Posts belonging to Category nanopore

3-D Printed Graphene Foam

Nanotechnologists from Rice University and China’s Tianjin University have used 3-D laser printing to fabricate centimeter-sized objects of atomically thin graphene. The research could yield industrially useful quantities of bulk graphene and is described online in a new study in the American Chemical Society journal ACS Nano.

Laser sintering was used to 3-D print objects made of graphene foam, a 3-D version of atomically thin graphene. At left is a photo of a fingertip-sized cube of graphene foam; at right is a close-up of the material as seen with a scanning electron microscope

This study is a first of its kind,” said Rice chemist James Tour, co-corresponding author of the paper. “We have shown how to make 3-D graphene foams from nongraphene starting materials, and the method lends itself to being scaled to graphene foams for additive manufacturing applications with pore-size control.”

Graphene, one of the most intensely studied nanomaterials of the decade, is a two-dimensional sheet of pure carbon that is both ultrastrong and conductive. Scientists hope to use graphene for everything from nanoelectronics and aircraft de-icers to batteries and bone implants. But most industrial applications would require bulk quantities of graphene in a three-dimensional form, and scientists have struggled to find simple ways of creating bulk 3-D graphene.

For example, researchers in Tour’s lab began using lasers, powdered sugar and nickel to make 3-D graphene foam in late 2016. Earlier this year they showed that they could reinforce the foam with carbon nanotubes, which produced a material they dubbed “rebar graphene” that could retain its shape while supporting 3,000 times its own weight. But making rebar graphene was no simple task. It required a pre-fabricated 3-D mold, a 1,000-degree Celsius chemical vapor deposition (CVD) process and nearly three hours of heating and cooling.  “This simple and efficient method does away with the need for both cold-press molds and high-temperature CVD treatment,” said co-lead author Junwei Sha, a former student in Tour’s lab who is now a postdoctoral researcher at Tianjin. “We should also be able to use this process to produce specific types of graphene foam like 3-D printed rebar graphene as well as both nitrogen- and sulfur-doped graphene foam by changing the precursor powders.” Sha and colleagues conducted an exhaustive study to find the optimal amount of time and laser power to maximize graphene production. The foam created by the process is a low-density, 3-D form of graphene with large pores that account for more than 99 percent of its volume.

The 3-D graphene foams prepared by our method show promise for applications that require rapid prototyping and manufacturing of 3-D carbon materials, including energy storage, damping and sound absorption,” said co-lead author Yilun Li, a graduate student at Rice.


How Yo Make Sea Water Drinkable

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. 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,” says Professor Rahul Raveendran Nair.

The new findings from a group of scientists at The University of Manchester have been published in the journal Nature Nanotechnology.


Powerful Anti-Aging Cream Using Nanotechnology

Wrinkle-smoothing hyaluronic acid can now be introduced into the skin without injections, thanks to an Israeli research team that spent years developing a nanotechnology for this purpose. Facial wrinkles, lines and sagging result from the body’s gradual loss of its ability to produce hyaluronic acid. In the past, treatments of hyaluronic acid couldn’t get into the skin’s deepest layers except by injection or in a powder form that must be mixed with water and therefore loses its potency.

That problem was solved by a research team headed by Prof. Rachel Lubart and Prof. Aharon Gedanken from the departments of chemistry and physics and Bar-Ilan University’s Institute for Nanotechnology and Advanced Materials (BINA). The Israeli scientists achieved this breakthrough by micronizingbreaking down its particles to the size of a micronhyaluronic acid. Based on this development, Israeli cosmetic pharmaceuticals pioneer Hava Zingboim has created Prophecy, the first-ever cream formula that allows hyaluronic acid to penetrate into the deeper skin layers.

Once they reach nano size, the hyaluronic acid molecules are transferred into the formula, which enables them to remain nano-sized throughout the process. The effect of the micronized hyaluronic acid applied to the skin is identical to the effect achieved when injecting hyaluronic acid into the skin, with the benefits of enhanced skin texture and a younger look.
According to a university statement, this is the only technology in the world capable of creating small molecules that remain small even when applied to the skin.


Wood Mixed With Nanoparticles Filters Toxic Water

Engineers at the University of Maryland have developed a new use for wood: to filter water. Liangbing Hu of the Energy Research Center and his colleagues added nanoparticles to wood, then used it to filter toxic dyes from water.

The team started with a block of linden wood, which they then soaked in palladium – a metal used in cars’ catalytic converters to remove pollutants from the exhaust. In this new filter, the palladium bonds to particles of dye. The wood’s natural channels, that once moved water and nutrients between the leaves and roots, now allow the water to flow past the nanoparticles for efficient removal of the toxic dye particles. The water, tinted with methylene blue, slowly drips through the wood and comes out clear.

VIDEO: Wood filter removes toxic dye from water

This could be used in areas where wastewater contains toxic dye particles,” said Amy Gong, a materials science graduate student, and co-first author of the research paper.

The purpose of the study was to analyze wood via an engineering lens. The researchers did not compare the filter to other types of filters; rather, they wanted to prove that wood can be used to remove impurities.

We are currently working on using a wood filter to remove heavy metals, such as lead and copper, from water,’ said Liangbing Hu, the lead researcher on the project. “We are also interested in scaling up the technology for real industry applications.” Hu is a professor of materials science and a member of the University of Maryland’s Energy Research Center.


Paper Filter Removes Harmful Viruses From Water

A simple paper sheet made by scientists at Uppsala University can improve the quality of life for millions of people by removing resistant viruses from water. The sheet, made of cellulose nanofibers, is called the mille-feuille filter as it has a unique layered internal architecture resembling that of the French puff pastry mille-feuille (Eng. thousand leaves).


 ‘With a filter material directly from nature, and by using simple production methods, we believe that our filter paper can become the affordable global water filtration solution and help save lives. Our goal is to develop a filter paper that can remove even the toughest viruses from water as easily as brewing coffee‘, says Albert Mihranyan, Professor of Nanotechnology at Uppsala University (Sweden), who heads the study. Access to safe drinking water is among the UN’s Sustainable Development Goals. More than 748 million people lack access to safe drinking water and basic sanitation. Water-borne infections are among the global causes for mortality, especially in children under age of five, and viruses are among the most notorious water-borne infectious microorganisms. They can be both extremely resistant to disinfection and difficult to remove by filtration due to their small size.

Today we heavily rely on chemical disinfectants, such as chlorine, which may produce toxic by-products depending on water quality. Filtration is a very effective, robust, energy-efficient, and inert method of producing drinking water as it physically removes the microorganisms from water rather than inactivates them. But the high price of efficient filters is limiting their use today.

Safe drinking water is a problem not only in the low-income countries. Massive viral outbreaks have also occurred in Europe in the past, including Sweden’, continues Mihranyan referring to the massive viral outbreak in Lilla Edet municipality in Sweden in 2008, when more than 2400 people or almost 20% of the local population got infected with Norovirus due to poor water.  Small size viruses have been much harder to get rid of, as they are extremely resistant to physical and chemical inactivation.


How To Monitor and Combat Diabetes With A Simple Patch

In the future, diabetics may be able to replace finger prick tests and injections with this non-invasive smart patch to keep their glucose levels in check.


The device is a type of patch which enables diabetic patients to monitor blood sugar levels via sweat without taking blood samples and control glucose levels by injecting medication“, says Kim Dae-Hyeong, researcher at the Institute for Basic Science (IBS), Seoul National University, South Korea.

After analyzing the patient’s sweat to sense glucose, the patch’s embedded sensors constantly test pH, humidity, and temperature – important factors for accurate blood sugar readings. The graphene-based patch is studded with micro-needles coated with medication that pierce the skin painlessly. When the patch senses above normal glucose levels a tiny heating element switches on which dissolves the medication coating the microneedles and releases it into the body. The prototype worked well in mice trials.

Diabetic patients can easily use our device because it does not cause any pain or stress them out. So they can monitor and manage blood glucose levels more often to prevent increasing it. Therefore, our device can greatly contribute to helping patients avoid complications of the disease“, comments Professor Kim Dae-Hyeong. Researchers want to lower the cost of production, while figuring out how to delivery enough medication to effectively treat humans, both major hurdles towards commercialization. The research was published in the journal Nature Nanotechnology in March.


How To Remove All Nanomaterials From Water

Nano implies small—and that’s great for use in medical devices, beauty products and smartphones—but it’s also a problem. The tiny nanoparticles, nanowires, nanotubes and other nanomaterials that make up our technology eventually find their way into water. The Environmental Protection Agency says more 1,300 commercial products use some kind of nanomaterial. And we just don’t know the full impact on health and the environment.

Michigan Technological

Look at plastic,” says Yoke Khin Yap, a professor of physics at Michigan Technological University. “These materials changed the world over the past decades—but can we clean up all the plastic in the ocean? We struggle to clean up meter-scale plastics, so what happens when we need to clean on the nano-scale?”

That challenge is the focus of a new study co-authored by Yap, recently published in the American Chemical Society’s journal Applied Materials and Interfaces. Yap and his team found a novel—and very simple—way to remove nearly 100 percent of nanomaterials from water.


How To Soak Up Oil Spills

In hopes of limiting the disastrous environmental effects of massive oil spills, Materials scientists from Drexel University and Deakin University, in Australia, have teamed up to manufacture and test a new material, called a boron nitride nanosheet, that can absorb up to 33 times its weight in oils and organic solvents—a trait that could make it an important technology for quickly mitigating these costly accidents.

The material, which literally absorbs the oil like a sponge, is the result of support from the Australian Research Council and is now ready to be tested by industry after two years of refinement in the laboratory at Deakin’s Institute for Frontier Materials (IFM).

Alfred Deakin Professor Ying (Ian) Chen, PhD, the lead author of a paper, recently published in Nature Communications, said the material is the most exciting advancement in oil spill remediation technology in decades.

nanopores to soak up oil spillsThe pores found in boron nitride nanosheets allow them to absorb more than 33 times its weight in oil and organic solvents

Oil spills are a global problem and wreak havoc on our aquatic ecosystems, not to mention cost billions of dollars in damage,” Chen said. “Everyone remembers the Gulf Coast disaster, but here in Australia they are a regular problem, and not just in our waters. Oil spills from trucks and other vehicles can close freeways for an entire day, again amounting to large economic losses,” he added.


Green: How To Clean Oil Sands Water Waste

Researchers have developed a process to remove contaminants from oil sands wastewater using only sunlight and nanoparticles that is more effective and inexpensive than conventional treatment methods.

Frank Gu, a professor in the Faculty of Engineering at the University of Waterloo and Canada Research Chair in Nanotechnology Engineering, is the senior researcher on the team that was the first to find that photocatalysis — a chemical reaction that involves the absorption of light by nanoparticles — can completely eliminate naphthenic acids in oil sands wastewater, and within hours. Naphthenic acids pose a threat to ecology and human health. Water in tailing ponds left to biodegrade naturally in the environment still contains these contaminants decades later.

oil sands pond

With about a billion tonnes of water stored in ponds in Alberta, removing naphthenic acids is one of the largest environmental challenges in Canada,” said Tim Leshuk, a PhD candidate in chemical engineering at Waterloo and the leader of the study . “Conventional treatments people have tried either haven’t worked, or if they have worked, they’ve been far too impractical or expensive to solve the size of the problem.  Waterloo’s technology is the first step of what looks like a very practical and green treatment method.


Water To Drink From The Sea

University of Illinois (U. of I.) engineers have found an energy-efficient material for removing salt from seawater that could provide a rebuttal to poet Samuel Taylor Coleridge’s lament, “Water, water, every where, nor any drop to drink.” The material, a nanometer-thick sheet of molybdenum disulfide (MoS2) riddled with tiny holes called nanopores, is specially designed to let high volumes of water through but keep salt and other contaminates out, a process called desalination. In a study published in the journal Nature Communications, the Illinois team modeled various thin-film membranes and found that MoS2 showed the greatest efficiency, filtering through up to 70 percent more water than graphene membranes.


Even though we have a lot of water on this planet, there is very little that is drinkable,” said study leader Narayana Aluru, a U. of I. professor ofmechanical science and engineering. “If we could find a low-cost, efficient way to purify sea water, we would be making good strides in solving the water crisis”.
Finding materials for efficient desalination has been a big issue, and I think this work lays the foundation for next-generation materials. These materials are efficient in terms of energy usage and fouling, which are issues that have plagued desalination technology for a long time,” said Aluru, who also is affiliated with the Beckman Institute for Advanced Science and Technology at the U. of I.

Most available desalination technologies rely on a process called reverse osmosis to push seawater through a thin plastic membrane to make fresh water. “Reverse osmosis is a very expensive process,” Aluru said. “It’s very energy intensive. A lot of power is required to do this process, and it’s not very efficient. In addition, the membranes fail because of clogging. So we’d like to make it cheaper and make the membranes more efficient so they don’t fail as often. We also don’t want to have to use a lot of pressure to get a high flow rate of water.


“Nanopore” Scanners To Find Early Signs Of Cancer

Using tiny “nanopore” scanners that can detect individual DNA molecules, Professor Amit Meller and colleagues are on the hunt for biological markers in cancer cells tha t may help clinicians diagnose colorectal and lung cancers at their earliest stages. Prof. Meller, of the Faculty of Biomedical Engineering at the Technion-Israel Institute of Technology, leads a research group that is a partner in BeyondSeq, an international research consortium looking for new methods of decoding genetic and epigenetic information from medical samples. BeyondSeq, supported by a €6 million grant from Horizon 2020, the European Union’s framework program, was one of only eight consortia chosen out of 450 submitted proposals.


We are the only lab in the consortium working on early diagnosis of cancer biomarkers, which…will allow doctors to combat the cancers much more effectively and save human lives,” Meller explained. “Currently there are no good ways to diagnose colorectal cancer and lung cancer at early stages. Usually these cancers are diagnosed at later stage (stage 2 or above) in which the patients may already have multiple secondary tumors, hence highly complicating treatment.


How To Stay Dry Underwater For Months

Imagine staying dry underwater for months. Now Northwestern University engineers have examined a wide variety of surfaces that can do just that — and, better yet, they know why. The research team is the first to identify the ideal “roughness” needed in the texture of a surface to keep it dry for a long period of time when submerged in water. The valleys in the surface roughness typically need to be less than one micron in width, the researchers found. That’s really small — less than one millionth of a meter — but these nanoscopic valleys have macroscopic impact. Understanding how the surfaces deflect water so well means the valuable feature could be reproduced in other materials on a mass scale, potentially saving billions of dollars in a variety of industries, from antifouling surfaces for shipping to pipe coatings resulting in lower drag. That’s science and engineering, not serendipity, at work for the benefit of the economy.

Dry underwater

The trick is to use rough surfaces of the right chemistry and size to promote vapor formation, which we can use to our advantage,” said Neelesh A. Patankar, a professor of mechanical engineering in the McCormick School of Engineering and Applied Science, who led the research. “When the valleys are less than one micron wide, pockets of water vapor or gas accumulate in them by underwater evaporation or effervescence, just like a drop of water evaporates without having to boil it. These gas pockets deflect water, keeping the surface dry,” he said.

In a study published today (Aug. 18) by the journal Scientific Reports, Patankar and his co-authors explain and demonstrate the nanoscale mechanics behind the phenomenon of staying dry underwater.