The aerogel removed most radioactive iodine from contaminated water samples within a minute. Credit: Fajal, S. et al.
Researchers have synthesised a porous, ultralight aerogel that can adsorb radioactive iodine from vapour and aqueous mediums1.
Radioactive iodine is a byproduct of the fission of uranium atoms in nuclear power plants. It can harm the environment through water discharged from nuclear reactor chiller plants and is toxic to humans if consumed via contaminated food or drink. It collects in the thyroid gland.
Scientists at the Indian Institute of Science Education and Research in Pune produced the aerogel using a host of organic compounds in a two-step process. They then did iodine-capture experiments at different temperatures and under different conditions. Dry conditions allowed the gel to adsorb slightly greater amounts of iodine than humid conditions.
The aerogel removed 99% molecular iodine from water and almost 85% of iodine molecules and polyiodides – a type of anion with three iodine atoms – from contaminated sea, lake and river water samples within one minute.
It could selectively remove anions of iodine even in the presence of other anions usually found in contaminated water. And it continued to show high adsorption capacity after five consecutive capture-release cycles, indicating its reusability.
In addition, the gel retained bound iodine for up to seven days, suggesting its stability and affinity for iodine. The researchers attribute these properties to macropores and micropores that form nearly 80% of void space in its volume. The pores can sequester iodine molecules and polyiodides.
