Nav: Home

IU scientists discover 'supramolecule' that could help reduce nuclear, agricultural waste

October 06, 2016

BLOOMINGTON, Ind. -- Indiana University researchers have reported the first definitive evidence for a new molecular structure with potential applications to the safe storage of nuclear waste and reduction of chemicals that contaminate water and trigger large fish kills.

The study, which appears online today in the German scientific journal Angewandte Chemie International Edition, provides experimental proof for the existence of a chemical bond between two negatively charged molecules of bisulfate, or HSO4.

The existence of this structure -- a "supramolecule" with two negatively charged ions -- was once regarded as impossible since it appears to defy a nearly 250-year-old chemical law that has recently come under new scrutiny.

"An anion-anion dimerization of bisulfate goes against simple expectations of Coulomb's law," said IU professor Amar Flood, who is the senior author on the study. "But the structural evidence we present in this paper shows two hydroxy anions can in fact be chemically bonded. We believe the long-range repulsions between these anions are offset by short-range attractions."

Flood is a professor in the IU Bloomington College of Arts and Sciences' Department of Chemistry. The first author on the study is Elisabeth Fatila, a postdoctoral researcher in Flood's lab.

In molecular chemistry, two monomer molecules connected by a strong covalent bond are called a "dimer." (A polymer is a chain of many monomers.) In supramolecular chemistry, the dimers are connected by many weak non-covalent bonds. A negatively charged particle is an anion.

A key part of Coulomb's law is the idea that two molecules with the same charge create a repellent force that prevents chemical bonding -- like two magnets with the same end put into close contact. But recently, experts have begun to argue that negatively charged molecules with hydrogen atoms, such as a bisulfate -- composed of hydrogen, sulfur and oxygen - can also form viable chemical bonds.

"Although supramolecular chemistry started out as an effort to create new molecular hosts that hold on to complementary molecular guests through non-covalent bonds, the field has recently branched out to explore non-covalent interactions between the guests in order to create new 'chemical species,'" Fatila said. The negatively charged bisulfate dimer in the IU study employs a self-complementary, anti-electrostatic hydrogen bond.

The molecule's existence is made possible through encapsulation inside a pair of cyanostar macrocycles, a molecule previously developed by Flood's lab at IU. Fatila and colleagues were trying to bind a single bisulfate molecule inside the cyanostar; the presence of two negatively charged bisulfate ions was a surprise.

"This paper is inspirational because it may launch a new approach to supramolecular ion recognition," said Jonathan Sessler, a professor of chemistry at the University of Texas at Austin who was not involved in the study. "I expect this will be the start of something new and important in the field."

The ability to produce a negatively charged bisulfate dimer might also advance the search for chemical solutions to several environmental challenges. Due to their ion-extraction properties, the molecules could potentially be used to remove sulfate ions from the process used to transform nuclear waste into storable solids -- a method called vitrification, which is harmed by these ions -- as well as to extract harmful phosphate ions from the environment.

"The eutrophication of lakes is just one example of the serious threat to the environment caused by the runoff of phosphates from fertilizers," Flood said, referring to uncontrolled plant growth that results from excess phosphate nutrients running into lakes and ocean. When these chemicals get into the water supply as runoff from fertilizer -- produced by dairy farms and used to increase crop yields -- they can trigger massive algae blooms that poison water supplies and kill fish in large numbers.

In August, Flood was also named the principal investigator on a new, separate grant from the National Science Foundation to specifically focus on removing these substances from the environment. The three-year, $600,000 award is a collaboration with Heather Allen, a professor at The Ohio State University, which is near a part of the country that has recently experienced large algae blooms due to agricultural runoff into Lake Erie.

The new molecule in the study was detected using equipment at the IU Bloomington Department of Chemistry's Nuclear Magnetic Resonance Facility, the Laboratory for Biological Mass Spectrometry and the IU Molecular Structure Center. Study co-authors are professor Krishnan Raghavachari, associate scientist Jonathan A. Karty, research associate Eric B. Twum, senior scientist Maren Pink and Ph.D. student Arkajyoti Sengupta, all of the IU Bloomington Department of Chemistry. Pink is also director of the IU Molecular Structure Center. Karty is the manager for the Mass Spectrometry lab. Twum is a spectroscopist in the Nuclear Magnetic Resonance Facility.

This study was first reported at the 11th International Symposium on Macrocyclic and Supramolecular Chemistry in Seoul, South Korea. The research was supported by the National Science Foundation.

The cynostar macrocycle developed by Flood's lab is the subject of a pending patent filed by the IU Research and Technology Corp.
-end-


Indiana University

Related Nuclear Waste Articles:

Waste not, want not
Nutritious feed for cattle is complex. As the summer season progresses, grass can become harder to digest.
US nuclear regulators greatly underestimate potential for nuclear disaster
The US Nuclear Regulatory Commission relied on faulty analysis to justify its refusal to adopt a critical measure for protecting Americans from nuclear-waste fires at dozens of reactor sites around the country, according to an article in the May 26 issue of Science magazine.
Potential approach to how radioactive elements could be 'fished out' of nuclear waste
Manchester scientists have revealed how arsenic molecules might be used to 'fish out' the most toxic elements from radioactive nuclear waste -- a breakthrough that could make the decommissioning industry even safer and more effective.
Researchers find new clues for nuclear waste cleanup
A Washington State University study of the chemistry of technetium-99 has improved understanding of the challenging nuclear waste and could lead to better cleanup methods.
Chemistry research breakthrough that could improve nuclear waste recycling technologies
Researchers from The University of Manchester have taken a major step forward by describing the quantitative modelling of the electronic structure of a family of uranium nitride compounds -- a process that could in the future help with nuclear waste recycling technologies.
Nuclear CSI: Noninvasive procedure could identify criminal nuclear activity
Determining if an individual has handled nuclear materials is a challenge national defense agencies currently face.
A new method to help solve the problem of nuclear waste
The article, published recently in Open Chemistry may lead to the development of a process to remove uranium from wastewater at the front-end of the nuclear fuel cycle, or even extracting natural uranium from sea water.
IU scientists discover 'supramolecule' that could help reduce nuclear, agricultural waste
A study from Indiana University published today in the German scientific journal Angewandte Chemie International Edition provides the first experimental proof for the existence of a chemical bond between two negatively charged molecules of bisulfate, or HSO4.
Why Americans waste so much food
Even though American consumers throw away about 80 billion pounds of food a year, only about half are aware that food waste is a problem.
'Dream Team' chosen to study basic science of nuclear waste
PNNL's 'Dream Team' has been selected to lead one of four new Energy Frontier Research Centers to accelerate scientific breakthroughs needed to support the Department of Energy's cleanup mission.

Related Nuclear Waste Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Digital Manipulation
Technology has reshaped our lives in amazing ways. But at what cost? This hour, TED speakers reveal how what we see, read, believe — even how we vote — can be manipulated by the technology we use. Guests include journalist Carole Cadwalladr, consumer advocate Finn Myrstad, writer and marketing professor Scott Galloway, behavioral designer Nir Eyal, and computer graphics researcher Doug Roble.
Now Playing: Science for the People

#529 Do You Really Want to Find Out Who's Your Daddy?
At least some of you by now have probably spit into a tube and mailed it off to find out who your closest relatives are, where you might be from, and what terrible diseases might await you. But what exactly did you find out? And what did you give away? In this live panel at Awesome Con we bring in science writer Tina Saey to talk about all her DNA testing, and bioethicist Debra Mathews, to determine whether Tina should have done it at all. Related links: What FamilyTreeDNA sharing genetic data with police means for you Crime solvers embraced...