Destruction of phenol aqueous solution by photocatalysis or direct photolysis.

The photodegradation of phenol has been investigated under a high-pressure mercury lamp with a kind of jacket (glass or quartz) depending on used UV light range and a variety of experimental conditions: UV (lambda > 200 nm) with oxygen or with TiO2 and oxygen or with N2; UV (lambda > 330 nm) with oxygen or with TiO2 and oxygen or with N2. Photocatalysis and direct photolysis of phenol have different reaction pathways. Direct photolysis of phenol yielded a brown-yellow complex organic polymer in both aerobic and anaerobic environments. The polymer cannot be mineralized in an anaerobic environment. The effects of catalyst amount and oxygen concentration in the reaction atmosphere on the destruction of phenol were studied. The results prove that an appropriate catalyst amount can avoid direct photolysis and increase the mineralization rate of phenol.