Researchers at the Department of Energy’s SLAC National Accelerator Laboratory and Stanford University have created a device half the size of a postage stamp, that is able to disinfect water when dropped into the water and placed under the sun within 20 mins.
Contrary to the current methods of either boiling water or placing it in the sun so that UV rays can kill the germs, it is more efficient and energy saving.
The surface of the device resembles a fingerprint under an electron microscope, consisting of very thin lines that researchers dubbed as “nanoflakes” of molybdenum disulfide stacked on edge on top of a rectangular glass.
How it works:
The electrons of these layers of molybdenum disulfide that are only a few atoms thick would leave their usual places when hit by an incoming light, causing the electrons and the “holes” they leave behind to undergo chemical reactions. And with accurate thickness, they are able to absorb the full range of visible sunlight. These layers are also topped by a thin layer of copper which produces hydrogen peroxide upon reaction, a common disinfectant that kills bacteria.
Molybdenum disulfide is relatively cheap and easy to make, hence would be ideal for developing countries. However, it has it’s drawbacks as it doesn’t remove chemical pollutants from water.
Also, as it has only been tested with three strains of bacteria, more tests have to be done to conclude if the device is effective and to ensure that it can be used in the real world.