Category Archives: water

Water-based ionic computing (neural computing networks)

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An ionic circuit comprising hundreds of ionic transistors
Caption: An ionic circuit comprising hundreds of ionic transistors. Credit: Woo-Bin Jung/Harvard SEAS

I love that image and it pertains to this September 29, 2022 news item on ScienceDaily,

Microprocessors in smartphones, computers, and data centers process information by manipulating electrons through solid semiconductors but our brains have a different system. They rely on the manipulation of ions in liquid to process information.

Inspired by the brain, researchers have long been seeking to develop ‘ionics’ in an aqueous solution. While ions in water move slower than electrons in semiconductors, scientists think the diversity of ionic species with different physical and chemical properties could be harnessed for richer and more diverse information processing.

Ionic computing, however, is still in its early days. To date, labs have only developed individual ionic devices such as ionic diodes and transistors, but no one has put many such devices together into a more complex circuit for computing — until now.

A team of researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS), in collaboration with DNA Script, a biotech startup, have developed an ionic circuit comprising hundreds of ionic transistors and performed a core process of neural net computing.

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A September 28, 2022 Harvard John A. Paulson School of Engineering and Applied Sciences news release (also on EurekAlert but published on Sept. 29, 2022), which originated the news item, provides details (Note: A link has been removed),

The researchers began by building a new type of ionic transistor from a  technique they recently pioneered. The transistor consists of an aqueous solution of quinone molecules, interfaced with two concentric ring electrodes with a center disk electrode, like a bullseye. The two ring electrodes electrochemically lower and tune the local pH around the center disk by producing and trapping hydrogen ions. A voltage applied to the center disk causes an electrochemical reaction to generate an ionic current from the disk into the water. The reaction rate can be sped up or down –– increasing or decreasing the ionic current — by tuning the local pH.  In other words, the pH controls, or gates, the disk’s ionic current in the aqueous solution, creating an ionic counterpart of the electronic transistor.

They then engineered the pH-gated ionic transistor in such a way that the disk current is an arithmetic multiplication of the disk voltage and a “weight” parameter representing the local pH gating the transistor. They organized these transistors into a 16 × 16 array to expand the analog arithmetic multiplication of individual transistors into an analog matrix multiplication, with the array of local pH values serving as a weight matrix encountered in neural networks.

“Matrix multiplication is the most prevalent calculation in neural networks for artificial intelligence,” said Woo-Bin Jung, a postdoctoral fellow at SEAS and the first author of the paper. “Our ionic circuit performs the matrix multiplication in water in an analog manner that is based fully on electrochemical machinery.”

“Microprocessors manipulate electrons in a digital fashion to perform matrix multiplication,” said Donhee Ham, the Gordon McKay Professor of Electrical Engineering and Applied Physics at SEAS and the senior author of the paper. “While our ionic circuit cannot be as fast or accurate as the digital microprocessors, the electrochemical matrix multiplication in water is charming in its own right, and has a potential to be energy efficient.”

Now, the team looks to enrich the chemical complexity of the system.

“So far, we have used only 3 to 4 ionic species, such as hydrogen and quinone ions, to enable the gating and ionic transport in the aqueous ionic transistor,” said Jung. “It will be very interesting to employ more diverse ionic species and to see how we can exploit them to make rich the contents of information to be processed.”

The research was co-authored by Han Sae Jung, Jun Wang, Henry Hinton, Maxime Fournier, Adrian Horgan, Xavier Godron, and Robert Nicol. It was supported in part by the Office of the Director of National Intelligence (ODNI), Intelligence Advanced Research Projects Activity (IARPA), under grant 2019-19081900002.

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

An Aqueous Analog MAC Machine by Woo-Bin Jung, Han Sae Jung, Jun Wang, Henry Hinton, Maxime Fournier, Adrian Horgan, Xavier Godron, Robert Nicol, Donhee Ham. Advanced Materials DOI: https://doi.org/10.1002/adma.202205096 First published online: 23 August 2022

This paper is behind a paywall.

As for the biotech startup mentioned as a collaborative partner in the research, DNA Script can be found here.

Using nanomagnets to remove plastic from water

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it seems Australian researchers are working hard to find ways of removing microplastics from water. I have two items, first, a November 29, 2022 news item on Nanowerk announces some of the latest work,

Researchers at RMIT University have found an innovative way to rapidly remove hazardous microplastics from water using magnets.

Lead researcher Professor Nicky Eshtiaghi said existing methods could take days to remove microplastics from water, while their cheap and sustainable invention achieves better results in just one hour.

The team says they have developed adsorbents, in the form of a powder, that remove microplastics 1,000 times smaller than those currently detectable by existing wastewater treatment plants. 

The researchers have successfully tested the adsorbents in the lab, and they plan to engage with industry to further develop the innovation to remove microplastics from waterways.

…

A November 30, 2022 RMIT University press release, which originated the news item, provides more technical detail about the work,

“The nano-pillar structure we’ve engineered to remove this pollution, which is impossible to see but very harmful to the environment, is recycled from waste and can be used multiple times,” said Eshtiaghi from RMIT’s School of Environmental and Chemical Engineering.

“This is a big win for the environment and the circular economy.”

How does this innovation work?

The researchers have developed an adsorbent using nanomaterials that they can mix into water to attract microplastics and dissolved pollutants.

Muhammad Haris, the first author and PhD candidate from RMIT’s School of Environmental and Chemical Engineering, said the nanomaterials contained iron, which enabled the team to use magnets to easily separate the microplastics and pollutants from the water.

“This whole process takes one hour, compared to other inventions taking days,” he said.

Co-lead researcher Dr Nasir Mahmood said the nano-pillar structured material was designed to attract microplastics without creating any secondary pollutants or carbon footprints.

“The adsorbent is prepared with special surface properties so that it can effectively and simultaneously remove both microplastics and dissolved pollutants from water,” said Mahmood from Applied Chemistry and Environmental Science at RMIT.

“Microplastics smaller than 5 millimetres, which can take up to 450 years to degrade, are not detectable and removable through conventional treatment systems, resulting in millions of tonnes being released into the sea every year. This is not only harmful for aquatic life, but also has significant negative impacts on human health.”

The team received scientific and technical support from the Microscopy and Microanalysis Facility and the Micro Nano Research Facility, part of RMIT’s newly expanded Advanced Manufacturing Precinct, to complete their research. 

What are the next steps?

Developing a cost-effective way to overcome these signficant challenges posed by microplastics was critical, Eshtiaghi said.

“Our powder additive can remove microplastics that are 1,000 times smaller than those that are currently detectable by existing wastewater treatment plants,” she said.

“We are looking for industrial collaborators to take our invention to the next steps, where we will be looking at its application in wastewater treatment plants.”

Eshtiaghi and her colleagues have worked with various water utilities across Australia, including with Melbourne Water and Water Corporation in Perth on a recent Australian Research Council Linkage project to optimise sludge pumping systems.

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

Self-assembly of C@FeO nanopillars on 2D-MOF for simultaneous removal of microplastic and dissolved contaminants from water by Muhammad Haris, Muhammad Waqas Khan, Ali Zavabeti, Nasir Mahmood and Nicky Eshtiaghi. Chemical Engineering Journal Available online 23 November 2022, 140390 DOI: https://doi.org/10.1016/j.cej.2022.140390

This paper is behind a paywall.

Back in 2019

Caption: This visual abstract depicts the findings of Kang et al.. Novel and robust nanocarbon springs were synthesized via solid pyrolysis with a controlled morphology, and simultaneously engineered nitrogen dopants and encapsulated magnetic nanoparticles. The carbocatalysts can effectively catalyze peroxymonosulfate to generate highly reactive radicals under hydrothermal conditions for decomposing microplastics into harmless substances in water. Credit: Kang et al/Matter

This July 31, 2019 Cell Press news release on EurekAlert announces a different approach, from an Australian team, to removing plastics from water,

Plastic waste that finds its way into oceans and rivers poses a global environmental threat with damaging health consequences for animals, humans, and ecosystems. Now, using tiny coil-shaped carbon-based magnets, researchers in Australia have developed a new approach to purging water sources of the microplastics that pollute them without harming nearby microorganisms. Their work appears July 31 in the journal Matter.

“Microplastics adsorb organic and metal contaminants as they travel through water and release these hazardous substances into aquatic organisms when eaten, causing them to accumulate all the way up the food chain” says senior author Shaobin Wang, a professor of chemical engineering at the University of Adelaide (Australia). “Carbon nanosprings are strong and stable enough to break these microplastics down into compounds that do not pose such a threat to the marine ecosystem.”

Although often invisible to the naked eye, microplastics are ubiquitous pollutants. Some, such as the exfoliating beads found in popular cosmetics, are simply too small to be filtered out during industrial water treatment. Others are produced indirectly, when larger debris like soda bottles or tires weather amid sun and sand.

To decompose the microplastics, the researchers had to generate short-lived chemicals called reactive oxygen species, which trigger chain reactions that chop the various long molecules that make up microplastics into tiny and harmless segments that dissolve in water. However, reactive oxygen species are often produced using heavy metals such as iron or cobalt, which are dangerous pollutants in their own right and thus unsuitable in an environmental context.

To get around this challenge, the researchers found a greener solution in the form of carbon nanotubes laced with nitrogen to help boost generation of reactive oxygen species. Shaped like springs, the carbon nanotube catalysts removed a significant fraction of microplastics in just eight hours while remaining stable themselves in the harsh oxidative conditions needed for microplastics breakdown. The coiled shape increases stability and maximises reactive surface area. As a bonus, by including a small amount of manganese, buried far from the surface of the nanotubes to prevent it from leaching into water, the minute springs became magnetic.

“Having magnetic nanotubes is particularly exciting because this makes it easy to collect them from real wastewater streams for repeated use in environmental remediation,” says Xiaoguang Duan, a chemical engineering research fellow at Adelaide who also co-led the project.

As no two microplastics are chemically quite the same, the researchers’ next steps will center on ensuring that the nanosprings work on microplastics of different compositions, shapes and origins. They also intend to continue to rigorously confirm the non-toxicity of any chemical compounds occurring as intermediates or by-products during microplastics decomposition.

The researchers also say that those intermediates and byproducts could be harnessed as an energy source for microorganisms that the polluting plastics currently plague. “If plastic contaminants can be repurposed as food for algae growth, it will be a triumph for using biotechnology to solve environmental problems in ways that are both green and cost efficient,” Wang says.

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

Degradation of Cosmetic Microplastics via Functionalized Carbon Nanosprings by Jian Kang, Li Zhou, Xiaoguang Duan, Hongqi Sun, Zhimin Ao, Shaobin Wang. Matter Volume 1, Issue 3, 4 September 2019, Pages 745-758 DOI: https://doi.org/10.1016/j.matt.2019.06.004

This paper is open access.

Comments

I’m glad to see this work and as for which approach might be preferable, I don’t know if there’s a clear winner. The 2022 work removes both microplastics and pollutants in one hour! An impressive feat, which leaves us with microplastics and pollutants to deal with. By contrast , the 2019 work transforms the microplastics into materials that don’t pose harm to the aquatic environment. Great although it takes eight hours. I wish the best for all the researchers working on this microplastics problem.

Pulling water from the air

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Adele Peters’ May 27, 2022 article for Fast Company describes some research into harvesting water from the air (Note: Links have been removed),

In Ethiopia, where an ongoing drought is the worst in 40 years, getting drinking water for the day can involve walking for eight hours. Some wells are drying up. As climate change progresses, water scarcity keeps getting worse. But new technology in development at the University of Texas at Austin could help: Using simple, low-cost materials, it harvests water from the air, even in the driest climates.

“The advantage of taking water moisture from the air is that it’s not limited geographically,” says Youhong “Nancy” Guo, lead author of a new study in Nature Communications that describes the technology.

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It’s a little surprising that Peters doesn’t mention the megadrought in the US Southwest, which has made quite a splash in the news, from a February 15, 2022 article by Denise Chow for NBC [{US} National Broadcasting Corporation] news online, Note: Links have been removed,

The megadrought that has gripped the southwestern United States for the past 22 years is the worst since at least 800 A.D., according to a new study that examined shifts in water availability and soil moisture over the past 12 centuries.

The research, which suggests that the past two decades in the American Southwest have been the driest period in 1,200 years, pointed to human-caused climate change as a major reason for the current drought’s severity. The findings were published Monday in the journal Nature Climate Change.

Jason Smerdon, one of the study’s authors and a climate scientist at Columbia University’s Lamont-Doherty Earth Observatory, said global warming has made the megadrought more extreme because it creates a “thirstier” atmosphere that is better able to pull moisture out of forests, vegetation and soil.

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Over the past two decades, temperatures in the Southwest were around 1.64 degrees Fahrenheit higher than the average from 1950 to 1999, according to the researchers. Globally, the world has warmed by about 2 degrees Fahrenheit since the late 1800s.

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It’s getting drier even here in the Pacific Northwest. Maybe it’s time to start looking at drought and water shortages as a global issue rather than as a regional issue.

Caption: An example of a different shape the water-capturing film can take. Credit: The University of Texas at Austin / Cockrell School of Engineering

Getting back to the topic, a May 23, 2022 University of Texas at Austin news release (also on EurkeAlert), which originated the Peters’ article, announces the work,

More than a third of the world’s population lives in drylands, areas that experience significant water shortages. Scientists and engineers at The University of Texas at Austin have developed a solution that could help people in these areas access clean drinking water.

The team developed a low-cost gel film made of abundant materials that can pull water from the air in even the driest climates. The materials that facilitate this reaction cost a mere $2 per kilogram, and a single kilogram can produce more than 6 liters of water per day in areas with less than 15% relative humidity and 13 liters in areas with up to 30% relative humidity.

The research builds on previous breakthroughs from the team, including the ability to pull water out of the atmosphere and the application of that technology to create self-watering soil. However, these technologies were designed for relatively high-humidity environments.

“This new work is about practical solutions that people can use to get water in the hottest, driest places on Earth,” said Guihua Yu, professor of materials science and mechanical engineering in the Cockrell School of Engineering’s Walker Department of Mechanical Engineering. “This could allow millions of people without consistent access to drinking water to have simple, water generating devices at home that they can easily operate.”

…

The researchers used renewable cellulose and a common kitchen ingredient, konjac gum, as a main hydrophilic (attracted to water) skeleton. The open-pore structure of gum speeds the moisture-capturing process. Another designed component, thermo-responsive cellulose with hydrophobic (resistant to water) interaction when heated, helps release the collected water immediately so that overall energy input to produce water is minimized.

Other attempts at pulling water from desert air are typically energy-intensive and do not produce much. And although 6 liters does not sound like much, the researchers say that creating thicker films or absorbent beds or arrays with optimization could drastically increase the amount of water they yield.

The reaction itself is a simple one, the researchers said, which reduces the challenges of scaling it up and achieving mass usage.

“This is not something you need an advanced degree to use,” said Youhong “Nancy” Guo, the lead author on the paper and a former doctoral student in Yu’s lab, now a postdoctoral researcher at the Massachusetts Institute of Technology. “It’s straightforward enough that anyone can make it at home if they have the materials.”

The film is flexible and can be molded into a variety of shapes and sizes, depending on the need of the user. Making the film requires only the gel precursor, which includes all the relevant ingredients poured into a mold.

“The gel takes 2 minutes to set simply. Then, it just needs to be freeze-dried, and it can be peeled off the mold and used immediately after that,” said Weixin Guan, a doctoral student on Yu’s team and a lead researcher of the work.

The research was funded by the U.S. Department of Defense’s Defense Advanced Research Projects Agency (DARPA), and drinking water for soldiers in arid climates is a big part of the project. However, the researchers also envision this as something that people could someday buy at a hardware store and use in their homes because of the simplicity.

Yu directed the project. Guo and Guan co-led experimental efforts on synthesis, characterization of the samples and device demonstration. Other team members are Chuxin Lei, Hengyi Lu and Wen Shi.

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

Scalable super hygroscopic polymer films for sustainable moisture harvesting in arid environments by Youhong Guo, Weixin Guan, Chuxin Lei, Hengyi Lu, Wen Shi & Guihua Yu. Nature Communications volume 13, Article number: 2761 (2022) DOI: https://doi.org/10.1038/s41467-022-30505-2 Published: 19 May 2022

This paper is open access.

Fluorine-based nanostructures for desalination

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A May 16, 2022 article by Qamariya Nasrullah for cosmosmagazine.com describes research from Japan on desalination (Note: A link has been removed),

Water supply is a growing global issue, especially with climate change bringing on more droughts. Seawater desalination is used worldwide to filter up to 97.4 million cubic metres per day. Two methods – thermal and reverse osmosis – predominate; both have huge energy costs.

In a pioneering study published in Science, researchers have used a fluorine-based nanostructure to successfully filter salt from water faster and more efficiently than other current technologies. But how does it work?

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A May 12, 2022 University of Tokyo press release (also on EurekAlert), which originated the news item, provides the answer to Nasrullah’s question,

If you’ve ever cooked with a nonstick Teflon-coated frying pan, then you’ve probably seen the way that wet ingredients slide around it easily. This happens because the key component of Teflon is fluorine, a lightweight element that is naturally water repelling, or hydrophobic. Teflon can also be used to line pipes to improve the flow of water. Such behavior caught the attention of Associate Professor Yoshimitsu Itoh from the Department of Chemistry and Biotechnology at the University of Tokyo and his team. It inspired them to explore how pipes or channels made from fluorine might operate on a very different scale, the nanoscale.

“We were curious to see how effective a fluorous nanochannel might be at selectively filtering different compounds, in particular, water and salt. And, after running some complex computer simulations, we decided it was worth the time and effort to create a working sample,” said Itoh. “There are two main ways to desalinate water currently: thermally, using heat to evaporate seawater so it condenses as pure water, or by reverse osmosis, which uses pressure to force water through a membrane that blocks salt. Both methods require a lot of energy, but our tests suggest fluorous nanochannels require little energy, and have other benefits too.”

The team created test filtration membranes by chemically synthesizing nanoscopic fluorine rings, which were stacked and embedded in an otherwise impermeable lipid layer, similar to the organic molecules that make up cell walls. They created several test samples with nanorings between about 1 and 2 nanometers. For reference, a human hair is almost 100,000 nanometers wide. To test the effectiveness of their membranes, Itoh and the team measured the presence of chlorine ions, one of the major components of salt — the other being sodium — on either side of the test membrane.

“It was very exciting to see the results firsthand. The smaller of our test channels perfectly rejected incoming salt molecules, and the larger channels too were still an improvement over other desalination techniques and even cutting-edge carbon nanotube filters,” said Itoh. “The real surprise to me was how fast the process occurred. Our sample worked around several thousand times faster than typical industrial devices, and around 2,400 times faster than experimental carbon nanotube-based desalination devices.”

As fluorine is electrically negative, it repels negative ions such as the chlorine found in salt. But an added bonus of this negativity is that it also breaks down what are known as water clusters, essentially loosely bound groups of water molecules, so that they pass through the channels quicker. The team’s fluorine-based water desalination membranes are more effective, faster, require less energy to operate and are made to be very simple to use as well, so what’s the catch?

“At present, the way we synthesize our materials is relatively energy-intensive itself; however, this is something we hope to improve upon in upcoming research. And, given the longevity of the membranes and their low operational costs, the overall energy costs will be much lower than with current methods,” said Itoh. “Other steps we wish to take are of course scaling this up. Our test samples were single nanochannels, but with the help of other specialists, we hope to create a membrane around 1 meter across in several years. In parallel with these manufacturing concerns, we’re also exploring whether similar membranes could be used to reduce carbon dioxide or other undesirable waste products released by industry.”

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

Ultrafast water permeation through nanochannels with a densely fluorous interior surface by Yoshimitsu Itoh, Shuo Chen, Jyota Hirahara, Takeshi Konda, Tsubasa Aoki, Takumi Ueda, Ichio Shimada, James J. Cannon, Cheng Shao, Junichiro Shiomi, Kazuhito V. Tabata, Hiroyuki Noji, Kohei Sato, and Takuzo Aida. Science • 12 May 2022 • Vol 376, Issue 6594 • pp. 738-743 • DOI: 10.1126/science.abd0966

This paper is behind a paywall.

Harvest fresh water from dry air with hydrogels

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Turning Air Into Drinking Water from University of Texas at Austin on Vimeo. Video by Thomas Swafford. Written by Sara Robberson Lentz.

Seems almost magical but it takes years to do this research. That video was posted in September 2019 and the latest research is being announced in a February 28, 2022 news item on phys.org,

Hydrogels have an astonishing ability to swell and take on water. In daily life, they are used in dressings, nappies, and more to lock moisture away. A team of researchers has now found another use: quickly extracting large amounts of freshwater from air using a specially developed hydrogel containing a hygroscopic salt. The study, published in the journal Angewandte Chemie, shows that the salt enhances the moisture uptake of the gel, making it suitable for water harvesting in dry regions.

A February 28, 2022 Wiley Publishing news release on EurekAlert delves further into hydrogels and the research into how they might be used to harvest water from the air,

Hydrogels can absorb and store many times their weight in water. In so doing, the underlying polymer swells considerably by incorporating water. However, to date, use of this property to produce freshwater from atmospheric water has not been feasible, since collecting moisture from the air is still too slow and inefficient.

On the other hand, moisture absorption could be enhanced by adding hygroscopic salts that can rapidly remove large amounts of moisture from the air. However, hygroscopic salts and hydrogels are usually not compatible, as a large amount of salt influences the swelling capability of the hydrogel and thus degrades its properties. In addition, the salt ions are not tightly coordinated within the gel and are easily washed away.

The materials scientist Guihua Yu and his team at the University of Texas at Austin, USA, have now overcome these issues by developing a particularly “salt-friendly” hydrogel. As their study shows, this gel gains the ability to absorb and retain water when combined with a hygroscopic salt. Using their hydrogel, the team were able to extract almost six liters of pure water per kilo of material in 24 hours, from air with 30% relative humidity.

The basis for the new hydrogel was a polymer constructed from zwitterionic molecules. Polyzwitterions carry both positive and negative charged functional groups, which helped the polymer to become more responsive to the salt in this case. Initially, the molecular strands in the polymer were tightly intermingled, but when the researchers added the lithium chloride salt, the strands relaxed and a porous, spongy hydrogel was formed. This hydrogel loaded with the hygroscopic salt was able to incorporate water molecules quickly and easily.

In fact, water incorporation was so quick and easy that the team were able to set up a cyclical system for continuous water separation. They left the hydrogel for an hour each time to absorb atmospheric moisture, then dried the gel in a condenser to collect the condensed water. They repeated this procedure multiple times without it resulting in any substantial loss of the amount of water absorbed, condensed, or collected.

Yu and the team say that the as-prepared hydrogel “should be optimal for efficient moisture harvesting for the potential daily water yield”. They add that polyzwitterionic hydrogels could play a fundamental role in the future for recovering atmospheric water in arid, drought-stricken regions.

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

Polyzwitterionic Hydrogels for Efficient Atmospheric Water Harvesting by Chuxin Lei, Youhong Guo, Weixin Guan, Hengyi Lu, Wen Shi, Guihua Yu. Angewandte Chemie International Edition Volume 61, Issue1 3 March 21, 2022 e202200271 DOI: https://doi.org/10.1002/anie.202200271 First published: 28 January 2022

This paper is behind a paywall.

Iran nanotechnology sector update

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It’s been a long time but last August I stumbled across a number of stories about Iran’s nanotechnology efforts.

First up, there’s an August 29, 2021 news item in Tehran Times,

As of the start of a national plan to develop the nanotechnology sector 15 years ago, more than 5,283 billion rials (about $125.7 million [US?] at the official exchange rate of 42,000 rials) has been allocated to nanotechnology projects, IRNA [Islamic Republic News Agency] reported on Saturday [August 28, 2021].

Nanotechnology’s trend of development is growing in Iran, as the number of nanoproducts and equipment developed in the previous [Iranian calendar] year (ended March 20 [2021]) increased to 750, compared with 647 a year before.

Some 223 product manufacturing companies and 59 equipment manufacturing companies are active in the field of nanotechnology and by the end of last year, which developed a total of 750 products and equipment.

Of the 750 products and equipment registered in the nanotechnology product database, 535 were related to nano-products and 215 were related to nano-equipment, both of which have experienced a growing trend over the past few years, although nano-products have grown more significantly.

…

Saeed Sarkar, the head of Iran’s Nanotechnology Innovation Council, said in June that Iran has created centers in six Asian countries for exporting nanotechnology products.

China, India, Indonesia, Syria, Turkey, and Iraq have received Iranian nanotechnology products and services.

Iranian-made nanotechnology products are currently exported to 49 countries in five continents, he added.

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Iran has been introduced as the 4th leading country in the world in the field of nanotechnology, publishing 11,546 scientific articles in 2020.

The country held a 6 percent share of the world’s total nanotechnology articles, according to StatNano’s monthly evaluation accomplished in WoS [Web of Science] databases.

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Then a national contest was announced in a September 1, 2021 news item in the Tehran Times, Note: Some of the information in this news item has been repeated from the August 31, 2021 news item],

The second round of the 10th National Nanotech Contest will be held on Friday [September 3, 2021] with 308 university students competing in 21 centers nationwide.

As the most significant academic event in the country, the national contest is held annually in the five fields of basic concepts, synthesis, analysis, applications, and commercialization of domestically-made products, ISNA reported.

The first round of the event was held July 31-August 2 [2021].

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Finally, there’s a September 5, 2021 article by Faranak Bakhtiari about nanotechnology and drought abatement measures for the Tehran Times,

Iran is located in an arid and semi-arid region, and Iranians have long sought to make the most of water.

In recent years, the drought has intensified making water resources fragile and it can be said that we have reached water bankruptcy in Iran.

However, water stress will continue this fall (September 23-December 21 [2021]), and the season is expected to be relatively hot and short of rain, according to Ahad Vazifeh, head of the national center for drought and crisis management.

In such a situation, officials and experts propose various solutions for optimal water management.

Alireza Qazizadeh, a water and environment expert, referring to 80 percent of the arid regions in the country, said that “Iran has one percent of the earth’s area and receives only 36 percent of renewable resources.

The country receives 250 mm of rainfall annually, which is about 400 billion cubic meters, considering 70 percent evaporation, there is only 130 billion cubic meters of renewable water and 13 billion cubic meters of input from border waters.”

Referring to 800 ml of average rainfall and 700 mm of global evaporation, he noted that 70 percent of rainfall in Iran occurs in only 25 percent of the country and only 25 percent rains in irrigation seasons.

Pointing to the need for 113 billion cubic meters of water in the current year (began on March 21), he stated that “of this amount, 102 billion is projected for agricultural use, 7 percent for drinking and 2 percent for industry, and at this point water stress occurs.

In 2001, 5.5 billion cubic meters of underground resources were withdrawn annually, and if we consider this amount as 20 years from that year until now, it means that we have withdrawn an equivalent of one year of water consumption from non-renewable resources, which is alarming.”

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Rasoul Sarraf, the Faculty of Materials at Shahid Modarres University, suggests a different solution and states that “To solve ease water stress, we have no choice but to use nanotechnology and solar power plants.

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A recent report by Nature Scientific Journal on Iran’s water crisis indicates that from 2002 to 2015, over 74 billion cubic meters have been extracted from aquifers, which is unprecedented and its revival takes thousands of years along with urgent action.

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Bakhtiari’s article does not mention how nanotechnology can be a factor in mitigating water shortages, rather it focuses on the urgency of the situation.

For anyone who thinks that droughts and water shortages do not affect Canada, take a good look at the Canadian Drought Monitor map (as of July 31, 2021). In an area known internationally for its rainfall (Vancouver and Vancouver Island in British Columbia), we had drought conditions ranging from severe to extreme. As for the rest of Canada, the prairie provinces seemed to have experienced the driest conditions with Manitoba experiencing some of the most extreme conditions in the country. From all reports, this will not be unusual in the future.

Artificial ionic neuron for electronic memories

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This venture into brain-like (neuromorphic) computing comes from France according to an August 17, 2021 news item on Nanowerk (Note: A link has been removed),

Brain-inspired electronics are the subject of intense research. Scientists from CNRS (Centre national de la recherche scientifique; French National Centre for Scientific Research) and the Ecole Normale Supérieure – PSL have theorized how to develop artificial neurons using, as nerve cells, ions to carry the information.

Their work, published in Science (“Modeling of emergent memory and voltage spiking in ionic transport through angstrom-scale slits”), reports that devices made of a single layer of water transporting ions within graphene nanoslits have the same transmission capacity as a neuron.

Caption Artificial neuron prototype: nanofluidic slits can play the role of ion channels and allow neurons to communicate. Ion clusters achieve the ion transport that causes this communication. Credit © Paul Robin, ENS Laboratoire de Physique (CNRS/ENS-PSL/Sorbonne Université/Université de Paris).

Au August 16, 2021 CNRS press release (also on EurekAlert but published August 6, 2021), which originated the news item, provides insight into the international interest in neuromorphic computing along with a few technical details about this latest research,

With an energy consumption equivalent to two bananas per day, the human brain can perform many complex tasks. Its high energy efficiency depends in particular on its base unit, the neuron, which has a membrane with nanometric pores called ion channels, which open and close according to the stimuli received. The resulting ion flows create an electric current responsible for the emission of action potentials, signals that allow neurons to communicate with each other.

Artificial intelligence can do all of these tasks but only at the cost of energy consumption tens of thousands of times that of the human brain. So the entire research challenge today is to design electronic systems that are as energy efficient as the human brain, for example, by using ions, not electrons, to carry the information. For this, nanofluidics, the study of how fluids behave in channels less than 100 nanometers wide, offer many perspectives. In a new study, a team from the ENS Laboratoire de Physique (CNRS/ENS-PSL/Sorbonne Université/Université de Paris) shows how to construct a prototype of an artificial neuron formed of extremely thin graphene slits containing a single layer of water molecules1. The scientists have shown that, under the effect of an electric field, the ions from this layer of water assemble into elongated clusters and develop a property known as the memristor effect: these clusters retain some of the stimuli that have been received in the past. To repeat the comparison with the brain, the graphene slits reproduce the ion channels, clusters and ion flows. And, using theoretical and digital tools, scientists have shown how to assemble these clusters to reproduce the physical mechanism of emission of action potentials, and thus the transmission of information.

This theoretical work continues experimentally within the French team, in collaboration with scientists from the University of Manchester (UK). The goal now is to prove experimentally that such systems can implement simple learning algorithms that can serve as the basis for tomorrow’s electronic memories.

1 Recently invented in Manchester by the group of André Geim (Nobel Prize in Physics 2010)

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

Modeling of emergent memory and voltage spiking in ionic transport through angstrom-scale slits by Paul Robin, Nikita Kavokine, Lydéric Bocquet. Science 06 Aug 2021: Vol. 373, Issue 6555, pp. 687-691 DOI: 10.1126/science.abf7923

This paper is behind a paywall.

Canadian and Guadeloupean oysters: exposure to nanoplastics and arsenic

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A May 27, 2021 news item on phys.org describes research into oysters and nanoplastics,

Oysters’ exposure to plastics is concerning, particularly because these materials can accumulate and release metals which are then absorbed by the mollusks. According to a recent study published in the journal Chemosphere, the combined presence of nanoplastics and arsenic affects the biological functions of oysters. This study was conducted by the Institut national de la recherche scientifique (INRS) in Québec City and the French National Centre for Scientific Research (CNRS) at the University of Bordeaux in France

…

A May 27, 2021 INRS news release (French language version here and an English language version on EurekAlert), which originated the news item, provides fascinating details,

The international research team chose to study arsenic, since it is one of the most common metals absorbed by the plastic debris collected from the beaches of Guadeloupe. “Oysters easily accumulate metals from the environment into their tissues. We therefore wanted to test whether the combined exposure to nanoplastics and arsenic would increase the bioaccumulation of this contaminant,” reported Marc Lebordais, the Master’s student in charge of the research.

The scientists proved that the bioaccumulation of arsenic does not increase when nanoplastics are also present. However, it remained higher in the gills of the Canadian Crassostrea virginica oyster [emphasis mine] than in the Isognomon alatus oyster, found in Guadeloupe. These results are the first to highlight the diverging sensitivity of different species. [emphasis mine]

Gene deregulation

In addition to bioaccumulation, the team also observed an overexpression of genes responsible for cell death and the number of mitochondria–a cell’s energy centres–in C. virginica. In I. alatus, the expression of these same genes was less significant.

“Evaluating the expression of genes involved in important functions, such as cell death and detoxification, gives us information on the toxicity of nanoplastics and arsenic on a cellular level,” explained the young researcher, who is co-directed by Professors Valérie Langlois of INRS and Magalie Baudrimont of the University of Bordeaux.

The food chain

The next step, after characterizing the presence of nanoplastics and arsenic in oysters, would be to study how these contaminants are transferred through the food chain.

“Analytical tools are currently being developed to quantify the presence of nanoplastics in biological tissues,” said Marc Lebordais. “Understanding the amount of nanoplastics in farmed oysters currently boils down to a technical issue.” ?

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

Molecular impacts of dietary exposure to nanoplastics combined with arsenic in Canadian oysters (Crassostrea virginica) and bioaccumulation comparison with Caribbean oysters (Isognomon alatus) by Marc Lebordais, Juan Manuel Gutierrez-Villagomez, Julien Gigault, Magalie Baudrimont, and Valérie Langlois. Chemosphere Volume 277, August 2021, 130331 DOI: https://doi.org/10.1016/j.chemosphere.2021.130331 First published online 19 March 2021.

This paper is open access.

Salt ‘creatures’ could help unclog industrial pipes

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I love the video (wish the narrator had a more conversational style rather than the ‘read aloud’ style so many of us adopted in school),

Joel Goldberg’s April 28, 2021 news article (short read) in Science magazine online describes the research (Note: A link has been removed),

Behold the salt monsters. These twisted mineral crystals—formed from the buildup of slightly salty water in power plant pipes—come in many shapes and sizes. But the tiny monsters are a big problem: Each year, they cost the world’s power plants at least $100 billion because workers have to purge the pipes and scrub the crystals from filters.

Now, a solution may be at hand. Engineers can reduce the damage by coating the insides of the pipes with textured, water-repellant [hydrophobic] surfaces …

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

Crystal critters: Self-ejection of crystals from heated, superhydrophobic surfaces by Samantha A. McBride, Henri-Louis Girard, and Kripa K. Varanasi. Science Advances 28 Apr 2021: Vol. 7, no. 18, eabe6960 DOI: 10.1126/sciadv.abe6960

This paper is open access. As research papers go, this is quite readable, from the Introduction (Note: Links have been removed),

Many of the uses for water are intimately familiar to us. Drinking water, wash water, water for agriculture, and even water used for recreation have an omnipresent and essential impact on our lives. However, water’s impact and importance extend far beyond these everyday uses. In many developed countries, thermoelectric power production is one of the largest sources of water consumption (1), where it is used to cool reactors and transport heat. In 2015, 41% of all surface water withdrawals in the United States went toward cooling in thermoelectric power plants (2). Thermoelectric power accounts for 90% of all electricity generated within the United States and encompasses many forms of power production, including nuclear, coal, natural gas, and oil.

…

There you go.

New water treatment with 3D-printed graphene aerogels

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Caption: Graphene aerogel on a single tissue. Credit: University at Buffalo

That image of the graphene aerogel on a tissue shows off its weightlessness very well.

Here’s more about the graphene aerogel water treatment from an April 14, 2021 news item on Nanowerk,

Graphene excels at removing contaminants from water, but it’s not yet a commercially viable use of the wonder material.

That could be changing.

In a recent study, University at Buffalo [UB] engineers report a new process of 3D printing graphene aerogels that they say overcomes two key hurdles — scalability and creating a version of the material that’s stable enough for repeated use — for water treatment.

“The goal is to safely remove contaminants from water without releasing any problematic chemical residue,” says study co-author Nirupam Aich, PhD, assistant professor of environmental engineering at the UB School of Engineering and Applied Sciences. “The aerogels we’ve created hold their structure when put in water treatment systems, and they can be applied in diverse water treatment applications.”

An April 14, 2021 UB news release (also on EurekAlert) by Melvin Bankhead III, which originated the news item, explains the breakthrough in more detail,

An aerogel is a light, highly porous solid formed by replacement of liquid in a gel with a gas so that the resulting solid is the same size as the original. They are similar in structural configuration to Styrofoam: very porous and lightweight, yet strong and resilient.

Graphene is a nanomaterial formed by elemental carbon and is composed of a single flat sheet of carbon atoms arranged in a repeating hexagonal lattice.

To create the right consistency of the graphene-based ink, the researchers looked to nature. They added to it two bio-inspired polymers — polydopamine (a synthetic material, often referred to as PDA, that is similar to the adhesive secretions of mussels), and bovine serum albumin (a protein derived from cows).

In tests, the reconfigured aerogel removed certain heavy metals, such as lead and chromium, that plague drinking water systems nationwide. It also removed organic dyes, such as cationic methylene blue and anionic Evans blue, as well as organic solvents like hexane, heptane and toluene.

To demonstrate the aerogel’s reuse potential, the researchers ran organic solvents through it 10 times. Each time, it removed 100% of the solvents. The researchers also reported the aerogel’s ability to capture methylene blue decreased by 2-20% after the third cycle.

The aerogels can also be scaled up in size, Aich says, because unlike nanosheets, aerogels can be printed in larger sizes. This eliminates a previous problem inherent in large-scale production, and makes the process available for use in large facilities, such as in wastewater treatment plants, he says. He adds the aerogels can be removed from water and reused in other locations, and that they don’t leave any kind of residue in the water.

Aich is part of a collaboration between UB and the University of Pittsburgh, led by UB chemistry professor Diana Aga, PhD, to find methods and tools to degrade per- and polyfluoroalkyl substances (PFAS), toxic materials so difficult to break down that they are known as “forever chemicals.” Aich notes the similarities to his work with 3D aerogels, and he hopes results from the two projects can be brought together to create more effective methods of removing waterborne contaminants.

“We can use these aerogels not only to contain graphene particles but also nanometal particles which can act as catalysts,” Aich says. “The future goal is to have nanometal particles embedded in the walls and the surface of these aerogels and they would be able to degrade or destroy not only biological contaminants, but also chemical contaminants.”

Aich, Chi, and Masud [Arvid Masud, PhD] hold a pending patent for the graphene aerogel described in the study, and they are looking for industrial partners to commercialize this process.

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

Emerging investigator series: 3D printed graphene-biopolymer aerogels for water contaminant removal: a proof of concept by Arvid Masud, Chi Zhoub and Nirupam Aich. Environ. Sci.: Nano, 2021,8, 399-414 DOI: https://doi.org/10.1039/D0EN00953A First published online: 09 Dec 2020

This paper is behind a paywall.