New sustainable method filters salt and lithium from seawater

Scientists have developed a new method to filter out salt and metal ions from water by mirroring the ion selectivity of cell membranes in their own membranes.

A research team from Monash University in Melbourne, Australia, CSIRO (the Commonwealth Scientific and Industrial Research Organisation) and the University of Texas at Austin discovered that the membranes of a metal-organic framework (MOF), which is a next-generation material, can mimic the filtering functions or ion selectivity of organic cell membranes. This process could then theoretically be used to efficiently extract lithium and minerals from water in a clean way.

MOF’s boost the largest internal surface of any known substance, which are sponge-like crystals that can be used to capture, store and release chemical compounds. Unfolded, a single gram of the material could theoretically cover an entire football field. As the demand for lithium increases, due to its use in batteries for mobile devices and electric cars, this new method of extracting lithium could ensure an unending supply of the metal.

“Produced water from shale gas fields in Texas is rich in lithium,” said Professor Benny Freeman. “Advanced separation materials concepts such as ours could potentially turn this waste stream into a resource recovery opportunity.”

The Texas shale fields can generate up to 300,000 gallons of produced water per week. From that, Freeman believes, enough lithium can be recovered to power up to 200 electric cars or 1.6 million smartphones.

“We can use our findings to address the challenges of water desalination,” said Huanting Wang, a Professor at Monash University. “Instead of relying on the current costly and energy intensive processes, this research opens up the potential for removing salt ions from water in a more energy efficient and environmentally sustainable way.”

However, these scientists aren’t the first to discover the benefits of a metal-organic framework. Last year a partnership between MIT and Berkeley researchers produced a solar-powered device capable of harvesting water from the air. Given the huge potential of MOFs, can you think of any other ways it can be used?