(GIST OF SCIENCE REPORTER) Cost-Effective and Environment-Friendly Water Desalination Technique

[March-2022]

Researchers at the Indian Institute of Technology Gandhinagar (IITGN) have developed a cost-effective and environment-friendly water desalination technique that can successfully remove more than 99% of salt ions and other impurities with natural processing to make seawater potable.
This is the first such method that could controllably manipulate graphite inside aqueous solutions without damaging the structural integrity of graphite. These findings were recently reported in Nature Communications.

According to a report from the World Health Organisation (WHO), nearly one-fifth of the world population lives in areas that are devoid of clean drinking water. The continuous increase in population and enormous energy demands has put immense pressure on conventional clean water resources.
On the other hand, 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.
With rising demand for potable water and continuously shrinking freshwater resources, more and more countries will have to turn to desalination of seawater to meet the needs.

The research is inspired by the trees’ natural intake of water that uses capillary effect. Selective transport of molecules and ions is commonly observed in biological systems.
Mimicking these biological channels could result in highly efficient filtration systems. The research team used capillary process in the technique, which does not cost any energy, and in fact, the 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.
The researchers found that this technique is self-sufficient and can successfully remove more than 99% of salt ions and other impurities from seawater, making it completely safe for drinking.
Moreover, carbon materials like graphite are antimicrobial, reducing the number of filters required in the desalination process.