A novel approach to desalinating water could be very beneficial in providing fresh water for many parts of the world needing clean water. This is a relatively inexpensive process which uses graphite to use solar energy far more efficiently than ever before.
Desalination is an important way to provide fresh water in many parts of the world, but it is usually an extremely energy intensive process. In order to produce fresh water, the brackish water must be heated to produce steam, which leaves the salts behind. Then, the steam is condensed to yield clean water.
Solar power would seem to be ideal for this application, but, until now, it has required intense concentration of sunlight in order to produce the heat needed to boil the water.
The method developed by Dr. Hadi Ghasemi at the University of Houston first microwaves graphite for a few seconds, causing it to fracture and pop “like popcorn.” This material floats on top of a container of water and draws small amounts of water up through capillary action. The pores in the material serve to further concentrate solar energy on those small amounts of water, causing it to steam. Since the solar energy is concentrated on just the top layer, the rest of the water stays cool, so far less energy is needed to produce the steam.
This allows cheaper and simpler equipment to be used to concentrate the solar energy and makes for a simpler system to produce clean water. And graphite is a cheap and plentiful material, which also makes this a promising technology.