The way things are going, our world is facing a future of climate change and water scarcity. That is why finding an environmental way to clean our drinking water is of the utmost importance. Now, researchers at the Chinese Academy of Sciences in Beijing and Yangzhou University (YZU) in Jiangsu think they have found a practical, efficient and non-toxic solution. They recently published their findings in the journal Chem.
They have developed a water system that used sunlight and 2D materials to purify water of 99.9999% of bacteria – including E. coli. Testing proved that in just 30 minutes, their eco-friendly system was able to purify enough daily drinking water for four people. That’s five times faster than any other metal-free photocatalyst we currently know of.
Plus, the reaction only consumes a tenth of the catalyst at a time. The efficiency comes from the unique structure of this material – the researchers loaded the edges of the sheets with carboxyl and carbonyl molecules, which drew additional electrons to these edges.
The inexpensive system works by shining ultraviolet light onto a two-dimensional sheet of a compound called graphitic carbon nitride inside a water container. This type of technique for water cleaning is known as photocatalytic disinfection. Senior author, Dan Wang, strongly believes that “the future application of photocatalytic disinfection technology can significantly relieve clean-water scarcity and global energy shortage.”
How It Works:
- The graphitic carbon nitride behaves as a photocatalyst in water – which means it absorbs (UV) light and speeds up (or catalyzes) the oxygen reactions that happen in water in the presence of certain wavelengths of light.
- These reactions produce molecules known as reactive oxygen species (ROS), which are great at killing microorganisms.
- This whole setup efficiently produced a ROS we all know as hydrogen peroxide.
- Once in the water, this antiseptic effectively kills bacteria by breaking through their cell walls and wreaking havoc on their insides, before safely dissociating into water and oxygen.
This scientific breakthrough could someday soon bring cheap, clean drinking water to people everywhere. The researchers are now working to implement their system into portable drinking containers so they can start being deployed to at-risk areas all around the world.
The best part is, a system like this would not be hard to reproduce on a larger scale too. Graphitic carbon nitride can be easily synthesized at a low cost, and the system itself is simple and inexpensive to put together.
Wang says:
The scale-up for both the catalysts and the device is not difficult. It’s a good first step, but the prototype won’t be enough on its own to purify water from other contaminants. Purification needs other devices for removing heavy-metal ions, adjusting pH, and removing residue. We need to combine our system with others to meet water-purification requirements.
