It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Friday, September 20, 2024
Charging ahead towards future low-cost polymer zinc-ion batteries
More sustainable solutions for future power sources
With global demand for lithium-ion batteries fast depleting reserves of raw materials, experts are seeking safe, affordable and reliable alternatives for rechargeable batteries.
Aqueous zinc-ion batteries (AZIBs) could be the answer to producing low-cost alternatives from abundant feedstocks, and Flinders University scientists are paving the way for the production of simple and practical polymer AZIBs using organic cathodes for more sustainable energy storage technology.
“Aqueous zinc-ion batteries could have real-world applications,” says Associate Professor in Chemistry Zhongfan Jia, a nanotech researcher at the College of Science and Engineering at Flinders University.
From electric vehicles to portable electronic devices, the demand and consumption of lithium-ion batteries (LIBs) have led to resource shortages and supply-chain issues of strategic metals including lithium and cobalt.
Meanwhile, millions of spent batteries, most of which are not properly recycled, have caused enormous waste and environmental risks - which future alternatives such as AIZBs promise to reduce.
“Among these alternatives, AZIBs stand out because of the much higher abundance of zinc in the earth's crust (ten times more than lithium), and their low toxicity and high safety.”
AZIBs usually use zinc metal as an anode and inorganic or organic compounds as a cathode. While substantial work has been devoted to improving the stability of zinc anodes, high-performing cathodes are needed and remain a major challenge.
“Our research is building conductivity using nitroxide radical polymer cathodes made from cheap commercial polymer and optimised the battery performance using low-cost additives,” says Associate Professor Jia, who leads a research group working on Sustainable Polymers for Energy and Environment.
“Our work reevaluated the use of high redox potential nitroxide radical polymers cathodes in AZIBs, and produced the highest mass loading so far,” he says, about a new online journal article in the Journal of Power Resources.
The study, led by Flinders master student Nanduni Gamage and postdoc fellow Dr Yanlin Shi, developed a lab-made pouch battery using scaled-up polymer (at approx. cost $20 / kg), a non-fluoro Zn(ClO4)2 electrolyte, and BP 2000 carbon black ($1 / kg) without binder to provide a capacity of nearly 70 mAh g-1 and a middle discharge voltage of 1.4 V.
With a mass loading of 50 mg cm-2, the pouch battery had a capacity of 60 mAh, which can easily power a small electric fan and a model car (see videos in the article).
Collaborators in the study, including Dr Jesús Santos-Peña, from the Université Paris Est Creteil CNRS in France, worked with other experts from the Flinders University Institute for Nanoscale Science and Technology.
In collaboration with Griffith University, the team has also recently developed organic radical/K dual-ion batteries, a technique that can also relieve dependence on lithium-ion batteries.
Acknowledgements: This project is supported by funding from the Australian Research Council (DP230100587, DP230100642, LE230100168) and the French-Australian International Research Network on Conversion and Energy Storage (IRN-FACES). The authors also acknowledge the Australian National Fabrication Facility (ANFF) SA node for supporting the electroanalytical and electrochemical synthesis labs at Flinders University.
Converting a low-cost industrial polymer into organic cathodes for high mass-loading aqueous zinc-ion batteries
New 'PVDF alternative battery binder' surpasses EU environmental regulations!
National Research Council of Science & Technology
image:
The research results of KERI's 'PVDF Replacement Battery Binder Technology' have been published as the cover article in the prestigious journal ‘Advanced Functional Materials’.
Credit: Korea Electrotechnology Research Institute
A team led by Dr. Hyeon-Gyun Im and Dr. Dong Jun Kang from the Insulation Materials Research Center of Korea Electrotechnology Research Institute (KERI), in collaboration with Dr. Jung-keun Yoo from KIST and Professor Jong-soon Kim from Sungkyunkwan University, have developed a technology that enhances the performance of binders—often the 'unsung heroes' in the field of secondary batteries—while using environmentally friendly materials. This technology has been published in a prestigious international journal.
The electrode, which has the greatest impact on the performance of secondary batteries, is manufactured by mixing an 'active material' that generates electricity, a 'conductive material' that facilitates the flow of electricity, and a 'binder' with a solvent. The role of the binder is to help the active material and conductive material adhere well to the metal plate (current collector) and to physically stabilize the electrode.
The binder has a relatively small proportion in the electrode, which has led to slower research progress in the past. However, with the increasing demand for high-capacity and high-performance batteries, interest in binders is growing. Currently, Polyvinylidene Fluoride (PVDF), a fluoropolymer material, is predominantly used as the binder material for lithium-ion battery positive electrodes. However, PVDF is dominated by some global companies in Japan and Europe, and there have been ongoing functional issues, such as decreased battery stability, associated with its use.
Specifically, PVDF is composed of a very strong carbon-fluorine (C-F) bond and is almost indestructible in nature, earning it the nickname 'zombie compound.' Due to its difficulty in decomposition, it remains in the environment for extended periods and is known to emit significant amounts of greenhouse gases when burned. Due to these environmental concerns, the European Union (EU) is considering regulating the use of PVDF. Therefore, the development of binder materials that surpass PVDF is extremely urgent.
KERI has addressed this issue by applying 'siloxane' to positive electrode binders. Siloxane is a compound composed of silicon and oxygen, known for its excellent electrical properties and chemical stability. Dr. Hyeon-Gyun Im and Dr. Dong Jun Kang’s team has secured a 'hybrid siloxane resin manufacturing technology' that combines the advantages of both organic and inorganic materials* through years of research on nanocomposites. They have also developed molecular structure design and synthesis control technologies applicable to positive electrode binders. * Organic and Inorganic Materials: In chemical structure, if a material lacks carbon atoms, it is classified as inorganic; if it contains carbon atoms, it is classified as organic. Inorganic materials are known for their strength and durability, making them suitable for use in aircraft parts and construction materials. Organic materials, due to the numerous bonds formed by carbon atoms, have complex molecules and exhibit a variety of physical properties (such as resistance and elasticity). Because of these characteristics, organic materials are widely used in electronics, clothing, and other products.
The research team conducted multiple validations by producing full cells using the applied technology. As a result, it was confirmed that the KERI technology exhibits over 1.4 times higher lifespan stability compared to conventional binders with PVDF. While PVDF is known for its physical and chemical stability and good adhesion properties, it has faced issues such as swelling and unwanted side reactions between internal materials as batteries have progressed toward higher capacity and performance. However, KERI's technology has surpassed these limitations.
The major advantage of this achievement is that it does not contain fluorine, making it environmentally friendly and safe for human health. The new technology is expected to not just avoid the EU's environmental regulations aimed at limiting the use of PVDF but significantly contribute to reducing the reliance on imported positive electrode binders.
Dr. Hyeon-Gyun Im from KERI stated, "While Korea’s battery industry is world-class, we currently rely entirely on imports for positive electrode binders due to the lack of specialized technology and companies domestically. Our environmentally friendly binder technology using siloxane has the potential to replace existing PVDF and enhance the safety and lifespan of products requiring high-capacity batteries, such as electric vehicles."
Additionally, the research results have been recognized for their excellence and were recently published as a back cover article in the prestigious journal ‘Advanced Functional Materials’. The “JCR Impact Factor” of the journal is 18.5, ranking in the top 5% of the field.
The research team anticipates that this achievement will attract significant interest from the secondary battery industry and plans to identify potential demand partners to facilitate technology transfer. Furthermore, they plan to apply the developed technology to dry positive electrode binder materials and continue research to extend its use to various areas, including zinc batteries and sodium batteries.
KERI has developed a battery positive electrode binder that can replace PVDF using siloxane.
KERI researchers are developing a battery positive electrode binder that can replace PVDF using siloxane.
Credit
Korea Electrotechnology Research Institute
<KERI is a government-funded research institute under the National Research Council of Science & Technology of the Ministry of Science and ICT.>
In the face of the global biodiversity crisis, more and more biobanks are being set up to safeguard and potentially restore genetic diversity. Preserved tissue or cells allow scientists and conservationists to overcome spatial and even temporal fragmentations of dwindling wildlife populations and employ assisted reproduction technologies – as long as biobanks can be used in a safe and ethically appropriate manner. In a new scientific paper in the journal “Cryobiology”, the BioRescue team systematically evaluates these ethical considerations related to, among others, animal welfare, sample ownership and good scientific practice. The team also presents a modification of its “ETHAS” tool as a clear, easy-to-adopt and standardised technique for a structured and organised ethical assessment and decision making in the context of biobanking.
Together with recent advances in assisted reproduction technologies (ART), biobanks promise to be a technique of last resort for maintaining genetic diversity in dwindling wildlife populations and even for saving species from the brink of extinction. For example, the rescue mission for the northern white rhinoceros (the BioRescue project) relies both on new developments of techniques such as oocyte collection, in vitro fertilisation, embryo transfer and stem cell differentiation for rhinos, and on the possibility to safely store egg cell, semen or tissue samples in liquid nitrogen. Biobanking is a guarantee to have biomaterial at the team’s disposal to develop these new techniques and employ them at suitable places and times. “We can bring together semen collected 20 years ago in North America with oocytes which were freshly collected in Kenya, create embryos in Italy and store them again in liquid nitrogen until we can transfer them into a surrogate mother”, says BioRescue project head Prof Thomas Hildebrandt from the German Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW). “None of that would be possible without cryostorage, so we are in fact building and using an icy bridge across space and time and overcome the severe fragmentation of the species’ genetic heritage for our mission.”
However, these new technological possibilities raise new ethical questions, which the BioRescue team has addressed by adjusting and extending its Ethical Assessment tool for ART procedures “ETHAS” to biobanking. “If we establish new opportunities for conservation by the use of new technologies such as biobanking, we need to ensure that we make wise and transparent decisions for the environment and the ecosystem, for the welfare of the animals involved, for society and its institutions and regulations, as well as for good scientific practice”, says Prof Barbara de Mori of Padua University, who heads the ethical research pillar in BioRescue. This includes issues such as
how to select biomaterial that is stored in so-called genome research banks (GRBs) – to avoid a skewed representation of individuals and species for a broader conservation perspective;
how to ensure the welfare of all animals involved – from the individuals from which samples are obtained to the individuals that will carry the preserved genetic information or act as surrogates in the context of ART;
how to deal with ownership and benefit sharing when established storage and relatively easy transport opens doors to potentially exploitative parachute science – exporting biological and cultural heritage and generating profit at the expense of local communities with no benefits to these communities.
“Last but not least we need to make sure that we meet high scientific and material standards, prevent misuse, conduct our research and conservation activities with the required transparency and listen carefully to societal stakeholders in complex ethical questions of what should be done”, sum up Hildebrandt and de Mori.
To help address these issues within scientific projects for conservation, BioRescue modified the established ethical assessment tool ETHAS so that it can be applied to biobanking of various types of biomaterial such as tissue, reproductive cells and embryos as well as cell cultures. “ETHAS is a checklist-based, systematic self-assessment tool that covers environmental ethics, animal welfare ethics, social ethics and research ethics of biobanking procedures”, explains Dr Pierfrancesco Biasetti, scientist at the Leibniz-IZW. “ETHAS connects and integrates all ethical and regulatory considerations into a single framework and thereby provides a clear, relatively easy-to-adopt and standardised method for structuring and organising ethical analysis and ethical decision making.” The goal is to ensure the highest ethical standards possible with a practical tool that can be incorporated in standard operating procedures.
The ethical evaluation of biobanking activities remains in its infancy, the BioRescue team sums up in the scientific paper; as does the integration of GRBs into the management of species of conservation concern. There is a pressing need not only to enhance ethical training for conservationists and biobanking practitioners but also to facilitate the establishment of GRBs as a pivotal strategy in supporting species conservation objectives. The collection and storage of samples and the development of living cell lines could then be seen as an integral part of routine conservation efforts rather than as exceptions – as should be its ethical evaluation.
Leipzig/Bremerhaven. Extremely clean air on the ground, warm air intrusions and sulphate aerosol at high altitudes - a Leipzig research project has gained new insights into clouds in Antarctica. From January to December 2023, the vertical distribution of aerosol particles and clouds in the atmosphere above the German Neumayer Station III of the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) was investigated from the ground for the first time. The height-resolved measurements were the first of their kind in Queen Maud Land, the area of the Antarctic that borders the Atlantic and covers an area larger than Greenland.
The observations were performed with the OCEANET-Atmosphere platform from the Leibniz Institute for Tropospheric Research (TROPOS). OCEANET-Atmosphere demonstrated its robustness already while it was drifting in the Arctic for a whole year on the RV Polarstern during the international MOSAiC expedition 2019/20. During the 12 months of operation in Antarctica, the platform was supervised on-site by TROPOS scientist Martin Radenz. Initial results have now been published in the renowned journal Bulletin of the American Meteorological Society (BAMS). The measurements were funded by the German Research Foundation (DFG) and carried out in close co-operation with the AWI.
The Antarctic continent and the Southern Ocean are important components of the global climate system. While Antarctica's climate was considered relatively stable in the last century, significant changes are now being observed. Climate projections indicate that the interior of the Antarctic will warm by more than 3 Kelvin, the sea ice extent will decrease by around 30 per cent and precipitation will increase in the 21st century. However, such projections are subject to major uncertainties and the global atmospheric circulation models are not yet able to correctly reproduce the cloud cover and radiative forcing over the Southern Ocean. This incorrect representation of clouds leads to distorted estimates of thermal radiation and sea surface temperature, which are a prerequisite for estimating the energy fluxes between the ocean and atmosphere. In addition, in order to be able to document any change in an environment, such as Antarctica, also its current state needs to be documented as good as possible.
Gaining knowledge about cloud formation in Antarctica is an essential need, as this takes place differently in the clean air of the southern hemisphere than in the northern hemisphere with more abundant land surfaces. A second major source of uncertainty is the transport of moisture and particles from the mid-latitudes and subtropics to the pole. The relatively flat surface between the Weddell Sea and the South Pole might be a kind of highway for warm and humid air masses.
In order to learn more about the clouds in Antarctica, the instrumentation at the German research station Neumayer III of the AWI were supplemented by remote-sensing measurements such as an atmospheric lidar and a cloud radar for around a full year in the framework of the project COALA (Continuous Observations of Aerosol-Cloud Interactions in the Antarctic). The importance of the project was well recognized by the priority program ‘Antarctic Research’ of the German Science Foundation (Deutsche Forschungsgemeinschaft, DFG), which provided the funding for the endeavour. Carrier of the instrumentation was the TROPOS OCEANET-Atmosphere container. The platform had previously drifted through the Arctic for a year on RV Polarstern during the MOSAiC expedition led by AWI in 2019/20. " The MOSAiC observations allowed us to show for the first time that the atmosphere at the North Pole is more polluted than previously assumed. But what about over the Antarctic? Fortunately, we had the opportunity to operate our OCEANET container there for a year," explains Dr Ronny Engelmann from TROPOS. OCEANET was installed 300 meters south of the German Antarctic Neumayer Station III at the beginning of 2023. OCEANET-Atmosphere is an autonomous, polar-tested, specially equipped 20-foot container packed with state-of-the-art atmospheric observation equipment. It is currently the only polar-capable single container platform that combines multiwavelength lidar, a cloud radar, a microwave radiometer, and a Doppler lidar to observe clouds and aerosols, including turbulent air motions.
OCEANET was supplied with power from the research station, where the researcher from Leipzig also lived and spent a year making sure that all the devices measured without interruption: Dr Martin Radenz from TROPOS joined the station's core team. He was one of the 10 people who spent the winter in the dark polar night at Neumayer Station III. "Being able to spend a year in Antarctica with the community of our small team, the fascinating nature, snowstorms and isolation was a unique experience," reports Martin Radenz. The green laser beam of the multiwavelength lidar, which scanned the atmosphere above Neumayer Station III, was a novelty in this part of Antarctica. A lidar, also known as a "light radar", sends short laser pulses from the ground into the atmosphere and receives the backscattered light with a special receiver. Information about the height, quantity and type of suspended particles (aerosols) in the atmosphere can be derived from the travel time, intensity and polarisation of the backscattered signals. To date, related measurements with cloud radar and aerosol lidar have only been carried out at McMurdo station on the other side of Antarctica, 3500 kilometres away, bordering the Pacific Ocean. Contrary to Neumayer III on the ice shelf, the US McMurdo station there is built on rock. The researchers also hope that the measurements taken at Neumayer Station III over ice shelves will provide them with new insights into cloud formation over the vast expanses of ice in the Antarctic. "It is particularly pleasing that, following COALA, the AWI now permanently deploys similar remote sensing devices at Neumayer Station III in cooperation with TROPOS. This will make an important contribution to recording the short-lived climate components aerosols and clouds in the Antarctic," says Prof Andreas Macke, Director of TROPOS and Head of the "Remote Sensing of Atmospheric Processes" department.
In January 2024, the OCEANET container was dismantled, transported to the edge of the ice shelf and loaded onto the resupply vessel. The devices arrived in Leipzig in March, the DFG COALA project was completed and the researchers took stock: "All the devices held out and recorded valuable data. We are particularly pleased about this because it would have taken months for a replacement part to arrive during the polar night. Our experience from the MOSAiC expedition three years earlier in the Arctic was a great help. Nevertheless, it was a real challenge to make the devices storm-proof and clean them of snow almost every day," reports Martin Radenz. For Radenz and his team, however, the effort was worth it. The measurements provided three new insights into the Antarctic under climate change:
Atmosphere only clean close to the surface The lidar measurements provided an insight into how many particles are floating above this part of Antarctica and at which altitudes. The lower part of the atmosphere (troposphere) with pristine conditions was mostly comparatively clean. In contrast, the team observed an unexpectedly large number of particles between an altitude of around 9 km and 17 km (stratosphere). "The optical properties of the aerosol derived from the lidar clearly indicate sulphate aerosol, which is mainly caused by volcanic eruptions. These aerosols were observed in the stratosphere since January 2023 and are therefore most likely related to the eruption of Hunga Tonga-Hunga Ha'apai in January 2022," says Martin Radenz. "The fact that volcanic dust can persist for a very long time over the south polar region surprised us just as much as the forest fire smoke over the north polar region, which we were able to observe for the first time during the MOSAiC expedition in 2020," reports Ronny Engelmann. The lidar measurements from the ground are particularly important, as the volcanic aerosol over Antarctica has apparently not been observed sufficiently from space before. At least no aerosol was detectable in the standard products of NASA's CALIOP satellite lidar. Aerosol in the stratosphere has an influence on the occurrence of polar stratospheric clouds (PSCs), where complex chemical processes take place and which are suspected of contributing to the hole in the ozone layer over the polar regions.
Aerosol-cloud interaction in shallow mixed-phase clouds While more aerosol was observed in the upper layers of the atmosphere than expected, the lower layers proved to be about as clean as assumed. The continuous measurements enabled the team to "watch" the clouds grow. For example, a stable mixed-phase cloud consisting of ice crystals and water droplets embedded in a layer of marine aerosol was observed for a period of 10 hours. "Our measurements confirm that practically all particles serve as cloud nuclei, to either form cloud droplets or ice crystals. Cloud growth is therefore limited by the amount of particles. If there were more particles, for example because more polluted air flows into the Antarctic, then there would also be more droplets and ice crystals in the clouds, which would change their lifespan and lead to yet unknown effects on weather and climate," explains Dr Patric Seifert from TROPOS.
Unusual warm air intrusions Warm air from lower latitudes could intensify climate change in Antarctica. It was therefore important to be able to analyse two extreme warm air intrusions in detail: One with intense snowfall in April, which brought 10 per cent of the snowfall of an entire year, and a second with record-breaking maximum temperatures and heavy ground icing due to supercooled drizzle in July. During this warm spell, the temperature rose to -2.3 degrees Celsius on 6 July 2023. "This is the highest temperature recorded in July at the German Antarctic Neumayer Station since continuous observations began in 1982. This means that it has never been so warm there in the middle of the polar night, the peak of the Antarctic winter," explains Martin Radenz. These unusually high temperatures led to supercooled drizzle. On the surface, a layer of clear ice of around 2 millimetres formed on top of the snow from the previous day. "What often happens here in Central Europe in winter is very unusual for the Antarctic during the dark polar night. Normally, temperatures at Neumayer Station III are below -30 degrees Celsius in July. Our observations over ice shelves are the first of their kind," emphasizes Radenz.
It took not long until the value of the remote sensing measurements was also recognized by the Alfred Wegener Institute that operates the Neumayer station. The deployment of OCEANET-Atmosphere was only the start of a long-term time series of profile measurements in this part of Antarctica: at the beginning of 2024, the Alfred Wegener Institute expanded the permanent observation capacities with a lidar and radar, thus ensuring that the unique OCEANET data set is continued. “The long-term climatology of aerosol and cloud parameters for the Neumayer station will thus be permanently extended to the vertical dimension," explains Dr Holger Schmithüsen from AWI.
The provision of an overview of the obtained results in the BAMS journal demonstrates the potential of the 1-year dataset for shedding light on the still barely characterized properties of clouds and aerosols above Antarctica. “But the BAMS article only provides a first glimpse into the highlights obtained during the measurements. Detailed statistics and process studies will follow in a subsequent step,” says Radenz. Over the next few months, the extensive data from Antarctica will be further analysed and compared with existing data sets from southern Chile, Cyprus, Germany and the Arctic. The researchers hope to gain new insights into why the clouds in the far south differ so much from those in the northern hemisphere. Plenty of datasets from key-regions of climate research are available for a comparison. As part of the DFG Transregio "Arctic Amplification" (AC3-TR), TROPOS has been investigating clouds in the Arctic together with the University of Leipzig since 2016. In addition, processes in the southern hemisphere have also become the focus of attention in recent years: in 2016/17, cloud researchers from Leipzig took part in the international Antarctic circumnavigation ACE. In 2018-2021, extensive measurements took place in southern Chile. Two major measurement campaigns in and around New Zealand are currently being prepared for 2025 and 2026: goSouth at the southern tip of the South Island, accompanied by HALO-South with the German research aircraft HALO and an expedition around New Zealand with the research vessel Sonne are the placemarks of the next series of experiments under the lead of TROPOS. "TROPOS is about to contribute important novel insights for improving the understanding of aerosol-cloud-climate processes in the clean and maritime southern hemisphere," concludes Prof Andreas Macke.
Tilo Arnhold
Twilight over Antarctica.
Credit
Martin Radenz, TROPOS
COALA-3 (IMAGE)
Leibniz Institute for Tropospheric Research (TROPOS)
Aurora Australis above the OCEANET container at the German research station Neumayer III in Antarctica.
Ground-Based Remote Sensing of Aerosol, Clouds, Dynamics, and Precipitation in Antarctica: First Results from the 1-Year COALA Campaign at Neumayer Station III in 2023
New method in the fight against forever chemicals
ETH Zurich
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The piezoelectric nanoparticle acts as a catalyst and initiates a chemical reaction: 90.5 % of the PFOS molecule is degraded and 29 % is defluorinated.
What do firefighting foam, non-stick cookware, water-repellent textiles and pesticides all have in common? They all contain per- and polyfluoroalkyl substances, or PFAS – human-made chemicals that don’t break down naturally. It’s no wonder, then, that PFAS are now contaminating soil and water and can also be detected in the bodies of humans and animals. The dangers are well known: these forever chemicals can damage the liver, trigger hormonal disorders and cause cancer, to mention just a few of their effects.
Researchers in the group under Salvador Pané i Vidal, Professor at ETH Zurich’s Institute of Robotics and Intelligent Systems, have developed a new method to break down a subgroup of PFAS called perfluorooctane sulfonates, or PFOS. Due to their toxicity, PFOS are now severely restricted or even banned. “The main problem is that the molecules consist of long carbon chains surrounded by fluorine atoms. This carbon-fluorine bond is so strong that you need a lot of energy to break it,” says Andrea Veciana, a doctoral student of Pané i Vidal’s.
Breaking down molecules with ultrasound and nanoparticles
To break up the PFOS molecules and thus degrade them in water, the researchers used piezocatalysis for the first time. “Piezo” refers to piezoelectricity, an electrical charge that is generated during mechanical deformation, and “catalysis” means accelerating a chemical reaction with suitable substances. “We’ve developed nanomaterials that are piezoelectric. To the naked eye, this material looks a bit like sand,” Veciana says. In the ultrasonic bath, these particles become electrically charged and act as a catalyst. Pané i Vidal adds: “It’s this electrical charge that sets the whole chain of reaction in motion and breaks down the PFOS molecules piece by piece. That’s why the nanoparticles are called piezoelectric.”
To measure the PFOS concentration in their samples, the researchers worked with Samy Boulos, analytical specialist from the Laboratory of Food Biochemistry. Using a mass spectrometer, the researchers were able to prove that 90.5 percent of the PFOS molecules were degraded. “However, we should point out that we were working with a very high concentration of 4 milligrams per litre,” Veciana says. “In the natural world, such as in lakes and rivers, the PFOS concentration is less than 1 microgram per litre. And the lower the concentration, the longer it takes for the PFOS to degrade.” Some of the technologies currently in development first concentrate the water and then destroy the PFOS. This would also be a key step in the piezocatalysis, one that would have to be implemented in a specific application such as a chemical industry effluent.
Better than previous methods
The potential of the new method becomes clear when considering the existing options for degrading PFAS. “One method is thermal decomposition, but that requires a temperature of over 1,000 degrees Celsius, which makes it highly energy intensive,” Veciana says. PFAS can also be degraded by photocatalysis. This process is similar to piezocatalysis but uses light for activation of the catalyst instead of mechanical energy. The main problem with this method is that in practice, the objective is to treat wastewater, and since wastewater is cloudy, there is a low light penetration. Veciana mentions a third method: “There’s also absorption, where you use a kind of sponge to soak up the pollutants from the water. But this merely shifts the problem from one place to another; now you need a solution for the PFAS-permeated sponge.”
The disadvantages of the existing methods were one of the reasons the ETH researchers went looking for a new way to break down PFAS. Piezocatalysis has the advantage of being able to work with different sources of mechanical energy. “If water has to be purified in wastewater treatment plants and there’s already turbulence in the water, that energy could perhaps be harnessed to break down the PFAS in it,” Veciana says.
Combating PFAS together
Unfortunately, what the researchers have achieved in the laboratory with water samples of 50 millilitres hasn’t yet been transferred into practice. “The scalability of our method is one of the biggest challenges,” Pané i Vidal says. “However, we’ve succeeded in showing that piezocatalysis works as a method for degrading PFOS and has advantages over previous methods.” Furthermore, their method can not only be used on PFOS, but on any other PFAS and micropollutant.
In general, methods for degrading PFAS should be used before the chemicals get into the environment, i.e. in industrial wastewater treatment plants, or on collected agricultural water for reuse. “Companies should take all possible measures to ensure that the water they release into the environment is as clean as possible,” Pané i Vidal says. Veciana adds: “PFAS are a global problem that should be tackled first and foremost through policy change and more transparency.” There’s already a lot of media coverage about a PFAS ban and stricter regulations to force the industry to be more transparent about the use of these chemicals. Veciana says: “Nevertheless, it’s also important to continue to innovate through research in order to reduce and remediate the existing exposure to PFAS as much as possible.”
Reference
Veciana A, Steiner S, Tang Q, Pustovalov V, Llacer-Wintle J, Wu J, Chen X, Manyiwa T, Ultra Jr. V, Garcia-Cirera B, Puigmartí-Luis J, Franco C, Janssen D, Nyström L, Boulos S, Pané S: Breaking the Perfluorooctane Sulfonate Chain: Piezocatalytic Decomposition of PFOS Using BaTiO3 Nanoparticles. Small Science 2400337. 28 August 2024, doi: 10.1002/smsc.202400337
Breaking the Perfluorooctane Sulfonate Chain: Piezocatalytic Decomposition of PFOS Using BaTiO3 Nanoparticles
Characterization of microbial structure and function in the rhizosphere of Boehmeria nivea L.：A comparative study of volcanic cone and crater
Higher Education Press
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a shows the relative abundance of phyla bacteria and fungi based on circular visualization (Circos). b shows the taxonomic characteristics of asv microbial community composition between the two sites based on the Manhattan map. The structural equation model (SEM) in c shows the direct and indirect effects of nivea rhizosphere microbial versatility in volcanic cones and craters.
Credit: Jin Chen, Yiming Zhang, Qingchen Xiao , Boyan Wang, Zishan Li, Keqing Lin, Xiaowan Geng, Xiaoyu Li
Volcanic activity alters the Earth's surface and promotes the development of new ecosystems, providing valuable models for studying soil formation processes such as microbial composition and vegetation succession. Increasing evidence suggests that soil microbes are pivotal in numerous ecological and biogeochemical processes, encompassing carbon mineralization, humus formation, and nutrient cycling. Given the intricate and dynamic interactions between soil properties, plant life, and soil microbial communities, a comprehensive understanding of soil microbial communities is critical to improving our understanding of ecosystem processes. The study shows that the rhizosphere microbial communities of volcanic Boehmeria nivea L. in Nvshan, Anhui Province shows significant spatial differences in diversity, structure, and function. Volcanic soil plays a key role in the formation of microbial community diversity and subsequently influences the diversity of microorganisms residing in the rhizosphere of ramie. The researchers’ finding appeared July 26, 2024 in Soil Ecology Letters.
Li Xiaoyu's team at Anhui Agricultural University conducted a series of studies on different sites of rhizosphere microbial communities in volcanic B. nivea, and obtained many interesting findings. For example, their findings suggest that fungal communities show greater vulnerability to changes in geography and environment. In addition, there were differences in the structural and functional diversity of the rhizosphere microbial communities in volcanic pits and volcanic cones, suggesting that the rhizosphere microbial communities were mainly affected by volcanic sites.
Professor Chen said: "We chose to study the Nvshan region in Anhui Province, a dormant volcano recognized globally as one of the best preserved ancient craters, located in the subtropical monsoon climate zone, with an average annual precipitation of 939.9 mm and an average annual temperature of 15 °C. The Nvshan volcanic area has obvious geomorphic features, including craters, lava platforms, lava flows and volcanic cones. The volcano has experienced many eruptions during its geological evolution, forming its unique landform landscape. Therefore, Nvshan Volcano provides a suitable, high-quality platform for the study of volcanic activity and environmental disturbances, and B. nivea, as a plant of important economic and ecological value, plays a key role in its rhizosphere microbial community."
In this study, they found that it was easier to support bacteria rather than fungi at various sites in the rhizosphere soil of B. nivea, a phenomenon that could be attributed to increased disturbance intensity, which could lead to the disappearance of rare fungal species and thus a decline in biodiversity. The Zi-Pi chart illustrates the critical role of key species one step supports this observation, showing that the proportion of bacterial generalist species is higher than that of fungi in both the crater (15.5% vs. 11.7%) and the cone (19.2% vs. 13.9%). Actinomycetes and Acidobacteria dominate the bacterial community, while ascomycetes and basidiomycetes dominate the fungal community. Actinomycetes play a crucial role in the breakdown of humus because they have multiple enzyme-mediated degradation capabilities and are able to thrive under nutritionally restricted conditions. In contrast, fungi show a greater ability to break down complex organic polymers, such as polyphenols, hemicellulose, and refractory cellulose, compared to bacteria.
Professor Chen added: "We also used RMT random matrix theory to establish bacterial and fungal co-occurrence networks to study cooccurrence patterns of microbial communities in volcanic pits and cones." Compared to bacterial networks, fungal networks have a more complex microbial community structure with greater modularity, with tightly connected nodes. Compared with crater, cone has lower avgCC value and higher avgK value in their respective bacterial networks. However, in its respective fungal networks, the cone had lower avgK and avgCC values, suggesting that it reduced the complexity of microbial symbiosis. In addition, based on the SEM results, we found that the influence of microbial α diversity on microbial versatility was more obvious than that of microbial β diversity. The α diversity of microorganisms in craters has a direct and positive impact on their respective multifunctional capabilities.
“By investigating the impact of volcano on rhizosphere microbial community of ramie, the mechanism of volcanic activity on soil ecosystem can be deeply understood, and scientific basis can be provided for the protection of ecological environment around volcano and rational use of land resources. In addition, the research on rhizosphere microbial community of ramie is helpful to explore the mechanism of microbial action in plant growth and soil ecosystem, and provide theoretical support and technical guidance for agricultural production and soil health management."
