Anyone who uses a cell phone, laptop or electric car must rely on lithium. There is a great demand for this element. Although lithium is in sufficient supply all over the world, obtaining and extracting lithium is still a challenging and inefficient process.
An interdisciplinary team of engineers and scientists is developing a method to extract lithium from contaminated water.
New research published this week in the proceedings of the National Academy of Sciences could simplify the process of extracting lithium from brine, potentially creating greater supply and reducing the cost of battery components to power electric vehicles, electronics and a wide range of other devices.
At present, lithium is most commonly obtained from salt water in South America by solar evaporation, which is an expensive process and may take several years. In addition, a large amount of lithium will be lost in this process.
The research teams at the University of Texas at Austin and the University of California at Santa Barbara have designed a membrane that can accurately separate lithium from other ions such as sodium, significantly improving the efficiency of collecting coveted elements.
Benny Freeman, Professor of mcketta Department of chemical engineering at the University of Texas at Austin, said: "the findings of this study are of great significance to solve the main resource constraints of lithium, and it is possible to extract lithium from water generated from oil and gas production for batteries and co-author of papers."
In addition to brine, wastewater from oil and gas production also contains lithium, but it has not been developed today. Researchers said that the water from the hydraulic fracturing of Eagle Ford shale in Texas could produce enough lithium for 300 electric vehicle batteries or 1.7 million smartphones in only one week. This example shows the scale of opportunities for this new technology in significantly increasing lithium supply and reducing the cost of equipment dependent on it.
The core of this discovery is the new polymer membrane made by researchers using crown ether, which is a ligand with specific chemical function and can bind some ions. Crown ethers have not been applied or studied as a part of water treatment membrane before, but they can be the key component of lithium extraction, a specific molecule in water.
In most polymers, sodium passes through the membrane faster than lithium. However, in these new materials, lithium moves faster than sodium, which is a common pollutant in lithium containing brine. Through computer modeling, the team found out why this happened. Sodium ions combine with crown ethers to slow them down, while lithium ions remain unbound, allowing them to pass through the polymer faster.
These findings represent a new frontier in membrane science and require comprehensive cooperation between universities in the fields of polymer synthesis, membrane characterization and modeling and simulation. The research was supported by the water and energy system materials center, the UT Austin energy frontier research center funded by the U.S. Department of energy.
