| The photocatalyzed degradation of 2,4-dinitrophenol (2,4-DNP) was accomplished by both direct sunlight and UV light in the presence of titanium dioxide. 2,4-DNP was oxidized by photocatalytically generated "holes". When colloidal suspensions of semiconductor materials are exposed to light, electrons are released to their surroundings and as a result, a species deficient in electrons "holes" is created. Titanium dioxide was used to generate the holes in this investigation. About 70-75% of the 2,4-DNP was degraded in 5 hours. As the surface of colloidal particles over which reaction occurs is large, efficiency of the process is high, reaching a maximum at pH 8. The process cost is low as the materials are inexpensive. The destruction exposed to sunlight and in cloudy day were also investigated. At pH 8, about 55% of the 2,4-DNP was degraded in 5 hours in sunlight and about 35% was degraded in cloudy day. The effect of quartz and glass material on degradation of 2,4-DNP was also studied. The higher degradation efficiency in quartz cuvette was explained by the fact that more UV light passes through the quartz material. |
