Hollow carbon beads for significant water evaporation enhancement

Floatable low-density millimetre-sized hollow carbon beads were prepared by a phase inversion method, and they were used to promote water evaporation under simulated sunlight. Hollow carbon beads with 1.5 mm diameter achieved an evaporation rate of 1.28 L m−2 h−1 that was around 237% of the rate attained without carbon beads when 714 g m−2 (0.5 g) of carbon beads were present. This significant enhancement of water evaporation rate is owing to the dramatic increase of the water surface temperature, which is brought about by the light-absorbing property of the floating hollow carbon beads. In addition, a good recyclability was also demonstrated. In general, these millimetre-sized hollow carbon beads accelerate the water evaporation process, making the collection and recycle process easier to suit the practical application.