Solar Photocatalysis for the Elimination of Trichloroethylene in the Gas Phase

In the present work, we have studied the photocatalytic degradation of trichloroethylene (TCE) under sunlight illumination with the aim of determining the feasibility of using this technology for gas purification. For these experiments, a continuous flow reactor was employed. This system is basically constituted by a Pyrex glass tube located in the focus of a compound parabolic collector made of anodized aluminum. Raschig rings of borosilicate glass coated with $TiO2$ and randomly packed within the reactor tube were used as photocatalyts. Results obtained using sunlight illumination indicate that this continuous flow solar reactor can achieve complete TCE degradation. Experimentally, it is found that for moderate conversions, the TCE degradation rate increases linearly with solar irradiance, but a dependence of lower order is observed when removal of the pollutant is almost complete. On the other hand, photonic efficiency decreases linearly with solar irradiance, and it is higher when the molar flow fed to the photoreactor increases. In contrast, the selectivity toward the different partial degradation products (dichloroacetyl chloride, $COCl2$⁠, etc.) is basically insensitive to solar irradiance.