New Device That Purifies Water Through Sunlight

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You can now bid adieu to bacteria with sunlight. A new solar energy based water disinfectant has come up with the best solution for cleaning drinking water problem. It is basically a nanostructured equipment and it is as big as half postage stamp. It mainly focuses on harnessing that part of solar spectrum that is visible to human eye. It is known for storing half of sun’s energy, it yields pure water much faster than the customary UV techniques.

Figure 1: Nanostructured device uses visible sunlight to kill bacteria

This device was formed through stacking of a very thin layers of molybdenum disulfide layers over the edge of a rectangular glass. Molybdenum disulfide is normally used in form of an industrial lubricant. But a team engineers was recently able to modify all properties of this compound by creating thin layers of molybdenum disulfide just a few atoms thick. The result was transformation of a lubricant in a photocatalyst. Whenever these films get struck by incoming light, several electrons of these scatter here and there. The electrons as well as the empty lacunas that are left behind show higher reactivity than others.

The biggest challenge in this project was tailoring the thickness of the layer that didn’t had to be too thick but needed to be capable enough of absorbing complete range of visible sunlight. Apart from this, every single layer was fixed with a thin a layer of copper. This one further behaves like a catalyst capable of creating reactive oxygen species like the hydrogen peroxide. Hydrogen peroxide is known for being a highly common disinfectant that can kill the bacteria in water surrounding it.

As the sun’s light acts as instigator that forms hydrogen peroxide, it becomes capable of killing around 99.999 percent of water bacteria within a short span of 20 minutes. As the reaction reaches its termination point, the disinfectants dissipate resulting in pure and clean water. Apart from being a speedy and efficient water purifier, the device gets an edge over others for being composed of molybdenum disulfides that are very inexpensive and simple in terms of creation. Alongwith, the device is capable of absorbing much broader solar wavelength than that consumed by other normal photocatalysts.