This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: We generally throw away a broken camera lens, earphones or an old phone that has stopped working and is beyond repair because they seem useless when they no longer function. However, these objects contain rare earth elements (REEs) that have applications in magnets, superconductivity, optics and batteries, among others.
When these objects end up in water, recovering REEs becomes difficult. Industrial activities can also introduce toxic metals such as lead, cadmium, nickel and manganese into the same water. The challenge is no longer simply how to remove these unwanted, harmful metal pollutants from water, but also how to efficiently recover the valuable REEs.
What if a single strategy could help address both issues? To that end, researchers from the Indian Institute of Technology Gandhinagar (IITGN), the University of Cambridge and the University of Birmingham have developed a protocol using a class of highly porous materials called metal-organic frameworks (MOFs). These materials can efficiently capture toxic metals from water as well as recover valuable REEs from waste streams.
Published in Nature Protocols, the study provides a framework for designing, characterizing and deploying MOFs for water remediation and circular resource applications under real-world conditions. Think of the MOF as a molecular fishing net. Its countless pores provide a vast surface for capture, while specially designed chemical sites act like hooks that can latch on to particular metals.
The researchers tuned this net so that it preferentially traps the metals they are looking for. It is like identifying and picking out red and green marbles from a bucket containing hundreds of marbles in different colors. Some MOFs can have internal surface areas of up to 7,000 square meters per gram.
To put that number in perspective, one gram may look like a tiny pinch of powder, but inside it is a surface area comparable to an entire football field. This huge internal surface makes MOFs attractive as adsorbents. In simple terms, they capture substances on their surfaces.
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