Photocatalytic Degradation of Caffeine in a Solar Reactor System

In this paper, solar photodegradation of caffeine in aqueous solution was studied, this organic compound is the most consumed stimulant around the world. The degradation experiments were carried outdoors in a solar reactor and Evonik-Degussa P25 TiO2 was used as catalyst. The photochemical and photocatalytic effect were tested in aqueous solutions of caffeine. Experimental results indicate that the organic compound is easily degraded over a very short period of time using 0.5 g L-1 of catalyst. The kinetic analysis indicates that the initial reaction rate of caffeine is described by the LH-HW model. However, the original compound cannot be mineralized very fast, caffeine is converted to other organic compounds with a longer lifetime before the mineralization, converting caffeine CO2 and water.