Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Nano design adjustment may help find, clear some water contaminants

18.12.2006
Toxins such as perchlorate and nitrates could be targeted

Experiments designed to test discrepancies in theoretical computational chemistry have turned up a barely two-angstrom difference that may lead to a new approach to locate and remove dangerous toxins such as perchlorate and nitrates from the environment.

The research targets toxic groundwater contaminants that contain negatively charged ions known as anions (a-NI-ens), which are historically difficult to remove. Perchlorate, a rocket fuel additive recently linked to thyroid deficiency in women, has contaminated more than 450 wells in California alone. Nitrate contamination, which results mainly from the use of nitrogen fertilizer, is a leading cause of shutdowns of wells and public water supplies in the United States.

"There is a need for improved materials that are effective at removing anions from the environment," said Darren W. Johnson, a University of Oregon chemist and co-principal investigator of a study appearing online Dec. 13 ahead of regular publication in the Journal of the American Chemical Society. "A current leading strategy is anion exchange, which uses a polymeric resin to exchange an anion for one that’s not a problem." (Two other currently used methods aimed at anions are biochemical denitrification and reverse osmosis.)

... more about:
»Design »Interaction »binding »nanometers »nitrate »occur

In the new study, led by UO doctoral student Orion B. Berryman, researchers focused on anion-pi interaction, in which a negatively charged species is attracted to a neutral electron-deficient aromatic ring, which could be incorporated into a specifically designed receptor.

Anion-pi interactions have been the focus of recent theoretical work, in which electronic structure calculations predicted that anion binding between halides and electron-deficient aromatic rings will occur over the center of a ring. However, the lab experiments on crystalline material found that the binding occurs as much as 2 angstroms, or 0.2 nanometers from the center.

"It's very important to consider these off-centered anion-interactions occurring through a charge-transfer interaction," Berryman said. "We looked at solid-state structures and the geometry of the interaction involved in a simple system. In these initial studies we noted significant color changes due to this off-center binding geometry found in the crystal structures."

Co-principal investigator Benjamin P. Hay, a chemist at the Pacific Northwest National Laboratory in Richland, Wash., where Berryman studied last fall as part of UO's National Science Foundation-funded internship program, said the study has important ramifications in anionophore design, crystal engineering and other aspects of supramolecular chemistry. In fact, he said, the findings indicate that prior designs may be flawed, incomplete or even misleading. "We discovered an unexpected bonding motif that involves the transfer of charge from the anion to the arene -- in other words, a covalent bonding motif," Hay said. "This is the first theoretical characterization of what we have termed an off-center, weak charge-transfer interaction."

Anions, of which notable examples include DNA, nitrate, pertechnetate, cyanide and chromate, play indispensable roles in biological and chemical processes, but they also can contribute significantly to environmental pollution that threatens aquatic life cycles and human health.

Johnson, in collaboration with UO chemist Michael M. Haley, now is seeking to design receptors that aim to the off-center location, with a goal of developing sensors for anion detection. Because Berryman's research produced sometimes intense color changes at binding sites, such an approach could lead to developing materials that sense the presence of these toxins and remediate them.

While 0.2 nanometers seems an insignificant distance, it could mean there's a 100 percent chance that binding cannot occur, Johnson said. "We're finding that from a design standpoint, that 0.2 nanometers is a big difference."

He noted that estimating or calculating the binding distances when optimizing a receptor for positively charged binding, or cation, such as the chelation of metals by EDTA (ethylenedinitrilotetraacetic acid), is done almost exactly --s (0.01 nanometers). EDTA is widely used in industrial cleaners, detergents and textile production.

Jim Barlow | EurekAlert!
Further information:
http://www.uoregon.edu

Further reports about: Design Interaction binding nanometers nitrate occur

More articles from Life Sciences:

nachricht Bare bones: Making bones transparent
27.04.2017 | California Institute of Technology

nachricht Link Discovered between Immune System, Brain Structure and Memory
26.04.2017 | Universität Basel

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

Bare bones: Making bones transparent

27.04.2017 | Life Sciences

Study offers new theoretical approach to describing non-equilibrium phase transitions

27.04.2017 | Physics and Astronomy

From volcano's slope, NASA instrument looks sky high and to the future

27.04.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>