Tag: water

EBS flux reveals fate of over-compressed water

EBS flux reveals fate of over-compressed water

ESRF users have exploited the high X-ray flux of the EBS to confirm that water freezes into a particular ‘cubic’ form of ice when it is compressed very quickly. Published in Nature Communications, the results clear up a long-standing mystery in high-pressure physics, and will provide insights into the composition of the Solar System’s icy moons.

Water is so familiar to us that the ancients considered it one of the four basic elements. To modern physicists, however, it is a marvel – a liquid that, unlike almost all others, becomes not easier but harder to solidify at high pressures and, when it does solidify, expands rather than contracts. The behaviour results from the way the constituent hydrogen atoms bond with one another, and is vital for life. Without it, lakes and seas would freeze from the bottom up, killing everything inside.

In fact, the freezing of water is even more complicated than this. Under various pressures and temperatures, water is known to form at least 19 distinct phases of ice. The one we know well on Earth has its oxygen and hydrogen atoms in hexagonal rings. On the other hand, the most common phase in the Universe is likely to be a type of low-density amorphous ice, without any long-range crystal structure at all. Another very common phase with big scientific interest is the cubic-bonded ice VII, which is stable over a vast pressure range from 2 to 80 gigapascals, equivalent to those present on icy planets and moons.

The gateway to ice VII may be higher pressures, but the speed of compression is critical. Take it slowly, and normal water freezes at about one gigapascal into ice VI, a tetrahedral phase, before forming ice VII at about 2 gigapascals. Go faster, though, and the freezing is waylaid, occurring at higher and higher pressures.

Until now, no-one has been sure what water ultimately freezes into when it is compressed very quickly. The answer is important, because the freezing of water on other planets and moons could have taken place when it was over-compressed during planetary impact.

Charles Pépin, Paul Loubeyre  and colleagues at the CEA Laboratory for Materials at Extreme Conditions at the Université Paris-Saclay in France, together with scientists at the ESRF in France and the Paul Scherrer Institute (PSI) in Switzerland, have finally solved the mystery using a range of cutting-edge instrumentation for time-resolved X-ray diffraction.

One part of the toolkit was a special “dynamic-piezo” diamond anvil cell (d-DAC), designed by the CEA team to compress water in a well-controlled manner. Another was the latest Jungfrau detector – the result of a joint PSI–ESRF development – which can record an X-ray image every few microseconds. Most importantly, however, was the extremely high flux of X-rays streaming through the ID09 beamline, provided by the EBS.

Read more at ESRF beamline

Mechanism behind the enormous density increase in highly-compressed liquid water

Mechanism behind the enormous density increase in highly-compressed liquid water

Researchers reveal details behind the microscopic mechanism that enables the large increase of density in compressed water using experimental data from the ESRF and first principles simulations.

Water is one of the most ubiquitous substances and essential for all forms of life on Earth. Its many thermodynamic anomalies render water one of the most extraordinary liquids known to mankind. Yet, after decades of intense research, the structural details at atomic length scales underlying these anomalies remain unclear.

An example of the strange behaviour of water is its density, which is highest at 4 C. This heavily affects water’s buoyancy and impacts ocean circulation and climate patterns. Likewise, water’s low density ice phase, common ice Ih, is less dense than liquid water, a fact that is vital for aquatic life and the stability of our ecosystems. Pressure is one of the fundamental experimental parameters and is often used by researchers to observe a system’s respond to it, yielding invaluable information about the interactions between atoms and molecules at play.

Now an international team of scientists lead by the ESRF have studied pressurized water in its liquid state at atomic length scales. “There is still a lot of controversy as to how hydrogen bonding between water molecules evolves under pressure, so our study aimed to shed light on this question”, explains Christoph Sahle, scientist in charge of beamline ID20 and co-corresponding author of the publication.

Read more on ESRF website

Effective and environmentally friendly removal of pharmaceuticals from wastewater under visible light

Effective and environmentally friendly removal of pharmaceuticals from wastewater under visible light

The research team working under the leadership of Prof. Anna Zielińska-Jurek from the Faculty of Chemistry at Gdańsk University of Technology, in cooperation with scientists from ASTRA beamline, developed and characterized a new semiconductor material based on bismuth orthovanadate (BiVO4) and copper oxide sub-nanoclusters (CuOx). This material, when exposed to visible light, is able to effectively remove pharmaceuticals in water. Measurements made at the SOLARIS synchrotron using X-ray absorption spectroscopy (XAS) revealed the oxidation state of copper oxides. The research results were published in the journal “Separation and Purification Technology” from Elsevier publisher.

The rapid development of medicine and the pharmaceutical industry has made pharmaceutical pollution one of the greatest environmental dangers. Some of the most frequently detected pharmaceuticals in Polish sewage are naproxen, a popular painkiller, and ofloxacin, an antibiotic. These compounds, found in rivers, lakes or seas, are persistent and not susceptible to biological degradation, and conventional methods used in sewage treatment plants are insufficient to remove them.

A promising way to remove pharmaceuticals from the aqueous phase is their degradation in the process of heterogeneous photocatalysis supported by peroxymonosulfate ions (HSO5−, PMS). These processes are based on the generation of highly reactive radicals under sunlight, which, as a result of reaction with pollutants, are able to purify water.

Read more on Solaris website

Clays transport more water into the Earth’s interior than we thought

Clays transport more water into the Earth’s interior than we thought

Nobody knows how much water is contained in the Earth’s interior. It’s 6400 kilometres from the surface to the centre, but the deepest point we can get to is mere 12 kilometres, so most estimations are based on assumptions and extrapolations about the composition of our planet’s mantle and core. A study by a research team led by Yongjae Lee from Yonsei University (South Korea), conducted at PETRA III as well as at Pohang (South Korea) and the Advanced Photons Source at Argonne National Laboratory (USA), now shows that minerals might carry more water into the Earth’s deep mantle than previously assumed.

Water affects many properties of Earth’s interior: heat, deformation, volcanic and seismic activity and more. These in turn have a direct influence on life on Earth. Knowing more precisely how water distribution across the Earth began and how it has changed over the Earth’s 4.6 billion-year history might give us clues as to how it will evolve in the future.

Experiments performed at DESY’s synchrotron facility PETRA III, PLS-II at Pohang, South Korea and the Advanced Photons Source at Argonne National Laboratory, USA demonstrated that sediment minerals from Earth’s continents called clays can significantly influence the water household of the Earth’s interior. This study was conducted as part of an effort to understand how the subduction process that sends tectonic plates down to the mantle affects the global transport and distribution of water through changes in the water content contained in minerals composing the subducting plate.

The team of scientists led by Yongjae Lee from Yonsei University (South Korea) used a heated diamond anvil cell, an experimental device that can expose material to extremely high pressures and temperatures, for experiments to simulate the path clay minerals would take in a cold subduction zone, where one tectonic plate disappears into the mantle underneath another tectonic plate. They then studied the breakdown of those clays in detail. The study published in Nature Communications concludes that clays in subducting sediments are responsible for delivering up to 22% of the total water transported into the lower mantle, which is a significant amount and helps constrain the question of how much water could be in the Earth’s deep interior in total.

When continental rocks weather and break down they eventually transform into clay minerals. “Clays are layered sheet silicates that are easily transported to the ocean via rivers and make up the top most part of the oceanic plate. When these sediments are transported via tectonic movement to the edges of the continents and dive down into the Earth’s interior via the subduction process, they are exposed to elevated pressures and temperatures,” explains Yoonah Bang, lead author and former student at Yonsei University. One of the major minerals contributing to the clays in the sediments is the alumina-carrying silicate mineral called pyrophyllite (Al2Si4O10(OH)2), “Using a pressure cell consisting of resistively heated diamond anvils, we are able to simulate pressures of up to some 230,000 atmospheres and temperatures of 900 degrees Celsius to mimic the subduction path pyrophyllite will take when it dives down to the lower mantle” says Bang.

In cold subduction zones like those located in the west Pacific, pyrophyllite transforms to the minerals gibbsite (Al(OH)3) and diaspore (AlO(OH)) at a depth of some 135 kilometres. During this process, the minerals take up water from the surrounding hydrated slab and carry it down to a depth of 185 kilometres. From here sequential transformations take place to other water-bearing minerals that eventually drag the same amount of water initially contained in pyrophyllite to a depth of 700 kilometres in the lower mantle. “This shows how important it is to clearly understand the role of clay minerals during the subduction process,” explains Y. Lee, who led this work. “Our research implies that clay minerals such as pyrophyllite would have transported about 2~3% of global ocean water down to the lower mantle over 2.5 billion years.”

“The findings contribute to the overall understanding of the hydration of the Earth through its history”, says Hanns-Peter Liermann, leader of the ‘Extreme Conditions Beamline’ P02.2 at PETRA III, where part of the research was performed.

Read more on DESY website

Image: An illustration depicting that water contained in clay minerals is transported to the lower mantle through breakdown reactions along the subducting plate

Credit: Authors/Original Publication

First-ever X-ray attosecond experiment on liquids provides new insights into water’s molecular properties

First-ever X-ray attosecond experiment on liquids provides new insights into water’s molecular properties

Theorists explain how X-ray measurement freezes hydrogen motion, with implications on other areas of chemistry

An international team has performed an attosecond-scale experiment at an X-ray free-electron laser on liquid water for the first time, and the results may change our interpretation of water’s behaviour. The experiment team, led by scientist Linda Young from Argonne National Laboratory in the US, found an unusual signal when they examined liquid water using X-ray flashes that were timed a few hundred attoseconds (an attosecond is a billionth of a billionth of a second). A theory team led by Robin Santra, lead scientist at the research centre DESY and a professor at Universität Hamburg in Germany, and Xiaosong Li, a professor at the University of Washington in the US, used quantum-mechanical techniques for the analysis. Based on the data of the new experiment, they found that a longstanding measurement of the structure of liquid water has been misinterpreted. The effects of this finding not only demonstrate the potential of attosecond research on condensed matter at X-ray lasers, which is so far unprecedented, but also may require a rethink on how a wide range of molecules beyond water, especially organic ones, are structured. The findings have been published in the journal Science.

DESY’s experience and techniques were crucial in this result and form a cornerstone towards the future Centre for Molecular Water Science (CMWS) that DESY is setting up. The experimental and theoretical teams for this result comprise scientists from Argonne National Laboratory, the University of Washington, Pacific Northwest National Laboratory, Washington State University, the University of Chicago, and SLAC National Accelerator Laboratory, all in the US; and DESY, Universität Hamburg, and the Hamburg Cluster of Excellence “CUI: Advanced Imaging of Matter,” all in Germany.

Read more on DESY website

Image: Georgi Dakovski operating the LCLS ChemRIXS beamline, where the experiment was carried out during the pandemic

Credit: Linda Young

Understanding sensitive soils to improve quality of surrounding water

Understanding sensitive soils to improve quality of surrounding water

Researchers from the Swedish University of Agricultural Sciences in Uppsala are investigating the impact of phosphorous – both that which exists naturally in soil and that which has been added as manure or fertilizer – on sensitive soils and local aquatic systems.

Phosphorus is an essential nutrient for crops and a component of many fertilizers, including animal manure. While it’s critical for plant growth, too much can damage the quality of water bodies near farms. Phosphorus runoff increases the nutrients within aquatic systems that feed algal blooms, which can lead to a decrease in oxygenated water and a reduction of biological diversity in lakes. Algal blooms can impact human health and wildlife as well as the economies of affected communities reliant on fishing and tourism.

“The transfer of phosphorus from land to aquatic recipients is not equally distributed, meaning some parts of the landscape are more vulnerable,” says Faruk Djodjic, Associate Professor at the Department of Aquatic Sciences and Assessment. “By identifying those vulnerable soil profiles and targeting them with mitigation measures, we can improve water and soil quality.”

With the help of the Canadian Light Source (CLS) at the University of Saskatchewan (USask), Djodjic and his colleagues were able to analyze samples to better understand the composition of sensitive soils.

The beamline data from SXRMB helped the researchers identify important compounds that govern phosphorus absorption or release.

Read more on CLS website

Electrocatalysis – Iron and Cobalt Oxyhydroxides examined

Electrocatalysis – Iron and Cobalt Oxyhydroxides examined

A team led by Dr. Prashanth W. Menezes (HZB/TU-Berlin) has now gained insights into the chemistry of one of the most active anode catalysts for green hydrogen production. They examined a series of Cobalt-Iron Oxyhydroxides at BESSY II and were able to determine the oxidation states of the active elements in different configurations as well as to unveil the geometrical structure of the active sites. Their results might contribute to the knowledge based design of new highly efficient and low cost catalytical active materials.

Very soon, we need to become fossil free, not only in the energy sector, but as well in industry. Hydrocarbons or other raw chemicals can be produced in principle using renewable energy and abundant molecules such as water and carbon dioxide with the help of electrocatalytically active materials. But at the moment, those catalyst materials either consist of expensive and rare materials or lack efficiency.

Key reaction in water splitting

A team led by Dr. Prashanth W. Menezes (HZB/TU-Berlin) has now gained insights into the chemistry of one of the most active catalysts for the anodic oxygen evolution reaction (OER), which is a key reaction to supply electrons for the hydrogen evolution reaction (HER) in water splitting. The hydrogen can then be processed into further chemical compounds, e.g., hydrocarbons. Additionally, in the direct electrocatalytic carbon dioxide reduction to alcohols or hydrocarbons, the OER also plays a central role.

Read more on the HZB website

Image: LiFex-1Cox Borophosphates have been used as inexpensive anodes for the production of green hydrogen. Their dynamic restructuring during OER as well as their catalytically active structure, have been elucidated via  X-ray absorption spectroscopy.

Credit: © P. Menezes / HZB /TU Berlin

Water improves material’s ability to capture CO2

Water improves material’s ability to capture CO2

With the help of the Advanced Light Source (ALS), researchers from UC Berkeley and ExxonMobil fine-tuned a material to capture CO2 in the presence of water.

About 65% of anthropogenic greenhouse gas emissions comes from the combustion of fossil fuels in power plants. So far, efforts to capture CO2 from power-plant flue gases and sequester it underground have mainly focused on coal-fired power plants. However, in the United States, natural gas has surpassed coal in the amount CO2 released, despite the fact that natural gas emits approximately half as much CO2 per unit of electricity. Therefore, new materials are urgently needed to address this situation.

Not all combustion is alike

Compared to coal-fired power plants, natural gas combined cycle (NGCC) plants produce flue gases with low CO2 concentrations. This reduces the carbon footprint, but increases the technical difficulty of CO2 capture. Also, materials capable of adsorbing such low concentrations of CO2 often require high temperatures to release it for sequestration, an important part of the cycle that offsets initial low-carbon benefits. NGCC emissions also have a higher concentration of O2, which has a corrosive effect on adsorbent materials, and both NGCC and coal flue streams are saturated in water, which can both degrade materials and reduce efficiency. Thus, an effective NGCC CO2-capture material must selectively bind low-concentration CO2 under humid conditions while being thermally and oxidatively stable.

>Read more on the Advanced Light Source website

Image: Single-crystal x-ray diffraction enables the precise determination of the positions of the atoms in metal–organic frameworks (MOFs), highly porous materials capable of soaking up vast quantities of a specific gas molecule, such as CO2. This structure represents 2-ampd–Zn2(dobpdc), a MOF with the same structure as 2-ampd–Mg2(dobpdc), the subject of this study. Light blue, blue, red, gray, and white spheres represent Zn, N, O, C, and H atoms, respectively.

Scientists observe ultrafast birth of free radicals in water

Scientists observe ultrafast birth of free radicals in water

What they learned could lead to a better understanding of how ionizing radiation can damage material systems, including cells.

Understanding how ionizing radiation interacts with water—like in water-cooled nuclear reactors and other water-containing systems—requires glimpsing some of the fastest chemical reactions ever observed.

In a new study conducted at the Department of Energy’s SLAC National Accelerator Laboratory, researchers have witnessed for the first time the ultrafast proton transfer reaction following ionization of liquid water. The findings, published today in Science, are the result of a world-wide collaboration led by scientists at the DOE’s Argonne National Laboratory, Nanyang Technological University, Singapore (NTU Singapore) and the German research center DESY.

The proton transfer reaction is a process of great significance to a wide range of fields, including nuclear engineering, space travel and environmental remediation. This observation was made possible by the availability of ultrafast X-ray free electron laser pulses, and is basically unobservable by other ultrafast methods. While studying the fastest chemical reactions is interesting in its own right, this observation of water also has important practical implications.

>Read more on the LCLS at SLAC website

Image: X-rays capture the ultrafast proton transfer reaction in ionized liquid water, forming the hydroxyl radical (OH) and the hydronium (H3O+) ion. Credit: Argonne National Laboratory

Record-shattering underwater sound

Record-shattering underwater sound

Researchers produced an underwater sound with an intensity that eclipses that of a rocket launch while investigating what happens when they blast tiny jets of water with X-ray laser pulses.

A team of researchers has produced a record-shattering underwater sound with an intensity that eclipses that of a rocket launch. The intensity was equivalent to directing the electrical power of an entire city onto a single square meter, resulting in sound pressures above 270 decibels. The team, which included researchers from the Department of Energy’s SLAC National Accelerator Laboratory, published their findings on April 10 in Physical Review Fluids.
Using the Linac Coherent Light Source (LCLS), SLAC’s X-ray laser, the researchers blasted tiny jets of water with short pulses of powerful X-rays. They learned that when the X-ray laser hit the jet, it vaporized the water around it and produced a shockwave. As this shockwave traveled through the jet, it created copies of itself, which formed a “shockwave train” that alternated between high and low pressures. Once the intensity of underwater sound crosses a certain threshold, the water breaks apart into small vapor-filled bubbles that immediately collapse. The pressure created by the shockwaves was just below this breaking point, suggesting it was at the limit of how loud sound can get underwater.

>Read more on the LCLS at SLAC website

Image: After blasting tiny jets of water with an X-ray laser, researchers watched left- and right-moving trains of shockwaves travel away from microbubble filled regions.
Credit: Claudiu Stan/Rutgers University Newark

Illuminating Water Filtration

Illuminating Water Filtration

Researchers using ultrabright x-rays reveal the molecular structure of membranes used to purify seawater into drinking water.

For the first time, a team of researchers from Stony Brook University and the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory have revealed the molecular structure of membranes used in reverse osmosis. The research is reported in a recently published paper in ACS Macro Letters, a journal of the American Chemical Society (ACS).
Reverse osmosis is the leading method of converting brackish water or seawater into potable or drinking water, and it is used to make about 25,000 million gallons of fresh water a day globally according to the International Water Association.
“Most of the earth’s water is in the oceans and only three percent is fresh water, so water purification is an essential tool to satisfy the increasing demand for drinking water,” said Brookhaven Lab senior scientist Benjamin Ocko. “Reverse osmosis is not a new technology; however, the molecular structure of many of the very thin polymer films that serve as the barrier layer in reverse osmosis membranes, despite its importance, was not previously known.”

>Read more on the NSLS-II website

Image: Qinyi Fu, Francisco J. Medellin-Rodriguez, Nisha Verma, and Benjamin Ocko (from left to right) prepare to mount the membrane samples that mimic the membranes used in reverse osmosis for the measurements in the Complex Materials Scattering (CMS) beamline at the National Synchrotron Light Source II (NSLS-II).

HIPPIE provides a closer look at water filtration

HIPPIE provides a closer look at water filtration

Clean fresh water is a scarce resource. Areas of the world suffering from drought have to filter the salt out of seawater to make it drinkable. In other areas, the water may instead have a high content of toxic compounds, such as arsenic.
If you think about a water filter as a kind of strainer with tiny holes through it, you would assume that since it does a pretty good job of filtering out the small ions of normal table salt, sodium, and chloride, from seawater it would work even better for the larger arsenic compounds. This is however not the case when it comes to desalination – the technology for producing fresh water from seawater; quite the opposite actually. While sodium and chloride are removed effectively, other, much larger contaminants pass through the filtration materials that are typically used. That indicates there must be another mechanism at work here.

>Read more on the MAX IV Laboratory website

Scientists develop printable water sensor

Scientists develop printable water sensor

X-ray investigation reveals functioning of highly versatile copper-based compound

A new, versatile plastic-composite sensor can detect tiny amounts of water. The 3d printable material, developed by a Spanish-Israeli team of scientists, is cheap, flexible and non-toxic and changes its colour from purple to blue in wet conditions. The researchers lead by Pilar Amo-Ochoa from the Autonomous University of Madrid (UAM) used DESY’s X-ray light source PETRA III to understand the structural changes within the material that are triggered by water and lead to the observed colour change. The development opens the door to the generation of a family of new 3D printable functional materials, as the scientists write in the journal Advanced Functional Materials (early online view).

>Read more on the PETRA III at DESY website

Image: When dried, for example in a water-free solvent, the sensor material turns purple.
Credit: UAM, Verónica García Vegas

Water is more homogeneous than expected

Water is more homogeneous than expected

In order to explain the known anomalies in water, some researchers assume that water consists of a mixture of two phases even under ambient conditions.

However, new X-ray spectroscopic analyses at BESSY II, ESRF and Swiss Light Source show that this is not the case. At room temperature and normal pressure, the water molecules form a fluctuating network with an average of 1.74 ± 2.1% donor and acceptor hydrogen bridge bonds per molecule each, allowing tetrahedral coordination between close neighbours.
Water at ambient conditions is the matrix of life and chemistry and behaves anomalously in many of its properties. Since Wilhelm Conrad Röntgen, two distinct separate phases have been argued to coexist in liquid water, competing with the other view of a single-phase liquid in a fluctuating hydrogen bonding network – the continuous distribution model. Over time, X-ray spectroscopic methods have repeatedly been interpreted in support of Röntgen’s postulate.

>Read more on the BESSY II at HZB website

Image: Water molecules are excited with X-ray light (blue). From the emitted light (purple) information on H-bonds can be obtained.
Credit: T. Splettstoesser/HZB

A timely solution for the photosynthetic oxygen evolving clock

A timely solution for the photosynthetic oxygen evolving clock

XFEL Hub collaboration reveals the intermediates of the photosynthetic water oxidation clock

A large international collaborative effort aided by the XFEL Hub at Diamond Light Source has generated the most detailed time-resolved studies to date of a key protein involved in photosynthesis. The pioneering work, recently published in Nature, shows how photosystem II harnesses light energy to produce oxygen – insights that could direct a next generation of photovoltaic cells. 
>Read more on the Diamond Light Source website

Image: this figure is issued from a video you can watch here.

Know your ennemy

Know your ennemy

Light source identifies a key protein interaction during E. coli infection

Escherichia coli is a common source for contaminated water and food products, causing the condition known as gastroenteritis with symptoms that include diarrhea, vomiting, fever, loss of energy, and dehydration. In fact, for children or individuals with weakened immune systems, this bacterial infection in the gut can be life-threatening.

One of the microbes responsible for gastroenteritis, known formally as enteropathogenic E. coli (EPEC), causes infections by directing a pointed, needle-like projection into the human intestinal tract, releasing toxins that make people sick.

“Enteropathogenic E. coli can fire toxic proteins from inside the bacterium right into the cells of your gut lining,” says Dustin Little, a post-doctoral researcher in the Brian Coombes lab at McMaster University’s Department of Biochemistry and Biomedical Sciences.

>Read more on the Canadian Light Source website

Image: Dustin Little and Brian Coombes in the lab.
Credit: Dustin Little.