Recovering rare earths using algal biofilms

Mitchell ZakRare earths are a critical resource that are used in a wide range of applications like computers, electric car batteries, windmill turbines, and other green-energy technologies. In spite of the name, they’re not actually that rare. However, they are found at low concentrations and are difficult to separate from one another. To deal with this, ChemE PhD student Mitchell Zak is investigating the use of algae to recover rare earths from mining effluents and other aqueous waste streams by having them adsorb onto the cell wall of the biomass in a process called biosorption.

A major issue with using microorganisms like algae for biosorption is that they have poor mechanical properties and small cell size, which makes it difficult to immobilize and implement in an engineered treatment system.

“To address the immobilization issues, we grow our algae in a much more concentrated form that allows growth to a surface known as a biofilm. My research project, Recovery of Rare Earth Elements Using Algal Biofilms Via Biosorption, focuses on seeing how effective algal biofilms are in terms of overall uptake, kinetics, and selectivity which hasn’t been assessed before,” says Mitchell.

Through guidance from his two supervisors, Professors Grant Allen and Vlad Papangelakis, and postdoctoral fellow Jens Kastenhofer, Mitchell is working hard to develop a low-cost and environmentally friendly method to recover rare earths. His hope is that the algal biomass could be used afterwards to produce other value-added products, such as biofuels.

This week, Mitchell successfully presented his research at the 13th International Water Association Specialist Conference on Wastewater Ponds and Algal Technologies in Melbourne, Australia. Congratulations to Mitchell on a job well done!


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