This September, Dr. Valtteri Suorsa and doctoral researchers Miho Otaki and Topi Suominen won the 2023 RSC Advances Outstanding Student Paper in Environmental Chemistry. In their work, they, along with other researchers, investigated how zirconium oxide selectively removes iodate from radioactively contaminated solutions, giving more detail on how to handle radioactive iodate in the environment.
Iodine is essential for humans because the thyroid requires it to manage breathing, digestion, the heart rate, and more. The thyroid’s almost exclusive use of iodine is also why forms of radioactive iodine, like the long-lived iodine-129, are particularly dangerous. Once absorbed by the body, iodine-129 can accumulate in the thyroid and cause concentrated and relatively high radiation doses, elevating the risk of thyroid cancer.
While some iodine-129 exists naturally, most comes from human nuclear activity. If managed incorrectly, iodine-129’s high mobility means that it can easily move through ecosystems and contaminate our groundwater and agriculture. Iodine-129 also has a half-life of 15.7 million years, which means that even if we went 300,000 years into the future - or the entire existence of humanity - 98.7% of it would still remain.
The removal of iodine is then complicated by iodine’s chemistry. Iodine can be present in many forms (I-, I2, IO3-, organic iodine compounds) depending on the prevailing conditions, all of which usually require different removal methods. Even though iodate (IO3-) is one of the most prevalent forms of iodine in the environment, it currently lacks a selective removal technique, or a removal technique directly targeting the iodine.
This was the problem that Suorsa and others set out to solve by demonstrating how zirconium oxides could selectively remove iodate from waste solutions. They also worked to understand the reaction mechanism of the adsorption, or the chemical process by which the zirconium oxide removed the iodate, to understand the limitations of their technique and learn how to develop even more efficient removal methods. Importantly, the zirconium oxides could be regenerated, and therefore reused, several times without any significant degradation in their performance.
The research Suorsa and others did on the purification of radioactive solutions is essential for ensuring the safe nuclear power and a clean environment. Zirconium oxide’s noted reusability also means that the research has good implications for radioactive iodate’s sustainable and economical removal.
”I regard this publication as the culmination of my PhD research. I really appreciated the fruitful collaboration with all the researchers participating in the process, but perhaps working and developing methods with your peers was the best part here.” said Suorsa. “For these reasons, it feels fantastic to receive this kind of award as PhD students. Without the support and trust from our supervisor Risto Koivula this would, of course, not have been possible.”
Today, Suorsa is working as a senior inspector at the Finnish Radiation Safety Authority (STUK), while Otaki is developing methods for separating the rare-earth elements and Suominen is working in Risto Koivula’s ion exchange group in the radiochemistry unit.
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RSC Advances is a chemistry journal managed by the UK’s Royal Society of Chemistry that had over 3000 published and 8000 submitted papers in 2023. 11 papers were given the award, each from a different research field, with Valtteri Suorsa, Miho Otaki, and Topi Suominen earning the award in Environmental Chemistry.
You can find their 2023 awarded paper "Anion exchange on hydrous zirconium oxide materials: application for selective iodate removal" here.
This work was also an expansion of their 2021 paper "Pure and Sb-doped ZrO2 for removal of IO3− from radioactive waste solutions".