With rapidly changing climate and escalating global warming, studies have predicted that in 2040 a quarter of the world’s children will live in regions where clear and drinkable water is lacking. To combat such a crisis, the desalination of seawater and the purification of wastewater are two possible methods.
The researchers at Linköping University, Sweden, headed by Shaobo Han have developed a cheap and eco-friendly steam generator to desalinate and purify water using sunlight. In comparison to direct water evaporation, the rate of steam production of this steam generator is 4-5 times higher.
Heat from the sun vaporises the water, while salt and other materials remain behind / Image: Thor Balkhed
Solar‐driven evaporation is efficacious in extracting freshwater by prolifically using solar energy. However, building a low-cost, workable solar steam generator with high conversion productivity is still a challenge.
According to the new study, scientists have invented a steam generator composed of an aerogel – containing cellulose-based structure decked with the organic conjugated polymer PEDOT: PSS.
Professor Simone Fabiano, head of the Organic Nanoelectronics group in the Laboratory of Organic Electronics, said,
A 2 mm layer of this material can absorb 99% of the energy in the sun’s spectrum…What’s particularly nice about this system is that all the materials are eco-friendly—we use nanocellulose and a polymer that has a very low impact on the environment and people. We also use very small amounts of material: the aerogel is made up of 90% air. We hope and believe that our results can help the millions of people who don’t have access to clean water.
The aerogel has a porous nanostructure, which indicates that large quantities of water can be absorbed into its pores. The polymer can hold the energy in sunlight, not least in the infrared part of the spectrum, where much of the sun’s heat is transported.
Shaobo Han with the sensor that can measure pressure, temperature and humidity / Image: Thor Balkhed
Tero-Petri Ruoko, a postdoc in the Laboratory of Organic Electronics and one of the authors of the study, said,
The aerogel is durable and can be cleaned in, for example, saltwater such that it can be used again immediately. This can be repeated many times. The water that passes through the system by evaporation becomes very high-quality drinking water.
There is a porous and insulating floating foam located between the water and the aerogel, which will keep the steam generator afloat. The heat from the sun vaporizes the water, keeping residual salt and other materials behind.
The water that passes through the system by evaporation becomes very high-quality drinking water. Hopefully, this could be a potent solution to deal with the inevitable water scarcity in the future.