Safe Water with the Power of Sunlight: Photocatalytic Water Purification Technology
Across the world, 750 million people lack access to safe drinking water in their daily lives. (WHO, [http://apps.who.int/iris/bitstream/10665/112727/1/9789241507240_eng.pdf?ua=1]). Further, in India, approximately 70% of the population uses groundwater for drinking water – the groundwater which contains toxic substances such as arsenic, hexavalent chromium from factories, and agrichemical runoff. This contaminated groundwater is directly responsible for health problems impacting as many as 50 million people. Photocatalytic water purification technology is expected to provide safe water at a low cost, anywhere in the world.
Gentle on the environment; detoxify harmful substances in drinking water
Titanium dioxide (TiO2) is one of the most well-known superior photocatalyst. When it is placed in water and exposed to ultraviolet light, the energy of that light is transmitted to the electrons in the titanium dioxide particles, and high-energy electrons (electron excitation) are generated on the surface of particles In addition to purifying toxic metals like arsenic and hexavalent chromium, these high-energy electrons react with oxygen in the water to generate reactive oxygen, purifying bacteria and organic substances. Reactive oxygen is also generated when the surface of photocatalytic particles from which electrons have already been ejected come in contact with water, contributing to the efficiency of the water purifying effect.
Developed new structure particles enabling a high processing speed and easy recovery
Zeolite’s surface has many microscopic pores, giving it a large surface-to-volume ratio. The new particle developed by Panasonic bonds titanium dioxide particles to the surface of zeolite using static electricity. The titanium dioxide is bonded without interference of other materials, so it doesn’t decrease its reactivity. Furthermore, there is no need for chemical substances like bonding agents.
When water containing this new photocatalytic particle is agitated, the titanium dioxide separates from the surface of the zeolite, spreading throughout the water to react with toxic substances. When agitation is discontinued, the titanium dioxide is adsorbed back into the surface of the zeolite, and the photocatalytic particles return to their original state. The size of these particles are microns scale, so they are easily removed from water after the purification process by filtration or sedimentation. The photocatalytic particles can be reused after collection.
50-100 times faster than conventional process, as much as 99.9% of toxic substances removed
The latest information
Aug., 2013 Panasonic Develops Highly Effective Water Purification System
Using New Unique Photocatalyst
Dec., 2014 Panasonic Proposals for “A Better Life” at Eco-Products 2014