The incredible properties of aerogel have allowed the material to be used for numerous purposes, from lining the walls of buildings in the form of insulation to making Mars habitable for humans. Now the wondrous material has also proven its abilities as a water-purifier.
A postdoctoral student at Sweden’s Linköping University has created a technology that converts liquid saltwater — or polluted water — into steam as a means to turn it into pure, clean drinking water.
The tech involves a substance that takes the form of an inexpensive and highly-porous aerogel composed mainly of cellulose (and air), to which an organic polymer known as PEDOT:PSS has been added.
Cellulose is the most abundant organic compound on Earth and is the main component of plants’ cell walls. PEDOT:PSS, on the other hand, is very good at absorbing the energy in sunlight, thanks to it being particularly well-tuned to sunlight’s heat-carrying infrared spectrum. The aerogel has a porous nanostructure, which means that large quantities of water can be absorbed into its pores.
The water-purifying process involves placing the aerogel on a porous and insulating floating foam that allows it to float on the water. Once in place, the gel then absorbs water from below, while absorbing solar heat from above. This causes the absorbed water to quickly heat up and turn to steam, at a rate that is reportedly four to five times higher than if the sun were simply heating the water directly.
The steam then condenses onto a plate located above the aerogel, forming into droplets of purified liquid water that trickle down into a collection trough. All of the salt or other impurities remain behind in the gel, which can be rinsed out and reused multiple times.
