Chemists work to desalt the ocean for drinking water, one nanoliter at a time

University of Texas at Austin: By creating a small electrical field that removes salts from seawater, chemists at The University of Texas at Austin and the University of Marburg in Germany have introduced a new method for the desalination of seawater that consumes less energy and is dramatically simpler than conventional techniques. The new method requires so little energy that it can run on a store-bought battery.

The process evades the problems confronting current desalination methods by eliminating the need for a membrane and by separating salt from water at a microscale.

The technique, called electrochemically mediated seawater desalination, was described last week in the journal Angewandte Chemie. The research team was led by Richard Crooks of The University of Texas at Austin and Ulrich Tallarek of the University of Marburg. It’s patent-pending and is in commercial development by startup company Okeanos Technologies.

“The availability of water for drinking and crop irrigation is one of the most basic requirements for maintaining and improving human health,” said Crooks, the Robert A. Welch Chair in Chemistry in the College of Natural Sciences. “Seawater desalination is one way to address this need, but most current methods for desalinating water rely on expensive and easily contaminated membranes. The membrane-free method we’ve developed still needs to be refined and scaled up, but if we can succeed at that, then one day it might be possible to provide fresh water on a massive scale using a simple, even portable, system.”

This new method holds particular promise for the water-stressed areas in which about a third of the planet’s inhabitants live. Many of these regions have access to abundant seawater but not to the energy infrastructure or money necessary to desalt water using conventional technology. As a result, millions of deaths per year in these regions are attributed to water-related causes....

A prototype "water chip" developed by researchers at The University of Texas at Austin in collaboration with a startup company. From the UT Austin website

UNESCO urged to explore guidelines on 'nano-ethics'

David Dickson in SciDev.net: The UN Educational, Scientific and Cultural Organization (UNESCO) has been urged to set up an expert group to seek a consensus of both developed and developing countries on how to tackle the ethical aspects of nanotechnology.

The proposal was made by speakers at a workshop in Bratislava, Slovakia, last week (27–29 May) organised by the Slovakian National Commission for UNESCO and the World Commission on the Ethics of Science and Technology (COMEST).

"All countries in the world will become involved in nanotechnology over the next ten or 20 years, and it is important to establish collaboration between North and South in developing an ethical roadmap on how the issues raised by this technology should be handled," said Ali Beitollahi, director of international relations for the Iran Nanotechnology Initiative Council (INIC).

The Bratislava meeting heard that the potential applications of nanotechnology — particularly in water treatment but also in fields such as health, agriculture and energy — could transform prospects for developing countries in ways similar to the wide-scale adoption of mobile phones.

"Nanoscience and nanotechnology are giving us new ways of thinking about development, and can play an important role in helping developing countries move towards sustainability," said COMEST member Abdoulaye Sene, an environmental sociologist at Senegal's Cheikh Anta Diop University....

A nano-whatsis, shot by Aydin4ik, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

Nanoscavengers could usher in next generation water purification

Andrew Myers in Stanford Engineering News: Among its many talents, silver is an antibiotic. Titanium dioxide is known to glom on to certain heavy metals and pollutants. Other materials do the same for salt. In recent years, environmental engineers have sought to disinfect, depollute, and desalinate contaminated water using nanoscale particles of these active materials. Engineers call them nanoscavengers. The hitch from a technical standpoint is that it is nearly impossible to reclaim the nanoscavengers once in the water.

In a paper published online May 14 in the journal Nature Communications, an interdisciplinary team of engineers at Stanford University announces it has developed a new type of nanoscavenger with a synthetic core that is ultraresponsive to magnetism, allowing the easy and efficient recovery of virtually every one of the nanoscale purifiers.

“In contaminated water, nanoscavengers float around, randomly bumping into and killing bacteria or attaching themselves to the molecular pollutants they are after,” said Shan Wang, the study’s senior author and a professor of material science and engineering and jointly of electrical engineering. “When the contaminants are either stuck to the nanoscavenger or dead, the magnet is turned on and the particles vanish.”

...In their natural state, the new nanoscavengers are not magnetic and would not be attracted to another magnetic material. When the composite discs are exposed to a strong magnetic field, however, the magnetism of the two opposing fields turn into alignment, not just becoming magnetic but compounding the magnetic effect.

In doing so, the nanoscavengers become ultraresponsive to magnetism, far more so than the base iron oxide used in today’s technologies. The Stanford team has dubbed its advance with the oxymoronic name: “synthetic antiferromagnetic cores.” The prefix anti- in this case means in opposite direction, not non-magnetic....

The disc-like synthetic nanoscavengers collected magnetically. (Image: Mingliang Zhang, Stanford School of Engineering.)

Nanotechnology could lighten Venezuela's oil footprint

Humberto Márquez in Tierramérica: Venezuela is studying the use of nanotechnology as a means of reducing emissions of greenhouse gases caused by the oil industry.  Nanotechnology operates at the sub-microscopic scale: a nanometer is a unit of measure equal to one billionth of a meter.

“We are seeking to use nanoparticles of metallic salts, such as iron, nickel or cobalt nitrates, as catalysts in oil-related processes that produce greenhouse gas emissions,” said Sarah Briceño, a researcher at the Center for Physics at the Venezuelan Institute of Scientific Research (IVIC).

Catalysts are substances used to speed up chemical processes, “and our goal is to develop catalysts adapted to Venezuelan industry that will make it possible to reduce greenhouse gas emissions from activities such as oil refining and fuel consumption by motor vehicles by up to 50 percent,” Briceño told Tierramérica.

Venezuela, a founding member of the Organization of the Petroleum Exporting Countries (OPEC), extracts close to three million barrels of oil a day and has over two billion barrels of heavy crude oil reserves....

From NASA: This false-colour (near-infra-red, red, green) image has been processed to emphasize details on the lake’s surface. The scene shows oil slicks (the various dark patches) in the south-eastern portion of the lake. The slicks come from leaks in the various oil production and storage platforms located on Lake Maracaibo.

Nanosized pollutants pose crop risks

Janet Raloff in Science News:  Nanoscale pollutants can enter crop roots, triggering a host of changes to plants’ growth and health, two studies find. These tiny particles can stunt plant growth, boost the plants’ absorption of pollutants, and increase the need for crop fertilizers.

Nanomaterials that get released in the exhaust from diesel-fueled tractors can rain down onto crop fields. Those used in fabrics, sunscreens and other products collect in the solids separated out of sewage and wastewater — nutrient-rich solids that are routinely spread on U.S. fields to improve soils. The new studies offer a glimpse at the toxic effects such nanoparticles may pose to future crops as exposures rise.

The new data now “forewarn of agriculturally associated human and environmental risks from the accelerating use of manufactured nanomaterials,” Patricia Holden of the University of California, Santa Barbara, and her colleagues report in one of the studies, published online August 20 in the Proceedings of the National Academy of Sciences.

Manufacturers have been turning to nanoparticles in recent years because they perform differently than larger-scale versions of the same product, notes Jason White of the Connecticut Agricultural Experiment Station in New Haven. If nanoscale materials behave differently, both chemically and physically, he asks, “Why should we have assumed they’d behave the same biologically?”...

Two microfabricated grippers touching each other inside a nanomanipulation setup in an electron microscope, shot by Kristian Molhave, Wikimedia Commons, under the Creative Commons Attribution 2.5 Generic license

Nanocrystal-coated fibers might reduce wasted energy

Purdue University: Researchers are developing a technique that uses nanotechnology to harvest energy from hot pipes or engine components to potentially recover energy wasted in factories, power plants and cars. "The ugly truth is that 58 percent of the energy generated in the United States is wasted as heat," said Yue Wu, a Purdue University assistant professor of chemical engineering. "If we could get just 10 percent back that would allow us to reduce energy consumption and power plant emissions considerably."

Researchers have coated glass fibers with a new "thermoelectric" material they developed. When thermoelectric materials are heated on one side electrons flow to the cooler side, generating an electrical current.

Coated fibers also could be used to create a solid-state cooling technology that does not require compressors and chemical refrigerants. The fibers might be woven into a fabric to make cooling garments. The glass fibers are dipped in a solution containing nanocrystals of lead telluride and then exposed to heat in a process called annealing to fuse the crystals together.

Such fibers could be wrapped around industrial pipes in factories and power plants, as well as on car engines and automotive exhaust systems, to recapture much of the wasted energy. The "energy harvesting" technology might dramatically reduce how much heat is lost, Wu said....

This image shows glass fibers coated with a thermoelectric material that generates electrical current when exposed to heat. The technology might be used to harvest energy from hot pipes or engine components, possibly representing a way to recover energy wasted in factories, power plants and cars. (Purdue University photo/Scott W. Finefrock)

Wireless nano sensors could save bridges and buildings

A little gee-whiz techno-speculation from Space Mart: Could inexpensive wireless sensors based on nanotechnology be used to alert engineers to problematic cracks and damage to buildings, bridges, and other structures before they become critical? A feasibility study published in the International Journal of Materials and Structural Integrity would suggest so.

Mohamed Saafi of the Department of Construction Engineering and Management, at North Dakota State University, in Fargo, and colleagues at the National Institute of Applied Sciences, in Tunisia, together with a team at the Department of Engineering Technology, at Alabama A and M University, point out that civil structures are prone to continuous and uncontrollable damage processes during their designed service lifespan. These damaging processes might be due to weather, aging of materials, earth tremors, and a lack of maintenance.

A continuous monitoring system is needed to improve safety. Unfortunately, the costs and required time expenditure often mean monitoring is not carried out in a timely manner and trivial problems, such as small cracks and fissures, ultimately become serious conditions that threaten the integrity of a structure. The researchers suggest that nanotechnology and wireless systems could be the answer.

…Long gauge nanotube sensors were employed for crack detection in the feasibility study. MEMS and nanosensors have already been used in a wide range of engineering and science fields such as transportation, communication, military and medicine. Their use in civil engineering is a new application with great potential.

"If designed properly, wireless MEMS and nanotechnology-based sensors could be used as embedded components to form self-sensing concrete structures," the team explains….

On the Brooklyn Bridge in 2005, shot by Victoria, Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 Generic license

Rivers are carbon processors, not inert pipelines

European Science Foundation: Microorganisms in rivers and streams play a crucial role in the global carbon cycle that has not previously been considered. Freshwater ecologist Dr Tom Battin, of the University of Vienna, told a COST ESF Frontiers of Science conference in October that our understanding of how rivers and streams deal with organic carbon has changed radically.

Microorganisms such as bacteria and single celled algae in rivers and streams decompose organic matter as it flows downstream. They convert the carbon it contains into carbon dioxide, which is then released to the atmosphere.

Recent estimates by Battin’s team and others conclude there is a net flux, or outgassing, of carbon dioxide from the world’s rivers and streams to the atmosphere of at least two-thirds to three-quarters of a gigatonne (Gt) of carbon per year. This flux has not been taken into account in the models of the global carbon cycle used to predict climate change.

“Surface water drainage networks perfuse and integrate the landscape, across the whole planet,” says Battin, “but they are missing from all global carbon cycling, even from the IPCC (Intergovernmental Panel on Climate Change) reports. Rivers are just considered as inert pipelines, receiving organic carbon from Earth and transporting it to the ocean.” This thinking, according to Battin, has changed radically in the last few years.

…In a disturbing development, Battin’s team lab has recently found that engineered nanoparticles can significantly compromise the freshwater microbes involved in carbon cycling. “This finding is a real challenge to science,” says Battin. “Engineered nanoparticles such as titanium dioxide are expected to increase in the environment, but it remains completely unknown how they might affect the functioning of ecosystems.”

The Rhine flows through Schaffhausen, shot by Pedro María Reyes Vizcaíno, Wikimedia Commons, under the Creative Commons Attribution ShareAlike 2.5 License

Nanotech to detect waterborne biohazards

Edie.net (UK): Space scientists from NASA are putting their expertise in cutting-edge nanotechnology to use in developing sensors to spot contamination in food and water. The biosensor can spot potentially deadly bacteria, viruses and parasites associated with waterborne illnesses at very low levels.

"The biosensor makes use of ultra-sensitive carbon nanotubes which can detect biohazards at very low levels," said Meyya Meyyappan, chief scientist for exploration technology and former director of NASA's Centre for Nanotechnology. "When biohazards are present, the biosensor generates an electrical signal, which is used to determine the presence and concentration levels of specific micro-organisms in the sample. Because of their tiny size, millions of nanotubes can fit on a single biosensor chip."

NASA has licensed the device to private company Early Warning, whose officials say food and drink companies, water agencies, industrial plants, hospitals and airlines could use the biosensor to prevent outbreaks of illnesses caused by pathogens - without needing a laboratory or technicians.

"Biohazard outbreaks from pathogens and infectious diseases occur every day," said Neil Gordon, president of Early Warning. "The key to preventing major outbreaks is frequent and comprehensive testing for each suspected pathogen, as most occurrences of pathogens are not detected until after people get sick or die….

Clean pool, dirty pool, shot by "andrius_v110," who has generously released the image into the public domain via Wikimedia Commons. Many thanks...

Cleaner water through nanotechnology

Water purification through nanotechnology is the topic of this article in Terra Daily, reporting on some research in the International Journal of Nanotechnology, a publication that you'll find next to the tabloids at the supermarket. Some Australian scientists believe that their nano-based process, which involves particles of pure silica coated with an active material of hydrocarbons plus a silicon anchor. This can clean toxic chemicals, bacteria, viruses, and other hazardous materials from water much more effectively and at lower cost than conventional water purification methods, they say. You just stir in the coated particles and then filter them out.

Photo by "Che," Wikimedia Commons