TiO2 nanoparticles have been known to inactivate viruses such as influenza, rotavirus, and astrovirus in suspensions or on surfaces. Through a photocatalytic reaction, TiO2 creates hydroxyl radicals in water, which are thought to destroy virions upon contact. (For more information, look up band bending)
Researchers at Rice University have discovered that when these TiO2 is treated with a silicon-containing compound (such as silica), its effectiveness as a virus-killer is increased three-fold. They tested this by treating a sample from the Yangtze River, which is known to be infested with waterborne viruses, with UV-activated TiO2/silica and found that it was 100% effective in killing viruses; in addition, this new mixture was able to decontaminate the water faster than TiO2 alone.
The implications of this research are that this new compound could be used cost-effectively to disinfect water in low-development countries; one of the researchers proclaimed it as “cheap and green” because TiO2 is a common ingredient in paint, the process of adding silica requires only trace amounts of silica, and the health hazard of this compound is low:
TiO2: NFPA: 1, 0, 0, -
Same health hazard as acetone
Exposure would cause some irritation