Harvesting Water from Air
Context in Current Affairs: A team of researchers at the Indian Institute of Technology-Guwahati (IIT-G) have developed a method for harvesting water from humid air.
About the Method
This method involves spraying a sponge-like porous polymeric material on a normal printer paper. As per the researchers, this method can also be used in underwater hulls of ships and submarines to prevent bio-fouling; and to prevent icing on aircraft windows. The method mainly uses the principle of hydrophobicity. The lotus leaves exhibit the property of hydrophobicity.
The Researchers have used the action of the insect-eating pitcher plant whose slippery surface makes insects landing on it to fall into itself to be digested. They used ‘Slippery liquid-infused porous surface’ (SLIPS) to effectively harvest water from foggy air. The SLIPS are capable of harvesting water from air without the use of an external cooling arrangement.
Conventionally, the Atmospheric water generator (AWG) that extracts water from humid ambient air, uses condensation, exposing to desiccants or pressurizing water.
Atmospheric Water Generator
The main principle of operation is condensation. Here the water vapour in the air is extracted as water by pressuring the air, cooling the air below its dew point and exposing the air to dessicants. A Dessicant is a hygroscopic substance. Dew Point is the point to which air should be cooled to make its saturated with water vapour. When cooled further, it will condense into liquid water (or dew).
Water Scarcity in India
India is currently facing one of the biggest water crisis in the world. More than 50% of Indian population has no safe access to drinking water. More than 200,000 people die of lack of access to safe water. More than 82% of households are without piped water supply. The Composite Water Management Index, 2018 noted that India will lose 6% of its economic GDP by 2050.