GT/ Driving on sunshine: Clean, usable liquid fuels made from solar power
Energy & green technology biweekly vol.50, 18th May — 9th June
TL;DR
- In order to move, cells must be able to rapidly change shape. A team of researchers show that cells achieve this by storing extra ‘skin’ in folds and bumps on their surface. This cell surface excess can be rapidly deployed to cover temporary protrusions and then folded away for next time.
- Why does it feel so difficult to shout upwind? The sensation is common enough to have found its way into an idiom about not being understood. Researchers wanted a scientific explanation for the phenomenon — and there wasn’t been one. They have now shown that our common sense understanding of this situation is wrong. It isn’t harder to shout into the wind; it’s just harder to hear yourself.
- A new study uncovers how the interplay between Sargassum spp., plastic marine debris and Vibrio bacteria creates the perfect “pathogen” storm that has implications for both marine life and public health. Vibrio bacteria are found in waters around the world and are the dominant cause of death in humans from the marine environment. For example, Vibrio vulnificus, sometimes referred to as flesh-eating bacteria, can cause life-threatening foodborne illnesses from seafood consumption as well as disease and death from open wound infections.
- Which energy type promotes the biodiversity of beetles living in dead wood in the forest? That depends entirely on where the beetles are in the food chain, according to new study.
- Researchers have developed a chemical process that can disassemble the epoxy composite of wind turbine blades and simultaneously extract intact glass fibers as well as one of the epoxy resin’s original building blocks in a high quality. The recovered materials could potentially be used in the production of new blades.
- Researchers develop a fabrication method to increase the efficacy and longevity of membrane separation technology. The team created a nanofibrous membrane with electrospinning, in which a liquid polymer droplet is electrified and stretched to make fibers, and increased the roughness of the membrane surface by loading it with silver nanoparticles. In water, this rough surface promotes a stable layer of water, which acts as a barrier to prevent oil droplets from entering the membrane. The technology is greater than 99% effective at separating a petroleum ether-in-water emulsion.
- New research found that Americans already bearing the brunt of climate change and health inequities are most at risk of impact by a lengthy power outage.
- Around 500 million years ago life in the oceans rapidly diversified. In the blink of an eye — at least in geological terms — life transformed from simple, soft-bodied creatures to complex multicellular organisms with shells and skeletons. Now, research has shown that the diversification of life at this time also led to a drastic change in the chemistry of Earth’s crust — the uppermost layer we walk on and, crucially, the layer which provides many of the nutrients essential to life.
- Researchers are embarking on a groundbreaking project to mimic the natural process of photosynthesis using bacteria to deliver electrons to a nanocrystal semiconductor photocatalyst. By leveraging the unique properties of microorganisms and nanomaterials, the system has the potential to replace current approaches that derive hydrogen from fossil fuels, revolutionizing the way hydrogen fuel is produced and unlocking a powerful source of renewable energy.
- Researchers confirm the superiority of seawater batteries that use chelating agents.
- And more!
Green Technology Market
Green technology is an applicable combination of advanced tools and solutions to conserve natural resources and environment, minimize or mitigate negative impacts from human activities on the environment, and ensure sustainability development. Green technology is also referred to as clean technology or environmental technology which includes technologies, such as IoT, AI, analytics, blockchain, digital twin, security, and cloud, which collect, integrate, and analyze data from various real-time data sources, such as sensors, cameras, and Global Positioning System (GPS).
Green technology, also known as sustainable technology, protects the environment by using various forms of sustainable energy. Some of the best examples of green technologies include solar panels, LED lighting, wind energy, electric vehicles, vertical farming, and composting.
The global Green Technology and Sustainability market size to grow from USD 11.2 billion in 2020 to USD 36.6 billion by 2025, at a Compound Annual Growth Rate (CAGR) of 26.6% during the forecast period. The growing consumer and industrial interest for the use of clean energy resources to conserve environment and increasing use of Radio Frequency Identification sensors across industries are driving the adoption of green technology and sustainability solutions and services in the market.
The blockchain segment is estimated to grow at the highest CAGR: Energy-intensive cryptocurrency mining has caused a spike in carbon emission, and hence blockchain is capable of driving innovation in the field of green technology.
Latest Research
Solar-driven liquid multi-carbon fuel production using a standalone perovskite–BiVO4 artificial leaf
by Motiar Rahaman, Virgil Andrei, Demelza Wright, Erwin Lam, Chanon Pornrungroj, Subhajit Bhattacharjee, Christian M. Pichler, Heather F. Greer, Jeremy J. Baumberg, Erwin Reisner in Nature Energy
In order to move, cells must be able to rapidly change shape. A team of researchers from the University of North Carolina at Chapel Hill show that cells achieve this by storing extra “skin” in folds and bumps on their surface. This cell surface excess can be rapidly deployed to cover temporary protrusions and then folded away for next time.
Cell membranes are very flexible, but they can only stretch by approximately 3% without rupturing. Having extra wrinkles of surface area that can expand on demand allows cells to move and divide while safely maintaining cell volume and membrane integrity.
“It’s a safety measure because you can’t stretch the cell membrane, and if it breaks, the cell will lyse and die, so cells need to have this reserve,” says first author Maryna Kapustina, a biophysicist at the University of North Carolina at Chapel Hill. “These projections can store massive amounts of cell surface and are highly dynamic, which means they can be rapidly dismounted and immediately rebuilt in other locations on the cell periphery.”
Cell surface protrusions came in various shapes and sizes. Some, called blebs, are small, rounded bumps on the cell surface with very little internal structure. Blebs form within seconds and shrink after several minutes. Larger locomotory protrusions take longer to form but can last for more than an hour thanks to their supportive internal structure, which is made of proteins such as microtubules and actin.
The researchers used electron and fluorescence microscopy to observe rounded, cigar-shaped, and irregularly shaped cells that were embedded in a 3D collagen matrix, a meshwork of collagen fibers that the cells could squeeze and migrate through. They used fluorescent tags to capture time-lapses of the cells’ surface dynamics and locomotion over the course of several hours.
The team showed that when the cells were rounded, their surfaces were rough and complex; covered with numerous tiny surface projections such as blebs, microvilli, filopodia, and folds. However, when the cells extended protrusions, these extra wrinkles of “skin” unfolded and their surfaces became relatively smooth, especially in the regions adjacent to the protrusions.
The researchers think that cell surface excess is important during both mesenchymal and ameboid locomotion, the two main ways that cells move. During mesenchymal locomotion, cells adhere to surfaces in their environment and then use contractile forces to push itself between the collagen fibers or crawl along 2D surfaces. During ameboid locomotion — which allows for much faster movement — cells don’t rely on adhesions but are instead propelled by the rapid movements of smaller “blebby” protrusions.
The team thinks that microtubules play an important role in regulating cell surface excess during both mesenchymal and ameboid locomotion, though their exact function is unclear.
“Microtubules might be providing mechanical support for the cell surface, or it might have something to with activating actin beneath the cell membrane to create an active site for a stable protrusion,” says Kapustina. “When you don’t have this active site to create a stable protrusion, the cells basically just form blebs.”
Perceived difficulty of upwind shouting is a misconception explained by convective attenuation effect.
by Ville Pulkki, Rapolas Daugintis, Timo Lähivaara, Aleksi Öyry in Scientific Reports
For years, Ville Pulkki has been wondering why it feels so difficult to shout upwind. The sensation is common enough to have found its way into an idiom about not being understood. But Pulkki,a professor of acoustics at Aalto University, wanted a scientific explanation for the phenomenon — and there wasn’t been one.
In a new study, Pulkki’s research team showed that our common sense understanding of this situation is wrong. It isn’t harder to shout into the wind; it’s just harder to hear yourself. In fact, acousticians have long known that sound carries better within the first 100 metres upwind. Many people have noticed that a siren sounds louder as it approaches and then quieter as it moves away. The mechanics behind this is similar to the Doppler effect, in which a sound changes frequency as it moves.
Pulkki’s earlier research had confirmed that wind doesn’t affect the emanation pattern of speech, so there was no reason why shouting into the wind would be difficult. He therefore asked one of his master’s students,Rapolas Daugintis, to study whether the phenomenon was due to how we hear.Daugintis carried out measurements and simulations to test the idea, and Senior Researcher Timo Lähivaara from the University of Eastern Finland contributed acoustic and flow field simulations. Their results were surprising but simple: it’s harder for people to hear themselves when shouting upwind.
‘When someone shouts upwind, their ears are situated downwind from their mouth, which means that their ears receive less sound — it’s harder from them to hear their shout than when there’s no wind,’ says Pulkki.
The same thing happens when someone is moving quickly even if there’s no wind blowing — if you’re cycling, for example. As a person bikes, their motion generates a wind around their head even in stationary air, and they end up shouting because they can’t hear their own voice well. So be careful what you shout upwind, for others might hear you just fine, even if you don’t. This information is particularly useful for people who work with sound, such as musicians.
‘My musician friend told me that when they have to sing on a sailboat, they always sit with their back against the wind in order to not strain their voice. The same phenomenon is at play here: because it’s harder for my friend to hear themself when singing upwind, it makes them unknowingly sing louder than usual,’ says Pulkki.
“Sargasso Sea Vibrio bacteria: underexplored potential pathovars in a perturbed habitat”
by Tracy J. Mincer, Ryan P. Bos, Erik R. Zettler, Shiye Zhao, Alejandro A. Asbun, William D. Orsi, Vincent S. Guzzetta, Linda A. Amaral-Zettler in Water Research
A new study uncovers how the interplay between Sargassum spp., plastic marine debris and Vibrio bacteria creates the perfect “pathogen” storm that has implications for both marine life and public health. Vibrio bacteria are found in waters around the world and are the dominant cause of death in humans from the marine environment. For example, Vibrio vulnificus, sometimes referred to as flesh-eating bacteria, can cause life-threatening foodborne illnesses from seafood consumption as well as disease and death from open wound infections.
Since 2011, Sargassum, free-living populations of brown macroalga, have been rapidly expanding in the Sargasso Sea and other parts of the open ocean such as the Great Atlantic Sargassum Belt, including frequent and unprecedented seaweed accumulation events on beaches. Plastic marine debris, first found in surface waters of the Sargasso Sea, has become a worldwide concern, and is known to persist decades longer than natural substrates in the marine environment.
Currently, little is known about the ecological relationship of vibrios with Sargassum. Moreover, genomic and metagenomic evidence has been lacking as to whether vibrios colonizing plastic marine debris and Sargassum could potentially infect humans. As summer kicks into high gear and efforts are underway to find innovative solutions to repurpose Sargassum, could these substrates pose a triple threat to public health?
Researchers from Florida Atlantic University and collaborators fully sequenced the genomes of 16 Vibrio cultivars isolated from eel larvae, plastic marine debris, Sargassum, and seawater samples collected from the Caribbean and Sargasso seas of the North Atlantic Ocean. What they discovered is Vibrio pathogens have the unique ability to “stick” to microplastics and that these microbes might just be adapting to plastic.
“Plastic is a new element that’s been introduced into marine environments and has only been around for about 50 years,” said Tracy Mincer, Ph.D., corresponding lead author and an assistant professor of biology at FAU’s Harbor Branch Oceanographic Institute and Harriet L. Wilkes Honors College. “Our lab work showed that these Vibrio are extremely aggressive and can seek out and stick to plastic within minutes. We also found that there are attachment factors that microbes use to stick to plastics, and it is the same kind of mechanism that pathogens use.”
The study, published in the journal Water Research, illustrates that open ocean vibrios represent an up to now undescribed group of microbes, some representing potential new species, possessing a blend of pathogenic and low nutrient acquisition genes, reflecting their pelagic habitat and the substrates and hosts they colonize. Utilizing metagenome-assembled genome (MAG), this study represents the first Vibrio spp. genome assembled from plastic debris.
The study highlighted vertebrate pathogen genes closely related to cholera and non-cholera bacterial strains. Phenotype testing of cultivars confirmed rapid biofilm formation, hemolytic and lipophospholytic activities, consistent with pathogenic potential. Researchers also discovered that zonula occludens toxin or “zot” genes, first described in Vibrio cholerae, which is a secreted toxin that increases intestinal permeability, were some of the most highly retained and selected genes in the vibrios they found. These vibrios appear to be getting in through the gut, getting stuck in the intestines and infecting that way.
“Another interesting thing we discovered is a set of genes called ‘zot’ genes, which causes leaky gut syndrome,” said Mincer. “For instance, if a fish eats a piece of plastic and gets infected by this Vibrio, which then results in a leaky gut and diarrhea, it’s going to release waste nutrients such nitrogen and phosphate that could stimulate Sargassum growth and other surrounding organisms.”
Findings show some Vibrio spp. in this environment have an ‘omnivorous’ lifestyle targeting both plant and animal hosts in combination with an ability to persist in oligotrophic conditions. With increased human-Sargassum-plastic marine debris interactions, associated microbial flora of these substrates could harbor potent opportunistic pathogens. Importantly, some cultivation-based data show beached Sargassum appear to harbor high amounts of Vibrio bacteria.
“I don’t think at this point, anyone has really considered these microbes and their capability to cause infections,” said Mincer. “We really want to make the public aware of these associated risks. In particular, caution should be exercised regarding the harvest and processing of Sargassum biomass until the risks are explored more thoroughly.”
Ambient and substrate energy influence decomposer diversity differentially across trophic levels
by Peter Kriegel, Sebastian Vogel, Romain Angeleri, et al in Ecology Letters
Energy is the key to life. For decades, scientists have been trying to decipher the connection between available energy and biodiversity in ecosystems.
In the process, clear correlations have emerged. For example, ecosystems with higher energy input, for example due to stronger solar radiation near the equator, are endowed with greater biodiversity. But ecosystems do not exclusively draw their energy directly from the sun. Energy can also be stored chemically, for example in resources such as wood.
Which type of energy promotes biodiversity? Does it happen uniformly along the food chain? These questions have remained unanswered until now.
The first answers have now come from researchers at the Julius-Maximilians-Universität (JMU) Würzburg Biocentre. A team led by ecologists Simon Thorn and Peter Kriegel has studied the species diversity of beetles that live in deadwood in forests. Data from all over Europe was collected for this purpose. Simon Thorn initiated and coordinated the project six years ago; he has recently started research at the Hessian Agency for Nature Conservation, Environment and Geology.
As the researchers show, the diversity of deadwood beetles is influenced differently by energy types depending on their position in the food chain. This evidence was obtained with data recorded along a gradient from northern to southern Europe from a total of 2,746 deadwood objects.
“Species like the stag beetle, whose larvae feed directly on dead wood and are thus at the bottom of the food chain, benefit in their diversity from the amount of energy stored in the wood,” says Peter Kriegel: “The more sugar compounds are stored in the heartwood, the greater their diversity.
At the top end of the food pyramid of deadwood beetles are species like the ant beetle, which eat other insects. Their diversity is largely unaffected by the energy stored in the wood. Instead, greater solar radiation plays an important role here.
“These results are important for basic ecological research,” says JMU forest ecologist Professor Jörg Müller, who was involved in the study. The results could help to slow down alarming developments such as insect decline. Next, the research team from the JMU Chair of Animal Ecology and Tropical Biology wants to turn its attention to biodiversity in deadwood which is not openly visible.
“Using methods such as DNA sequencing, we want to detect the molecular traces of hidden organisms: Bacteria, fungi without fruiting bodies, but also groups of insects which are difficult to determine and are therefore often neglected,” explains Peter Kriegel. Then the question will be whether the respective tree species or the sunlight is more important for a high species diversity.
Catalytic disconnection of C–O bonds in epoxy resins and composites
by Alexander Ahrens, Andreas Bonde, Hongwei Sun, Nina Kølln Wittig, Hans Christian D. Hammershøj, Gabriel Martins Ferreira Batista, Andreas Sommerfeldt, Simon Frølich, Henrik Birkedal, Troels Skrydstrup in Nature
The new chemical process is not limited to wind turbine blades but works on many different so-called fibre-reinforced epoxy composites, including some materials that are reinforced with especially costly carbon fibres.
Thus, the process can contribute to establishing a potential circular economy in the wind turbine, aerospace, automotive and space industries, where these reinforced composites, due to their light weight and long durability, are used for load-bearing structures. Being designed to last, the durability of the blades poses an environmental challenge. Wind turbine blades mostly end up at waste landfills when they are decommissioned, because they are extremely difficult to break down. If no solution is found, we will have accumulated 43 million tonnes of wind turbine blade waste globally by 2050.
The newly discovered process is a proof-of-concept of a recycling strategy that can be applied to the vast majority of both existing wind turbine blades and those presently in production, as well as other epoxy-based materials. Aarhus University, together with the Danish Technological Institute, have filed a patent application for the process. Specifically, the researchers have shown that by using a ruthenium-based catalyst and the solvents isopropanol and toluene, they can separate the epoxy matrix and release one of the epoxy polymer’s original building blocks, bisphenol A (BPA), and fully intact glass fibres in a single process.
However, the method is not immediately scalable yet, as the catalytic system is not efficient enough for industrial implementation — and ruthenium is a rare and expensive metal. Therefore, the scientists from Aarhus University are continuing their work on improving this methodology.
“Nevertheless, we see it as a significant breakthrough for the development of durable technologies that can create a circular economy for epoxy-based materials. This is the first publication of a chemical process that can selectively disassemble an epoxy composite and isolate one of the most important building blocks of the epoxy polymer as well as the glass or carbon fibres without damaging the latter in the process,” says Troels Skrydstrup, one of the lead authors of the study.
Polyacrylonitrile nanofibrous membrane composited with zeolite imidazole skeleton-8 and silver nanoclusters for efficient antibacterial and emulsion separation
by Huaxiang Chen, Hao Zhou, Mingchao Chen, Yan Quan, Chenglong Wang, Yujie Gao, Jindan Wu in Biointerphases
When oil contaminates water, it creates a film that reduces oxygen levels and introduces toxic substances. This can lead to the death of aquatic plants and animals, contaminate soil, and ultimately threaten human health.
Separating oil from polluted water is therefore of great importance. Current methods can be expensive and challenging, and some may introduce further pollutants into the system. For example, membrane materials can act as a barrier to intercept oil, but their efficiency is low and they aren’t suited for long-term use. Researchers in China developed a fabrication method to increase the efficacy and longevity of membrane separation technology. The technology is greater than 99% effective at separating a petroleum ether-in-water emulsion.
The team created a nanofibrous membrane with electrospinning, in which a liquid polymer droplet is electrified and stretched to make fibers. They increased the roughness of the membrane surface by loading it with silver nanoparticles. In water, this rough surface promotes a stable layer of water, which acts as a barrier to prevent oil droplets from entering the membrane.
“This hydration layer efficiently impedes the passage of oil droplets, reducing membrane pollution and enhancing the composite membrane’s permeability and separation efficiency,” said author Jindan Wu.
Silver nanoparticles also enhance the membrane’s antibacterial properties. Incorporating them minimizes the risk of membrane corrosion that can be caused by microorganisms.
“We have discovered that the membrane’s surface roughness and hydration layer strength are critical factors that impact its separation performance and anti-fouling ability,” said Wu. “This concept of depositing particles on nanofibrous membranes also has potential for broad applications with other materials.”
The current output capabilities of this fabrication method are relatively low. However, the group hopes developing such materials will contribute to a comprehensive solution for treating water pollution.
“Water pollution is caused by multiple sources, and oily wastewater is just one of them,” said Wu. “It is of vital importance to develop materials that can treat for dyes, heavy metals, and bacteria present in water.”
Spatiotemporal distribution of power outages with climate events and social vulnerability in the USA
by Vivian Do, Heather McBrien, Nina M. Flores, Alexander J. Northrop, Jeffrey Schlegelmilch, Mathew V. Kiang, Joan A. Casey in Nature Communications
Joan Casey lived through frequent wildfire-season power outages when she lived in northern California. While waiting for the power to return, she wondered how the multi-day blackouts affected a community’s health.
“For me it was an inconvenience, but for some people it could be life-threatening,” said Casey, now an assistant professor in the University of Washington’s Department of Environmental and Occupational Health Sciences. “If you had an uncle that had an electric heart pump, basically, his heart wouldn’t work without power. You could use a backup battery for eight hours, but after that, if you don’t have access to electricity, you have to go to the emergency room. This is a really dangerous situation.”
Years later, Casey has answers. A study analyzed three years of power outages across the U.S., finding that Americans already bearing the brunt of climate change and health inequities are clustered in four regions — Louisiana, Arkansas, central Alabama and northern Michigan — and that they are most at risk of impact by a lengthy blackout. The findings could help shape the future of local energy infrastructure, especially as climate change intensifies and the American power grid continues to age. Last year’s Inflation Reduction Act included billions of dollars to revamp energy systems, and Casey hopes federal agencies will consult the newly published findings to target energy upgrades.
The study is the first county-level analysis of power outages, which the federal government reports only at the state level. That poses a problem for researchers: a federally reported outage in Washington state could occur in Seattle, Spokane, or somewhere in between, making it difficult to understand specifically which population is affected. Casey and her team found that between 2018 and 2020, more than 231,000 power outages lasting more than an hour occurred nationwide. Of those, 17,484 stretched at least eight hours — a duration widely viewed as medically relevant. Most counties that experienced an electrical outage had at least one event lasting more than eight hours. These counties were most concentrated in the South, Northeast and Appalachia.
Next, researchers looked at how power outages overlapped with severe weather. They wanted to know which weather events are most likely to cause an outage, and which parts of the U.S. are most often hit with a blackout-causing storm. They found that heavy precipitation in a given area makes a power outage five times more likely. Tropical cyclones, storms with high winds that originate over tropical oceans, make a power outage 14 times more likely. And a tropical cyclone with heavy precipitation on a hot day — like the hurricanes that each fall hit the Gulf Coast? They make power outages 52 times more likely.
“We look at weather reports and decide whether or not to bring an umbrella or stay home,” Casey said. “But thinking about being prepared for an outage when one of these events is rolling through is a new element to consider.”
Then came questions of equity. Incorporating a combination of socioeconomic and medical factors, Casey’s team identified communities that would likely be especially vulnerable during a long power outage. Using that data, the researchers were able to identify communities that experienced both high social vulnerability and frequent power outages. A map of those counties shows a bright cluster in Louisiana and Arkansas, with more clusters in central Alabama and northern Michigan. In those places especially, the country’s inevitable change in energy infrastructure provides the greatest opportunity to improve public health.
“Any time we can identify another factor that we can intervene on to get closer to health equity, it’s exciting,” Casey said. “I think we’re going to see tremendous change, especially in the way our energy systems are set up, in the next couple decades. It’s this huge opportunity to get equity into every conversation and talk about what we’re going to do to make two decades from now look different from where we are.”
Evolution of the crustal phosphorus reservoir
by Craig R. Walton, Jihua Hao, Fang Huang, Frances E. Jenner, Helen Williams, Aubrey L. Zerkle, Alex Lipp, Robert M. Hazen, Shanan E. Peters, Oliver Shorttle in Science Advances
Around 500 million years ago life in the oceans rapidly diversified. In the blink of an eye — at least in geological terms — life transformed from simple, soft-bodied creatures to complex multicellular organisms with shells and skeletons.
Now, research led by the University of Cambridge has shown that the diversification of life at this time also led to a drastic change in the chemistry of Earth’s crust — the uppermost layer we walk on and, crucially, the layer which provides many of the nutrients essential to life. The researchers identified that, following the so-called Cambrian explosion, quantities of the life-giving nutrient phosphorus tripled in crustal rocks — a change that supported the continued expansion of life on Earth.
“We found that ancient life had a profound impact on its environment — even to the point of resetting the chemistry of the continental crust,” said Craig Walton, lead author of the research who is from Cambridge’s Department of Earth Sciences.
Using a database of information on ancient rocks, which has been complied by scientists across the globe, the researchers built a map to show how the chemistry of Earth’s crust has fluctuated over the last 3000 million years. They found that, following the increase in phosphorus at the time of the Cambrian explosion, contents of this key-nutrient in crustal rocks have continued to grow up until the present-day.
“From about 540 million years onwards, we see that life transformed the composition of the upper part of Earth’s crust,” said co-author Oliver Shorttle, who is jointly based at Cambridge’s Department of Earth Sciences and Institute of Astronomy. “This shows how the development of life can influence the growth of further life, and in turn how much life a planet can go on to support.”
Life in all its varied forms — from the prodigious whale to minute plankton — relies on six key ingredients: carbon, hydrogen, nitrogen, phosphorus and sulfur. The researchers investigated phosphorus because it is not only universally needed by life, but also difficult to tap into because it is locked up in minerals inside Earth’s crust.
“Phosphorus is also thought to be one of the nutrients that limits the amount of life that can exist in the oceans,” said Shorttle. He explained that, by mapping out phosphorus in rocks through time, they could identify how much of this element is available to life, and, by extension, get an idea of how much life has existed on the planet.
Unlike carbon and nitrogen, which are key constituents of our atmosphere, phosphorus must be extracted out of rocks before life can use it. The process starts with the break-down of rocks due to interactions with rainwater — releasing phosphate which is then washed by rivers into the oceans. Once in the oceans, phosphorus is metabolized by organisms such as plankton or eukaryotic algae, which are then consumed by larger animals higher up the food chain.
When these organisms die, most of the phosphorus is returned back into the oceans. This efficient recycling process is a key control on the amount of total phosphorus in the ocean, which in turn supports life, “It enables us to have all the life we see around us today, so understanding when this process started is really key,” said Walton. But, all of this biological reprocessing power relies on oxygen. This is what fuels the bacteria responsible for the breakdown of dead organic material that returns phosphorus back into the oceans.
The researchers think that a surge in oxygen at around the time of the Cambrian explosion might explain why phosphorus increased in rocks. “If oxygen did increase at that time, then more oxygen may have been available to break down deep sea biomass and recycle phosphorus to shallow coastal regions,” said Walton. Moving this phosphorus back towards the land meant it was better preserved in rocks that make up the continents. “That series of changes were ultimately responsible for fuelling the activity of complex life as we know it,” said Walton.
But, he added, “It’s tricky to unravel the sequence of events — whether complex life evolved in part because of increased supplies of oxygen and phosphorus to start with, or if they were in fact fully responsible for increasing availability of both, is still a controversial topic.” Walton and the team now looking to investigate the trigger for and timing of this phosphorus enrichment in the crust in more detail.
Shewanella oneidensis MR-1 respires CdSe quantum dots for photocatalytic hydrogen evolution
by Emily H. Edwards, Jana Jelušić, Ryan M. Kosko, Kevin P. McClelland, Soraya S. Ngarnim, Wesley Chiang, Sanela Lampa-Pastirk, Todd D. Krauss, Kara L. Bren in Proceedings of the National Academy of Sciences
As the world faces an increasing demand for clean and sustainable energy sources, scientists are turning to the power of photosynthesis for inspiration. With the goal of developing new, environmentally friendly techniques to produce clean-burning hydrogen fuel, a team of researchers at the University of Rochester is embarking on a groundbreaking project to mimic the natural process of photosynthesis using bacteria to deliver electrons to a nanocrystal semiconductor photocatalyst.
In a paper, Kara Bren, the Richard S. Eisenberg Professor in Chemistry at Rochester, and Todd Krauss, a professor of chemistry, demonstrate that thebacteria Shewanella oneidensisoffer an effectively free, yet efficient, way to provide electrons to their artificial photosynthesis system. By leveraging the unique properties of these microorganisms along with nanomaterials, the system has the potential to replace current approaches that derive hydrogen from fossil fuels, revolutionizing the way hydrogen fuel is produced and unlocking a powerful source of renewable energy.
“Hydrogen is definitely a fuel of high interest for the DOE right now,” Bren says. “If we can figure out a way to efficiently extract hydrogen from water, this could lead to an incredible amount of growth in clean energy.”
Hydrogen is “an ideal fuel,” Bren says, “because it’s environmentally-friendly and a carbon-free alternative to fossil fuels.”
Hydrogen is the most abundant element in the universe and can be produced from a variety of sources, including water, natural gas, and biomass. Unlike fossil fuels, which produce greenhouse gases and other pollutants, when hydrogen is burned, the only byproduct is water vapor. Hydrogen fuel also has a high energy density, which means it contains a lot of energy per unit of weight. It can be used in a variety of applications, including fuel cells, and can be made on both small and large scales, making it feasible for everything from home use to industrial manufacturing.
Despite hydrogen’s abundance, there is virtually no pure hydrogen on Earth; it is almost always bound to other elements, such as carbon or oxygen, in compounds like hydrocarbons and water. To use hydrogen as a fuel source, it must be extracted from these compounds. Scientists have historically extracted hydrogen either from fossil fuels, or, more recently, from water. To achieve the latter, there is a major push to employ artificial photosynthesis.
During natural photosynthesis, plants absorb sunlight, which they use to power chemical reactions to convert carbon dioxide and water into glucose and oxygen. In essence, light energy is converted into chemical energy that fuels the organism. Similarly, artificial photosynthesis is a process of converting an abundant feedstock and sunlight into a chemical fuel. Systems that mimic photosynthesis require three components: a light absorber, a catalyst to make the fuel, and a source of electrons. These systems are typically submerged in water, and a light source provides energy to the light absorber. The energy allows the catalyst to combine the provided electrons together with protons from the surrounding water to produce hydrogen gas. Most of the current systems, however, rely on fossil fuels during the production process or don’t have an efficient way to transfer electrons.
“The way hydrogen fuel is produced now effectively makes it a fossil fuel,” Bren says. “We want to get hydrogen from water in a light-driven reaction so we have a truly clean fuel — and do so in a way that we don’t use fossil fuels in the process.”
Krauss’s group and Bren’s group have been working for about a decade to develop an efficient system that employs artificial photosynthesis and utilizes semiconductor nanocrystals for light absorbers and catalysts. One challenge the researchers faced was figuring out a source of electrons and efficiently transferring the electrons from the electron donor to the nanocrystals. Other systems have used ascorbic acid, commonly known as vitamin C, to deliver electrons back to the system. While vitamin C might seem inexpensive, “you need a source of electrons that is almost free or the system becomes too expensive,” Krauss says.
In their paper, Krauss and Bren report on an unlikely electron donor: bacteria. They found that Shewanella oneidensis, bacteria first gathered from Lake Oneida in upstate New York, offers an effectively free, yet efficient, way to provide electrons to their system. While other labs have combined nanostructures and bacteria, “all of those efforts are taking electrons from the nanocrystals and putting them into the bacteria, then using the bacterial machinery to prepare fuels,” Bren says. “As far as we know, ours is the first case to go the opposite way and use the bacteria as an electron source to a nanocrystal catalyst.”
When bacteria grow under anaerobic conditions — conditions without oxygen — they respire cellular substances as fuel, releasing electrons in the process. Shewanella oneidensis can take electrons generated by its own internal metabolism and donate them to the external catalyst.
Bren envisions that, in the future, individual homes could potentially have vats and underground tanks to harness the power of the sun to produce and store small batches of hydrogen, allowing people to power their homes and cars with inexpensive, clean-burning fuel. Bren notes there are currently trains, buses, and cars powered by hydrogen fuel cells but almost all the hydrogen that is available to power these systems comes from fossil fuels.
“The technology’s out there,” she says, “but until the hydrogen’s coming from water in a light-driven reaction — without using fossil fuels — it isn’t really helping the environment.”
Effects of chelating agent on the nanostructure of nickel hexacyanoferrate and its performance in seawater battery application
by Hyebin Jeong, Sang Hyun Ahn, Changshin Jo in Chemical Engineering Journal
Water blankets around 70 percent of the Earth’s surface. Moreover, 97 percent of all the water on earth is seawater, which is impotable because of its salt content. But what if we could harness its potential as a new source of renewable energy?
Recently, a research team led by Professor Changshin Jo (Graduate Institute of Ferrous & Energy Materials Technology (GIFT), Department of Chemical Engineering) and Ph.D. candidate Hyebin Jeong (Chemical Engineering) at POSTECH has made strides in this area by confirming the superior performance of seawater batteries (SWBs) that incorporate chelating agents.
Lithium-ion batteries have become ubiquitous in portable electronic devices and automotive batteries. However, they are not without limitations, as they present a risk of explosion and may become unusable if lithium supplies are depleted. To address these challenges, the development of next-generation batteries is currently underway. Among them, seawater batteries represent a promising option that utilizes Na-ions found in seawater to generate energy. These batteries offer the distinct advantage of easy resource accessibility and are environmentally friendly, as they require no separate treatment processes.
The high salinity of seawater can be attributed to the presence of Na-ions, which are utilized by seawater batteries to generate and store electrical energy as they move back and forth between the cathode and anode. However, one of the challenges in suing nickel hexacyanoferrate (NiHCF) as an intercalation cathode material for SWBs is the high occurrence of defects during fabrication. To address this issue, the research team synthesize NiHCF with a chelating agent (Sample A) and compared its performance with untreated NiHCF (Sample B) to evaluate the effectiveness of the chelating agent.
A look at the two samples under a microscope reveals the striking difference in their shape and structure. Sample B consists of randomly aggregated nanosized primary particles to form micro-level particles, whereas Sample A comprises individual 200–300 nanometer-sized cubic-shaped particles. Although the individual particle size of Sample B is smaller, it is less advantageous for battery production due to the aggregation of multiple particles into larger cohesive structures.
The researchers additionally assessed the electrochemical performance of both samples. Firstly, they measured the water content, and it was found that Sample A had lower water content than Sample B did. Generally, higher water content tends to impede electrochemical performance. Furthermore, measurements of current and voltage showed that Sample A had high energy efficiency and capacity.
The research team achieved a groundbreaking feat by performing 2,000 cycles of charging and discharging on batteries using two samples, where Sample A demonstrated a remarkable capacity retention rate of approximately 92.8%. Furthermore, the defect generation rate, a previous drawback of NiHCF, was observed to decrease to 6% in Sample A.
The results of the study demonstrate the superior performance achieved by adding a chelating agent to nickel hexacyanoferrate and using this as a cathode material in seawater batteries. This discovery can promote the development of seawater batteries as a promising candidate for next-generation energy storage systems.
