IIT Gandhinagar develops cheap method to make seawater drinkable

Researchers claim that the cost-effective and environment-friendly water desalination technique can be used to remove over 99 per cent of salt ions and other impurities with natural processing.  

Researchers at the Indian Institute of Technology (IIT) Gandhinagar have developed a new technique to make seawater potable drinkable. The researchers claim that the cost-effective and environment-friendly water desalination technique can be used to remove over 99 per cent of salt ions and other impurities with natural processing.  

According to the team, the first such method can be used to manipulate graphite, without damaging its structural integrity, inside aqueous solutions.  The technique can prove useful in designing filters for gas purification, proton exchange in a fuel cell, chemical separation, recovery of precious metal from waste among others, the team said and added that It can also be suitable for dehumidification applications as expanded graphite has high water evaporation rates. 

The finding has been published in the journal, ‘Nature Communications’.  

RO technique for desalination expensive, energy-intensive 

“The widely used reverse osmosis (RO) technique for desalination is expensive, wastes more water and is highly energy-intensive, which typically requires hydrostatic pressures of 60-80 bar,” said Gopinadhan Kalon, physics and materials engineering, IIT Gandhinagar. The team created controllable water transport channels in graphite crystal with the help of an electric field and potassium chloride ions that allowed only freshwater to move through the crystal and blocked all salt ions. 

“The team used capillary process which does not cost any energy and in fact evaporation of water happened spontaneously without the need of any external pressure. The evaporation rates provided a back-calculated pressure of 50-70 bar arising from the capillary and other forces that are present inside the nanoscale channels,” he said. The team is now working on developing a direct point-of-use water filter using this technique to make it accessible for the masses. 

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