Scientists discover a game-changing way to remove salt from water

The planet is warming, industries are pumping more salt water into the environment and when the water wars are upon us, drinking water will be more valuable than gold.

That’s why the ability to quickly and easily desalinate water has long been a goal of scientists around the world. And now, a group of researchers from Columbia University believe they’ve found a way to do it.

The process is called Temperature Swing Solvent Extraction and it’s designed to purify hypersaline brines (water that contains a high concentration of salts, making it up to seven times as salty as seawater). This kind of waste water is produced by industrial processes and during oil and gas production, and it poses a major pollution risk to groundwater.

The research team, led by Ngai Yin Yip, a Columbia Engineering assistant professor of earth and environmental engineering, mixed a solvent (dyed red) in with a sample of hypersaline brine (dyed blue).

The liquids appear to stay separated in the jar, but after heating them, and then decanting the red solvent into another jar to be heated separately, the team was left with a layer of clear water.

What’s most exciting about the process is its implications. The team was able to remove up to 98.4 per cent of the salt, which is comparable to the current “gold standard” process, reverse osmosis. But unlike reverse osmosis or other methods of desalination, this process doesn’t require high temperatures or high pressures — just a low-grade heat of less than 70°C.

And that makes it a game changer — both for treating waste water and even creating drinking water fit for human consumption.

“TSSE could be a disruptive technology,” said Yip. “It’s effective, efficient, scalable, and can be sustainably powered.”