Graphene Nanocomposite Foam Material Harvests Water from Air


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Researchers in China have demonstrated a graphene nanocomposite foam-based water harvesting system to harvest water from air. The team reports their findings in ACS Applied Materials & Interfaces (“Superelastic Graphene Nanocomposite for High Cycle-Stability Water Capture-Release under Sunlight”).
Only 30% of all freshwater on the planet is not locked up in ice caps or glaciers (not for much longer, though). Of that, some 20% is in areas too remote for humans to access and of the remaining 80% about three-quarters comes at the wrong time and place – in monsoons and floods – and is not always captured for use by people. The remainder is less than 0.08 of 1% of the total water on the planet (read more: “Nanotechnology and water treatment“)
An abundance of water equivalent to about 10% of the total freshwater in lakes exists in the earth atmosphere, which can be a non-negligible freshwater resource to fight against the water shortage.
That’s where the graphene nanocomposite foam comes in: The foam realizes water harvesting through a capture-release cycle:
1) the capture process is composed of moisture adsorption from air by lithium chloride (LiCl) and water preservation by poly(vinyl alcohol) (PVA) and
2) the release relies on the solar-to-thermal transformer, reduced graphene oxide (rGO), to facilitate evaporation. In addition, polyimide is employed as a substrate material for the purpose of 3D porous structure formation and mechanical property enhancement.

 

graphene nanocomposite foam for harvesting water from air
 

Photograph, schematic diagram, and SEM images of the graphene nanocomposite foam. (a) Photograph of the graphene nanocomposite foam. (b) Schematic diagram of the graphene nanocomposite foam. Foam was prepared through a three-step process: freeze-drying, thermal annealing, and hydrophilic treatment. rGO/PI nanosheet, as the basic unit, can achieve the water harvesting capture-release cycle without additional energy input. (c) SEM image presents a porous structure of the rGO/PI foam without hydrophilic treatment. (d) Magnified SEM image of the rGO/PI foam without hydrophilic treatment to show a relatively smooth surface of the nanosheet. (e) SEM image of the graphene nanocomposite foam after hydrophilic treatment. (f) Magnified SEM image of the hydrophilic rGO/PI foam with bumped nanostructures. (g) Schematic diagram of the water vapor capture-release cycle.

LiCl and PVA were responsible for the water capture and water storage, respectively. Adsorbed water was stored as crystallized water in LiCl hydrates and the free water molecules were restrained by hydroxyl groups on PVA through the hydrogen bond, which led to the transformation of the nanosheet from dry status to wet status. Opposite procedure, from wet status to dry status, was realized by the rGO converting the solar energy to thermal energy to facilitate water evaporation under irradiation. (Reprinted with permission by American Chemical Society) (click on image to enlarge)

 

The as-fabricated foam can adsorb water up to 2.87 g per gram in 24 hours at a relative humidity of 90% and a temperature of 30°C, and release almost all the uptake water when it is exposed under a flux of 1 sun (1000 W per square meter, equal to the light intensity of natural sunlight) for 3 hours.
At the same time, the functional foam shows superelasticity, lightweight, and remarkable reusability, thus revealing its possibility to practical use.
The researchers write that, even though the rGO/PI nanocomposite foam can harvest freshwater from air, it is essential to enhance water harvesting efficiency.
“Another big challenge impedes the water harvesting system utilization to explore a more cost-effective way to prepare the products,” they conclude. “Though the three-step synthesis method and the composition of the foam have been optimized, it is still necessary to reduce the cost and increase the fabrication efficiency. Meanwhile, environmentally friendly materials are recommended, which would take the water harvesting system one step further to commercial application and large-scale production.”
By Michael Berger – Nanowerk

Sources

Bo ChenXue Zhao, and Ya Yang*§ 
 CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Micro-Nano Energy and Sensor, Beijing Institute of Nanoenergy and NanosystemsChinese Academy of Sciences, Beijing 100083, P. R. China
 School of Nanoscience and TechnologyUniversity of Chinese Academy of Sciences, Beijing 100049, P. R. China
§ Center on Nanoenergy Research, School of Physical Science and TechnologyGuangxi University, Nanning, Guangxi 530004, P. R. China
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The Fourth Industrial Revolution: Leveraging Nanotechnology Applications In Manufacturing


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The Fourth Industrial Revolution has made for big strides in manufacturing, especially with the additions of robotics and 3D printing. But one field has been advancing the notion of thinking small. Nanotechnology, or the study and application of manipulating matter at the nanoscale, has uncovered the existence of a world that’s a thousand times smaller than a fly’s eye. It has also led to the development of materials and techniques that have enhanced production capabilities.

Nanotechnology continues to have a broad impact on different sectors. In fact, the worldwide market will likely exceed $125 billion by 2024. Ranging from stain-resistant fabric to more affordable solar cells, nanotechnology applications have been improving our daily lives. As research continues, advances in this space are opening up possibilities for more promising innovations.

A Closer Look at the Nanoscale

In the metric system, “nano” means a factor of one billionth—which means that a nanometer (nm) is at one-billionth of a meter. Forms of matter at the nanoscale usually have lengths from the atomic level of around 0.1 nm up to 100 nm.

What makes the nanoscale extraordinary is that the properties and characteristics of matter are different on this level. Some materials can become more efficient at conducting electricity or heat. Others reflect light better. There are also materials that become stronger. The list goes on. For instance, the metal copper on the nanoscale is transparent. Gold, which is normally unreactive, becomes chemically active. Carbon, which is soft in its usual form, becomes incredibly hard when packed into a nanoscopic arrangement called a “nanotube”. These characteristics are crucial for numerous nanotechnology applications.

a photo quote of Dr. K. Eric Drexler in relation to nanotechnology applications

Dr. K. Eric Drexler weighs in on the uses of nanotechnology and on understanding where nanotechnology will lead.

The reason why chemical properties alter in the nanoscale is that it’s easier for particles to move around and between one another. Additionally, gravity becomes much less important than the electromagnetic forces between atoms and molecules. Thermal vibrations also become extremely significant. In short, the rules of science are very different at the nanoscale. It’s one of the factors that make nanotechnology research and nanotechnology applications so fascinating.

Creating lighter, sturdier and safer materials are possible with nanotechnology. Many of those materials can also withstand great pressures and weights. Nanomaterials, or structures in the nanoscale, enable the advanced manufacturing of innovative, next-generation products that provide higher performance at a lower cost and improved sustainability.

Exploring the Nanotech Space, One Atom at a Time

A few well-known companies have been exploring the substantial profit potential of nanotechnology applications.

IBM has invested more than $3 billion for the development of semiconductors that will be seven nanometers or less. The company has also been exploring new nanomanufacturing techniques. Additionally, IBM holds the distinction of producing the world’s smallest and fastest graphene chip.

an image of a nanotechnology applications material amid nanotechnology research
Uses of nanotechnology in relation to metal-organic frameworks (MOFs) have cost-advantage production economics.

Samsung has also been active in nanotechnology research. The electronics giant has filed more than 400 patents related to graphene. Such patents involve manufacturing processes and touch screens, among other nanotechnology applications. Moreover, Samsung has funded an effort to develop its first generation graphene batteries.

future-of-aviation

Read More: Electric Aircraft And The Future Of Aviation

One of the notable startups that has been gaining traction in this space is NuMat Technologies. The company creates intelligently engineered systems through the integration of programmable nanomaterials. NuMat is also the first company in the world to commercialize products enabled by metal-organic frameworks (MOFs). These are nanomaterials with vast surface areas, highly tunable porosities, and near-infinite combinatorial possibilities. Nanotechnology applications of MOFs involve products with improved performance and otherwise-unachievable flexibility in form factors. Additionally, they have cost-advantage production economics.

Founder Benjamin Hernandez believes that one of the most important uses of nanotechnology is solving challenges related to sustainability.

“I think conceptually that’s kind of the wave of the future, using atomic-scale machines or engineering to solve complex macro problems,” Hernandez said.

Moreover, NuMat uses artificial intelligence to design MOFs. The company has total funding of $22.3 million so far. NuMat continues extensive research to develop more nanotechnology applications for the future.

a photo quote of Markus Antonietti in relation to nanotechnology applications
For something so small, it’s understandable that few fully grasp the uses of nanotechnology.

Making a Difference with Nanotechnology Research

The ones mentioned above are just a few of the thousand uses of nanotechnology. Achievements in the field seem to be announced almost daily. However, businesses must also place greater importance on using nanotechnology for more sustainable manufacturing. After all, advantages include reduced consumption of raw materials. Another benefit is the substitution of more abundant or less toxic materials than the ones presently used. Moreover, nanotechnology applications can lead to the development of cleaner and less wasteful manufacturing processes.

Professor Sijie Lin at Tongji University is optimistic about the prevalence of sustainability in nanotechnology applications.

“Designing safer nanomaterials and nanostructures has gained increasing attention in the field of nanoscience and technology in recent years,” Lin said. “Based on the body of experimental evidence contributed by environmental health and safety studies, materials scientists now have a better grasp on the relationships between the nanomaterials’ physicochemical characteristics and their hazard and safety profiles.”

According to Markus Antonietti, director of Max Planck Institute for Colloids and Interfaces at Max Planck Institute for Evolutionary Biology, more work needs to be done in increasing awareness on nanotechnology applications or uses of nanotechnology. “But there also needs to be a focus on education and getting information to the public at large,” he noted. “The best part is that all of this could happen immediately if we simply spread the information in an understandable way. People don’t read science journals, so they don’t even know that all of this is possible.”

Article Re-Posted from Bold Business

For more on Bold Business’ examination of the Fourth Industrial Revolution, check out these stories on 3D Printing and Supply-Chain Automation.

Graphene takes a Step Toward Renewable Fuel – Converting water and carbon dioxide to the renewable energy of the future


graphenetakeJianwu Sun at Linköping University inspecting the growth reactor for growth of cubic silicon carbide. Credit: Thor Balkhed/LiU

Using the energy from the sun and graphene applied to the surface of cubic silicon carbide, researchers at Linköping University, Sweden, are working to develop a method to convert water and carbon dioxide to the renewable energy of the future.

They have now taken an important step toward this goal, reporting a method that makes it possible to produce graphene with several layers in a tightly controlled process. The researchers have also shown that graphene acts as a superconductor in certain conditions. Their results have been published in the scientific journals Carbon and Nano Letters.

Carbon, oxygen and hydrogen are the three elements obtained by taking apart molecules of carbon dioxide and water. The same elements are the building blocks of chemical substances used for fuel, such as ethanol and methane. The conversion of carbon dioxide and water to renewable fuel could provide an alternative to fossil fuels and contribute to reducing carbon dioxide emissions into the atmosphere. Jianwu Sun, senior lecturer at Linköping University, is trying to find a way to do just that.

Researchers at Linköping University have previously developed a world-leading method to produce cubic silicon carbide, which consists of silicon and carbon. The cubic form has the ability to capture energy from the sun and create charge carriers. This is, however, not sufficient. Graphene, one of the thinnest materials ever produced, plays a key role in the project. The material comprises a single  of  atoms bound to each other in a hexagonal lattice. Graphene has a high ability to conduct an electric current, a property that would be useful for solar energy conversion. It also has several unique properties, and possible uses of graphene are being extensively studied all over the world.

jianwu-sun-ifm-liu-tb-dsc2960Read Original Post from Linkoping University

In recent years, the researchers have attempted to improve the process by which graphene grows on a surface in order to control the properties of the graphene. Their recent progress is described in an article in the scientific journal Carbon.

“It is relatively easy to grow one layer of graphene on silicon carbide. But it’s a greater challenge to grow large-area uniform graphene that consists of several layers on top of each other. We have now shown that it is possible to grow uniform graphene that consists of up to four layers in a controlled manner,” says Jianwu Sun of the Department of Physics, Chemistry and Biology at Linköping University.

One of the difficulties posed by multilayer graphene is that the surface becomes uneven when different numbers of layers grow at different locations. The edge when one layer ends has the form of a tiny, nanoscale staircase. Flat layers are desirable, so these steps are a problem, particularly when the steps accumulate in one location, like a wrongly built staircase in which several steps have been united to form one large step. The researchers have now found a way to remove these large, united steps by growing the graphene at a carefully controlled temperature. Furthermore, the researchers have shown that their method makes it possible to control how many layers the graphene will contain. This is the first key step in an ongoing research project whose goal is to make fuel from water and .

In a closely related article in the journal Nano Letters, the researchers describe investigations into the electronic properties of multilayer graphene grown on cubic silicon carbide.

“We discovered that multilayer graphene has extremely promising electrical properties that enable the material to be used as a superconductor, a material that conducts electrical current with zero electrical resistance. This special property arises solely when the graphene layers are arranged in a special way relative to each other,” says Jianwu Sun.

Theoretical calculations had predicted that multilayer  would have superconductive properties, provided that the layers are arranged in a particular way. In the new study, the researchers demonstrate experimentally for the first time that this is the case. Superconducting magnets are extremely powerful magnets used in medical magnetic resonance cameras and in particle accelerators. There are many potential areas of application for superconductors, such as electrical supply lines with zero energy loss, and high-speed trains that float on a magnetic field. Their use is currently limited by the inability to produce superconductors that function at room temperature. Currently available superconductors function only at extremely low temperatures.

 Explore further: Atoms use tunnels to escape graphene cover

More information: Yuchen Shi et al, Elimination of step bunching in the growth of large-area monolayer and multilayer graphene on off-axis 3C SiC (111), Carbon (2018). DOI: 10.1016/j.carbon.2018.08.042

Weimin Wang et al. Flat-Band Electronic Structure and Interlayer Spacing Influence in Rhombohedral Four-Layer Graphene, Nano Letters (2018). DOI: 10.1021/acs.nanolett.8b02530

 

Rice University: Nanotubes change the shape of water


nanotubeschange water Rice UMolecular models of nanotube ice produced by engineers at Rice University show how forces inside a carbon nanotube at left and a boron nitride nanotube at right pressure water molecules into taking on the shape of a square tube. The …more

First, according to Rice University engineers, get a nanotube hole. Then insert water. If the nanotube is just the right width, the water molecules will align into a square rod.

Rice materials scientist Rouzbeh Shahsavari and his team used molecular models to demonstrate their theory that weak van der Waals forces between the inner surface of the nanotube and the  are strong enough to snap the oxygen and hydrogen atoms into place.

Shahsavari referred to the contents as two-dimensional “ice,” because the  freeze regardless of the temperature. He said the research provides valuable insight on ways to leverage atomic interactions between nanotubes and  molecules to fabricate nanochannels and energy-storing nanocapacitors.

A paper on the research appears in the American Chemical Society journal Langmuir.

Shahsavari and his colleagues built molecular models of carbon and  with adjustable widths. They discovered boron nitride is best at constraining the shape of water when the nanotubes are 10.5 angstroms wide. (One angstrom is one hundred-millionth of a centimeter.)

The researchers already knew that  in tightly confined water take on interesting structural properties. Recent experiments by other labs showed strong evidence for the formation of nanotube ice and prompted the researchers to build density functional theory models to analyze the forces responsible.

Shahsavari’s team modeled water molecules, which are about 3 angstroms wide, inside carbon and boron nitride nanotubes of various chiralities (the angles of their atomic lattices) and between 8 and 12 angstroms in diameter. They discovered that nanotubes in the middle diameters had the most impact on the balance between molecular interactions and van der Waals pressure that prompted the transition from a square water tube to ice.

“If the nanotube is too small and you can only fit one water molecule, you can’t judge much,” Shahsavari said. “If it’s too large, the water keeps its amorphous shape. But at about 8 angstroms, the nanotubes’ van der Waals force starts to push water molecules into organized square shapes.”

He said the strongest interactions were found in boron nitride  due to the particular polarization of their atoms.

Shahsavari said nanotube ice could find use in molecular machines or as nanoscale capillaries, or foster ways to deliver a few molecules of water or sequestered drugs to targeted cells, like a nanoscale syringe.

 Explore further: Scientists say boron nitride-graphene hybrid may be right for next-gen green cars

More information: Farzaneh Shayeganfar et al, First Principles Study of Water Nanotubes Captured Inside Carbon/Boron Nitride Nanotubes, Langmuir (2018). DOI: 10.1021/acs.langmuir.8b00856

Canadian Nanotechnology Firm Finds Water in the Driest of Air


A Canadian startup could have a new breakthrough in pulling moisture from the driest of places. For years, researchers around the world have been looking for new technology and methods of making drinkable water out of the atmosphere.

The company Awn Nanotech, based out of Montreal, have been leveraging the latest in nanotechnology to make that water harvesting a reality. Awn Nanotech, most recently, released new information about their progress at the American Physical Society’s March meeting — the world’s largest gathering of physicists.

Founder Richard Boudreault made the presentation, who is both a physicist and an entrepreneur with a sizeable number of other tech-based startup companies under his belt. He said the company got its inspiration after hearing about the water crises in southern California and South Africa. While most others were looking to solve the problem by desalination techniques and new technologies, he wanted to look to the sky instead.

He also wondered if he could create a more cost-efficient alternative to the other expensive options on the market. By tapping into nanotechnology, he could pull the particles toward each other and use the natural tension found in the surface as a force of energy to power the nanotechnology itself.

“It’s extremely simple technology, so it’s extremely durable,” Boudreault said at the press conference.

Boudreault partnered with college students throughout Canada to develop a specific textile. The fine mesh of carbon nanotubes would be both hydrophilic (attracts water to the surface) on one side and hydrophobic (repels water away from the surface) on the other.

Water particles hit the mesh and get pushed through the film from one side to the other. This ultimately forms droplets.

“Because of the surface tension, (the water) finds its way through,” Boudreault explained. The water then gets consolidated into storage tanks as clean water where it can await consumption. While there’s no need for power with the system, the Awn Nanotech team realized they could significantly speed up the water harvesting process by adding a simple fan. The team quickly added a small fan of a size that cools a computer. To make sure the fan also kept energy usage low, the fan itself runs on a small solar panel.

There have been some other attempts around the world to scale up water harvesting technology. In April 2017, a team from MIT partnered with University of California at Berkeley to harvest fog. They turned their attention to already very moist air and created a much cheaper alternative to other fog-harvesting methods using metal-organic frameworks.

However, unlike the small frameworks developed by the MIT researchers, Boudreault said that they’ve quickly scaled up their technology. In fact, the Awn Nanotech team has already created a larger alternative to their smaller scale that can capture 1,000 liters in one day. They’re currently selling their regular-scale water capture systems for $1,000 each, but the company intends on partnering with agricultural companies and farms for the more extensive systems.

Graphene Oxide Membrane (Sieve) Turns Seawater into Drinking Water: University of Manchester


Graphene Seives 58e264acaef12

Newsfacts:

New research shows graphene can filter common salts from water to make it safe to drink Findings could lead to affordable desalination technology

 Graphene membrane

Graphene-oxide membranes have attracted considerable attention as promising candidates for new filtration technologies. Now the much sought-after development of making membranes capable of sieving common salts has been achieved.

New research demonstrates the real-world potential of providing clean drinking water for millions of people who struggle to access adequate clean water sources.
The new findings from a group of scientists at The University of Manchester were published today in the journal Nature Nanotechnology.
Previously graphene-oxide membranes have shown exciting potential for gas separation and water filtration.

Graphene-oxide membranes developed at the National Graphene Institute have already demonstrated the potential of filtering out small nanoparticles, organic molecules, and even large salts. Until now, however, they couldn’t be used for sieving common salts used in desalination technologies, which require even smaller sieves.

Previous research at The University of Manchester found that if immersed in water, graphene-oxide membranes become slightly swollen and smaller salts flow through the membrane along with water, but larger ions or molecules are blocked.

The Manchester-based group have now further developed these graphene membranes and found a strategy to avoid the swelling of the membrane when exposed to water.
The pore size in the membrane can be precisely controlled which can sieve common salts out of salty water and make it safe to drink.
Realisation of scalable membranes with uniform pore size down to atomic scale is a significant step forward and will open new possibilities for improving the efficiency of desalination technology.

Professor Rahul Raveendran Nair

As the effects of climate change continue to reduce modern city’s water supplies, wealthy modern countries are also investing in desalination technologies. Following the severe floods in California major wealthy cities are also looking increasingly to alternative water solutions.

When the common salts are dissolved in water, they always form a ‘shell’ of water molecules around the salts molecules. This allows the tiny capillaries of the graphene-oxide membranes to block the salt from flowing along with the water. Water molecules are able to pass through the membrane barrier and flow anomalously fast which is ideal for application of these membranes for desalination.

Professor Rahul Nair, at The University of Manchester said: “Realisation of scalable membranes with uniform pore size down to atomic scale is a significant step forward and will open new possibilities for improving the efficiency of desalination technology.

“This is the first clear-cut experiment in this regime. We also demonstrate that there are realistic possibilities to scale up the described approach and mass produce graphene-based membranes with required sieve sizes.”

Mr. Jijo Abraham and Dr. Vasu Siddeswara Kalangi were the joint-lead authors on the research paper: “The developed membranes are not only useful for desalination, but the atomic scale tunability of the pore size also opens new opportunity to fabricate membranes with on-demand filtration capable of filtering out ions according to their sizes.” said Mr. Abraham.

By 2025 the UN expects that 14% of the world’s population will encounter water scarcity. This technology has the potential to revolutionise water filtration across the world, in particular in countries which cannot afford large scale desalination plants.

It is hoped that graphene-oxide membrane systems can be built on smaller scales making this technology accessible to countries which do not have the financial infrastructure to fund large plants without compromising the yield of fresh water produced.

Advanced materials

A UK-based team of researchers has created a graphene-based sieve capable of removing salt from seawater.
The sought-after development could aid the millions of people without ready access to clean drinking water. The promising graphene oxide sieve could be highly efficient at filtering salts, and will now be tested against existing desalination membranes.
It has previously been difficult to manufacture graphene-based barriers on an industrial scale. Reporting their results in the journal Nature Nanotechnology, scientists from the University of Manchester, led by Dr Rahul Nair, shows how they solved some of the challenges by using a chemical derivative called graphene oxide.
Advanced materials is one of The University of Manchester’s research beacons – examples of pioneering discoveries, interdisciplinary collaboration and cross-sector partnerships that are tackling some of the biggest questions facing the planet. #ResearchBeacons

 

Ceramic membranes separate tiny organic molecules with a molar mass of 200 Dalton


ceramicmembrCeramic membranes by the Fraunhofer Institute for Ceramic Technologies and Systems IKTS. Credit: Fraunhofer IKTS

Water is vital – therefore, waste water has to be cleaned as efficiently as possible. Ceramic membranes make this possible. Researchers from the Fraunhofer Institute for Ceramic Technologies and Systems IKTS in Hermsdorf, Germany were able to significantly reduce the separation limits of these membranes and to reliably filter off dissolved organic molecules with a molar mass of only 200 Dalton. Even industrial sewage water can thus be cleaned efficiently.

Anyone who has dragged himself along a sunny coastal path at the height of summer with too little in his bag knows all too well: without water, we cannot make it too long. Water is one of the foundations of life. In industry, water is a must, as well: in many production processes, it serves as a solvent, detergent, to cool or to transfer heat. As more and more water is consumed, waste water has to be treated and reused. Ceramic membranes offer a good way to do this: since they are separated mechanically – similar to a coffee filter – they are particularly energy-efficient. However, this method previously came to an end when a molecular size of 450 Daltons was reached: smaller molecules could not be separated with . According to experts, it was even considered impossible to go below this limit.

Molecules as small as 200 Daltons can be separated

Dr. Ingolf Voigt, Dr.-Ing. Hannes Richter and Dipl.-Chem. Petra Puhlfuerss from the Fraunhofer IKTS have achieved the impossible. “With our ceramic membranes, we have achieved, for the first time, a molecular separation limit of 200 Daltons – and, thereby, a whole new quality,” says Voigt, Deputy Institute Director of the IKTS and Site Manager in Hermsdorf.

ceramicmembrWatch a Short Video

 

But how did the researchers manage to do this? On the way to making the impossible possible, it was first necessary to overcome various obstacles. The first was in the production of the itself: if such small molecules were to be separated reliably, a membrane was needed that had pores smaller than the molecules which were to be separated. In addition, all of the pores had to be as similar in size as possible, since a single larger opening is sufficient to allow molecules to slip through. The challenge was therefore to produce pores which were as small as possible, with all of them having more or less the same size. “We achieved these results by refining sol-gel technology,” says Richter, Head of Department at the IKTS. The second hurdle was to make such membrane layers defect-free over larger surfaces. The Fraunhofer researchers have succeeded in doing this, as well. “Whereas only a few square centimeters of surface are usually coated, we equipped a pilot system with a membrane area of 234 square meters, which means that our membrane is several magnitudes larger,” explains Puhlfuerss, scientist at the IKTS.

Transfer from the laboratory into practice

Commissioned by Shell, the pilot system was built by the company Andreas Junghans – Anlagenbau und Edelstahlbearbeitung GmbH & Co. KG in Frankenberg, Germany and is located in Alberta, Canada. There the system has been successfully purifying since 2016, which is used for the extraction of oil from oil sand. The researchers are currently planning an initial production facility with a membrane area of more than 5,000 square meters.

The innovative ceramic membranes also offer advantages in industrial production processes: they can be used to purify partial currents directly in the process as well as to guide the cleaned water in the cycle, which saves water and energy.

For the development of the ceramic nanofiltration membrane, Dr. Ingolf Voigt, Dr.-Ing. Hannes Richter and Dipl.-Chem. Petra Puhlfuerss received this year’s Joseph von Fraunhofer Prize. The jury justifies the award by mentioning, among other things, “the first-ever realization for filtration applications within this material class.”

Explore further: New, water-based, recyclable membrane filters all types of nanoparticles

 

UC Riverside: Squeezing every drop (almost 100%) of fresh water from waste brine (salt solutions)


squeezingeveHot brines used in traditional membrane distillation systems are highly corrosive, making the heat exchangers and other system elements expensive, and limiting water recovery (a). To improve this, UCR researchers developed a self-heating …more

Engineers at the University of California, Riverside have developed a new way to recover almost 100 percent of the water from highly concentrated salt solutions. The system will alleviate water shortages in arid regions and reduce concerns surrounding high salinity brine disposal, such as hydraulic fracturing waste.

The research, which involves the development of a carbon nanotube-based heating element that will vastly improve the recovery of fresh during membrane distillation processes, was published today in the journal Nature Nanotechnology. David Jassby, an assistant professor of chemical and environmental engineering in UCR’s Bourns College of Engineering, led the project.

While reverse osmosis is the most common method of removing salt from seawater, wastewater, and brackish water, it is not capable of treating highly concentrated salt solutions. Such solutions, called brines, are generated in massive amounts during reverse osmosis (as waste products) and hydraulic fracturing (as produced water), and must be disposed of properly to avoid environmental damage. In the case of , produced water is often disposed of underground in injection wells, but some studies suggest this practice may result in an increase in local earthquakes.

One way to treat brine is membrane distillation, a thermal desalination technology in which heat drives water vapor across a membrane, allowing further water recovery while the salt stays behind. However, hot brines are highly corrosive, making the heat exchangers and other system elements expensive in traditional membrane distillation systems. Furthermore, because the process relies on the heat capacity of water, single pass recoveries are quite low (less than 10 percent), leading to complicated heat management requirements.

“In an ideal scenario, thermal desalination would allow the recovery of all the water from brine, leaving behind a tiny amount of a solid, crystalline salt that could be used or disposed of,” Jassby said. “Unfortunately, current processes rely on a constant feed of hot brine over the membrane, which limits water recovery across the membrane to about 6 percent.”

To improve on this, the researchers developed a self-heating carbon nanotube-based membrane that only heats the brine at the membrane surface. The new system reduced the heat needed in the process and increased the yield of recovered water to close to 100 percent.

In addition to the significantly improved desalination performance, the team also investigated how the application of alternating currents to the heating element could prevent degradation of the carbon nanotubes in the saline environment. Specifically, a threshold frequency was identified where electrochemical oxidation of the nanotubes was prevented, allowing the nanotube films to be operated for significant lengths of time with no reduction in performance. The insights provided by this work will allow carbon nanotube-based heating elements to be used in other applications where electrochemical stability of the nanotubes is a concern.

Explore further: Researchers develop hybrid nuclear desalination technique with improved efficiency

More information: Frequency-dependent stability of CNT Joule heaters in ionizable media and desalination processes, Nature Nanotechnology, nature.com/articles/doi:10.1038/nnano.2017.102

 

Water is surprisingly ordered on the nanoscale



Nanometric-sized water drops are everywhere – in the air as droplets or aerosols, in our bodies as medication, and in the earth, within rocks and oil fields. To understand the behavior of these drops, it is necessary to know how they interact with their hydrophobic environment. 

This interaction takes places at the curved droplet interface, a sub-nanometric region that surrounds the small pocket of water. Researchers from EPFL, in collaboration with the institute AMOLF in the Netherlands, were able to observe what was going on in this particular region. 

They discovered that molecules on the surface of the drops were much more ordered than expected. Their surprising results have been published in Nature 
Communications. They pave the way to a better understanding of atmospheric, biological and geological processes.

 Unique perspective on miniscule droplets

 

At EPFL, Sylvie Roke, director of the Julia Jacobi Chair of Photomedicine -Laboratory for Fundamental BioPhotonics, has developed a unique method for examining the surface of these droplets that are as thick as one thousandth of a hair, with a volume of an attoliter (18 zeros behind the comma). 

“The method involves overlapping ultrashort laser pulses in a mixture of water droplets in liquid oil and detecting photons that are scattered only from the interface”, explains Roke. “These photons have the sum frequency of the incoming photons and are thus of a different color. With this newly generated color we can know the structure of the only the interface.”

Hydrogen bonding as strong as in ice


 The surface of the water droplets turns out to be much more ordered than that of normal water and is comparable to super cooled (liquid < 0 °C water) water in which the water molecules have very strong hydrogen bond interactions. In ice, these interactions lead to a stable tetrahedral surrounding of each water molecule. Surprisingly, this type of structure was found on the surface of the droplets even at the room temperature – 50 °C above were it would normally appear. 

Chemical processes


This research provides valuable insight into the properties of nanometric water drops. “The chemical properties of these drops depend on how the water molecules are organized on the surface, so it’s really important to understand what’s going on there,” explained Roke. Further research could target the surface properties of water droplets with adding salt, a more realistic model of marine aerosols that consist of salty water surrounded by a hydrophobic environment. Salt may either enhance the water network or reduce its strength. “Or, it may not do anything at all. Given the surprising results found here, we can only speculate”, says Roke.

 

The surface of the water droplets turns out to be much more ordered than that of normal water and is comparable to super cooled (liquid < 0 °C water) water in which the water molecules have very strong hydrogen bond interactions. @ EPFL- Julia Jacobi Chair of Photomedicine – Laboratory for fundamental BioPhotonics

 

The interfacial structure of water droplets in a hydrophobic liquid

Nikolay Smolentsev, Wilbert J. Smit, Huib J. Bakker & Sylvie Roke

Nature Communications 8, Article number: 15548 (2017)

doi:10.1038/ncomms15548

Turning Seawater into Drinking Water ~ Graphene Sieves May Hold the Key


Graphene Seives 58e264acaef12A graphene membrane. Credit: The University of Manchester

 

“By 2025 the UN expects that 14% of the world’s population will encounter water scarcity.”

Graphene-oxide membranes have attracted considerable attention as promising candidates for new filtration technologies. Now the much sought-after development of making membranes capable of sieving common salts has been achieved.

New research demonstrates the real-world potential of providing for millions of people who struggle to access adequate clean water sources.

The new findings from a group of scientists at The University of Manchester were published today in the journal Nature Nanotechnology. Previously graphene-oxide membranes have shown exciting potential for gas separation and water filtration.

Graphene-oxide membranes developed at the National Graphene Institute have already demonstrated the potential of filtering out small nanoparticles, organic molecules, and even large salts. Until now, however, they couldn’t be used for sieving common salts used in technologies, which require even smaller sieves.

Previous research at The University of Manchester found that if immersed in water, graphene-oxide membranes become slightly swollen and smaller salts flow through the membrane along with water, but larger ions or molecules are blocked.

The Manchester-based group have now further developed these and found a strategy to avoid the swelling of the membrane when exposed to water. The in the membrane can be precisely controlled which can sieve common salts out of salty water and make it safe to drink.

As the effects of climate change continue to reduce modern city’s water supplies, wealthy modern countries are also investing in desalination technologies. Following the severe floods in California major wealthy cities are also looking increasingly to alternative water solutions.

WEF 2017 graphene-water-071115-rtrde3r1-628x330 (2)World Economic Forum: Can Graphene Make the World’s Water Clean?

 

 

 

 

When the common salts are dissolved in water, they always form a ‘shell’ of around the salts molecules. This allows the tiny capillaries of the graphene-oxide membranes to block the from flowing along with the water. Water molecules are able to pass through the membrane barrier and flow anomalously fast which is ideal for application of these membranes for desalination.

Professor Rahul Nair, at The University of Manchester said: “Realisation of scalable membranes with uniform pore size down to atomic scale is a significant step forward and will open new possibilities for improving the efficiency of desalination .

“This is the first clear-cut experiment in this regime. We also demonstrate that there are realistic possibilities to scale up the described approach and mass produce graphene-based membranes with required sieve sizes.”

Mr. Jijo Abraham and Dr. Vasu Siddeswara Kalangi were the joint-lead authors on the research paper: “The developed membranes are not only useful for desalination, but the atomic scale tunability of the pore size also opens new opportunity to fabricate membranes with on-demand filtration capable of filtering out ions according to their sizes.” said Mr. Abraham.

By 2025 the UN expects that 14% of the world’s population will encounter water scarcity. This technology has the potential to revolutionize water filtration across the world, in particular in countries which cannot afford large scale desalination plants.

It is hoped that graphene-oxide systems can be built on smaller scales making this technology accessible to countries which do not have the financial infrastructure to fund large plants without compromising the yield of fresh produced.

Explore further: Researchers develop hybrid nuclear desalination technique with improved efficiency

More information: Tunable sieving of ions using graphene oxide membranes, Nature Nanotechnology, nature.com/articles/doi:10.1038/nnano.2017.21