Clean water remains a luxury in some parts of the world.
According to the CDC, roughly 780 million people worldwide do not have access to an improved water source.
Since the ocean makes up 70 percent of the earth’s surface, it could be a source of drinking water. Unfortunately, the water is oversaturated with salt. As a result, it can’t be consumed without desalination.
Therein lies another problem.
The two most common desalination methods — reverse osmosis and distillation — require a lot of energy. In fact, the energy cost is so high that many countries cannot afford the process.
Now a global research team has devised an alternative.
The researchers managed to transform brackish water into safe, clean drinking water using a metal-organic framework (MOFs) and sunlight. What’s more, the whole process took less than 30 minutes.
In a statement, lead author of the study and researcher from Monash University in Australia, Professor Huanting Wang said:
“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.”
The researchers published their work in the journal Nature Sustainability.
Using the Power of Sunlight to Purify Seawater
Metal-organic frameworks are a class of compounds that consist of metal ions. These ions, in turn, form a crystalline material with the largest surface area of any material known to man.
For the study, the researchers created a dedicated MOF called PSP-ML-53. After that, they put their new adsorbent to work by trapping salt and impurities in brackish and seawater.
The MOF was able to selectively pulled ions out of the water and hold them on its surface. Within 30 minutes, the adsorbent had reduced the total dissolved solids (TDS) in the water from 2,233 parts per million (ppm) to under 500 ppm.
That’s significantly below the 600 ppm that the World Health Organization recommends for safe drinking water.
The team filtered harmful particles and generated 139.5L of clean water per kilogram of MOF per day. Furthermore, they performed the task in a more energy-efficient manner than the current desalination processes.
“This study has successfully demonstrated that the photoresponsive MOFs are a promising, energy-efficient, and sustainable adsorbent for desalination,” Professor Wang said.
Besides providing potable water, the technique can help with sustainable mining. It can serve as low energy, environmentally-friendly means of extracting minerals, the researchers noted.
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