Making clean drinking water from saltwater is a relatively simple process.
You let the sun evaporate the water, trap the steam, condense it on a plastic surface and there you go.
The only problem is, it takes so damn long. Eight hours of sunning will only produce about a cup of water in 24 hours, according to NPR.
But one engineer has found a secret ingredient to speed up this process immensely.
Hadi Ghasemi of the University of Houston and a team from MIT have created a cheap materialthat uses solar energy to desalinate water unbelievably fast.
He told NPR,
Why do we need to heat the bulk of the liquid to get steam? Why not concentrate the solar energy at ‘hot spots?’
The trick to using all the energy to create the steam lies within the graphite in pencils.
The team put graphite in a microwave for seven seconds, causing the gases in the mineral’s outer layer to pop like popcorn.
This yielded a thin, sponge-like material full of holes that floats on water.
These holes become filled with water while soaking up solar energy, evaporating the water inside.
According to Ghasemi,
It creates steam at a low concentration of solar energy. So you don’t need such expensive optical systems to concentrate the solar energy.
Now the team just needs to figure out how to dispose of the salt residue.
MIT’s Gang Chen told NPR,
Eventually the pores [of the graphite] will be clogged.
They also want to decrease the amount of sunlight needed, as the material currently requires a cheap lens or mirror to work.
But regardless of how this is accomplished, the materials involved are still much cheaper than similar devices available, and therefore could hold the key to supplying clean water to the 780 million people living without it.
