The growing menace due to increasing use of fossil fuels has pressed urgent needs for identifying sustainable and cleaner energy sources worldover. While renewable energy sources like the sun and wind are increasingly gaining acceptance, it may not alone suffice to meet the ever growing energy demands. Given the energy-scarce situation, a group of scientists from Pune’s Indian Institute of Science Education and Research (IISER) has successfully extracted more than 95 per cent of uranium from natural seawater during an experiment. Uranium concentration in seawater, which is about 3 micrograms / litre of seawater, makes its extraction a highly challenging task. For the successful extraction of uranium, several gallons of seawater would have to be processed, making it a costly affair.Some estimates say the ocean is rich in mineral resources, including uranium, but has remained out of human bounds, so far. There is at least 1,000-times more uranium diluted in ocean waters than what is estimated to be present on land. Led by Sujit Ghosh from the department of Chemistry at IISER,Pune, the researchers designed a sponge-like macroporous (size more than 50 nanometres) adsorbent Metal-Organic-Framework (MOF) which showed high uranium extraction capabilities. For the experiment, the researchers collected seawater samples of the Arabian Sea from Juhu beach in Mumbai. The MOF, when infused with a special hybrid material of a special functional group of chemicals, was found to selectively attract uranium cations more than 95 per cent under two hours. “The design is such that the macroporous nature allows uranium cation to enter and remain inside the natural trap site which gets created inside the MOF,” Ghosh said.As it is just the traces of uranium which gets extracted even after processing large volumes of seawater, industries often adopt uranium extraction using adsorbents.
