Lithium, often referred to as the “energy metal of the 21st century” [1], is facing rapidly growing demand driven by the expansion of lithium-ion battery technologies. It is projected that by 2030 global demand will exceed proven reserves by nearly twofold, underscoring the need for alternative extraction methods. Direct lithium extraction (DLE) offers a promising solution by enabling recovery from both conventional brines and unconventional sources, including lithium-rich waters associated with oil and gas condensate fields.
This study explores a membrane-based DLE approach for the selective recovery of lithium from oilfield brines. The membrane consists of a polyamide (PA) support that is functionalised with zeolitic imidazolate framework-8 (ZIF-8), which is a metal–organic framework that is characterised by uniform microporosity, an optimal pore size and a high surface area [2]. The PA provides a robust and cost-effective substrate, while the ZIF-8 imparts strong ion selectivity, facilitating the preferential transport of lithium over the competing cations present in brines [3].
An integrated extraction sequence was developed and evaluated, comprising brine pre-treatment, membrane separation, and final carbonation. Applied to a sample from an East Siberian oilfield, this process yielded lithium carbonate with a purity of 98.44%, demonstrating both technical feasibility and efficiency of the approach. These results highlight the potential of MOF-modified membranes for the valorisation of oilfield brines, paving the way for their future industrial-scale implementation.
1. Garcia L.V. et al. Lithium in a Sustainable Circular Economy: A Comprehensive Review // Processes. 2023. Vol. 11, № 2. P. 418.
2. Zhao J. et al. Preparation and Lithium-Ion Separation Property of ZIF-8 Membrane with Excellent Flexibility // Membranes (Basel). 2023. Vol. 13, № 5. P. 500.
3. Yu H. et al. Selective lithium extraction from diluted binary solutions using MOF-based membrane capacitive deionization // Desalination. 2023. Vol. 556, P. 116569.
