Lithium will power our low-carbon future. It is essential for lightweight batteries used to store renewable energy and power electric cars. There are three main sources of lithium: geothermal brines found in granite bedrock, brines sourced from salt lakes (see image below), and lithium-bearing minerals from rocks. At present lithium is recovered from brines using chemical processing and/or evaporation. These are expensive or take a long time, and generate large quantities of waste. New supplies of lithium are needed to meet the growing global demand, and sustainable methods of extraction are also required. This applied geoscience PhD project will contribute to these goals by providing key data on the factors that control lithium behaviour in the critical zone, assessing the potential for using microbes to recover lithium, and assessing the environmental impact of lithium extraction, and therefore help support the transition to a low carbon economy.
This project will investigate how microbial activity contributes to the weathering and mobilisation of lithium from different resource types, the potential for lithium biorecovery, and the environmental impacts of lithium extraction, through the testing the following hypotheses:
• Microbial communities are present in lithium deposits, they contribute to the biogeochemical weathering of hard rock minerals, and influence the behaviour of lithium in brines.
• Microbes can be used to recover lithium from brines, such as through sorption to biomass, or via the precipitation of lithium biominerals.
• Lithium mine waste from a range of geological settings does not contain potentially toxic elements. The composition of lithium mine waste is poorly characterised in general, and we will seek to address this by characterising the composition of soils and wastes from lithium extraction.
The research will involve field and laboratory work, and as well as being part of the GeoNetZero CDT, the student will have access to a variety of training opportunities, please see http://blogs.exeter.ac.uk/em3group/2020/11/05/phd-lithium/ for full details and how to apply.
The ideal candidate will have a strong background in a relevant discipline, such as Earth Sciences, Geoscience, Geology, Microbiology, Molecular Biology, Environmental Chemistry, or Biology, with a particular interest in environmental geomicrobiology and geochemistry.