Nanostructures Sop Up Radioactive Ions

Titanate nanotubes and nanofibers could offer an inexpensive means for removing radioactive cesium and iodide ions from contaminated water (Angew. Chem. Int. Ed., DOI: 10.1002/anie.201103286). These ions are the products of uranium fission, and they can easily dissolve in reactor water during an accident at a nuclear facility. A team led by Huaiyong Zhu of Australia’s Queensland University of Technology reports that titanate nanotubes and nanofibers made inexpensively from titanium dioxide can chemisorb ¹³⁷Cs⁺ and ¹³¹I^– and trap them for safe disposal. In the case of ¹³⁷Cs⁺, titanate nanotubes proved to be the most effective, soaking up 80% of the ions in a 250 ppm solution and extracting all the ions when the concentration was below 80 ppm. To use the titanate nanostructures to remove ¹³¹I^– from aqueous solutions, the researchers had to anchor silver oxide nanoparticles to the surface of the tubes and fibers. It’s these particles that soak up the iodide ions while the titanate plays a supporting role. The researchers hope the knowledge they’ve gleaned will lead to adsorbents for removing other toxic ions found in groundwater or wastewater.