Photocatalytic Oxidation of Organic Contaminants in Water: An Aid to Environmental Preservation

The advantages of photocatalytic oxidation with titanium dioxide over conventional photochemical oxidations include the longer wavelength of the exciting wavelength (up to 380 nm) and the fact that no expensive oxidizing chemicals are consumed: atmospheric oxygen is the oxidant. Disadvantages include low photon efficiencies of the oxidation and long settling times with ultrafine catalysts. The latter can be avoided by using immobilized catalysts but oxidation rates are less than with free suspensions. The rates of phenol degradation and mineralization with various electrically-powered and, solar-powered light sources are given using catalysts in free suspension and immobilized. The utility of a new photocatalytic total organic carbon analyzer in environmental preservation is discussed