Removing radioactive iodide

30 Oct 2015 NUS scientists discovered an interesting application for Reuleaux disks.

Basic bismuth nitrate (BBN) crystals were prepared in the form of the novel Reuleaux triangle disks shape. These crystals show good promise as agents in the capture of radioactive iodine.

With the explosion of research in the field of nanocrystal engineering, one would assume that most, if not all the possible geometric shapes that can be adopted by crystals have already been uncovered. A team led by Prof FAN Wai Yip from the Department of Chemistry in NUS reported the first synthesis of Reuleaux triangle disks composed of basic bismuth nitrate Bi(NO3)3, more commonly known as BBN. Guitar picks are a familiar example of the unique shape, which prior to this, has never been manifested in natural systems. Analysis of the intermediates revealed a unique growth process, shedding light on the mystery behind the formation of the Reuleaux triangle shape (see Figure). These findings are expected to conjure a myriad of possibilities in multiple disciplines.

An interesting application can be found even for the Reuleaux disks. As observed in the unfortunate Fukushima disaster in 2011, power plant accidents can result in the leakage of high concentrations of iodine radioisotopes into the environment, causing widespread and severe health problems. Studies on adsorbents for the capture and containment of radioactive iodine have identified bismuth salts as a possible candidate. It turns out that the Reuleaux BBN disks showed very good promise indeed, with high removal capacities, fast capture kinetics, good selectivity and sorption irreversibility.


Figure shows the formation of the Reuleaux triangle shape. [Image credit: Fan WY]



Ng CHB, Fan WY. “Reuleaux Triangle Disks: New Shape on the Block.” J. Am. Chem. Soc. 136 (2014) 12840.