests research from Singapore. A*STAR researchers have produced a catalyst with gold-nanoparticle antennas that can improve water quality in daylight and also generate hydrogen as a green energy source.

This water purification technology was developed by He-Kuan Luo, Andy Hor and colleagues from the A*STAR Institute of Materials Research and Engineering (IMRE). “Any innovative and benign technology that can remove or destroy organic pollutants from water under ambient conditions is highly welcome,” explains Hor, who is executive director of the IMRE and also affiliated with the National University of Singapore.

A Dec. 17, 2014 A*STAR research highlight, which originated the news item, describes the photocatalytic process the research team developed and tested,

Photocatalytic materials harness sunlight to create electrical charges, which provide the energy needed to drive chemical reactions in molecules attached to the catalyst’s surface. In addition to decomposing harmful molecules in water, photocatalysts are used to split water into its components of oxygen and hydrogen; hydrogen can then be employed as a green energy source.

Hor and his team set out to improve an existing catalyst. Oxygen-based compounds such as strontium titanate (SrTiO3) look promising, as they are robust and stable materials and are suitable for use in water. One of the team’s innovations was to enhance its catalytic activity by adding small quantities of the metal lanthanum, which provides additional usable electrical charges.

Catalysts also need to capture a sufficient amount of sunlight to catalyze chemical reactions. So to enable the photocatalyst to harvest more light, the scientists attached gold nanoparticles to the lanthanum-doped SrTiO3 microspheres (see image). These gold nanoparticles are enriched with electrons and hence act as antennas, concentrating light to accelerate the catalytic reaction.

The porous structure of the microspheres results in a large surface area, as it provides more binding space for organic molecules to dock to. A single gram of the material has a surface area of about 100 square meters. “The large surface area plays a critical role in achieving a good photocatalytic activity,” comments Luo.

To demonstrate the efficiency of these catalysts, the researchers studied how they decomposed the dye rhodamine B in water. Within four hours of exposure to visible light 92 per cent of the dye was gone, which is much faster than conventional catalysts that lack gold nanoparticles.

These microparticles can also be used for water splitting, says Luo. The team showed that the microparticles with gold nanoparticles performed better in water-splitting experiments than those without, further highlighting the versatility and effectiveness of these microspheres.

The researchers have provided an illustration of the process,

Improved photocatalyst microparticles containing gold nanoparticles can be used to purify water. © 2014 A*STAR Institute of Materials Research and Engineering

Improved photocatalyst microparticles containing gold nanoparticles can be used to purify water.
© 2014 A*STAR Institute of Materials Research and Engineering

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

Novel Au/La-SrTiO3 microspheres: Superimposed Effect of Gold Nanoparticles and Lanthanum Doping in Photocatalysis by Guannan Wang, Pei Wang, Dr. He-Kuan Luo, and Prof. T. S. Andy Hor. Chemistry – An Asian Journal Volume 9, Issue 7, pages 1854–1859, July 2014. Article first published online: 9 MAY 2014 DOI: 10.1002/asia.201402007

© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This article is behind a paywall.

Do Tenebrionind beetles collect dew or condensation—a water issue at the nanoscale

Up until now, the research I’ve stumbled across about Tenebrionind beetles and their water-collecting ways has been from the US but this latest work comes from a France/Spain,/UK collaboration which focused on a specific question, exactly where do these beetles harvest their water from? A Dec. 8, 2014 news item on Nanotechnology Now describes this latest research,

Understanding how a desert beetle harvests water from dew could improve drinking water collection in dew condensers

Insects are full of marvels – and this is certainly the case with a beetle from the Tenebrionind family, found in the extreme conditions of the Namib desert. Now, a team of scientists has demonstrated that such insects can collect dew on their backs – and not just fog as previously thought. This is made possible by the wax nanostructure on the surface of the beetle’s elytra. … They bring us a step closer to harvesting dew to make drinking water from the humidity in the air. This, the team hopes, can be done by improving the water yield of man-made dew condensers that mimick the nanostructure on the beetle’s back.

A Dec. 8, 2014  Springer press release (also on EurekAlert), which originated the news item, describes how this research adds to the body of knowledge about the ability to harvest water from the air,

It was not clear from previous studies whether water harvested by such beetles came from dew droplets, in addition to fog. Whereas fog is made of ready-made microdroplets floating in the air, dew appears following the cooling of a substrate below air temperature. This then turns the humidity of air into tiny droplets of water because more energy – as can be measured through infrared emissions – is sent to the atmosphere than received by it. The cooling capability is ideal, they demonstrated, because the insect’s back demonstrates near-perfect infrared emissivity.

Guadarrama-Cetina [José Guadarrama-Cetina] and colleagues also performed an image analysis of dew drops forming on the insect’s back on the surface of the elytra, which appears as a series of bumps and valleys. Dew primarily forms in the valleys endowed with a hexagonal microstructure, they found, unlike the smooth surface of the bumps. This explains how drops can slide to the insect’s mouth when they reach a critical size.

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

Dew condensation on desert beetle skin by J.M. Guadarrama-Cetina, A. Mongruel, M.-G. Medici, E. Baquero, A.R. Parker, I. Milimouk-Melnytchuk, W. González-Viñas, and D. Beysens. Eur. Phys. J. E (European Physics Journal E 2014) 37: 109, DOI 10.1140/epje/i2014-14109-y

This paper is currently (Dec. 8, 2014) open access. I do not know if this will be permanent or if access rights will change over time.

My previous postings on the topic of water and beetles have focused on US research of the Stenocara beetle (aka Namib desert beetle) which appears to be a member of the Tenebrionind family of beetles mentioned in this latest research.

The European researchers have provided an image of the beetle they were examining,

A preserved specimen of the Tenebrionind beetle (Physasterna cribripes) was used for this study, displaying the insect’s mechanisms of dew harvesting. © J.M. Guadarrama-Cetina et al.

A preserved specimen of the Tenebrionind beetle (Physasterna cribripes) was used for this study, displaying the insect’s mechanisms of dew harvesting. © J.M. Guadarrama-Cetina et al.

As for my other pieces on this topic, there’s a July 29, 2014 post, a June 18, 2014 post, and a Nov. 26, 2012 post.

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

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

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

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

Nanex Canada will be headquartered in Montreal.

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

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

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

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

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

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

 

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

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

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

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

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

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

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

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

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

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

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

I have mentioned NanoStruck several times here:

March 14, 2014 posting

Feb. 19, 2014 posting

Feb. 10, 2014 posting

Dec. 27, 2013 posting

New ways to think about water

This post features two items about water both of which suggest we should reconsider our ideas about it. This first item concerns hydrogen bonds and coordinated vibrations. From a July 16 2014 news item on Azonano,

Using a newly developed, ultrafast femtosecond infrared light source, chemists at the University of Chicago have been able to directly visualize the coordinated vibrations between hydrogen-bonded molecules — the first time this sort of chemical interaction, which is found in nature everywhere at the molecular level, has been directly visualized. They describe their experimental techniques and observations in The Journal of Chemical Physics, from AIP [American Institute of Physics] Publishing.

“These two-dimensional infrared spectroscopy techniques provide a new avenue to directly visualize both hydrogen bond partners,” said Andrei Tokmakoff, the lab’s primary investigator. “They have the spectral content and bandwidth to really interrogate huge parts of the vibrational spectrum of molecules. It’s opened up the ability to look at how very different types of vibrations on different molecules interact with one another.”

A July 15, 2014 AIP news release by John Arnst (also on EurekAlert), which originated the news item, provides more detail,

Tokmakoff and his colleagues sought to use two-dimensional infrared spectroscopy to directly characterize structural parameters such as intermolecular distances and hydrogen-bonding configurations, as this information can be encoded in intermolecular cross-peaks that spectroscopy detects between solute-solvent vibrations.

“You pluck on the bonds of one molecule and watch how it influences the other,” Tokmakoff said. “In our experiment, you’re basically plucking on both because they’re so strongly bound.”

Hydrogen bonds are typically perceived as the attractive force between the slightly negative and slightly positive ends of neutrally-charged molecules, such as water. While water stands apart with its unique polar properties, hydrogen bonds can form between a wide range of molecules containing electronegative atoms and range from weakly polar to nearly covalent in strength. Hydrogen bonding plays a key role in the action of large, biologically-relevant molecules and is often an important element in the discovery of new pharmaceuticals.

For their initial visualizations, Tokmakoff’s group used N-methylacetamide, a molecule called a peptide that forms medium-strength hydrogen-bonded dimers in organic solution due to its polar nitrogen-hydrogen and carbon-oxygen tails. By using a targeted three-pulse sequence of mid-infrared light and apparatus described in their article, Tokmakoff’s group was able to render the vibrational patterns of the two peptide units.

“All of the internal vibrations of hydrogen bonded molecules that we look at become intertwined, inextricably; you can’t think of them as just a simple sum of two parts,” Tokmakoff said.

More research is being planned while Tokmakoff suggests that water must be rethought from an atomistic perspective (from the news release),

Future work in Tokmakoff’s group involves visualizing the dynamics and structure of water around biological molecules such as proteins and DNA.

“You can’t just think of the water as sort of an amorphous solvent, you really have to at least on some level think of it atomistically and treat it that way,” Tokmakoff said. “And if you believe that, it has huge consequences all over the place, particularly in biology, where so much computational biology ignores the fact that water has real structure and real quantum mechanical properties of its own.”

The researchers have provided an illustration of hydrogen’s vibrating bonds,

The hydrogen-bonding interaction causes the atoms on each individual N-methylacetamide molecule to vibrate in unison. CREDIT: L. De Marco/UChicago

The hydrogen-bonding interaction causes the atoms on each individual N-methylacetamide molecule to vibrate in unison.
CREDIT: L. De Marco/UChicago

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

Direct observation of intermolecular interactions mediated by hydrogen bonding by Luigi De Marco, Martin Thämer, Mike Reppert, and Andrei Tokmakoff. J. Chem. Phys. 141, 034502 (2014); http://dx.doi.org/10.1063/1.4885145

This paper is open access. (I was able to view the entire HTML version.)

A July 15, 2014 University of Southampton press release on EurekAlert offers another surprise about water,

University of Southampton researchers have found that rainwater can penetrate below the Earth’s fractured upper crust, which could have major implications for our understanding of earthquakes and the generation of valuable mineral deposits.

The reason that water’s ability to penetrate below the earth’s upper crust is a surprise (from the news release),

It had been thought that surface water could not penetrate the ductile crust – where temperatures of more than 300°C and high pressures cause rocks to flex and flow rather than fracture – but researchers, led by Southampton’s Dr Catriona Menzies, have now found fluids derived from rainwater at these levels.

The news release also covers the implications of this finding,

Fluids in the Earth’s crust can weaken rocks and may help to initiate earthquakes along locked fault lines. They also concentrate valuable metals such as gold. The new findings suggest that rainwater may be responsible for controlling these important processes, even deep in the Earth.

Researchers from the University of Southampton, GNS Science (New Zealand), the University of Otago, and the Scottish Universities Environmental Research Centre studied geothermal fluids and mineral veins from the Southern Alps of New Zealand, where the collision of two tectonic plates forces deeper layers of the earth closer to the surface.

The team looked into the origin of the fluids, how hot they were and to what extent they had reacted with rocks deep within the mountain belt.

“When fluids flow through the crust they leave behind deposits of minerals that contain a small amount of water trapped within them,” says Postdoctoral Researcher Catriona, who is based at the National Oceanography Centre. “We have analysed these waters and minerals to identify where the fluids deep in the crust came from.

“Fluids may come from a variety of sources in the crust. In the Southern Alps fluids may flow upwards from deep in the crust, where they are released from hot rocks by metamorphic reactions, or rainwater may flow down from the surface, forced by the high mountains above. We wanted to test the limits of where rainwater may flow in the crust. Although it has been suggested before, our data shows for the first time that rainwater does penetrate into rocks that are too deep and hot to fracture.”

Surface-derived waters reaching such depths are heated to over 400°C and significantly react with crustal rocks. However, through testing the researchers were able to establish the water’s meteoric origin.

Funding for this research, which has been published in Earth and Planetary Science Letters, was provided by the Natural Environmental Research Council (NERC). Catriona and her team are now looking further at the implications of their findings in relation to earthquake cycles as part of the international Deep Fault Drilling Project [DFDP], which aims to drill a hole through the Alpine Fault at a depth of about 1km later this year.

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

Incursion of meteoric waters into the ductile regime in an active orogen by Catriona D. Menzies, Damon A.H. Teagle, Dave Craw, Simon C. Cox, Adrian J. Boyce, Craig D. Barrie, and Stephen Roberts. Earth and Planetary Science Letters Volume 399, 1 August 2014, Pages 1–13 DOI: 10.1016/j.epsl.2014.04.046

Open Access funded by Natural Environment Research Council

This is the first time I’ve seen the funding agency which made the paper’s open access status possible cited.

Fewer silver nanoparticles washed off coated textiles

This time I have two complementary tidbits about silver nanoparticles, their use in textiles, and washing. The first is a June 30, 2014 news item on Nanowerk, with the latest research from Empa (Swiss Federal Laboratories for Materials Science and Technology) on silver nanoparticles being sloughed off textiles when washing them,

The antibacterial properties of silver-coated textiles are popular in the fields of sport and medicine. A team at Empa has now investigated how different silver coatings behave in the washing machine, and they have discovered something important: textiles with nano-coatings release fewer nanoparticles into the washing water than those with normal coatings …

A June 30,  2014 Empa news release, which originated the news item, describes the findings in more detail,

If it contains ‘nano’, it doesn’t primarily leak ‘nano': at least that’s true for silver-coated textiles, explains Bernd Nowack of the «Technology and Society» division at Empa. During each wash cycle a certain amount of the silver coating is washed out of the textiles and ends up in the waste water. [emphasis mine] Empa analysed this water; it turned out that nano-coated textiles release hardly any nano-particles. That’s quite the opposite to ordinary coatings, where a lot of different silver particles were found. Moreover, nano-coated silver textiles generally lose less silver during washing. This is because considerably less silver is incorporated into textile fabrics with nano-coating, and so it is released in smaller quantities for the antibacterial effect than is the case with ordinary coatings. A surprising result that has a transformative effect on future analyses and on the treatment of silver textiles. «All silver textiles behave in a similar manner – regardless of whether they are nano-coated or conventionally-coated,» says Nowack. This is why nano-textiles should not be subjected to stricter regulation than textiles with conventional silver-coatings, and this is relevant for current discussions concerning possible special regulations for nano-silver.

But what is the significance of silver particles in waste water? Exposed silver reacts with the (small quantities of) sulphur in the air to form silver sulphide, and the same process takes place in the waste water treatment plant. The silver sulphide, which is insoluble, settles at the bottom of the sedimentation tank and is subsequently incinerated with the sewage sludge. So hardly any of the silver from the waste water remains in the environment. Silver is harmless because it is relatively non-toxic for humans. Even if silver particles are released from the textile fabric as a result of strong sweating, they are not absorbed by healthy skin.

I’ve highlighted Nowack’s name as he seems to have changed his opinions since I first wrote about his work with silver nanoparticles in textiles and washing in a Sept. 8, 2010 posting,

“We found that the total released varied considerably from less than 1 to 45 percent of the total nanosilver in the fabric and that most came out during the first wash,” Bernd Nowack, head of the Environmental Risk Assessment and Management Group at the Empa-Swiss Federal Laboratories for Materials Testing and Research, tells Nanowerk. “These results have important implications for the risk assessment of silver textiles and also for environmental fate studies of nanosilver, because they show that under certain conditions relevant to washing, primarily coarse silver-containing particles are released.”

How did the quantity of silver nanoparticles lost in water during washing change from “less than 1 to 45 percent of the total nanosilver in the fabric” in a 2010 study to “Empa analysed this water; it turned out that nano-coated textiles release hardly any nano-particles” in a 2014 study? It would be nice to find out if there was a change in the manufacturing process and whether or not this is global change or one undertaken in Switzerland alone.

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

Presence of Nanoparticles in Wash Water from Conventional Silver and Nano-silver Textiles by Denise M. Mitrano, Elisa Rimmele, Adrian Wichser, Rolf Erni, Murray Height, and Bernd Nowack. ACS Nano, Article ASAP DOI: 10.1021/nn502228w Publication Date (Web): June 18, 2014

Copyright © 2014 American Chemical Society

This paper is behind a paywall.

The second tidbit is from Iran and may help to answer my questions about the Empa research. According to a July 7, 2014 news item on Nanowerk (Note: A link has been removed),

Writing in The Journal of The Textile Institute (“Effect of silver nanoparticles morphologies on antimicrobial properties of cotton fabrics”), researchers from Islamic Azad University in Iran, describe the best arrangement for increasing the antibacterial properties of textile products by studying various structures of silver nanoparticles.

A July 7, 2014 news release from the Iran Nanotechnology Initiative Council (INIC), which originated the news item, provides more details,

By employing the structure presented by the researchers, the amount of nanoparticles stabilization on the fabric and the durability of its antibacterial properties increase after washing and some problems are solved, including the change in the fabric color.

Using the results of this research creates diversity in the application of various structures of nanoparticles in the complementary process of cotton products. Moreover, the color of the fabric does not change as the amount of consumed materials decreases, because the excess use of silver was the cause of this problem. On the other hand, the stability and durability of nanoparticles increase against standard washing. All these facts result in the reduction in production cost and increase the satisfaction of the customers.

The researchers have claimed that in comparison with other structures, hierarchical structure has much better antibacterial activity (more than 91%) even after five sets of standard washing.

This work on morphology would seem to answer my question about the big difference in Nowack’s description of the quantity of silver nanoparticles lost due to washing. I am assuming, of course, that something has changed with regard to the structure and/or shape of the silver nanoparticles coating the textiles used in the Empa research.

Getting back to the work in Iran, here’s a link to and a citation for the paper,

Effect of silver nanoparticles morphologies on antimicrobial properties of cotton fabrics by Mohammad Reza Nateghia & Hamed Hajimirzababa. The Journal of The Textile Institute Volume 105, Issue 8, 2014 pages 806-813 DOI: 10.1080/00405000.2013.855377 Published online: 21 Jan 2014

This paper is behind a paywall.

UNESCO course: Nanotechnology for Water and Wastewater Treatment 2015 call for applications

Despite an initially puzzling announcement from UNESCO (United Nations Educational, Scientific, and Cultural Organization), I was able to track down a description for the course on studyfinder.nl,

Nanotechnology for Water and Wastewater Treatment

UNESCO-IHE Institute for Water Education

Certificate / Diploma Short course Delft [Netherlands]

Field of study     Agriculture and environment
Course description     The course overviews the state-of-the-art and novel developments of nanotechnology in applications for drinking water production and wastewater treatment.
Study subjects     Framework: Nanoparticles and Water; Environmental Fate; Risk Analysis. Nanotechnology for Water/Wastewater Treatment: Physical, Chemical and Biological Properties of Nanoparticles. High-Performance Water and Wastewater Purification Systems: Nanofiltration, Nanosorbents and Nanocatalysts. Nanoparticles that Sense and Treat Disease: Biosensors and Desinfectants.
Course objectives     Apply innovative applications of nanotechnology in drinking water production and wastewater treatment. Familiar with the state-of-the-art, impact and cost-benefit analysis of nanotechnology processes for water and wastewater treatment. Communicate successfully on nanoscience and nanotechnology interfacing with environmental chemistry, environmental engineering and bioprocess.

Duration     2 weeks full-time
Language of instruction     English

There is a bit more information on the UNESCO website’s Short Courses Nanotechnology for Water and Wastewater Treatment webpage,

The emergence of nanobiotechnology and the incorporation of living microorganisms in biomicroelectronic devices are revolutionizing interdisciplinary opportunities for microbiologists and biotechnologists to participate in understanding microbial processes in and from the environment. Moreover, it offers revolutionary perspectives to develop and exploit these processes in completely new ways.

This short course presents an opportunity to learn and discuss about various innovative research aspects of nanoscience and nanotechnology interfacing with environmental chemistry, environmental engineering and bioprocess technology amongst professionals as well as young researchers and PhD students.

You can access the 2015 call for applications on this UNESCO webpage. For more information contact,

Piet Lens

Professor of Environmental Biotechnology

Phone +31152151816
Email