Evaporative water purification is an ancient technique, but a research team at the University of Science and Technology has come up with a new plan to purify drinking water with sunlight, wood and bacteria. It is reported that this new set of wood-based equipment, can use bacteria to build a key nanostructure. When sunlight converges on the device, the heated liquid water accelerates evaporation. Water vapor can be directed to another separate container to recondense into clean drinking water, but other harmful contaminants are left behind.
We’ve seen water purification solutions based on a variety of materials and configurations, such as water absorption below by machines floating on the lake, foam sponges made of graphene, and solar distillers made from carbon-soaked paper and cellulose aerogels.
However, the new water purifier of the research team of the Chinese University of Science and Technology is a photoabsorbent carbon nanotube placed at the top of the multi-layered structure, a glass bubble in the middle of the insulation, and the bottom of the wood floating on the surface of the water. But the key ingredient in this package is bacteria that are not visible to the naked eye.
The team first applied fermentation to the wood surface, and then, with glass bubbles and carbon nanotubes, bacteria built cellulose nanofibers around them to bind the whole thing together.
This natural porous structure design helps the wood retain moisture and move upward. When the absorbent carbon nanotube layer reaches the top, it is heated and evaporated. At the same time, the glass-like aerogel layer acts as insulation to prevent the release of heat down.
According to the team, this solar evaporator solution is more efficient than most designs, with evaporation rates of 2.9 kg/m3/h, a solar conversion rate of 80%, and a relatively rich and affordable wood and carbon nanotube material.
Details of the study have been published in the recently published nano Letters.
Originally titled “Sustainable Wood-Based Hierarchical Solar Steam Generator: A Biomimetic Design with Reduced Vaporization Enthalpy of Water.”