Droughts are posing severe risks to many communities around the world. If some years ago lack of access to fresh water resources was mostly a problem of the developing world, now there is simply no guarantee for anyone anywhere- perfect example here is the terrible drought in California.
In the light of the devastating events from recent years, scientists and engineers are doubling their efforts to find ways to convert the endless resource of saline water into fresh drinking water. Desalination plants are now increasingly appearing in parts of the world, with the Middle East leading the way, but these are still quite expensive and relatively inefficient. This is not only because they rely on reverse osmosis, a process which is far from perfect, but also because the demand is much bigger than what can be supplied.
A team of scientists from University of Illinois came up with a new material, which they claim, can quickly, cheaply and efficiently filter out salts and pollution, leaving only fresh drinking water behind. The material is molybdenum disulphide (MoS2), shaped into a sheet with only a nanometer thickness, and tiny nanopores. The material acts as a filtering membrane, which was much more efficient and effective in desalination than even graphene.
In comparison with current techniques, MoS2 allows much larger amounts of water to pass through, with much lower resistance. This is solely due to the chemical characteristics of the molecule- Molybdenum in the center attracts water, while sulphur on the sides pushes it away. The molecule also has a special geometry of the pores, which allows filtering to take place without the need of any fictionalization, as it is the case with graphene.
The newly discovered material gives a very real possibility for effective desalination of ocean water. The scientists are convinced that scaling up the material to industrial level will be successful- the only thing standing in front of them now is to partner with manufacturers.
More details about the method and the findings can be found in the authors’ publication in Nature Communications.
Image (c) Mohammad Heiranian/University of Illinois