Sunlight drives graphene-based membrane to extract lithium from brine
Graphene nanoribbons create sub-nanometre channels to selectively separate lithium from magnesium-rich brines.
The graphene-based membrane, reported in Advanced Functional Materials, uses sunlight to enhance selective ion transport.
The technology was developed by researchers at Pohang University of Science and Technology (POSTECH), South Korea; Griffith University, Australia; and King Khalid University, Saudi Arabia.
The membrane combines edge-functionalised graphene nanoribbons with photothermally reduced graphene oxide (PrGO).
The paper, Edge-functionalised graphene nanoribbons/graphene nanofiltration membrane for solar-driven lithium recovery from brine, describes how the graphene nanoribbons provide functional sites that help lithium ions shed part of their hydration layer and move through sub-nanometre coordination channels, while the PrGO component improves structural stability.
Computational modelling shows that the combined framework lowers the energy barrier for lithium transport compared with other ions.
Under simulated sunlight, the membrane achieved a lithium-to-magnesium separation factor of 26 and reduced the Mg²⁺/Li⁺ ratio from 19.8 to 0.7, enriching lithium by 28 times.
The researchers say the solar-driven approach could offer a scaleable route for more sustainable lithium extraction from brines.
