Retrieving and reusing precious metals from recycled electronic wastes
Precious elements such as gold, palladium and platinum all play a critical role in the global economy. They also happen to be rather rare. “This combination of demand and scarcity poses potential risks to the many supply chains that depend on these elements,” says John Kwame Bediako, a researcher at the LUT School of Engineering Sciences in Finland. According to Bediako, a potential solution could be found in a rather unlikely place: rubbish. “Our frequent replacement of electrical and electronic devices has created a growing volume of e-wastes, with precious metal contents increasingly surpassing those found in natural ore deposits,” he explains. With the support of the IONIC BARRIER project, funded by the Marie Skłodowska-Curie Actions programme, Bediako is leading an effort to design techniques to recycle e-wastes, retrieve the precious elements they contain, and reprocess these metals to meet growing industrial demands. “By shifting towards a circular economy and reducing the EU’s dependence on imported raw materials, we aim to create a domestic source of valuable raw materials for the European manufacturing and hi-tech industries,” adds Bediako.
An innovative ionic barrier-based technique
At the heart of the project is an ionic barrier-based technique designed to recover precious metals from e-wastes. “Leveraging the properties and advantages of adsorption and hydroxide precipitation and crystallisation, we designed high internal pH-driven ionic barrier-based protocols for recovering specific metals from aqueous solutions using polyelectrolyte complexation,” remarks Bediako. As Bediako explains, the techniques take the form of polyelectrolyte complex (PEC) capsules, with different capsules having different pH environments geared towards the selective recovery of a specific precious metal. “Implemented using strategic recovery routes, the capsules essentially adsorb and recover elements from discarded leached e-wastes,” notes Bediako. During testing of the PEC-based ionic barrier capsules, researchers successfully removed nearly 100 % of adsorbed precious metals from a simulated solution using an acidified thiourea.
Driving Europe’s circular economy
The pioneering work carried out by the project could serve as a foundation for future research on recycling e-wastes and retrieving and reusing the critical raw materials they contain. “I am confident that, in the near future, the ionic barrier technique developed in this project will become a widely accepted process that will play a key role in driving Europe’s circular economy,” concludes Bediako. To ensure this happens, Bediako has promoted the project and its work at a wide range of workshops, seminars and conferences, and has published several articles, including in the ‘Chemical Engineering Journal’, ‘Chemosphere’ and ‘Chemical Engineering Science’, amongst others. He was also named Best Young Scientist (oral presentation) at the International Conference on Challenges in Environmental Science and Engineering 2023. He is currently applying for a grant from the European Research Council, with the aim of further advancing the results achieved during the IONIC BARRIER project.
Keywords
IONIC BARRIER, electronic devices, e-wastes, precious metals, supply chains, recycle, circular economy, raw materials
