Richard Haverkamp with Benoit Guieysse, Olivia Buwalda, Karla Wolmarans (Massey University) and international collaborators (Max IV, Lund University and ANSTO)
The race to mine rare earth elements is increasingly competitive as the impetus for renewable energy escalates. Many devices, including smartphones, electric vehicles and wind turbines rely on rare earth elements.
Extracting rare earth elements from the Earth’s crust requires energy intensive mining and lacks elemental sensitivity. Greener and more selective rare earth production is required to meet global sustainability goals and support renewable technologies.
Green mining may be possible using algae. Specifically, microalgae can synthesize phosphate-rich granules that can selectively sequester rare earth elements. However, the chemistry of this interaction is not well understood.
The research team used the Medium Energy X-ray Absorption Spectroscopy (MEX1 and MEX2) beamlines to investigate phosphorous in the granules (MEX2) and the associated rare earth elements (MEX1). The MEX2 data showed that microalgae capture phosphorous from the environment and convert it into intracellular granules of phytic acid, which aids in separating rare earth elements from environmental samples.
The microalgae were able to extract and separate the rare earth elements gadolinium and cerium via the phosphorous granules.
Observed differences in microalgal uptake between gadolinium and cerium may suggest a selective extraction technique that could be generalized to other rare earth elements. This finding opens the doors to more sustainable methods of rare earth mining.
The microalgae response can also be applied to wastewater treatment where phosphorous needs to be removed, or for the storage and relocation of phosphorous to places of need such as agriculture.
Reference:
Plouviez M, Guieysse B, Wolmarans K, Matinong AME, Buwalda O, Thånell K, Beinik I, Tuyishime JRM, Mitchell V, Kappen P, Flynn D, Jauffrais T and Haverkamp RG. 2024. Microalgae for the extraction and separation of rare earths: An STXM study of Ce, Gd, and P. ACS Sustainable Resource Management 1(10): 2225-2233. https://pubs.acs.org/doi/10.1021/acssusresmgt.4c00237
Related research:
Plouviez M, Guieysse B, Buwalda O, Wolmarans K, Thånell K, Beinik I, Tuyishime JRM, Mitchell V, Kappen P and Haverkamp RG. 2024. Phosphorus storage in microalgae: STXM and XAS P K-edge investigation. https://doi.org/10.1021/acssusresmgt.4c00130
