Water decontamination using titanium dioxide (TiO2) as photocatalyst is being used in some places around the world. Under ultraviolet light (UV) the TiO2 reacts with organic pollutants due to it strong oxidative potential. It is also demonstrated that with natural sunlight the TiO2 can degrade the 4-chlorophenol pollutant from water. Also other water contaminant can be removed from water without using UV light on it. But the TiO2 photocatalytic decontamination is not limited only to water. When irradiated with UV light, the TiO2 can degrade acetone, 2-propanol and toluene in dry and humid air streams. Also the TiO2 can be added to paints, cements, windows, tiles, or other products for its sterilizing, deodorizing and anti-fouling properties and is used as a hydrolysis catalyst. The janus particles are particles with a hemisphere with one material and the other coated with other material. In the right place and conditions, it can achieve autonomous movement. Under UV light, a particle of TiO2 in methanol solution have the behavior of a “microfirework” and then merges each other when the UV light is turned off. If we have more TiO2 janus particles, under UV light they can spread away each other, covering more area of decontamination. Once the UV light is turned off, the particles can return to their original place allowing the recuperation of catalyst for other possible uses. This is important because the TiO2 dust has recently been classified by the International Agency for Research on Cancer (IARC) as an IARC Group 2B carcinogen possibly carcinogenic to humans.
1. S. Gelover, P. Mondragón, A. Jiménez. Titanium dioxide sol–gel deposited over glass and its application as a photocatalyst for water decontamination
2. S. Hager, R. Bauer. Heterogeneous photocatalytic oxidation of organics for air purification by near UV irradiated titanium dioxide.
3. Y. Hong, M. Diaz, U. M. Cordova-Figueroa, A. Sen. Light-Driven Titanium-Dioxide-Based Reversible Microfireworks and Micromotor/Micropump Systems. (2010)
4. Kutal, C., Serpone, N. (1993). Photosensitive Metal Organic Systems: Mechanistic Principles and Applications. American Chemical Society, Washington D.C.