Biobased materials used to recover rare earth elements

What do corn cobs and tomato skins have to do with electronics? They can both be used to recover valuable rare earth elements, like neodymium, from electronic waste. Penn Condition researchers used microparticles and nanoparticles created from organic materials to capture rare earth elements from aqueous alternatives.

Their findings, available online now, will also be published in the November issue of the Chemical Engineering Journal.

“Waste like corn cobs, wood pulp, cotton and tomato peels often end up in landfills or in compost,” the author said. correspondent Amir Sheikhi, assistant professor of chemical engineering. “We wanted to transform this waste into micro or nanoscale particles capable of extracting rare earths from electronic waste.”

Rare earth metals are used to make powerful magnets used in electric and hybrid car motors, speakers, headphones, computers, wind turbines, television screens, and so on. However, extracting these metals proves to be difficult and costly for the environment, according to Sheikhi, as vast land is required to extract even small amounts of metals. Instead, efforts have turned to recycling metals from electronic waste such as old computers or circuit boards.

The challenge is to effectively separate metals from waste , said Sheikhi.

“Using the organic materials as a platform, we have created highly functional microparticles and nanoparticles that can attach to metals like neodymium and separate them from the fluid around them,” Sheikhi said. “Via electrostatic interactions, negatively charged micro- and nanoscale materials bind to positively charged neodymium ions, pulling them apart.”

To prepare for the experiment, the team of Sheikhi crushed tomato peels and corn cobs and cut wood pulp and cotton paper into small fine pieces and soaked them in water. Then, they chemically reacted these materials in a controlled way to disintegrate them into three distinct fractions of functional materials: microproducts, nanoparticles and solubilized biopolymers. The addition of microproducts or nanoparticles to neodymium methods triggered the separation process, resulting in the sixteen neodymium samples.

In this most recent post, Sheikhi improved on the separation process demonstrated in previous work and extracted larger neodymium sample sizes from less concentrated solutions.

Sheikhi plans to expand its separation mechanism to real-world scenarios and partner with interested industries to further test the process.

“In the near future, we want to test our process on realistic industrial samples,” said Sheikhi.

“We also hope to adjust the selectivity of materials towards other rare earth elements and precious metals, such as gold and silver, so that they can also be separated from the waste.”

In addition to Sheikhi, Mica Pitcher, PhD student in chemistry e Penn State and first author of the article Breanna Huntington, Penn State undergraduate student in agricultural and biological engineering and Juliana Dominick, Penn State undergraduate student in biomedical engineering, contributed to the article.

Penn Point out supported this work.

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