Aug 19, 2019 | Updated: 08:55 AM EDT

Simple Efficient Way of Removing Salt From Water Discovered

May 08, 2019 03:38 PM EDT

(Photo :
New Desalination Approach (IMAGE)
(Photo : Chanhee Boo/Columbia Engineering) This is an illustration describing fresh water production from hypersaline brines by temperature swing solvent extraction.

Amine Solvents (IMAGE)
(Photo : Robert Winton and Ngai Yin Yip/Columbia Engineering) These are amine solvents (top phase) extracting water from hypersaline brines (bottom phase).

There will come a time when drinking water will be more valuable than gold. Given the state of our environment today, with industries pumping more salt water and various pollutants contaminating groundwater rendering it unfit for consumption, that may not be as far fetched as we many of us probably think.

Which is why the ability to quickly and easily convert saltwater to clear water has been a goal of several scientists around the world. Currently, the gold standard of doing so is with reverse osmosis, but this process is quite tedious and requires high pressure and temperature to complete. Recently the capability of quick desalination thru a relatively easy process was discovered by a group of researchers from Columbia University as published in the Environmental Science and Technology Letters.

The process that they have presented is called Temperature Swing Solvent Extraction (TSSE). It is designed to purify hypersaline brines (these are 7 times more salty than saltwater); which is a by-product of industrial processes, in particular of oil and gas production. Unconverted, hypersaline brine is a major groundwater contaminant as well.

The research team, led by Columbia Engineering's assistant professor of earth and environmental engineering Ngai Yin Yip stated that the science behind it is complicated, and according to him the process 'utilizes low-temperature heat and a low-polarity solvent with temperature-dependent water solubility for the selective extraction of water over salt from saline feeds.' He further stated that this process is completely different in comparison to current desalination technology since it is membrane-less and not based on evaporative phase change.'

The science behind the process, as they say, might seem complicated but when the researchers showed how it was done, it seemed pretty simple. They mixed a solvent in with a sample of hypersaline brine. In the jar, they appeared separated but after heating them -low-grade heat of less than 70°C (158°F), and decanting the red solvent into another jar to be heated separately, what was left was a layer of clear water.

What is noteworthy is the implications of the process itself wherein the team was able to remove up to 98.4% much like reverse osmosis though without the use of high pressure or temperature, and this is exactly why it's considered a game-changer for treating wastewater and creating drinking water fit for consumption.
As Yip said, "It is effective, efficient, scalable, and can be sustainably powered."

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