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Textiles help selectively recover gold from electronic waste

On the other hand, fibrous materials underwater are easy to control and can be made into different shapes during the weaving process, which makes them have great potential for industrial application. However, due to their thin thickness and low strength, they break easily when gold repair is applied to the support.

The KIST researchers thus chemically immobilized alkaline molecules on the surface of polyacrylonitrile (PANF) fibers to improve both molecular gold recovery performance and structural stability. The amine-containing polymer fiber has a significantly larger surface area, which can improve the adsorption performance of gold ions (Au) in waste by up to 2.5 times (from 576 mg/g to 1,462 mg/g) compared to the granular gold adsorption material previously developed by the team.

The developed fibrous adsorbent showed a gold recovery efficiency of more than 99.9% in solutions obtained by leaching real CPUs and achieved a gold recovery efficiency of almost 100% in a wide range of pH 1–4, including most waste liquids.

The researchers found it remarkable that only gold ions can be recovered with a high purity of more than 99.9%, even in the presence of 14 other metal ions coexisting in the solution. Moreover, the gold recovery rate remained at 91% even after 10 uses.

“By enabling efficient and environmentally friendly recovery of metal resources, the fibrous adsorbent developed by KIST can reduce Korea’s dependence on raw material imports and prepare for the risk of rising raw material prices,” said Jae-Woo Choi, senior author of the research. said in a media statement. “We plan to expand the scope of future research to selectively recover several target metals in addition to gold.”

For context, Choi explained that Korea relies on imports for most of its metal resources and that in recent years, due to resource depletion and rising commodity prices, recycling plans have emerged.

Companies such as SK Hynix have laid out plans to increase the percentage of copper, gold and other metals recovered and reused from waste generated in the semiconductor manufacturing process to more than 30% by 2030. Samsung Electronics, on the other hand, is running a used cell phone fundraising program in partnership with E-circulation Governance, a non-profit organization.

The researcher also noted that the global circular economy market is expected to more than double in size, from approximately $338 billion in 2022 to $712 billion in 2026.