Many organic waste finds its fate only in landfills around the world, but researchers at Penn State University have found an innovative use for this waste, as they used micro and nanoparticles that were prepared from these organic materials to capture rare earth elements, such as neodymium, from aqueous solutions. for electronic waste.
The results of their study will be published in the November issue of Chemical Engineering.
"Waste products - such as corn cobs, wood pulp, cotton, and tomato peels - often end up in landfills or in compost," said Amir Sheikhi, assistant professor of chemical engineering at Pennsylvania State University, in a university press release. These are converted into nanoparticles capable of extracting rare earth elements from e-waste.”
mesh material
Rare earth metals, such as neodymium (a silvery-white rare metal), are used to make powerful magnets used in electric and hybrid car engines, speakers, headphones, computers, wind turbines, television screens, and other modern electronic devices.
However - according to Sheikhi - the mining of these elements presents a great challenge, and is environmentally costly, as large areas of land are required to extract the least quantities of these minerals;
So efforts have shifted to recycling metals from e-waste items, such as old computers or electronic circuit boards, but the challenge is effectively separating the metals and waste.
Sheikhi added, "By using organic materials as a platform, we were able to create high-performance micro and ultrafine particles that can stick to metals such as neodymium and separate them from the surrounding fluids," and "through electrostatic interactions, negatively charged micro and nanomaterials bind to positively charged neodymium ions and separate them." ".
Neodymium is used to manufacture strong magnets that are used in many modern electronic devices (Wikimedia)
Experiment preparation
To set up the experiment, Sheikhi's team crushed tomato peels, corn cobs, wood pulp and cotton paper into fine pieces and soaked them in water, then chemically treated these materials in a controlled manner to break them down into 3 distinct parts of the functional materials: micro-products, nanoparticles, and dissolved biopolymers. .
After soaking the materials extracted from electronic waste in water, they interacted with the plant waste after converting it into nanoparticles, resulting in the extraction of earth elements.
The addition of nanoparticles to solutions containing rare-earth neodymium triggered the separation process, which resulted in the capture of neodymium samples.
Sheikhi plans to expand his separation mechanism and use it in the real world in partnership with interested industries.
"In the near future we want to test our process on real industrial samples," he says. "We also hope to adjust the material's selectivity towards other rare earth elements and precious metals, such as gold and silver, so that we can separate them from waste products as well."