image: Porous porphyrin polymer (COP-180) can extract gold from a computer circuit board and produce pure gold nuggets. view more
Credit: Image credit: Yeongran Hong
Reserachers report a porphyrin polymer that can capture precious metals from chemically digested electronic waste. Used circuit boards, screens, and other electronic waste contain precious metals, such as gold and palladium. However, most electronic waste ends up in landfills due to a lack of safe and efficient methods to recover ores. Yeongran Hong, J. Fraser Stoddart, and colleagues report the synthesis of a porphyrin polymer that captures precious metals from chemically digested electronic waste, raising the possibility that an industrial hazard could become a sustainable source of precious metals. Porphyrins are molecules with ring structures with a high affinity for binding transition metals, such as precious metals, in their center. The authors synthesized the polymer COP-180 by linking porphyrin rings. Using standardized test solutions, the authors showed that COP-180 takes up platinum at the expected rate, whereas gold is adsorbed at a rate 10 times higher than expected. The authors ascribe the increased efficiency to reductive adsorption, which allows the gold atoms to cluster in crystals. To further test COP-180, the authors collected circuit boards at a local outlet for electronic waste. After digesting the boards with an acidic solution, the authors added COP-180, finding that the polymer captured the gold with 94% efficiency. According to the authors, the gold captured by $5 worth of COP-180 would be worth an estimated $64, with profit margins expected to increase when the polymer is reused.
ARTICLE #20-00606: "Precious metal recovery from electronic waste by a porous porphyrin polymer," by Yeongran Hong et al.
MEDIA CONTACT: Cafer T. Yavuz, Korea Advanced Institute of Science and Technology, Daejeon, KOREA; e-mail: yavuz@kaist.ac.kr or cafertyavuz@gmail.com
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Journal
Proceedings of the National Academy of Sciences