Researchers at the Massachusetts Institute of Technology (MIT) have developed a portable desalination unit, weighing less than 10 kilograms, that can easily remove various particles and salts to turn seawater into drinkable water.
This portable device, which requires less energy than a cell phone charger to operate, automatically produces drinking water that meets World Health Organization quality standards . The technology works with the push of a button.
Unlike other portable desalination units that force water through filters, this device uses to electricity remove particles from the water. Eliminating the need for filter replacement significantly reduces long-term maintenance requirements.
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The desalination plant could be used in remote areas and areas with very limited water resources, such as communities on small islands or on cargo ships. It could also be used to help refugees facing natural disasters or soldiers involved in long-term military operations.
“This is really the culmination of a 10-year journey that my team and I have been on. We worked for years on the processes for individual desalination processes, and pushing all of these advances into one box, building a system, was a really meaningful and rewarding experience for me,” says Jongyoon Han, professor and member of the Research Laboratory of Electronics (RLE).
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Seawater is turned into drinkable water with filter-free technology
Commercially available portable desalination units typically require high-pressure pumps to push water through filters. The device created by the MIT researchers, however, relies on a technique called ion concentration polarization (ICP). Instead of filtering water, the ICP process applies an electric field to membranes placed above and below a channel of water. The membranes repel positively or negatively charged particles—including salt molecules, bacteria, and viruses—as they pass through. The charged particles are then fed into a second stream of water that is eventually discarded.
The process allows clean water to pass through the channel. Since it only requires a low-pressure pump, ICP uses less energy than other techniques.
However, the ICP technique doesn't always remove all the salts floating in the middle of the channel. So the researchers added a second process, known as electrodialysis, to remove the remaining salt ions.
The researchers designed the device for non-expert use, and with the push of a single button, the process of desalinizing and purifying water can be started. Once the salt level and particle count are reduced to certain limits, the device notifies the user that the seawater has now been converted to drinkable water.
The researchers also created a app smartphone that can control the desalination unit wirelessly and report real-time data on energy consumption and salt levels in the water.
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Seawater to drinking water: Testing desalination technology
After the lab experiments, the researchers tested the device in real-world conditions. They placed the box near the shore and dropped the feeding tube into the water. In about half an hour, the device had filled a plastic cup with clean, drinkable water.
One of the biggest challenges in designing the portable desalination system was creating a device that anyone could use, the researchers say. However, efforts are underway to make the device even more user-friendly and to improve its energy efficiency and production rate.
The researchers want to apply the knowledge they gained over the years working on the desalination plant to quickly detect contaminants in drinking water. Contamination could significantly increase maintenance requirements and energy costs.
Finally, another limitation is the use of expensive materials. It would be interesting to see similar systems with low-cost materials.
Source: news.mit.edu
