Navigation Links
Green sludge can protect groundwater from radioactive contamination
Date:3/17/2011

Radioactive waste decaying down at the dump needs millions of years to stabilize. The element Neptunium, a waste product from uranium reactors, could pose an especially serious health risk should it ever seep its way into groundwater even 5 million years after its deposition. Now, researchers at the University of Copenhagen have shown the hazardous waste can be captured and contained. The means? A particular kind of green goop that occurs naturally in oxygen-poor water.

Bo C. Christiansen is a geochemist at the University of Copenhagen who specializes in "green rust". In a recent article published in the prestigious journal Geochimica et Cosmochimica Acta, Christiansen describes how green rust is able to, so to say, encapsulate and contain neptunium. It's an insight that can greatly influence how and where to dispose of radioactive waste.

"Our study shows that even the safest encapsulation of radioactive waste could be made safer if radioactive waste canisters are buried in a place where green rust will form," explains Christiansen.

For years green rust was perceived as a problem. The substance was investigated primarily by material scientists who wanted to know how to avoid green rust formation in reinforced concrete. In recent years however, a group of chemists, physicists and geologists at the Department of Chemistry's Nano-Geoscience Research Group have been studying the substance's beneficial properties. The results have exceeded all expectations.

"Neptunium is a relatively exotic problem. Not a lot of people need to safeguard a radioactive waste depot. But green rust appears to be effective against nearly any kind of pollution," says Bo Christiansen.

Green rust is a type of clay referred to as an anionic clay. Because it consists of iron which has not entirely rusted, green rust has an electron deficit. This makes it react very readily with other pollutants, some of which are quite prevalent.

"A while ago we showed how green rust can react with the carcinogenic chromium (6) and convert it to chromium (3). "Besides being non-toxic, chromium (3) is one of the trace elements that the human body needs," says Christiansen.

Large quantities of green rust are rarely present at any given moment due to it's very high level of reactivity. On the other hand, it's easy to make. Green rust will form if iron sulphate and caustic soda are present in water. But it won't last long. As soon as oxygen is added to the mix, the rust will become ordinary red rust, known by its ochre characteristics.

Experiments demonstrating green rust's ability to immobilize neptunium have been conducted partly at SKB Swedish Nuclear Fuel and Waste Management's full scale pilot research facility at Okskarshamn on the Swedish east coast and also in part at the Karlsruhe Institute of Technology in Germany.

Typically, radioactive waste is disposed of in iron-lined copper canisters. This is suitable as long as the canisters are surrounded by water. However, any future ice-age will draw water levels downwards. Should the copper dry, it will begin to decay. And as the copper disappears, it will only take a short time for the iron to begin rusting away. Ultimately, the radioactive waste gains entry to the groundwater. Therefore, to ensure the security of radioactive waste, green rust could be established to surround the canisters.

"Green rust is no quick-fix to clean up after pollution that suddenly presents itself. But our experiments have shown the surprising result that nature can help to clean itself. Even when the pollution is with a substance as serious as neptunium," says Bo Christiansen who expects the results to inform and be applied to the design and modeling of future radioactive storage.


'/>"/>

Contact: Jes Andersen
jean@science.ku.dk
452-360-1140
University of Copenhagen
Source:Eurekalert  

Related biology news :

1. MU scientists go green with gold, distribute environmentally friendly nanoparticles
2. Carbon dioxide scrubber captures greenhouse gases
3. Green coffee-growing practices buffer climate-change impacts
4. Greenhouse gas auction revenues can help cut Md. electric use significantly, says study
5. Green tea may delay onset of type 1 diabetes
6. Potent greenhouse gas more prevalent in atmosphere than previously assumed
7. What is really happening to the Greenland icecap?
8. A green future for scrap iron
9. Expert recommends town councils to design low-allergy impact green spaces
10. Parasite-resistant peppers green alternatives to chemical pesticides
11. MIT analysis shows how cap-and-trade plans can cut greenhouse emissions
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Green sludge can protect groundwater from radioactive contamination
(Date:3/28/2017)... , March 28, 2017 The ... Hardware (Camera, Monitors, Servers, Storage Devices), Software (Video Analytics, ... Region - Global Forecast to 2022", published by MarketsandMarkets, ... 2016 and is projected to reach USD 75.64 Billion ... and 2022. The base year considered for the study ...
(Date:3/24/2017)... Controller General of Immigration from Maldives Mr. Mohamed Anwar and ... international IAIR Award for the most innovative high security ePassport and eGates  ... ... Maldives Immigration Controller General, Mr. Mohamed Anwar ... right) have received the IAIR award for the "Most innovative high security ...
(Date:3/23/2017)... , March 23, 2017 The report "Gesture Recognition and ... Industry, and Geography - Global Forecast to 2022", published by MarketsandMarkets, the market ... CAGR of 29.63% between 2017 and 2022. Continue ... ... ...
Breaking Biology News(10 mins):
(Date:10/12/2017)... NY (PRWEB) , ... October 12, 2017 , ... ... of Sciences today announced the three Winners and six Finalists of the 2017 ... given annually by the Blavatnik Family Foundation and administered by the New York ...
(Date:10/12/2017)... ... 12, 2017 , ... AMRI, a global contract research, development ... patient outcomes and quality of life, will now be offering its impurity solutions ... new regulatory requirements for all new drug products, including the finalization of ICH ...
(Date:10/11/2017)... ... , ... Personal eye wash is a basic first aid supply for any work environment, but ... do you rinse first if a dangerous substance enters both eyes? It’s one less decision, ... its unique dual eye piece. , “Whether its dirt and debris, or an acid or ...
(Date:10/11/2017)... ROTTERDAM, the Netherlands and LAGUNA HILLS, ... that The Institute of Cancer Research, London ... will use MMprofiler™ with SKY92, SkylineDx,s prognostic tool to risk-stratify ... high-risk trial known as MUK nine . The University ... this trial, which is partly funded by Myeloma UK, and ...
Breaking Biology Technology: