Tag Archives: Holland

3D brain-on-a-chip from the University of Twente

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Dutch researchers have developed a 3D brain-on-a-chip according to a June 23, 2016 news item on Nanowerk,

To study brain cell’s operation and test the effect of medication on individual cells, the conventional Petri dish with flat electrodes is not sufficient. For truly realistic studies, cells have to flourish within three-dimensional surroundings.

Bart Schurink, researcher at University of Twente’s MESA+ Institute for Nanotechnology, has developed a sieve with 900 openings, each of which has the shape of an inverted pyramid. On top of this array of pyramids, a micro-reactor takes care of cell growth. Schurink defends his PhD thesis June 23 [2016].

A June 23, 2016 University of Twente press release, which originated the news item, provides more detail,

A brain-on-a-chip demands more than a series of electrodes in 2D, on which brain cells can be cultured. To mimic the brain in a realistic way, you need facilities for fluid flow, and the cells need some freedom for themselves even when they are kept at predefined spaces. Schurink therefore developed a micro sieve structure with hundreds of openings on a 2 by 2 mm surface. Each of these holes has the shape of  an inverted pyramid. Each pyramid, in turn, is equipped with an electrode, for measuring electrical signals or sending stimuli to the network. At the same time, liquids can flow through tiny holes, needed to capture the cells and for sending nutrients or medication to a single cell.

NEURONAL NETWORK

After neurons have been placed inside all the pyramids, they will start to form a network. This is not just a 2D network between the holes: by placing a micro reactor on top of the sieve, a neuron network can develop in the vertical direction as well. Growth and electrical activity can be monitored subsequently: each individual cell can be identified by the pyramid it is in. Manufacturing this system, demands a lot of both the production facilities at UT’s NanoLab and of creative solutions the designers come up with. For example, finding the proper way of guaranteeing  the same dimensions for every hole, is quite challenging.

Schurink’s new µSEA (micro sieve electrode array) has been tested with living cells, from the brains of laboratory rats. Both the positioning of the cells and neuronal network growth have been tested. The result of this PhD research is a fully new research platform for performing research on the brain, diseases and effects of medication.

Schurink (1982) has conducted his research within the group Meso Scale Chemical Systems, of Prof Han Gardeniers. The group is part of the MESA+ Institute for Nanotechnology of the University of Twente. Schurink’s thesis is titled ‘Microfabrication and microfluidics for 3D brain-on-chip’ …

I have written about one other piece about a ‘3D’ organ-on-a-chip project in China (my Jan. 29, 2016 posting).

Artists classified the animal kingdom?

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Where taxonomy and biology are concerned, my knowledge begins and end with Carl Linnaeus, the Swedish scientist who ushered in modern taxonomy. It was with some surprise that I find out artists also helped develop the field. From a June 21, 2016 news item on ScienceDaily,

In the sixteenth and seventeenth centuries artists were fascinated by how the animal kingdom was classified. They were in some instances ahead of natural historians.

This is one of the findings of art historian Marrigje Rikken. She will defend her PhD on 23 June [2016] on animal images in visual art. In recent years she has studied how images of animals between 1550 and 1630 became an art genre in themselves. ‘The close relationship between science and art at that time was remarkable,’ Rikken comments. ‘Artists tried to bring some order to the animal kingdom, just as biologists did.’

A June 21, 2016 Universiteit Leiden (Leiden University, Netherlands) press release, which originated the news item, expands on the theme,

In some cases the artists were ahead of their times. They became interested in insects, for example, before they attracted the attention of natural historians. It was artist Joris Hoefnagel who in 1575 made the first miniatures featuring beetles, butterflies and dragonflies, indicating how they were related to one another. In his four albums Hoefnagel divided the animal species according to the elements of fire, water, air and earth, but within these classifications he grouped animals on the basis of shared characteristics.

Courtesy: Universiteit Leiden

Beetles, butterflies, and dragonflies by Joris Hoefnagel. Courtesy: Universiteit Leiden

The press release goes on,

Other illustrators, print-makers and painters tried to bring some cohesion to the animal kingdom.  Some of them used an alphabetical system but artist Marcus Gheeraerts  published a print as early as 1583 [visible below, Ed.] in which grouped even-toed ungulates together. The giraffe and sheep – both visible on Gheeraerts’ print – belong to this species of animals. This doesn’t apply to all Gheeraerts’ animals. The mythical unicorn, which was featured by Gheeraerts, no longer appears in contemporary biology books.

Wealthy courtiers

According to Rikken, the so-called menageries played an important role historically in how animals were represented. These forerunners of today’s zoos were popular in the sixteenth and seventeenth centuries particularly among wealthy rulers and courtiers. Unfamiliar exotic animals regularly arrived that were immediately committed to paper by artists. Rikken: ‘The toucan, for example, was immortalised in 1615 by Jan Brueghel the Elder, court painter in Brussels.’  [See the main image, Ed.].’

In the flesh

Rikken also discovered that the number of animals featured in a work gradually increased. ‘Artists from the 1570s generally included one or just a few animals per work. With the arrival of print series a decade later, each illustration tended to include more and more animals. This trend reached its peak in the lavish paintings produced around 1600.’ These paintings are also much more varied than the drawings and prints. Illustrators and print-makers often blindly copied one another’s motifs, even showing the animals in an identical pose. Artists had no hesitation in including the same animal in different positions. Rikken: ‘This allowed them to show that they had observed the animal in the flesh.’

Even-toed ungulates by Marcus Gheeraerts. Courtesy: Leiden Universiteit

Even-toed ungulates by Marcus Gheeraerts. Courtesy: Leiden Universiteit

Yet more proof or, at least, a very strong suggestion that art and science are tightly linked.

Making diesel cleaner

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A Dec. 10, 2015 news item on Nanowerk announces a new method for producing diesel fuels (Note: A link has been removed),

Researchers from KU Leuven [Belgium] and Utrecht University [Netherlands] have discovered a new approach to the production of fuels (Nature, “Nanoscale intimacy in bifunctional catalysts for selective conversion of hydrocarbons”). Their new method can be used to produce much cleaner diesel. It can quickly be scaled up for industrial use. In 5 to 10 years, we may see the first cars driven by this new clean diesel.

A Dec. 10, 2015 KU Leuven press release, which originated the news item, provides more detail about the research,

The production of fuel involves the use of catalysts. These substances trigger the chemical reactions that convert raw material into fuel. In the case of diesel, small catalyst granules are added to the raw material to sufficiently change the molecules of the raw material to produce useable fuel.

Catalysts can have one or more chemical functions. The catalyst that was used for this particular study has two functions, represented by two different materials: a metal (platinum) and a solid-state acid. During the production process for diesel, the molecules bounce to and fro between the metal and the acid. Each time a molecule comes into contact with one of the materials, it changes a little bit. At the end of the process, the molecules are ready to be used for diesel fuel.

The assumption has always been that the metal and the solid-state acid in the catalyst should be as close together as possible. That would speed up the production process by helping the molecules bounce to and fro more quickly. Professor Johan Martens (KU Leuven) and Professor Krijn de Jong (Utrecht University) have now discovered that this assumption is incorrect. [emphasis mine] If the functions within a catalyst are nanometres apart, the process yields better molecules for cleaner fuel.

“Our results are the exact opposite of what we had expected. At first, we thought that the samples had been switched or that something was wrong with our analysis”, says Professor Martens. “We repeated the experiments three times, only to arrive at the same conclusion: the current theory is wrong. There has to be a minimum distance between the functions within a catalyst. This goes against what the industry has been doing for the past 50 years.”

The new technique can optimise quite a few molecules in diesel. Cars that are driven by this clean diesel would emit far fewer particulates and CO². The researchers believe that their method can be scaled up for industrial use with relative ease, so the new diesel could be used in cars in 5 to 10 years.

The new technique can be applied to petroleum-based fuels, but also to renewable carbon from biomass.

A fifty year old assumption has been found wrong. Interesting, non? In any event, here’s a link to and a citation for the paper,

Nanoscale intimacy in bifunctional catalysts for selective conversion of hydrocarbons by Jovana Zecevic, Gina Vanbutsele, Krijn P. de Jong, & Johan A. Martens. Nature 528, 245–248 (10 December 2015)  doi:10.1038/nature16173 Published online 09 December 2015

This paper is behind a paywall.

Why Factory publishes book about research on nanotechnology in architecture

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The book titled, Barba. Life in the Fully Adaptable Environment, published by nai010 and the Why Factory, a think tank operated by Dutch architectural firm, MVRDV, and Delft University of Technology in the Netherlands, is a little difficult to describe.  From a Nov. 16, 2015 MVRDV press release,

Is the end of brick and mortar near? How could nanotechnology change buildings and cities in the future? A speculation of The Why Factory on this topic is illustrated in the best tradition of science fiction in the newly published book Barba. Life in the Fully Adaptable Environment. It forms the point of departure for a series of interactive experiments, installations and proposals towards the development of new, body-based and fully adaptive architectures. A beautiful existential story comes alive. A story closer to us then you’d ever have thought. Imagine a new substance that could be steered and altered in real time. Imagine creating a flexible material that could change its shape, that could shrink and expand, that could do almost anything. The Why Factory calls this fictional material Barba. With Barba, we would be able to adapt our environment to every desire and to every need.

The press release delves into the inspiration for the material and the book,

… The first inspiration came from ‘Barbapapa’, an illustrated cartoon character from the 1970s. Invented and drawn by Talus Taylor and Annette Tison, the friendly, blobby protagonist of the eponymous children’s books and television programme could change his shape to resemble different objects. With Barbapapa’s smooth morphosis in mind, The Why Factory wondered how today’s advancements in robotics, material science and computing might allow us to create environments that transform themselves as easily as Barbapapa could. Neither Barbapapa’s inventors nor anybody else from the team behind the cartoon were involved in this project, but The Why Factory owes them absolute gratitude for the inspiration of Barbapapa.

“Barba is a fantastic matter that does whatever we wish for” says Winy Maas, Professor at The Why Factory and MVRDV co-founder. “You can programme your environment like a computer game. You could wake up in a modernist villa that you transform into a Roman Spa after breakfast. Cities can be totally transformed when offices just disappear after office hours.”

The book moves away from pure speculation, however, and makes steps towards real world application, including illustrated vision, programming experiments and applied prototypes. As co-author of the book, Ulf Hackauf, explains, “We started this book with a vision, which we worked out to form a consistent future scenario. This we took as a point of departure for experiments and speculations, including programming, installations and material research. It eventually led us to prototypes, which could form a first step for making Barba real.”

Barba developed through a series of projects organized by The Why Factory and undertaken in collaboration between Delft University of Technology, ETH Zürich and the European Institute of Innovation and Technology. The research was developed over the course of numerous design studios at the Why Factory and elsewhere. Students and collaborators of the Why Factory have all contributed to the book.

The press release goes on to offer some information about Why Factory,

The Why Factory explores possibilities for the development of our cities by focusing on the production of models and visualisations for cities of the future. Education and research of The Why Factory are combined in a research lab and platform that aims to analyse, theorise and construct future cities. It investigates within the given world and produces future scenarios beyond it; from universal to specific and global to local. It proposes, constructs and envisions hypothetical societies and cities; from science to fiction and vice versa. The Why Factory thus acts as a future world scenario making machinery, engaging in a public debate on architecture and urbanism. Their findings are then communicated to the wider public in a variety of ways, including exhibitions, publications, workshops, and panel discussions.

Based on the Why Factory description, I’m surmising that the book is meant to provoke interactivity in some way. However, there doesn’t seem to be a prescribed means to interact with the Why Factory or the authors (Winy Maas, Ulf Hackauf, Adrien Ravon, and Patrick Healy) so perhaps the book is meant to be a piece of fiction/manual for interested educators, architects, and others who want to create ‘think tank’ environments where people speculate about nanotechnology and architecture.

In any event, you can order the book from this nai010 webpage,

How nanotechnology might drastically change cities and architecture

> New, body-based and fully adaptive architecture
How could nanotechnology change buildings and cities in the future? Imagine a new substance, that could be steered and altered in real time. Imagine …

As for The Why Factory, you can find out more here on the think tank’s About page.

One last comment, in checking out MVRDV, the Dutch architectural firm mentioned earlier as one of The Why Factory’s operating organizations, I came across this piece of news generated as a consequence of the Nov. 13, 2015 Paris bombings,

The Why Factory alumna Emilie Meaud died in Friday’s Paris attacks. Our thoughts are with their family, friends and colleagues.

Nov 17, 2015

To our great horror and shock we received the terrible news that The Why Factory alumna Emilie Meaud (29) died in the Paris attacks of last Friday. She finished her master in Architecture at TU-Delft in 2012 and worked at the Agence Chartier-Dalix. She was killed alongside her twin sister Charlotte. Our thoughts are with their family, friends and colleagues.

Amen.

Computer chips derived in a Darwinian environment

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Courtesy: University of Twente

Courtesy: University of Twente

If that ‘computer chip’ looks a brain to you, good, since that’s what the image is intended to illustrate assuming I’ve correctly understood the Sept. 21, 2015 news item on Nanowerk (Note: A link has been removed),

Researchers of the MESA+ Institute for Nanotechnology and the CTIT Institute for ICT Research at the University of Twente in The Netherlands have demonstrated working electronic circuits that have been produced in a radically new way, using methods that resemble Darwinian evolution. The size of these circuits is comparable to the size of their conventional counterparts, but they are much closer to natural networks like the human brain. The findings promise a new generation of powerful, energy-efficient electronics, and have been published in the leading British journal Nature Nanotechnology (“Evolution of a Designless Nanoparticle Network into Reconfigurable Boolean Logic”).

A Sept. 21, 2015 University of Twente press release, which originated the news item, explains why and how they have decided to mimic nature to produce computer chips,

One of the greatest successes of the 20th century has been the development of digital computers. During the last decades these computers have become more and more powerful by integrating ever smaller components on silicon chips. However, it is becoming increasingly hard and extremely expensive to continue this miniaturisation. Current transistors consist of only a handful of atoms. It is a major challenge to produce chips in which the millions of transistors have the same characteristics, and thus to make the chips operate properly. Another drawback is that their energy consumption is reaching unacceptable levels. It is obvious that one has to look for alternative directions, and it is interesting to see what we can learn from nature. Natural evolution has led to powerful ‘computers’ like the human brain, which can solve complex problems in an energy-efficient way. Nature exploits complex networks that can execute many tasks in parallel.

Moving away from designed circuits

The approach of the researchers at the University of Twente is based on methods that resemble those found in Nature. They have used networks of gold nanoparticles for the execution of essential computational tasks. Contrary to conventional electronics, they have moved away from designed circuits. By using ‘designless’ systems, costly design mistakes are avoided. The computational power of their networks is enabled by applying artificial evolution. This evolution takes less than an hour, rather than millions of years. By applying electrical signals, one and the same network can be configured into 16 different logical gates. The evolutionary approach works around – or can even take advantage of – possible material defects that can be fatal in conventional electronics.

Powerful and energy-efficient

It is the first time that scientists have succeeded in this way in realizing robust electronics with dimensions that can compete with commercial technology. According to prof. Wilfred van der Wiel, the realized circuits currently still have limited computing power. “But with this research we have delivered proof of principle: demonstrated that our approach works in practice. By scaling up the system, real added value will be produced in the future. Take for example the efforts to recognize patterns, such as with face recognition. This is very difficult for a regular computer, while humans and possibly also our circuits can do this much better.”  Another important advantage may be that this type of circuitry uses much less energy, both in the production, and during use. The researchers anticipate a wide range of applications, for example in portable electronics and in the medical world.

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

Evolution of a designless nanoparticle network into reconfigurable Boolean logic by S. K. Bose, C. P. Lawrence, Z. Liu, K. S. Makarenko, R. M. J. van Damme, H. J. Broersma, & W. G. van der Wiel. Nature Nanotechnology (2015) doi:10.1038/nnano.2015.207 Published online 21 September 2015

This paper is behind a paywall.

Final comment, this research, especially with the reference to facial recognition, reminds me of memristors and neuromorphic engineering. I have written many times on this topic and you should be able to find most of the material by using ‘memristor’ as your search term in the blog search engine. For the mildly curious, here are links to two recent memristor articles, Knowm (sounds like gnome?) A memristor company with a commercially available product in a Sept. 10, 2015 posting and Memristor, memristor, you are popular in a May 15, 2015 posting.

Structural memory of water and the picosecond timescale

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Water is a unique liquid and researchers from Germany and the Netherlands can detail at least part of why that’s so according to a Sept. 18, 2015 news item on Nanowerk,

A team of scientists from the Max Planck Institute for Polymer Research (MPI-P) in Mainz, Germany and FOM Institute AMOLF in the Netherlands have characterized the local structural dynamics of liquid water, i.e. how quickly water molecules change their binding state. Using innovative ultrafast vibrational spectroscopies, the researchers show why liquid water is so unique compared to other molecular liquids. …

With the help of a novel combination of ultrafast laser experiments, the scientists found that local structures persist in water for longer than a picosecond, a picosecond (ps) being one thousandth of one billionth of a second ((1012 s). This observation changes the general perception of water as a solvent.

A Sept. 18, 2015 Max Planck Institute for Polymer Research press release (also on EurekAlert), which originated the news item, details the research,

… “71% of the earth’s surface is covered with water. As most chemical and biological reactions on earth occur in water or at the air water interface in oceans or in clouds, the details of how water behaves at the molecular level are crucial. Our results show that water cannot be treated as a continuum, but that specific local structures exist and are likely very important” says Mischa Bonn, director at the MPI-P.

Water is a very special liquid with extremely fast dynamics. Water molecules wiggle and jiggle on sub-picosecond timescales, which make them undistinguishable on this timescale. While the existence of very short-lived local structures – e.g. two water molecules that are very close to one another, or are very far apart from each other – is known to occur, it was commonly believed that they lose the memory of their local structure within less than 0.1 picoseconds.

The proof for relatively long-lived local structures in liquid water was obtained by measuring the vibrations of the Oxygen-Hydrogen (O-H) bonds in water. For this purpose the team of scientists used ultrafast infrared spectroscopy, particularly focusing on water molecules that are weakly (or strongly) hydrogen-bonded to their neighboring water molecules. The scientists found that the vibrations live much longer (up to about 1 ps) for water molecules with a large separation, than for those that are very close (down to 0.2 ps). In other words, the weakly bound water molecules remain weakly bound for a remarkably long time.

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

Strong frequency dependence of vibrational relaxation in bulk and surface water reveals sub-picosecond structural heterogeneity by Sietse T. van der Post, Cho-Shuen Hsieh, Masanari Okuno, Yuki Nagata, Huib J. Bakker, Mischa Bonn & Johannes Hunger. Nature Communications 6, Article number: 8384 doi:10.1038/ncomms9384 Published 18 September 2015

This is an open access paper,

Clothing which turns you into a billboard

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This work from a Belgian-Dutch initiative has the potential to turn us into billboards. From a Sept. 2, 2015 news item on Nanowerk,

Researchers from Holst Centre (set up by TNO and imec), imec and CMST, imec’s associated lab at Ghent University [Belgium], have demonstrated the world’s first stretchable and conformable thin-film transistor (TFT) driven LED display laminated into textiles. This paves the way to wearable displays in clothing providing users with feedback.

Here’s what it looks like,

A Sept. 2, 2015 Holst Centre press release, which originated the news item, provides more details,

“Wearable devices allow people to monitor their fitness and health so they can live full and active lives for longer. But to maximize the benefits wearables can offer, they need to be able to provide feedback on what users are doing as well as measuring it. By combining imec’s patented stretch technology with our expertise in active-matrix backplanes and integrating electronics into fabrics, we’ve taken a giant step towards that possibility,” says Edsger Smits, Senior research scientist at Holst Centre.

The conformable display is very thin and mechanically stretchable. A fine-grain version of the proven meander interconnect technology was developed by the CMST lab at Ghent University and Holst Centre to link standard (rigid) LEDs into a flexible and stretchable display. The LED displays are fabricated on a polyimide substrate and encapsulated in rubber, allowing the displays to be laminated in to textiles that can be washed. Importantly, the technology uses fabrication steps that are known to the manufacturing industry, enabling rapid industrialization.

Following an initial demonstration at the Society for Information Display’s Display Week in San Jose, USA earlier this year, Holst Centre has presented the next generation of the display at the International Meeting on Information Display (IMID) in Daegu, Korea, 18-21 August 2015. Smaller LEDs are now mounted on an amorphous indium-gallium-zinc oxide (a-IGZO) TFT backplane that employs a two-transistor and one capacitor (2T-1C) pixel engine to drive the LEDs. These second-generation displays offer higher pitch and increased, average brightness. The presentation will feature a 32×32 pixel demonstrator with a resolution of 13 pixels per inch (ppi) and average brightness above 200 candelas per square meter (cd/m2). Work is ongoing to further industrialize this technology.

There are some references for the work offered at the end of the press release but I believe they are citing their conference presentations,

9.4: Stretchable 45 × 80 RGB LED Display Using Meander Wiring Technology, Ohmae et al. SID 2015, June 2015

1.2: Rollable, Foldable and Stretchable Displays, Gelinck et al. IMID, Aug. 2015.

13.4 A conformable Active Matrix LED Display, Tripathi et al. IMID, Aug. 2015

For anyone interested in imec formerly the Interuniversity Microelectronics Centre, there’s this Wikipedia entry, and in TNO (Nederlandse Organisatie voor Toegepast Natuurwetenschappelijk Onderzoek in Dutch), there’s this Wikipedia entry.

MOFs (metal-organic frameworks) to clean up nuclear waste?

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There’s a possibility that metal-organic frameworks could be used to clean up nuclear waste according to an Aug. 5, 2015 news item on phys.org,

One of the most versatile and widely applicable classes of materials being studied today are the metal-organic frameworks. These materials, known as MOFs, are characterized by metal ions or metal-ion clusters that are linked together with organic molecules, forming ordered crystal structures that contain tiny cage-like pores with diameters of two nanometers or less.

MOFs can be thought of as highly specialized and customizable sieves. By designing them with pores of a certain size, shape, and chemical composition, researchers can tailor them for specific purposes. A few of the many, many possible applications for MOFs are storing hydrogen in fuel cells, capturing environmental contaminants, or temporarily housing catalytic agents for chemical reactions.

At [US Department of Energy] Brookhaven National Laboratory, physicist Sanjit Ghose and his collaborators have been studying MOFs designed for use in the separation of waste from nuclear reactors, which results from the reprocessing of nuclear fuel rods. He is targeting two waste products in particular: the noble gases xenon (Xe) and krypton (Kr).

An Aug. 4, 2015 Brookhaven National Laboratory news release, which originated the news item, describes not only the research and the reasons for it but also the institutional collaborations necessary to conduct the research,

There are compelling economic and environmental reasons to separate Xe and Kr from the nuclear waste stream. For one, because they have very different half-lives – about 36 days for Xe and nearly 11 years for Kr – pulling out the Xe greatly reduces the amount of waste that needs to be stored long-term before it is safe to handle. Additionally, the extracted Xe can be used for industrial applications, such as in commercial lighting and as an anesthetic. This research may also help scientists determine how to create MOFs that can remove other materials from the nuclear waste stream and expose the remaining unreacted nuclear fuel for further re-use. This could lead to much less overall waste that must be stored long-term and a more efficient system for producing nuclear energy, which is the source of about 20 percent of the electricity in the U.S.

Because Xe and Kr are noble gases, meaning their outer electron orbitals are filled and they don’t tend to bind to other atoms, they are difficult to manipulate. The current method for extracting them from the nuclear waste stream is cryogenic distillation, a process that is energy-intensive and expensive. The MOFs studied here use a very different approach: polarizing the gas atoms dynamically, just enough to draw them in using the van der Waals force. The mechanism works at room temperature, but also at hotter temperatures, which is key if the MOFs are to be used in a nuclear environment.

Recently, Ghose co-authored two papers that describe MOFs capable of adsorbing Xe and Kr, and excel at separating the Xe from the Kr. The papers are published in the May 22 online edition of the Journal of the American Chemical Society and the April 16 online edition of the Journal of Physical Chemistry Letters.

“Only a handful of noble-gas-specific MOFs have been studied so far, and we felt there was certainly scope for improvement through the discovery of more selective materials,” said Ghose.

Both MOF studies were carried out by large multi-institution collaborations, using a combination of X-ray diffraction, theoretical modeling, and other methods. The X-ray work was performed at Brookhaven’s former National Synchrotron Light Source (permanently closed and replaced by its successor, NSLS-II) and the Advanced Photon Source at Argonne National Laboratory (ANL), both DOE Office of Science User Facilities.

The JACS paper was co-authored by researchers from Brookhaven Lab, Stony Brook University (SBU), Pacific Northwest National Laboratory (PNNL), and the University of Amsterdam. Authors on the JPCL paper include scientists from Brookhaven, SBU, PNNL, ANL, the Deutsches Elektronen-Synchrotron (DESY) in Germany, and DM Strachan, LLC.

Here’s more about the first published paper in the Journal of Physical Chemistry Letters (JCPL) (from the news release)

A nickel-based MOF

The MOF studied in the JCPL paper consists of nickel (Ni) and the organic compound dioxido-benzene-dicarboxylate (DOBC), and is thus referred to as Ni-DOBDC. Ni-DOBDC can adsorb both Xe and Kr at room temperature but is highly selective toward Xe. In fact, it boasts what may be the highest Xe adsorption capacity of a MOF discovered to date.

The group studied Ni-DOBC using two main techniques: X-ray diffraction and first-principles density functional theory (DFT). The paper is the first published report to detail the adsorption mechanism by which the MOF takes in these noble gases at room temperature and pressure.

“Our results provide a fundamental understanding of the adsorption structure and the interactions between the MOF and the gas by combining direct structural analyses from experimental X-ray diffraction data and DFT calculations,” said Ghose.

The group was also able to discover the existence of a secondary site at the pore center in addition to the six-fold primary site. The seven-atom loading scheme was initially proposed by theorist Yan Li, an co-author of the JCPL paper and formerly on staff at Brookhaven (she is now an editor at Physical Review B), which was confirmed experimentally and theoretically. Data also indicate that Xe are adsorbed more strongly than Kr, due to its higher atomic polarizability. They also discovered a temperature-dependence of the adsorption that furthers this MOF’s selectivity for Xe over Kr. As the temperature was increased above room temperature, the Kr adsorption drops more drastically than for Xe. Over the entire temperature range tested, Xe adsorption always dominates that of Kr.

“The high separation capacity of Ni-DOBDC suggests that it has great potential for removing Xe from Kr in the off-gas streams in nuclear spent fuel reprocessing, as well as filtering Xe at low concentration from other gas mixtures,” said Ghose.

Ghose and Li are now preparing a manuscript that will discuss a more in-depth investigation into the possibility of packing in even more Xe atoms.

“Because of the confinement offered by each pore, we want to see if it’s possible to fit enough Xe in each chamber to form a solid,” said Li.

Ghose and Li hope to experimentally test this idea at NSLS-II in the future, at the facility’s X-ray Powder Diffraction (XPD) beamline, which Ghose has helped develop and build. Additional future studies of these and other MOFs will also take place at XPD. For example, they want to see what happens when other gases are present, such as nitrogen oxides, to mimic what happens in an actual nuclear reactor.

Then, there was the second paper published in the Journal of the American Chemical Society (JACS),

Another MOF, Another Promising Result

In the JACS paper, Ghose and researchers from Brookhaven, SBU, PNNL, and the University of Amsterdam describe a second MOF, dubbed Stony Brook MOF-2 (SBMOF-2). It also captures both Xe and Kr at room temperature and pressure, although is about ten times as effective at taking in Xe, with Xe taking up as much as 27 percent of its weight. SBMOF-2 had been theoretically predicted to be an efficient adsorbent for Xe and Kr, but until this research there had been no experimental results to back up the prediction.

“Our study is different than MOF research done by other groups,” said chemist John Parise, a coauthor of the JACS paper who holds a joint position with Brookhaven and SBU. “We did a lot of testing and investigated the capture mechanism very closely to get clues that would help us understand why the MOF worked, and how to tailor the structure to have even better properties.”

SBMOF-2 contains calcium (Ca) ions and an organic compound with the chemical formula C34H22O8. X-ray data show that its structure is unusual among microporous MOFs. It has fewer calcium sites than expected and an excess of oxygen over calcium. The calcium and oxgyen form CaO6, which takes the form of a three-dimensional octahedron. Notably, none of the six oxygen atoms bound to the calcium ion are shared with any other nearby calcium ions. The authors believe that SBMOF-2 is the first microporous MOF with these isolated CaO6 octahedra, which are connected by organic linker molecules.

The group discovered that the preference of SBMOF-2 for Xe over Kr is due to both the geometry and chemistry of its pores. All the pores have diamond-shaped cross sections, but they come in two sizes, designated type-1 and type-2. Both sizes are a better fit for the Xe molecule. The interiors of the pores have walls made of phenyl groups – ring-shaped C6H5 molecules – along with delocalized electron clouds and H atoms pointing into the pore. The type-2 pores also have hydroxyl anions (OH-) available. All of these features provide are potential sites for adsorbed Xe and Kr atoms.

In follow-up studies, Ghose and his colleagues will use these results to guide them as they determine what changes can be made to these MOFs to improve adsorption, as well as to determine what existing MOFs may yield similar or better performance.

Here are links to and citations for both papers,

Understanding the Adsorption Mechanism of Xe and Kr in a Metal–Organic Framework from X-ray Structural Analysis and First-Principles Calculations by Sanjit K. Ghose, Yan Li, Andrey Yakovenko, Eric Dooryhee, Lars Ehm, Lynne E. Ecker, Ann-Christin Dippel, Gregory J. Halder, Denis M. Strachan, and Praveen K. Thallapally. J. Phys. Chem. Lett., 2015, 6 (10), pp 1790–1794 DOI: 10.1021/acs.jpclett.5b00440 Publication Date (Web): April 16, 2015

Copyright © 2015 American Chemical Society

Direct Observation of Xe and Kr Adsorption in a Xe-Selective Microporous Metal–Organic Framework by Xianyin Chen, Anna M. Plonka, Debasis Banerjee, Rajamani Krishna, Herbert T. Schaef, Sanjit Ghose, Praveen K. Thallapally, and John B. Parise. J. Am. Chem. Soc., 2015, 137 (22), pp 7007–7010 DOI: 10.1021/jacs.5b02556 Publication Date (Web): May 22, 2015
Copyright © 2015 American Chemical Society

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