New Desalination Technique Yields Both Drinking Water and Lithium

Feb. 12, 2018
New membrane successfully separates useful ions while making safe drinking water

Scientists from both Australia and the U.S. have unveiled a new desalination process that makes safe drinking water while also recovering lithium ions. The lithium ions can then be put to use in batteries.

The integral part of this new technique is the use of metal-organic frameworks (MOFs). MOFs possess the largest internal surface area of any known material, which makes it acutely effective at capturing, storing or releasing different molecules. Beyond the uses in this new process, MOFs may also be utilized for carbon emission sponges, high-precision chemical sensors and urban water filters.

Unlike reverse osmosis (RO) membranes, the water filtration process utilizing this new technique does not require water to be forced through at high pressures as RO does, saving significant energy costs. The MOF material is more efficient, dehydrating specific ions as they pass through.

Because lithium ions are abundant in seawater, these ions are left behind for harvesting following the process of desalination.

“This has implications for the mining industry who currently use inefficient chemical treatments to extract lithium from rocks and brines,” said Huanting Wang, an author of the new study. “Global demand for lithium required for electronics and batteries is very high. These membranes offer the potential for a very effective way to extract lithium ions from seawater, a plentiful and easily accessible resource.”

Other potential uses for the new process could involve filtering wastewater from industrial processes such as fracking.