Category Archives: environment

Nanodiamond-embedded membrane filters for clean water

This December 9, 2020 news item on Nanowerk announces research into a nanodiamond filter which can clean hot wastewater,

Although most of the planet is covered by water, only a fraction of it is clean enough for humans to use. Therefore, it is important to recycle this resource whenever possible. Current purification techniques cannot adequately handle the very hot wastewater generated by some industries.

A December 9, 2020 American Chemical Society (ACS) news release, which originated the news item, provides more detail,

Some oil recovery methods and other industrial processes result in hot wastewater, which requires energy-intensive cooling before it can be purified through traditional reverse osmosis membranes. After purification, the water then needs to be heated before it can be re-used. At such high temperatures, traditional reverse osmosis membranes filter slowly, allowing more salts, solids and other contaminants to get through. Researchers have embedded extremely tiny nanodiamonds — carbon spheres produced by explosions in small, closed containers without oxygen present — onto these membranes in previous studies. Although the membranes effectively and quickly filtered large volumes of water and can protect against fouling, they were not tested with very hot samples. To optimize the membranes for use with hot wastewater, Khorshidi, Sadrzadeh and colleagues wanted to modify the nanodiamond spheres and embed them in a new way.

The team attached amines to nanodiamonds and bathed them in an ethyl acetate solution to prevent the spheres from clumping. Then, a monomer was added that reacted with the amines to create chemical links to the traditional membrane base. Synergistic effects of the amine links and the ethyl acetate treatment resulted in thicker, more temperature-stable membranes, contributing to improvements in their performance. By increasing the amount of amine-enhanced nanodiamonds in the membrane, the researchers obtained higher filtration rates with a greater proportion of impurities being removed, even after 9 hours at 167 F, when compared to membranes without nanodiamonds. The new method produced membranes that could more effectively treat wastewater at high temperatures, the researchers say.

The authors acknowledge funding from Canada’s Oil Sands Innovation Alliance and The Natural Sciences and Engineering Research Council of Canada (NSERC).

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

Nanodiamond-Enabled Thin-Film Nanocomposite Polyamide Membranes for High-Temperature Water Treatment by Pooria Karami, Behnam Khorshidi, Laleh Shamaei, Eric Beaulieu, João B. P. Soares, and Mohtada Sadrzadeh. ACS Appl. Mater. Interfaces 2020, 12, 47, 53274–53285 DOI: https://doi.org/10.1021/acsami.0c15194 Publication Date: November 10, 2020 Copyright © 2020 American Chemical Society

This paper is behind a paywall.

Self-repairing gelatin-based film for electronics?

A December 2, 2020 news item on phys.org announces research that might make shattered mobile phones a rare occurrence,

Dropping a cell phone can sometimes cause superficial cracks to appear. But other times, the device can stop working altogether because fractures develop in the material that stores data. Now, researchers reporting in ACS [American Chemical Society] Applied Polymer Materials have made an environmentally friendly, gelatin-based film that can repair itself multiple times and still maintain the electronic signals needed to access a device’s data. The material could be used someday in smart electronics and health-monitoring devices.

A December 2, 2020 American Chemical Society (ACS) news release (also on EurekAlert), which originated the news item, explains how this work could have environmental impact and then launches into a more technical description of the research,

Global consumer demand for hand-held smart devices is rapidly growing, but because of their fragility, the amount of electronic waste is also increasing. Self-repairing films have been developed, but most only work a single time, and some are made with potentially harmful agents that curtail their use in biomedical applications. Researchers have tried incorporating gelatin in electronic devices because it is transparent, readily available and safe. In tests, however, damaged gelatin film was not restored quickly. Yu-Chi Chang and colleagues wanted to see if they could make a repeatedly self-healing gelatin-based film that would mend cracks in minutes and preserve electrical functionality.

The researchers mixed gelatin and glucose to create a flexible film that they sandwiched between conductive material to simulate an electronic device. After bending the simulated electronic device, the team saw breaks in the gelatin-glucose film disappear within 3 hours at room temperature and within 10 minutes when warmed to 140 F. Gelatin without glucose did not self-repair under the same conditions. The glucose-based gelatin also transferred an electrical signal following multiple rounds of damage and repair, with an unexpected improvement to the film’s electrical performance. The experiments show that glucose and gelatin probably form reversible and interlocking imide bonds during the healing process. The new film could help maintain the durability of touchscreen and flexible display devices, advanced robotics and assisted health technologies, the researchers say.

The American Chemical Society (ACS) is a nonprofit organization chartered by the U.S. Congress. ACS’ mission is to advance the broader chemistry enterprise and its practitioners for the benefit of Earth and its people. The Society is a global leader in providing access to chemistry-related information and research through its multiple research solutions, peer-reviewed journals, scientific conferences, eBooks and weekly news periodical Chemical & Engineering News. ACS journals are among the most cited, most trusted and most read within the scientific literature; however, ACS itself does not conduct chemical research. As a specialist in scientific information solutions (including SciFinder® and STN®), its CAS division powers global research, discovery and innovation. ACS’ main offices are in Washington, D.C., and Columbus, Ohio.  

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

A Green Strategy for Developing a Self-Healing Gelatin Resistive Memory Device by Yu-Chi Chang, Jia-Cheng Jian, Ya Lan Hsu, Wei-Yun Huang, and Sheng-Joue Young. ACS Appl. Polym. Mater. 2020, 2, 11, 5318–5326 DOI: https://doi.org/10.1021/acsapm.0c01119 Publication Date:November 4, 2020 Copyright © 2020 American Chemical Society

This paper is behind a paywall.

One comment: Despite use of the term ‘resistive memory device’ in the title, they are not talking about the memristor (for memory resistor; a circuit element), often featured here in pieces about neuromorphic (brainlike) computing.

Spinach could help power fuel cells.

By Source (WP:NFCC#4), Fair use, https://en.wikipedia.org/w/index.php?curid=65303730

I was surprised to see a reference to the cartoon character, Popeye, in the headline (although it’s not carried forward into the text) for this October 5, 2020 news item on ScienceDaily about research into making fuel cells more efficient,

Spinach: Good for Popeye and the planet

“Eat your spinach,” is a common refrain from many people’s childhoods. Spinach, the hearty, green vegetable chock full of nutrients, doesn’t just provide energy in humans. It also has potential to help power fuel cells, according to a new paper by researchers in AU’s Department of Chemistry. Spinach, when converted from its leafy, edible form into carbon nanosheets, acts as a catalyst for an oxygen reduction reaction in fuel cells and metal-air batteries.

An October 5, 2020 American University news release (also on EurekAlert) by Rebecca Basu, which originated the news item, provides more detail about the research,

An oxygen reduction reaction is one of two reactions in fuel cells and metal-air batteries and is usually the slower one that limits the energy output of these devices. Researchers have long known that certain carbon materials can catalyze the reaction. But those carbon-based catalysts don’t always perform as good or better than the traditional platinum-based catalysts. The AU researchers wanted to find an inexpensive and less toxic preparation method for an efficient catalyst by using readily available natural resources. They tackled this challenge by using spinach.

“This work suggests that sustainable catalysts can be made for an oxygen reduction reaction from natural resources,” said Prof. Shouzhong Zou, chemistry professor at AU and the paper’s lead author. “The method we tested can produce highly active, carbon-based catalysts from spinach, which is a renewable biomass. In fact, we believe it outperforms commercial platinum catalysts in both activity and stability. The catalysts are potentially applicable in hydrogen fuel cells and metal-air batteries.” Zou’s former post-doctoral students Xiaojun Liu and Wenyue Li and undergraduate student Casey Culhane are the paper’s co-authors.

Catalysts accelerate an oxygen reduction reaction to produce sufficient current and create energy. Among the practical applications for the research are fuel cells and metal-air batteries, which power electric vehicles and types of military gear. Researchers are making progress in the lab and in prototypes with catalysts derived from plants or plant products such as cattail grass or rice. Zou’s work is the first demonstration using spinach as a material for preparing oxygen reduction reaction-catalysts. Spinach is a good candidate for this work because it survives in low temperatures, is abundant and easy to grow, and is rich in iron and nitrogen that are essential for this type of catalyst.

Zou and his students created and tested the catalysts, which are spinach-derived carbon nanosheets. Carbon nanosheets are like a piece of paper with the thickness on a nanometer scale, a thousand times thinner than a piece of human hair. To create the nanosheets, the researchers put the spinach through a multi-step process that included both low- and high-tech methods, including washing, juicing and freeze-drying the spinach, manually grinding it into a fine powder with a mortar and pestle, and “doping” the resulting carbon nanosheet with extra nitrogen to improve its performance. The measurements showed that the spinach-derived catalysts performed better than platinum-based catalysts that can be expensive and lose their potency over time.

The next step for the researchers is to put the catalysts from the lab simulation into prototype devices, such as hydrogen fuel cells, to see how they perform and to develop catalysts from other plants. Zou would like to also improve sustainability by reducing the energy consumption needed for the process.

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

Spinach-Derived Porous Carbon Nanosheets as High-Performance Catalysts for Oxygen Reduction Reaction by Xiaojun Liu, Casey Culhane, Wenyue Li, and Shouzhong Zou. ACS Omega 2020, 5, 38, 24367–24378 DOI: https://doi.org/10.1021/acsomega.0c02673 Publication Date:September 15, 2020 Copyright © 2020 American Chemical Society

This paper appears to be open access.

Scotland as an Arctic power? Hmmm

This is intriguing. The Woodrow Wilson International Center for Scholars’ (Wilson Center’s) Polar Institute is hosting a conversation about Scotland’s future role in the Arctic that will be livestreamed on Tuesday, November 24, 2020 12:30 pm ET (9:30 am PT).

Here’s more from the Oct. 29, 2020 Wilson Center announcement (received via email),

Scotland’s Offer to the Arctic

Scotland’s Shetland Archipelago is a mere 400 miles south of the Arctic Circle. Due in part to this proximity, Scotland is seeking to establish itself as a European gateway to the High North. Similar rural and demographic features mean that Scottish and Arctic communities share many present-day priorities, from strengthening rural resilience to improving connectivity and promoting sustainable economic growth.

Scotland’s engagement with the Arctic region has intensified steadily over recent years. Published in September 2019, the Scottish Government’s first Arctic policy framework sets out “Scotland’s offer to the Arctic,” a prospectus for cooperation and knowledge exchange around the issues and ambitions that Scotland has in common with the Arctic.

On November 24th [2020], join us for a conversation on the future of cooperation between Scotland, Europe, and the Arctic. The live webstream will begin at 12:30 PM EST.

You might find this contextual information about Scotland’s Arctic Policy Framework, BREXIT, and the European Union (EU) useful (from a Sept. 24, 2020 post by the Polar Research and Policy Initiative on the Polar Connection website,

While the EU, the UK and Scotland are navigating the complex dynamics of Brexit to understand its implications on the three entities and their present and future interrelationships and interactions, one stage where the question of their future interplay rears its head is the Arctic region where the three have cooperated greatly in the past.

… the UK’s updated [in 2018 after the UK voted to leave the EU, i.e., BREXIT] Arctic policy framework clarified that leaving the EU “will not diminish our cooperation with EU nations but will enhance the possibility for forging even closer ties with non-EU nations”. It also observed how Scotland shared especially rich economic, social and cultural links with the Arctic region due to its history and geography, and acknowledged Scotland’s commitment to addressing climate change, promoting climate justice, driving the transition to a global low-carbon economy, developing its own Arctic Strategy on devolved matters, and collaborating, along with Northern Ireland, with Euro-Arctic states through the Northern Periphery and Arctic Programme.

In recognition of its shared history, geography, opportunities and challenges with several Arctic states, the Scottish Government itself has taken great interest in the Arctic in recent years. …

As the northernmost near-Arctic non-Arctic state, the UK is currently the northernmost EU state with Arctic interests, apart from Finland, Sweden and the Kingdom of Denmark (though Greenland is not a member of the EU) that are also member states of the Arctic Council. As the northernmost region/country within the UK, it is principally from Scotland that the UK derives that strategic advantage. Furthermore, as Finland and Sweden do not have direct access to the Arctic Ocean, save through Norway or Russia, and Greenland is not a part of the EU, the Scottish ports in Shetland [emphasis mine] and Orkney are currently the northernmost ports in the EU with direct maritime access to the North Sea and the Arctic Ocean.

I highlighted Shetland as there has been a pertinent development since Sept. 2019 according to a Sept. 11, 2020 article by Colby Cosh for the (Canada) National Post,

The council of the Shetland Islands, in which one official SNP [Scottish Nationalist Party] member is outnumbered 21-1 by independents of various stripes, voted 18-2 on Wednesday in favour of a motion to “formally begin exploring options for achieving financial and political self-determination.” [emphasis mine] As the makeup of the council implies, Shetland, about 170 kilometres north of the Scots mainland, has never been comfortable with the SNP’s goal of an independent, sovereign Scotland. In 2014’s Scottish independence referendum, Shetland delivered a 64 per cent vote for No.

Without knowing much about the politics it’s difficult to know if this is a serious attempt at separation or if it’s a gambit designed to get Shetland more autonomy without losing any advantages associated with being part of a larger entity.

Nevertheless, all this ‘arctic action’ is intriguing especially in light of the current loss of arctic ice and the attempts by various jurisdictions (including Canada) to establish or re-establish territorial rights.

Brain cell-like nanodevices

Given R. Stanley Williams’s presence on the author list, it’s a bit surprising that there’s no mention of memristors. If I read the signs rightly the interest is shifting, in some cases, from the memristor to a more comprehensive grouping of circuit elements referred to as ‘neuristors’ or, more likely, ‘nanocirucuit elements’ in the effort to achieve brainlike (neuromorphic) computing (engineering). (Williams was the leader of the HP Labs team that offered proof and more of the memristor’s existence, which I mentioned here in an April 5, 2010 posting. There are many, many postings on this topic here; try ‘memristors’ or ‘brainlike computing’ for your search terms.)

A September 24, 2020 news item on ScienceDaily announces a recent development in the field of neuromorphic engineering,

In the September [2020] issue of the journal Nature, scientists from Texas A&M University, Hewlett Packard Labs and Stanford University have described a new nanodevice that acts almost identically to a brain cell. Furthermore, they have shown that these synthetic brain cells can be joined together to form intricate networks that can then solve problems in a brain-like manner.

“This is the first study where we have been able to emulate a neuron with just a single nanoscale device, which would otherwise need hundreds of transistors,” said Dr. R. Stanley Williams, senior author on the study and professor in the Department of Electrical and Computer Engineering. “We have also been able to successfully use networks of our artificial neurons to solve toy versions of a real-world problem that is computationally intense even for the most sophisticated digital technologies.”

In particular, the researchers have demonstrated proof of concept that their brain-inspired system can identify possible mutations in a virus, which is highly relevant for ensuring the efficacy of vaccines and medications for strains exhibiting genetic diversity.

A September 24, 2020 Texas A&M University news release (also on EurekAlert) by Vandana Suresh, which originated the news item, provides some context for the research,

Over the past decades, digital technologies have become smaller and faster largely because of the advancements in transistor technology. However, these critical circuit components are fast approaching their limit of how small they can be built, initiating a global effort to find a new type of technology that can supplement, if not replace, transistors.

In addition to this “scaling-down” problem, transistor-based digital technologies have other well-known challenges. For example, they struggle at finding optimal solutions when presented with large sets of data.

“Let’s take a familiar example of finding the shortest route from your office to your home. If you have to make a single stop, it’s a fairly easy problem to solve. But if for some reason you need to make 15 stops in between, you have 43 billion routes to choose from,” said Dr. Suhas Kumar, lead author on the study and researcher at Hewlett Packard Labs. “This is now an optimization problem, and current computers are rather inept at solving it.”

Kumar added that another arduous task for digital machines is pattern recognition, such as identifying a face as the same regardless of viewpoint or recognizing a familiar voice buried within a din of sounds.

But tasks that can send digital machines into a computational tizzy are ones at which the brain excels. In fact, brains are not just quick at recognition and optimization problems, but they also consume far less energy than digital systems. Hence, by mimicking how the brain solves these types of tasks, Williams said brain-inspired or neuromorphic systems could potentially overcome some of the computational hurdles faced by current digital technologies.

To build the fundamental building block of the brain or a neuron, the researchers assembled a synthetic nanoscale device consisting of layers of different inorganic materials, each with a unique function. However, they said the real magic happens in the thin layer made of the compound niobium dioxide.

When a small voltage is applied to this region, its temperature begins to increase. But when the temperature reaches a critical value, niobium dioxide undergoes a quick change in personality, turning from an insulator to a conductor. But as it begins to conduct electric currents, its temperature drops and niobium dioxide switches back to being an insulator.

These back-and-forth transitions enable the synthetic devices to generate a pulse of electrical current that closely resembles the profile of electrical spikes, or action potentials, produced by biological neurons. Further, by changing the voltage across their synthetic neurons, the researchers reproduced a rich range of neuronal behaviors observed in the brain, such as sustained, burst and chaotic firing of electrical spikes.

“Capturing the dynamical behavior of neurons is a key goal for brain-inspired computers,” said Kumar. “Altogether, we were able to recreate around 15 types of neuronal firing profiles, all using a single electrical component and at much lower energies compared to transistor-based circuits.”

To evaluate if their synthetic neurons [neuristor?] can solve real-world problems, the researchers first wired 24 such nanoscale devices together in a network inspired by the connections between the brain’s cortex and thalamus, a well-known neural pathway involved in pattern recognition. Next, they used this system to solve a toy version of the viral quasispecies reconstruction problem, where mutant variations of a virus are identified without a reference genome.

By means of data inputs, the researchers introduced the network to short gene fragments. Then, by programming the strength of connections between the artificial neurons within the network, they established basic rules about joining these genetic fragments. The jigsaw puzzle-like task for the network was to list mutations in the virus’ genome based on these short genetic segments.

The researchers found that within a few microseconds, their network of artificial neurons settled down in a state that was indicative of the genome for a mutant strain.

Williams and Kumar noted this result is proof of principle that their neuromorphic systems can quickly perform tasks in an energy-efficient way.

The researchers said the next steps in their research will be to expand the repertoire of the problems that their brain-like networks can solve by incorporating other firing patterns and some hallmark properties of the human brain like learning and memory. They also plan to address hardware challenges for implementing their technology on a commercial scale.

“Calculating the national debt or solving some large-scale simulation is not the type of task the human brain is good at and that’s why we have digital computers. Alternatively, we can leverage our knowledge of neuronal connections for solving problems that the brain is exceptionally good at,” said Williams. “We have demonstrated that depending on the type of problem, there are different and more efficient ways of doing computations other than the conventional methods using digital computers with transistors.”

If you look at the news release on EurekAlert, you’ll see this informative image is titled: NeuristerSchematic [sic],

Caption: Networks of artificial neurons connected together can solve toy versions the viral quasispecies reconstruction problem. Credit: Texas A&M University College of Engineering

(On the university website, the image is credited to Rachel Barton.) You can see one of the first mentions of a ‘neuristor’ here in an August 24, 2017 posting.

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

Third-order nanocircuit elements for neuromorphic engineering by Suhas Kumar, R. Stanley Williams & Ziwen Wang. Nature volume 585, pages518–523(2020) DOI: https://doi.org/10.1038/s41586-020-2735-5 Published: 23 September 2020 Issue Date: 24 September 2020

This paper is behind a paywall.

Wood pulp and pomegranate peels as clothing

Lilly Smith’s Sept. 11, 2020 article for Fast Company profiles a new article of clothing from Volllebak (first mentioned here in a March 11, 2019 posting titled: It’s a very ‘carbony’ time: graphene jacket, graphene-skinned airplane, and schwarzite),

The Vollebak hoodie is made out of sustainably sourced eucalyptus and beech trees. The wood pulp from the trees is then turned into a fiber through a closed-loop production process (99% of the water and solvent used to turn pulp into fiber is recycled and reused). The fiber is then woven into the fabric you pull over your head.

The hoodie is a light green because it’s dyed with pomegranate peels, which typically are thrown out. The Vollebak team went with pomegranate as the natural dye for the hoodie for two reasons: It’s high in a biomolecule called tannin, which makes it easy to extract natural dye, and the fruit can withstand a range of climates (it loves heat but can tolerate temperatures as low as 10 degrees). Given that the material is “robust enough to survive our planet’s unpredictable future,” according to Vollebak cofounder Nick Tidball, it’s likely to remain a reliable part of the company’s supply chain even as global warming causes more extreme weather patterns.

… the hoodie won’t degrade from normal wear and tear—it needs fungus, bacteria, and heat in order to biodegrade (sweat doesn’t count). It will take about 8 weeks to decompose if buried in compost, and up to 12 if buried in the ground—the hotter the conditions, the faster it breaks down. “Every element is made from organic matter and left in its raw state,” says Steve Tidball, Vollebak’s other cofounder (and Nick’s twin brother). “There’s no ink or chemicals to leach into the soil. Just plants and pomegranate dye, which are organic matter. So when it disappears in 12 weeks, nothing is left behind.”

The article hosts a picture of the hoodie as does Vollebak website’s Product, Plant and Pomegranate Hoodie webpage,

Plant and Pomegranate Hoodie. Built from eucalyptus trees and dyed in a giant vat of fruit. The waiting list is now open.

5,000 years ago our ancestors made their clothes from nature, using grass, tree bark, animal skins and plants. We need to get back to the point where you could throw your clothes away in a forest and nature would take care of the rest. The Plant and Pomegranate Hoodie feels like a normal hoodie, looks like a normal hoodie, and lasts as long as a normal hoodie. The thing that makes it different is simply the way it starts and ends its life. All the materials we’ve used were grown in nature. Each hoodie is made from eucalyptus trees from sustainably managed forests before being submerged in a giant vat of pomegranate dye to give it its colour. As it’s made entirely from plants, the hoodie is fully biodegradable and compostable. When you decide your hoodie has reached the end of its life – whether that’s in 3 years’ time or 30 – you can put it out with the compost or bury it in your garden. Because the hoodie that starts its life in nature is designed to end up there too. Launching September 2020, the waiting list is now open.

Not much information, eh? I found the same dearth of detail the last time I looked for more technical information about a Vollebak product (their graphene jacket).

As for composting or burying the hoodies, how does that work? I live in an apartment building; I don’t think composting is allowed in my apartment and the building owners will likely get upset if I start digging holes in the front yard. There is a park nearby but it is city property and I’m pretty sure that digging into it to bury a hoodie will turn out to be illegal.

There is a recycling bin for organics but I don’t know if the businesses tasked with picking up the organic refuse and dealing with it will be familiar with biodegradable hoodies and I ‘m not sure hoodie disposal in the organics would be allowed by the city, which oversees the recycling programme.

These are not insurmountable problems but if people want to be mindful about their purchases and future disposal of said purchases, research may be needed.

City University of Hong Kong (CityU) and its anti-bacterial graphene face masks

This looks like interesting work and I think the integration of visual images and embedded video in the news release (on the university website) is particularly well done. I won’t be including all the graphical information here as my focus is the text.

A Sept. 10, 2020 City University of Hong Kong (CityU) press release (also on EurekAlert) announces a greener, more effective face mask,

Face masks have become an important tool in fighting against the COVID-19 pandemic. However, improper use or disposal of masks may lead to “secondary transmission”. A research team from City University of Hong Kong (CityU) has successfully produced graphene masks with an anti-bacterial efficiency of 80%, which can be enhanced to almost 100% with exposure to sunlight for around 10 minutes. Initial tests also showed very promising results in the deactivation of two species of coronaviruses. The graphene masks are easily produced at low cost, and can help to resolve the problems of sourcing raw materials and disposing of non-biodegradable masks.

The research is conducted by Dr Ye Ruquan, Assistant Professor from CityU’s Department of Chemistry, in collaboration with other researchers. The findings were published in the scientific journal ACS Nano, titled “Self-Reporting and Photothermally Enhanced Rapid Bacterial Killing on a Laser-Induced Graphene Mask“.

Commonly used surgical masks are not anti-bacterial. This may lead to the risk of secondary transmission of bacterial infection when people touch the contaminated surfaces of the used masks or discard them improperly. Moreover, the melt-blown fabrics used as a bacterial filter poses an impact on the environment as they are difficult to decompose. Therefore, scientists have been looking for alternative materials to make masks.

Converting other materials into graphene by laser

Dr Ye has been studying the use of laser-induced graphene [emphasis mine] in developing sustainable energy. When he was studying PhD degree at Rice University several years ago, the research team he participated in and led by his supervisor discovered an easy way to produce graphene. They found that direct writing on carbon-containing polyimide films (a polymeric plastic material with high thermal stability) using a commercial CO2 infrared laser system can generate 3D porous graphene. The laser changes the structure of the raw material and hence generates graphene. That’s why it is named laser-induced graphene.

Graphene is known for its anti-bacterial properties, so as early as last September, before the outbreak of COVID-19, producing outperforming masks with laser-induced graphene already came across Dr Ye’s mind. He then kick-started the study in collaboration with researchers from the Hong Kong University of Science and Technology (HKUST), Nankai University, and other organisations.

Excellent anti-bacterial efficiency

The research team tested their laser-induced graphene with E. coli, and it achieved high anti-bacterial efficiency of about 82%. In comparison, the anti-bacterial efficiency of activated carbon fibre and melt-blown fabrics, both commonly-used materials in masks, were only 2% and 9% respectively. Experiment results also showed that over 90% of the E. coli deposited on them remained alive even after 8 hours, while most of the E. coli deposited on the graphene surface were dead after 8 hours. Moreover, the laser-induced graphene showed a superior anti-bacterial capacity for aerosolised bacteria.

Dr Ye said that more research on the exact mechanism of graphene’s bacteria-killing property is needed. But he believed it might be related to the damage of bacterial cell membranes by graphene’s sharp edge. And the bacteria may be killed by dehydration induced by the hydrophobic (water-repelling) property of graphene.

Previous studies suggested that COVID-19 would lose its infectivity at high temperatures. So the team carried out experiments to test if the graphene’s photothermal effect (producing heat after absorbing light) can enhance the anti-bacterial effect. The results showed that the anti-bacterial efficiency of the graphene material could be improved to 99.998% within 10 minutes under sunlight, while activated carbon fibre and melt-blown fabrics only showed an efficiency of 67% and 85% respectively.

The team is currently working with laboratories in mainland China to test the graphene material with two species of human coronaviruses. Initial tests showed that it inactivated over 90% of the virus in five minutes and almost 100% in 10 minutes under sunlight. The team plans to conduct testings with the COVID-19 virus later.

Their next step is to further enhance the anti-virus efficiency and develop a reusable strategy for the mask. They hope to release it to the market shortly after designing an optimal structure for the mask and obtaining the certifications.

Dr Ye described the production of laser-induced graphene as a “green technique”. All carbon-containing materials, such as cellulose or paper, can be converted into graphene using this technique. And the conversion can be carried out under ambient conditions without using chemicals other than the raw materials, nor causing pollution. And the energy consumption is low.

“Laser-induced graphene masks are reusable. If biomaterials are used for producing graphene, it can help to resolve the problem of sourcing raw material for masks. And it can lessen the environmental impact caused by the non-biodegradable disposable masks,” he added.

Dr Ye pointed out that producing laser-induced graphene is easy. Within just one and a half minutes, an area of 100 cm² can be converted into graphene as the outer or inner layer of the mask. Depending on the raw materials for producing the graphene, the price of the laser-induced graphene mask is expected to be between that of surgical mask and N95 mask. He added that by adjusting laser power, the size of the pores of the graphene material can be modified so that the breathability would be similar to surgical masks.

A new way to check the condition of the mask

To facilitate users to check whether graphene masks are still in good condition after being used for a period of time, the team fabricated a hygroelectric generator. It is powered by electricity generated from the moisture in human breath. By measuring the change in the moisture-induced voltage when the user breathes through a graphene mask, it provides an indicator of the condition of the mask. Experiment results showed that the more the bacteria and atmospheric particles accumulated on the surface of the mask, the lower the voltage resulted. “The standard of how frequently a mask should be changed is better to be decided by the professionals. Yet, this method we used may serve as a reference,” suggested Dr Ye.

Laser-induced graphene (LIG), Rice University, and Dr. Ye were mentioned here in a May 9, 2018 titled: Do you want that coffee with some graphene on toast?

Back to the latest research, read the caption carefully,

Research shows that over 90% of the E. coli deposited on activated carbon fibre (fig c and d) and melt-blown fabrics (fig e and f) remained alive even after 8 hours. In contrast, most of the E. coli deposited on the graphene surface (fig a and b) were dead. (Photo source: DOI number: 10.1021/acsnano.0c05330)

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

Self-Reporting and Photothermally Enhanced Rapid Bacterial Killing on a Laser-Induced Graphene Mask by Libei Huang, Siyu Xu, Zhaoyu Wang, Ke Xue, Jianjun Su, Yun Song, Sijie Chen, Chunlei Zhu, Ben Zhong Tang, and Ruquan Ye. ACS Nano 2020, 14, 9, 12045–12053 DOI: https://doi.org/10.1021/acsnano.0c05330 Publication Date:August 11, 2020 Copyright © 2020 American Chemical Society

This paper is behind a paywall.

A robot that sucks up oil spills

I was surprised to find out that between 1989 when the Exxon Valdez oil spill fouled the coastline along Alaska and northern British Columbia and 2010 when the BP (British Petroleum) oil spill fouled the Gulf of Mexico and a number of US states, which border it, and Mexico’s state coastlines, there had been virtually no improvement in the environmental remediation technologies for oil spills (see my June 4, 2010 posting).

This summer we’ve had two major oil spills, one in the Russian Arctic (as noted in my August 14, 2020 posting; scroll down to the subhead ‘As for the Russian Arctic oil spill‘) and in the Indian Ocean near Mauritius and near a coral reef and marine protected areas (see this August 13, 2020 news item on the Canadian Broadcasting Corporation [CBC] news online website).

No word yet on whether or not remediation techniques have improved but this August 6, 2020 article by Adele Peters for Fast Company highlights a new robotic approach to cleaning marine oil spills,

A decade after a BP drilling rig exploded in the Gulf of Mexico, sending an estimated 168 million gallons of oil gushing into the water over the course of months, local wildlife are still struggling to recover. Many of the people who worked to clean up the spill are still experiencing health effects. At the time, the “cleanup” strategy involved setting oil slicks on fire and spraying mass quantities of a chemical meant to disperse it, both of which helped get rid of the oil, but also worsened pollution [emphasis mine].

A new robot designed to clean oil spills, now in development, demonstrates how future spills could be handled differently. The robot navigates autonomously on the ocean surface, running on solar power. When oil sensors on the device detect a spill, it triggers a pump that pushes oil and water inside, where a custom nanomaterial sucks up the oil and releases clean water.

Kabra [Tejas Sanjay Kabra, a graduate student at North Carolina State University] 3D-printed a small prototype of the robot, which he tested in a lab, a swimming pool, and then the open ocean. (The small version, about two feet across, can collect 20 gallons of oil at a time; the same device can be scaled up to much larger sizes). He now hopes to bring the product to market as quickly as possible, as major oil spills continue to occur—such as the spill in Russia in June that sent more than 20,000 metric tons of diesel into a pristine part of the Arctic.

Peters’s article provides more details and features an embedded video.

Kabra calls his technology, SoilioS (Spilled OIL recovery by Isis & Oleophilic Sponge) and he entered it in the 2020 James Dyson Awards. The undated James Dyson Award news release announcing the 2020 national winners does not include Kabra’s entry. Mind you, over 1700 inventors entered the 2020 competition.

I hope Kabra perseveres as his robot project looks quite interesting for a number of reasons as can be seen in his entry submission (from the James Dyson Award website),

Initially, I started with a literature review on various Nanomaterials made from tree leaves with specific properties of Hydrophobicity and oleophilicity. Then I narrowed down my research on four different types of leaves i.e., Holy basil, betel, subabul, and mango. Nanoparticles from these leaves were made by green synthesis method and SEM, EDX and XRD tests were conducted. From these tests, I found that the efficiency of material made from the subabul tree was max (82.5%). In order to carry out surface cleaning at sea, different robot designs were studied. Initially, the robot was built in a box structure with arms. The arms contained Nano-capillary; however, the prototype was bulky and inefficient. A new model was devised to reduce the weight as well as increase the efficiency of absorbing the oil spill. The new robot was designed to be in a meta-stable state. The curves of the robot are designed in such a way that it gives stability as well as hold all the components. The top part of the robot is a hollow dome to improve the stability in water. The robot is 3D printed to reduce weight. The 3D printed robot was tested in a pool. Further, work is going on to build a 222 feet robot to test with hardware suitable for sea.

Here’s what SoilioS looks like,

[downloaded from https://www.jamesdysonaward.org/en-US/2020/project/soilios/]

Kabra described what makes his technology from what is currently the state-of-the-art and his future plans (from the James Dyson Award website),

The current technology uses carbon Nano-particle, and some other uses plastic PVC with a chemical adhesive, which is harmful to the environment. On the other hand, SoilioS uses Nano-material made from tree leaves. The invented technology absorbs the oil and stores inside the container with a recovery rate of 80%. The recovered oil can be used for further application; however, on the other hand, the current products burn the oil [emphasis mine] at the cleaning site itself without any recovery rate, thereby increasing pollution. The durability of the invented technology is 8-10 years, and the Nanomaterial used for cleaning the oil spill is reusable for 180 cycles. On the other hand, the durability of the current technology is up to 3-5 years, and the material used is non-reusable. The cost of the invented product is only $5 and on the other hand, the existing technology costs up to $750.

I aim to develop, manufacture, and practically test the robot prototype in the sea so that it can be used to solve oil spill issues and can save billions of dollars. I hope this device will help the environment in a lot of ways and eventually decrease the side effects caused due to oil spills such as leukemia and dying marine life. Currently, I am testing the product on different grades of oil to improve its efficiency further and improving its scope of the application so that it can also be used in industries and household purposes.

I wish Kabra good luck as he works to bring his technology to market.

Spray-on coatings for cheaper smart windows

An August 6, 2020 RMIT University (Australia) press release (also on EurekAlert but published August 5, 2020) by Gosia Kaszubska announces a coating that makes windows ‘smart’,

A simple method for making clear coatings that can block heat and conduct electricity could radically cut the cost of energy-saving smart windows and heat-repelling glass [electrochromic windows?].

The spray-on coatings developed by researchers at RMIT are ultra-thin, cost-effective and rival the performance of current industry standards for transparent electrodes.

Combining the best properties of glass and metals in a single component, a transparent electrode is a highly conductive clear coating that allows visible light through.

The coatings – key components of technologies including smart windows, touchscreen displays, LED lighting and solar panels – are currently made through time-consuming processes that rely on expensive raw materials.

The new spray-on method is fast, scalable and based on cheaper materials that are readily available.

The method could simplify the fabrication of smart windows, which can be both energy-saving and dimmable, as well as low-emissivity glass, where a conventional glass panel is coated with a special layer to minimise ultraviolet and infrared light.

Lead investigator Dr Enrico Della Gaspera said the pioneering approach could be used to substantially bring down the cost of energy-saving windows and potentially make them a standard part of new builds and retrofits.

“Smart windows and low-E glass can help regulate temperatures inside a building, delivering major environmental benefits and financial savings, but they remain expensive and challenging to manufacture,” said Della Gaspera, a senior lecturer and Australian Research Council DECRA Fellow at RMIT.

“We’re keen to collaborate with industry to further develop this innovative type of coating.

“The ultimate aim is to make smart windows much more widely accessible, cutting energy costs and reducing the carbon footprint of new and retrofitted buildings.”

The new method can also be precisely optimised to produce coatings tailored to the transparency and conductivity requirements of the many different applications of transparent electrodes.

Global demand for smart glazing

The global market size for smart glass and smart windows is expected to reach $6.9 billion by 2022, while the global low-E glass market is set to reach an estimated $39.4 billion by 2024.

New York’s Empire State Building reported energy savings of $US2.4 million and cut carbon emissions by 4,000 metric tonnes after installing smart glass windows.

Eureka Tower in Melbourne features a dramatic use of smart glass in its “Edge” tourist attraction, a glass cube that projects 3m out of the building and suspends visitors 300m over the city. The glass is opaque as the cube moves out over the edge of the building and becomes clear once fully extended.

First author Jaewon Kim, a PhD researcher in Applied Chemistry at RMIT,  said the next steps in the research were developing precursors that will decompose at lower temperatures, allowing the coatings to be deposited on plastics and used in flexible electronics, as well as producing larger prototypes by scaling up the deposition.

“The spray coater we use can be automatically controlled and programmed, so fabricating bigger proof-of-concept panels will be relatively simple,” he said.

Caption: The ultra-thin clear coatings are made with a new spray-on method that is fast, cost-effective and scalable. Credit: RMIT University

That is an impressive level of transparency. As per usual, here’s a link to and a citation for the paper (should you wish to explore further),

Ultrasonic Spray Pyrolysis of Antimony‐Doped Tin Oxide Transparent Conductive Coatings by Jaewon Kim, Billy J. Murdoch, James G. Partridge, Kaijian Xing, Dong‐Chen Qi, Josh Lipton‐Duffin, Christopher F. McConville, Joel van Embden, Enrico Della Gaspera. Advanced Materials Interfaces DOI: https://doi.org/10.1002/admi.202000655 First published: 05 August 2020

This paper is behind a paywall.

Transforming electronics with metal-breathing bacteria

‘Metal-breathing’ bacteria, eh? A July 28, 2020 news item on Nanowerk announces the research into new materials for electronics (Note: A link has been removed),

When the Shewanella oneidensis bacterium “breathes” in certain metal and sulfur compounds anaerobically, the way an aerobic organism would process oxygen, it produces materials that could be used to enhance electronics, electrochemical energy storage, and drug-delivery devices.

The ability of this bacterium to produce molybdenum disulfide – a material that is able to transfer electrons easily, like graphene – is the focus of research published in Biointerphases (“Synthesis and characterization of molybdenum disulfide nanoparticles in Shewanella oneidensis MR-1 biofilms”) by a team of engineers from Rensselaer Polytechnic Institute.

A July 28, 2020 Rensselaer Polytechnic Institute (RPI) news release (also on EurekAlert) by Torie Wells, which originated the news item, describes the work in more detail,

“This has some serious potential if we can understand this process and control aspects of how the bacteria are making these and other materials,” said Shayla Sawyer, an associate professor of electrical, computer, and systems engineering at Rensselaer.

The research was led by James Rees, who is currently a postdoctoral research associate under the Sawyer group in close partnership and with the support of the Jefferson Project at Lake George — a collaboration between Rensselaer, IBM Research, and The FUND for Lake George that is pioneering a new model for environmental monitoring and prediction. This research is an important step toward developing a new generation of nutrient sensors that can be deployed on lakes and other water bodies.

“We find bacteria that are adapted to specific geochemical or biochemical environments can create, in some cases, very interesting and novel materials,” Rees said. “We are trying to bring that into the electrical engineering world.”

Rees conducted this pioneering work as a graduate student, co-advised by Sawyer and Yuri Gorby, the third author on this paper. Compared with other anaerobic bacteria, one thing that makes Shewanella oneidensis particularly unusual and interesting is that it produces nanowires capable of transferring electrons [emphasis mine].

“That lends itself to connecting to electronic devices that have already been made,” Sawyer said. “So, it’s the interface between the living world and the manmade world that is fascinating.”

Sawyer and Rees also found that, because their electronic signatures can be mapped and monitored, bacterial biofilms could also act as an effective nutrient sensor that could provide Jefferson Project researchers with key information about the health of an aquatic ecosystem like Lake George.

“This groundbreaking work using bacterial biofilms represents the potential for an exciting new generation of ‘living sensors,’ which would completely transform our ability to detect excess nutrients in water bodies in real-time. This is critical to understanding and mitigating harmful algal blooms and other important water quality issues around the world,” said Rick Relyea, director of the Jefferson Project.

Sawyer and Rees plan to continue exploring how to optimally develop this bacterium to harness its wide-ranging potential applications.

“We sometimes get the question with the research: Why bacteria? Or, why bring microbiology into materials science?” Rees said. “Biology has had such a long run of inventing materials through trial and error. The composites and novel structures invented by human scientists are almost a drop in the bucket compared to what biology has been able to do.”

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

Synthesis and characterization of molybdenum disulfide nanoparticles in Shewanella oneidensis MR-1 biofilms by James D. Rees, Yuri A. Gorby, and Shayla M. Sawyer. Biointerphases 15, 041006 (2020) DOI: https://doi.org/10.1116/6.0000199 Published Online: 24 July 2020

This paper is behind a paywall.