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From hazardous iodine waste to Lithium-ion battery

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In a recent paper published in the journal ACS Materials Letters, research groups of Prof. Sujit K. Ghosh and Prof. Satishchandra Ogale have synthesised a covalent-organic framework to sequester hazardous iodine waste and have employed it as a cathode material for Lithium-ion battery. Here, BS-MS student Satyam Saurabh, who is the first author of the paper, describes the main findings of the paper. Satyam recently completed his BS-MS programme at IISER Pune and plans to join a PhD programme in the area of materials chemistry. 

The beginning of the 21st century has seen an intense policy debate on the scarcity of fossil fuels and, particularly in recent times, climate change, and biodiversity loss that pose an existential threat to nature, the environment, and humanity. Replacing fossil fuels with carbon-free nuclear energy has the potential threat of releasing radioactive iodine during nuclear waste processing and in the event of a nuclear accident.

Handling of hazardous waste is a critical global issue, as efforts to improve the situation remain ongoing due to the continuous production of such waste from rapid industrialisation and population growth. In this context, the development of revolutionary new concepts of efficient iodine capture and simultaneously using them in energy applications is one of the most urgent needs with the view to maintaining a hazard-free green working environment and a sustained clean energy supply. 

In this work, we developed a new cost-effective and scalable route to synthesise a sponge-like COF-TCO (covalent-organic framework). This helps in selective and rapid iodine sequestration in diverse conditions of vapour and aqueous medium.


Schematic illustration of sequestration of iodine waste in a covalent organic framework and its further use as cathode material for Li-ion battery. (Photo Courtesy: Prof. Sujit Ghosh's Group; Image: Reprinted with permission from ACS Materials Lett. 2023, 5, 9, 2422-2430. Copyright (2023) American Chemical Society. Please note further use of the image requires permission from the journal). 


The presence of imine bond, free nitrogen group, and phenyl group synergy allowed a remarkable selectivity towards the iodine capture even in different pH conditions and concurrent competing ions. The COF exhibits a high removal efficiency of iodine from a wide range of water systems including lake water (Pashan Lake, Pune), river water (Mula Mutha, Pune), and seawater (Arabian Sea, Mumbai). To the best of our knowledge, this is one of the first such reports where iodine is captured from different water systems, including potable water, lake water, river water, and seawater, to explore the practical utility of the material.

Further extensive computational analyses, which are correlated with experiments, demonstrated ultrahigh iodine selectivity, as well as the associated mechanistic understanding. 

We found that the iodine-captured COF-TCO when deployed for a Li-ion battery application, exhibited notably significant specific capacity and acted as a superior cathode material. Thus, the hazardous iodine was not only sequestrated to reduce its adverse environmental impact but also further deployed into Li-ion battery applications.

The versatile attributes of excellent selectivity, rapid kinetics, effective recyclability, and affordability of the approach we devised allow the ability to both capture hazardous iodine and serve energy-related purposes simultaneously. We believe this study will lead to new avenues for the utilisation of toxic and hazardous materials in energy applications. 

- by Satyam Saurabh

Article Citation

Covalent organic framework featuring high iodine uptake for Li-ion battery: unlocking the potential of hazardous waste. Satyam Saurabh, Samraj Mollick, Yogeshwar D. More, Abhik Banerjee, Sahel Fajal, Nikhil Kumar, Mandar M. Shirolkar, Satishchandra B. Ogale, and Sujit K. Ghosh, ACS Materials Lett. 2023, 5, 9, 2422–2430.