It’s one of life’s most frustrating ironies that Earth’s surface is over 70 percent water, but most of that is undrinkable. Desalination is an important technology that may help unlock more drinking water, and now two independent teams have developed new types of solar-powered desalination systems using very different mechanisms.
The first of the two comes from researchers at MIT and in China and could provide more than 1.5 gallons of fresh drinking water per hour for every square meter of solar collecting area – that’s more than twice the amount produced by similar systems.
Using sunlight heat, the innovative system involves evaporating and condensing saltwater through four layers of different materials, which eventually separate the salt from the water in an extremely efficient way.
The second system, designed by researchers at the University of Bath uses a very different mechanism — rather than moving the water through a membrane and leaving the salt behind, this device does the opposite, pulling the salt out of the water.
This feat is possible using an ionic system. Separating two chambers is a thin, synthetic, semi-permeable membrane that only allows salt ions to pass through when an electric current is applied. That current doesn’t need to be too strong and can be sourced from solar power.
The researchers on both projects say that these two designs would be useful for small-scale water desalination, possibly in portable units. That means they could be deployed in developing countries or in disaster-stricken areas, to provide drinking water when regular infrastructure is otherwise unavailable.