OSAKA, JAPAN, Dec. 23, 2014 -- Many countries across the globe face a number of issues regarding contaminated water resources. In India, for example, approximately 70 percent of the population uses water not from taps but primarily that from underground sources. Further, these water supplies can be polluted with harmful substances such as agrochemical residues, arsenic of Himalayan ore veins and hexavalent chromium produced from leather tanneries.
This contamination has come to be seen as a societal problem, having caused health problems for as many as 50 million people. Panasonic recently announced, however, that it has developed its own photocatalytic water purification technology. This technology uses photocatalysts and the ultraviolet (UV) rays from sunlight to detoxify polluted water at high speeds, creating safe and drinkable water.
When photocatalysts are exposed to UV light, formed reactive oxygen purifies the toxic substances. However, TiO2, a type of photocatalyst, comes in extremely fine particles and is troublesome to collect once dispersed in water. Methods of binding it to larger matter have hence been used, but they in turn have suffered a loss of surface active sit.
As such, Panasonic has developed a way of binding TiO2 to another particle -- zeolite -- which enables photocatalysts to maintain their inherent surface active site. Moreover, since the two particles are bound together by electrostatic force, there is no need for binder chemicals.
When these novel photocatalytic particles are agitated, TiO2 is released from the zeolite and dispersed throughout the water. As a result, reaction speed is markedly elevated compared to conventional methods of fixing it on a surface of substrates, enabling a large volume of water to be processed in a short amount of time. Leaving the water still will cause TiO2 to bind to zeolite again, making it easy to separate and recover the photocatalysts from the water -- ultimately allowing them to be reused at a later time.
Along with being driven by light, another key feature of photocatalysts is that they remove any necessity of pharmaceuticals. As such, they offer a low-cost and environmentally friendly way of treating water.
Panasonic aims to provide this water to small rural communities, for example, using trucks equipped with photocatalytic water purification systems. Beyond this, the company is looking at linking up with local water supply operators to establish water purification facilities and is also considering the licensing of this technology to businesses. Panasonic is working to lower costs and maintenance requirements with the water purification systems -- its goal being to make this technology available across India and other emerging nations.
See also:
"White House, EPA honors 16-year-old NH student for developing sustainable water purification method"
"Basin Water to offer NSF 61 certified photocatalytic membrane systems"
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