A sunlight-harvesting graphene film can produce steam without boiling the water. The material, which has been made by Chinese scientists, could convert sea or wastewater into drinking water in places where fuel or access to electricity is limited.
Desalinating seawater to make drinking water usually means boiling it, and then collecting and condensing the steam. Heating water to its boiling point, however, requires a great deal of energy either in the form of fuel or electricity. There are solar stills that desalinate water using only sunlight, but they’re slow and not always efficient enough to provide sufficient drinking water for a person’s daily needs.
Xianbao Wang and colleagues from Hubei University have now made a graphene aerogel film capable of producing water vapour at room temperature using only sunlight. The aerogel floats on the surface, where it heats up only a small section of the water column, ‘while the temperature of the bulk water is far below the boiling point’, as Wang explains.
Source: Chemistry World