Unprecedented: Scientists have extracted rare earth minerals from a living plant

The researchers describe the process, capable of extracting the coveted rare earth minerals from a living plant, as a “self-organizing mechanism in disequilibrium”, and compare it to a “chemical garden”. The study shows the viability of phytomining, say its authors.

A team of scientists from the Guangzhou Institute of Geochemistry (GIG), in China, and Virginia Tech, in the United States, made an unprecedented discovery: they identified, for the first time, a naturally formed mineral with rare earth elements (REEs) inside a living plant.

Researchers found nanoscale monazite, a high-value mineral, crystallized in the tissues of a perennial fern, the Blechnum orientale.

The discovery was presented in a publication earlier this month in the journal Environmental Science & Technology.

According to a statement from the GIG, cited by , the discovery “opens up new possibilities for the direct recovery of functional materials based on rare earth elements”.

“This discovery not only clarifies the mechanisms of enrichment of REEs during chemical and biological weathering processes, but also opens new avenues for the direct recovery of functional materials from REEs”, say the authors of the study.

As are crucial materials used in the production of wind turbines, airplanes, semiconductors and advanced technology, being elements and highly sought after by economies such as the China, Russia, United States and Europe.

They are 17 elements that include the 15 lanthanidesin addition to scandium (21Sc) and yttrium (39Y), which tend to occur in the same mineral deposits as lanthanides and have similar chemical properties.

Training in environmental conditions

Monazite is a phosphate mineral rich in rare earth elements such as cerium, lanthanum and neodymium — essential elements for modern technology. The mineral is highly valued for its mechanical, physical and thermal properties.

There’s a high melting point and presents corrosion resistance and radiation damage, characteristics that make it suitable for applications in coatings, lasers, light emitters, ionic conductors and radioactive waste management.

What makes this discovery particularly relevant is the way the mineral formed. Typically, monazite rresult of geological processes under high pressure and temperatures of hundreds of degrees Celsius.

The study shows that plants can facilitate its mineralization under environmental conditions, at the Earth’s surface. This biological process “demonstrates the viability of phytomining”, write the study authors.

Phytomining is an ecological strategy that uses “hyperaccumulator” plants to extract metals from the soil. These plants can concentrate heavy metals in their tissues at levels hundreds or thousands of times higher than those in the surrounding soil.

The strategy consists of grow these plants in metal-rich soils and subsequently recover the desired metals from the harvested biomass. According to researchers, this approach “reduces dependence on mining conventional and mitigates associated environmental and geopolitical risks”.

The study, a collaboration between the Guangzhou Institute of Geochemistry (of the Chinese Academy of Sciences) and Virginia Tech, in the United States, also describes the mechanism that is at the origin of the formation of the mineral.

The team collected plant and soil samples from rare earth deposits in the Guangzhou region of China. The analysis revealed that REEs were mainly concentrated in fern pinnules.

The article explains that minerals crystallize in the extracellular tissues of the plant (on the outside of cells) to prevent non-nutritive elements from entering tissues and as a detoxification mechanism. The authors describe the process as “self-organized and in disequilibrium, similar to a chemical garden”.