Researchers discover efficient and sustainable way to filter salt and metal ions from water

A collaborative study by Monash University, CSIRO, and the University of Texas at Austin that was published today in Sciences Advances may provide a ground-breaking new solution for the two billion people who lack access to clean and safe drinking water globally.

The key is metal-organic frameworks (MOFs), a remarkable next-generation material with the biggest interior surface area of any material that is currently known. Chemical substances may be captured, stored, and released using the sponge-like crystals. Specifically, the ions and salt in seawater.

Lately, researchers led by Dr. Huacheng Zhang, Professor Huanting Wang, Associate Professor Zhe Liu, and their colleagues at Monash University's Faculty of Engineering in Melbourne, Australia, along with Dr. Anita Hill of CSIRO and Professor Benny Freeman of the McKetta Department of Chemical Engineering at The University of Texas at Austin, have found that MOF membranes can replicate the 'ion selectivity', or filtering function, of organic cell membranes.

With more research and development, these membranes have the potential to be extremely successful in both extracting salts from seawater and separating metal ions, providing the mining and water sectors with a completely new and innovative technical solution.

Reverse osmosis membranes, which are the final step in most water treatment procedures and account for over half of global desalination capacity, might reduce their energy usage by a ratio of two to three. Their main limitations stem from the fact that they don't work on the concepts of selective ion transport in biological channels or ion dehydration, which were the subjects of Roderick MacKinnon and Peter Agre's 2003 Chemistry Nobel Prize.

Membrane techniques are being developed in the mining sector to recover important metals and lessen water pollution. Lithium-ion batteries, for instance, are now the most widely used power source for mobile electronics. Nevertheless, given the present rates of use, production of lithium is expected to be required from non-traditional sources, such as recovery from waste process streams and saline water. Direct extraction and purification of lithium from such a complicated liquid system would have significant economic effects if it were technologically and economically possible.

This new study makes these advancements conceivable. Prof. Huanting Wang of Monash University stated, "We can use our findings to address the challenges associated with water desalination." This study offers the possibility of extracting salt ions from water in a significantly more economical and ecologically friendly manner than depending on the existing expensive and energy-intensive methods."

Furthermore, this is only the beginning of this phenomenon's potential. We will keep investigating potential uses for these membranes' lithium ion selectivity. Since saltwater contains a lot of lithium ions, this has consequences for the mining sector, which now extracts lithium from rocks and brines using ineffective chemical processes. There is a huge demand worldwide for lithium, which is needed for batteries and electronics. The extraction of lithium ions from seawater, a copious and accessible resource, may be accomplished rather well with the help of these membranes."

CSIRO's Dr. Anita Hill stated that the discovery adds to the expanding body of knowledge on MOFs and presents another possible practical use for the next-generation material. "From a public health standpoint, the idea of using MOFs for sustainable water filtration is tremendously exciting, and providing an improved method of extracting lithium ions to meet global demand could create new industries for Australia," Dr. Hill stated.

Professor Benny Freeman of the University of Texas in Austin states, "Water produced from Texas's shale gas fields is rich in lithium." This and other cutting-edge separation materials approaches may be able to recover resources from this waste stream. I am extremely appreciative that the Australian-American Fulbright Commission provided me with the chance to collaborate with these esteemed colleagues from Monash and CSIRO for the U.S. Fulbright Distinguished Chair in Science, Technology, and Innovation, which is funded by the Commonwealth Scientific and Industrial Research Organization (CSIRO)."

Provided by Monash University