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Scientists from the Korean Institute of Civil Engineering and Building Technology (KICT) have invented a stable electro-spun nanofiber membrane that could make ocean water drinkable in a matter of minutes. This development could, as a result, end worldwide water shortages.

Although similar technology currently exists, researchers say their new device could last about 14 times longer than others before being replaced.

Current desalination membranes need frequent replacement 

According to the World Health Organization, about 785 million people globally cannot access clean drinking water. The earth holds a large amount of water. However, most of it is seawater which is not drinkable. Only 2.5% of the total amount of water on the earth is freshwater. Seawater is toxic to humans as the body cannot eliminate the high amount of salt from seawater. Consuming it in high amounts could be fatal.

Many countries, especially those located in the Middle East, desalinate their ocean water to make it drinkable. Some states in the U.S also do this. There are several methods used to desalinate water. However, the one used most in the U.S states is membrane desalination.

In membrane desalination, pressure forces water through the membranes. A limitation of the method is that membranes have to be frequently replaced because they become wet and inefficient. Current membranes can be used for approximately 50 hours. The new coaxial electro-spun nanofiber membrane, however, can be used for longer before it becomes too wet to work.  This membrane can work for up to 1 month. It can also perform a 99.99% salt rejection from the water.

How the new membrane works

The co-axial electrospinning technique can help make membranes with a three-dimensional (3D) hierarchal structure. To make the membrane, the team used vinyl Dene fluoride-co-hexafluoropropylene and silica aerogel core and the sheath, respectively. The sheath material had a lower thermal conductivity than other polymers used in membranes; thus, it had a higher water vapor flux during distillation.

According to Dr. Yunchul Woo from KICT,  the new membrane has can treat seawater without becoming wet for a prolonged period. It might be a suitable membrane for red-scale and pilot-scale membrane distillation use.