New Technology Makes Seawater Drinkable Using Sunlight
How did humans ever suffer water scarcity on a planet whose surface is 71% water? Hopefully, that's one of those surprising general trivia questions that future generations will ask themselves.
Why? Because a group of international researchers has just unveiled a technology that is able to transform brackish water and seawater into safe, clean drinking water in less than 30 minutes using metal-organic frameworks (MOFs) and sunlight.
MOFs are incredibly porous materials with very high surface areas — they consist of metal ions that form a crystalline material with the largest surface area of any material known.
In this case, the team of researchers developed a completely new MOF, dubbed PSP-MIL-53, which is able to trap impurities and salt from seawater and dirty water. Essentially, when the material is placed in the water, it pulls the ions out of the liquid and holds them on its surface.
In their study, the research team showed that, using their MOF, they were able to reduce the total dissolved solids (TDS) in the water from 2,233 parts per million (ppm) to under 500 ppm. That's far below the World Health Organization's recommended threshold of 600 ppm for safe drinking water.
What's more, all of this was achieved in under 30 minutes and using much less energy than other desalination methods. The team also showed that the MOF crystals could also be regenerated for reuse within four minutes by exposing them to sunlight.
“Desalination has been used to address escalating water shortages globally," Lead author Professor Huanting Wang from the Department of Chemical Engineering at Monash University in Australia said in a press release.
"Due to the availability of brackish water and seawater, and because desalination processes are reliable, treated water can be integrated within existing aquatic systems with minimal health risks,” he continued.
The problem is that thermal desalination processes that rely on evaporation typically require high energy consumption. Other methods, such as reverse osmosis are also highly energy-intensive and require a lot of chemicals for cleaning and dechlorination.
“Sunlight is the most abundant and renewable source of energy on Earth.," Professor Wang explains. "Our development of a new adsorbent-based desalination process through the use of sunlight for regeneration provides an energy-efficient and environmentally-sustainable solution for desalination."