Engineers at the University at Buffalo School of Engineering and Applied Sciences have developed a solar-powered water purifier using carbon-dipped paper, which has the potential to be an efficient and inexpensive way to turn saltwater and contaminated water into potable water for personal use.
To conduct the research, the team built a small-scale solar still the size of a mini refrigerator. It’s made of expanded polystyrene foam, a common plastic that acts as a thermal insulator, and porous paper coated in carbon black.
The paper absorbs water, while the carbon black absorbs sunlight and transforms the solar energy into heat used during evaporation.
The device, which they call a ‘solar vapor generator’, cleans or desalinates water by using the heat converted from sunlight. When the sun evaporates the water, salt, bacteria or other unwanted elements are left behind as the liquid moves into a gaseous state.
The water vapor then cools and returns to a liquid state, where it is collected in a separate container without the salt or contaminants.
Only 12% of the available energy was lost during the evaporation process, according to the university. This is possible partly because the device converts only surface water, which evaporated at 44°C.
The researchers believe the still is capable of producing 3-10 liters of water per day, an improvement over most commercial solar stills of similar size that produce 1-5 liters per day, according to the team.
The idea could help address global drinking water shortages, especially in developing areas and regions affected by natural disasters.