A lot of time and money have gone into nuclear research and development lately, along with studies concerning whether or not it's a feasible and scalable means for power in the near and far future. Though seen less in the media, the problem of what to do with all the waste products from reactors is nevertheless a growing concern as countries postulate nuclear power for their growing or developing infrastructures.

Current materials used for cleansing nuclear waste of radioactive materials include metal oxides and polymer resins, but their performance is limited to working well in an either basic or acidic solution. A new material developed at Northwestern University, called KSM-1, does a more thorough job in both conditions, and across the entire pH spectrum. The material is composed of layers of potassium, manganese, tin and sulfur.

KSM-1 has proven to be very efficient in removing strontium, one of the more dangerous byproducts of nuclear fission, from a mock solution composed of sodium and non-radioactive strontium. The non-radioactive version of the element reacts identically to strontium-90, the harmful ion found in nuclear waste.

"It is a very difficult job to capture strontium in vast amounts of liquid nuclear waste. Sodium and calcium ions, which are nonradioactive, are present in such enormous amounts compared to strontium that they can be captured instead of the radioactive material, interfering with remediation," said Mercouri G. Kanatzidis, Charles E. and Emma H. Morrison Professor of Chemistry at the Weinberg College of Arts and Sciences at Northwestern. "The metal sulfide did much, much better than we expected at removing strontium in such an excess of sodium. We were really amazed at how well it discriminates against sodium and think we have something special. As far as we can tell, this is the best material out there for this kind of application."

The removal of radioactive particles from liquid nuclear waste could allow the safer storage or disposal of the harmful byproducts and the remaining purified water to be recycled or safely drained to other facilities.

The group's work was published online last week at the Proceedings of the National Academy of Science (PNAS) in a paper titled "Layered Metal Sulfide: Exceptionally Selective Agents for Radioactive Strontium Removal."