Ultraviolet light is a very effective, easy way to clean contaminated water, preventing and reducing the occurrence of a wide variety of bacterial and viral diseases in areas without access to clean water. The technique, Solar Water Disinfection, works simply through the action of ultraviolet light.
Creating a cheap, easy, way to clean water has long been a goal of researchers, as Christine Lepisto of TreeHugger notes, “approached by a number of innovative scientists with ideas ranging from using common chemicals to clean water to developing technological solutions such as hand-cranked pre-filter and UV treatment bottles that could be distributed widely in problem areas.”
A new approach that uses the “ability of photocatalysts to accelerate the UV-decontamination power of simple sunlight” has been put forward by the young researcher Deepika Kurup.
She put two photocatalysts to the test, titanium dioxide (TiO2) and zinc oxide (ZnO). They were coated on rods fitted to the center of two quart plastic water bottles.
These were then used as part of a simple and effective experiment. Three UV-treatment vessels with catalytic rods were created. Two of them contained the two photocatalysts, and a third a combined coating. And a fourth plastic bottle without any photocatalyst served was used as a control. The water from the bottles was then sampled every three hours, while “using an incubator she developed herself to grow colonies in order to test the water contamination levels.”
The results of the experiment showed that the TiO2-ZnO combination rods were able to significantly accelerate the decontamination of the water, resulting in a greatly reduced treatment time.
Since the materials used to create this very-fast solar water treatment method are cheap and ‘relatively available’, it’s potentially a very good fit for the rural areas in ‘developing’ countries. In addition to speed, another advantage is that the photo-catalysts are completely reusable, and should last a long time.
For the fate of the sons of men and the fate of beasts is the same; as one dies, so dies the other. They all have the same breath, and man has no advantage over the beasts; for all is vanity. - Ecclesiastes 3:19