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.

CLICK ON THE IMAGE TO ENJOY THE VIDEO

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.

Source: http://www.manchester.ac.uk/
AND
http://www.reuters.com/

Super-Efficient Production Of Hydrogen From Solar Energy

Hydrogen is an alternative source of energy that can be produced from renewable sources of sunlight and water. A group of Japanese researchers has developed a photocatalyst that increases hydrogen production tenfold.

When light is applied to photocatalysts, electrons and holes are produced on the surface of the catalyst, and hydrogen is obtained when these electrons reduce the hydrogen ions in water. However, in traditional photocatalysts the holes that are produced at the same time as the electrons mostly recombine on the surface of the catalyst and disappear, making it difficult to increase conversion efficiency.

Professor Tachikawa’s research group from the Kobe University developed a photocatalyst made of mesocrystal, deliberately creating a lack of uniformity in size and arrangement of the crystals. This new photocatalyst is able to spatially separate the electrons and electron holes to prevent them recombining. As a result, it has a far more efficient conversion rate for producing hydrogen than conventional nanoparticulate photocatalysts (approximately 7%).

The team developed a new method called “Topotactic Epitaxial Growth” that uses the nanometer-sized spaces in mesocrystals.
Using these findings, the research group plans to apply mesocrystal technology to realizing the super-efficient production of hydrogen from solar energy. The perovskite metal oxides, including strontium titanate, the target of this study, are the fundamental materials of electronic elements, so their results could be applied to a wide range of fields.

The discovery was made by a joint research team led by Associate Professor Tachikawa Takashi (Molecular Photoscience Research Center, Kobe University) and Professor Majima Tetsuro (Institute of Scientific and Industrial Research, Osaka University). Their findings were published  in the online version of Angewandte Chemie International Edition.

Source: http://www.kobe-u.ac.jp/

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.

Source: http://www.mse.umd.edu/

How To Color Textiles Without Polluting Environment

Fast fashion” might be cheap, but its high environmental cost from dyes polluting the water near factories has been well documented. To help stem the tide of dyes from entering streams and rivers, scientists report in the journal ACS Applied Materials & Interfaces a nonpolluting method to color textiles using 3-D colloidal crystals.

peacock feathers

Peacock feathers, opals and butterfly wings have inspired a new way to color voile fabrics without the pollutants of traditional dyes.

Dyes and pigments are chemical colors that produce their visual effect by selectively absorbing and reflecting specific wavelengths of visible light. Structural or physical colors — such as those of opals, peacock feathers and butterfly wings — result from light-modifying micro- and nanostructures. Bingtao Tang and colleagues from Universty of Maryland wanted to find a way to color voile textiles with structural colors without creating a stream of waste.

The researchers developed a simple, two-step process for transferring 3-D colloidal crystals, a structural color material, to voile fabrics. Their “dye” included polystyrene nanoparticles for color, polyacrylate for mechanical stability, carbon black to enhance color saturation and water. Testing showed the method could produce the full spectrum of colors, which remained bright even after washing. In addition, the team said that the technique did not produce contaminants that could pollute nearby water.

Source: http://pubs.acs.org/

Water Repellent Spray Coating

Scientists at The Australian National University (ANU) have developed a new spray-on material with a remarkable ability to repel water. The new protective coating could eventually be used to waterproof mobile phones, prevent ice from forming on aeroplanes or protect boat hulls from corroding.

water-repellent-coating-2

The surface is a layer of nanoparticles, which water slides off as if it’s on a hot barbecue,” said PhD student William Wong, from the Nanotechnology Research Laboratory at the ANU Research School of Engineering. The team created a much more robust coating than previous materials by combining two plastics, one tough and one flexible.

It’s like two interwoven fishing nets, made of different materials,” Mr Wong said. The water-repellent or superhydrophobic coating is also transparent and extremely resistant to ultraviolet radiation. Lead researcher and head of the Nanotechnology Research Laboratory, Associate Professor Antonio Tricoli, said the new material could change how we interact with liquids“It will keep skyscraper windows clean and prevent the mirror in the bathroom from fogging up,” Associate Professor Tricoli said. “The key innovation is that this transparent coating is able to stabilise very fragile nanomaterials resulting in ultra-durable nanotextures with numerous real-world applications.”

The team developed two ways of creating the material, both of which are cheaper and easier than current manufacturing processes. One method uses a flame to generate the nanoparticle constituents of the material. For lower temperature applications, the team dissolved the two components in a sprayable form. In addition to waterproofing, the new ability to control the properties of materials could be applied to a wide range of other coatings, said Mr Wong. “A lot of the functional coatings today are very weak, but we will be able to apply the same principles to make robust coatings that are, for example, anti-corrosive, self-cleaning or oil-repellent,” he said.

The research is published in ACS Appl. Mater. Interfaces 2016, 8, 13615−13623.

Source: http://www.anu.edu.au/

Nano Device Cleans Germs from Water In 20 Minutes

In many parts of the world, the only way to make germy water safe is by boiling, which consumes precious fuel, or by putting it out in the sun in a plastic bottle so ultraviolet rays will kill the microbes. But because UV rays carry only 4 percent of the sun’s total energy, the UV method takes six to 48 hours, limiting the amount of water people can disinfect this way.

Now researchers at the Department of Energy’s SLAC National Accelerator Laboratory and Stanford University have created a nanostructured device, about half the size of a postage stamp, that disinfects water much faster than the UV method by also making use of the visible part of the solar spectrum, which contains 50 percent of the sun’s energy.

clean waterA researcher holds a small, nanostructured device that uses sunlight to disinfect water. By harnessing a broad spectrum of sunlight, it works faster than devices that use only ultraviolet rays

In experiments reported today in Nature Nanotechnology, sunlight falling on the little device triggered the formation of hydrogen peroxide and other disinfecting chemicals that killed more than 99.999 percent of bacteria in just 20 minutes. When their work was done the killer chemicals quickly dissipated, leaving pure water behind.

Our device looks like a little rectangle of black glass. We just dropped it into the water and put everything under the sun, and the sun did all the work,” said Chong Liu, lead author of the report. She is a postdoctoral researcher in the laboratory of Yi Cui, a SLAC/Stanford associate professor and investigator with SIMES, the Stanford Institute for Materials and Energy Sciences at SLAC.

Under an electron microscope the surface of the device looks like a fingerprint, with many closely spaced lines. Those lines are very thin films – the researchers call them “nanoflakes” – of molybdenum disulfide that are stacked on edge, like the walls of a labyrinth, atop a rectangle of glass. In ordinary life, molybdenum disulfide is an industrial lubricant. But like many materials, it takes on entirely different properties when made in layers just a few atoms thick. In this case it becomes a photocatalyst.

By making their molybdenum disulfide walls in just the right thickness, the scientists got them to absorb the full range of visible sunlight. And by topping each tiny wall with a thin layer of copper, which also acts as a catalyst, they were able to use that sunlight to trigger exactly the reactions they wanted – reactions that produce “reactive oxygen species” like hydrogen peroxide, a commonly used disinfectant, which kill bacteria in the surrounding water.

Source: https://www6.slac.stanford.edu/

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).

cellulosa-nanofiber6230

 ‘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.

Source: http://www.uu.se/

Solar Hubs Provide Clean Water, Electricity & Internet to 3000 people

The Italian company Watly aims to deliver a hat trick of very needful things to the developing world, in the form of both a standalone unit and as a network of units. The team of this ambitious company describes their creation as the “biggest solar-powered computer in the world,” which combines solar photovoltaics (PV) and battery storage for powering the unit (and for charging external devices), with a water filtration system and an internet connectivity and telecommunications hub. The Watly system, which has been in the works for the last few years, and has now attracted the attention of The Discovery Channel, was run as a pilot program at a village in Ghana, where the 2.0 version of the device was successfully deployed to deliver clean drinking water to residents.

watly solar hub

The next step, however, is to build out the Watly 3.0 system, which is the full-sized version of the device, measuring some 40 meters long, and which is expected to be able to provide as much as 5000 liters of water per day, every day, for at least 15 years, along with producing solar electricity and charging services to as many as 3000 people. According to the company, one unit could offset the emissions equivalent of 2500 barrels of oil over the course of those 15 years, along with providing clean water and an off-grid power source. To get to that next step, Watly has turned to – wait for it – crowdfunding with an Indiegogo campaign that seeks to raise money for the installation of the 3.0 version as a pilot program in Africa (location TBD).

Along with the solar power and drinking water, Watly aims to provide an internet/telecom hub for local residents, with an onboard system for connecting to 3G/4G, radio link data systems, and/or satellites, as well as to communicate with other Watly units to act as a node in an “EnergyNet.”

Watly is a powerful communication device that can collect and send any kind of data (videos, images, audios, texts, ratios, etc.) to the Internet as well as to any other compatible communication device. A single Watly is a standing alone machine, but two or more Watlys become a network where each node is auto-powered, self-sustained and multi-functional.

Source: https://watly.co/

New Efficient Materials For Solar Fuel Cells

University of Texas at Arlington (UTA) chemists have developed new high-performing materials for cells that harness sunlight to split carbon dioxide and water into useable fuels like methanol and hydrogen gas. These “green fuels” can be used to power cars, home appliances or even to store energy in batteries.

solar fuel cells

Technologies that simultaneously permit us to remove greenhouse gases like carbon dioxide while harnessing and storing the energy of sunlight as fuel are at the forefront of current research,” said Krishnan Rajeshwar, UTA distinguished professor of chemistry and biochemistry and co-founder of the University’s Center of Renewable Energy, Science and Technology. “Our new material could improve the safety, efficiency and cost-effectiveness of solar fuel generation, which is not yet economically viable,” he added.

The new hybrid platform uses ultra-long carbon nanotube networks with a homogeneous coating of copper oxide nanocrystals. It demonstrates both the high electrical conductivity of carbon nanotubes and the photocathode qualities of copper oxide, efficiently converting light into the photocurrents needed for the photoelectrochemical reduction process. Morteza Khaledi, dean of the UTA College of Science, said Rajeshwar’s work is representative of the University’s commitment to addressing critical issues with global environmental impact under the Strategic Plan 2020.

Source: https://www.uta.edu/

Compact, Ultra Sensitive BioSensor Gives Infos From A Blood Drop

Imagine a hand-held environmental sensor that can instantly test water for lead, E. coli, and pesticides all at the same time, or a biosensor that can perform a complete blood workup from just a single drop. That’s the promise of nanoscale plasmonic interferometry, a technique that combines nanotechnology with plasmonics—the interaction between electrons in a metal and light.

Now researchers from Brown University’s School of Engineering have made an important fundamental advance that could make such devices more practical. The research team has developed a technique that eliminates the need for highly specialized external light sources that deliver coherent light, which the technique normally requires. The advance could enable more versatile and more compact devices.

  • FluorescencePlasmonicInterferometryPlasmonic interferometers that have light emitters within them could make for better, more compact biosensors.

It has always been assumed that coherent light was necessary for plasmonic interferometry,” said Domenico Pacifici, a professor of engineering who oversaw the work with his postdoctoral researcher Dongfang Li, and graduate student Jing Feng. “But we were able to disprove that assumption.”

The research is described in Nature Scientific Reports.

Source: https://news.brown.edu/

Nanoparticles Activated By Solar Energy Boil Water

Young researchers created a superconducting heat ink that functions as a solar heater. It heats water up to 68 degrees Celsius and is 40 percent cheaper than commercial inks.

hot shower 2

A pipe exposed to the sun reaches a temperature of 40 C°, if we add the superconducting ink the temperature increases 70 percent and reaches 68 C°,” says Sandra Casillas Bolaños, master at the Technological Institute of the Lagoon (ITL), in north of Mexico, and head of the project.

She explains that the ink acts as a boiler that contains nanoparticles activated by solar energy and increasing the temperature.

 

The ink is made of two layers, the first is an internal magnetic titanium nanoparticle, which is responsible for trapping the heat and the second is external and consists of a coating of tungsten (filament in light bulbs) which researchers transform into a nano salt and adhere with polyvinyl alcohol, to finish with a layer of copper.

Casillas Bolaños states that by a treatment called burnishing copper blackens in order that trap and retain heat inside the particles. “Thus the center is heated more intensely: first the titanium, then tungsten and finally the copper“.

The project has been developed for two years and the product is classified as an ink because it uses a series of solvents making it fast drying and with an odor similar to hair dye. The ink is applied on the surface of a conventional pipe that carries water and to potentiate the heat, students working on the project with professor Casillas Bolaños in the nonmetallic materials field, put two layers of PET bottles over the tubes in order to create a greenhouse effect and raise the temperature faster, as well as protect the ink from outdoor wear.

The technology has been implemented in some houses, where, by flowing for five meters water at 68 C° is obtained instantly, and even in cloudy weather the ink nicely captures the heat. Sandra Casillas adds that the ink was implemented in a major sports complex of the city to heat the pool, where two million cubic meters of water are heated from 26 to 37 C°. To achieve this, the researcher and her team placed tubes covered with ink on the edge of the indoor pool and a pump pulls the liquid from seven o’clock until the sun sets. As it flows, the water is heated and reaches the ideal temperature.

The ink is in the process of patenting and is intended to be market at 600 pesos a liter (about 40 dollars); however, for house piping only 150 pesos (10 dollars) are invested because very little is needed, says Casillas Bolaños.

Source: http://www.alphagalileo.org/

How To Move Ten Times Faster in Water

Scientists at the University College London (UCL) have identified a new and potentially faster way of moving molecules across the surfaces of certain materials.

The team carried out sophisticated computer simulations of tiny droplets of water as they interact with graphene surfaces. These simulations reveal that the molecules can “surf” across the surface whilst being carried by the moving ripples of graphene.

moving fast in water

The study, published in Nature Materials, demonstrates that because the molecules were swept along by the movement of strong ripples in the carbon fabric of graphene, they were able to move at an exceedingly fast rate, at least ten times faster than previously observed.

Furthermore, the researchers found that by altering the size of the ripples, and the type of molecules on the surface, they could achieve fast and controlled motion of molecules other than water. This opens up a range of possibilities for industrial applications such as improved sensors and filters.

graphene and water

Professor Angelos Michaelides, from the Thomas Young Centre and London Centre for Nanotechnology (LCN) at UCL, lead researcher of the study, explained: “Atoms and molecules usually move across materials by hopping from one point on their surface to the next. However, through computer simulations we have uncovered an interesting new diffusion mechanism for motion across graphene that is inherently different from the usual random movements we see on other surfaces.

Source: https://www.ucl.ac.uk/