Influence of palladium content dispersed in the TiO2 photocatalyst for degradation of volatile organic compounds in gas emission.

Heterogeneous photocatalysis is highlighted to treat volatile organic compound (VOC) emission. Then, this work analysed the influence of palladium (Pd) content loaded in TiO2 on n-octane and iso-octane photodegradation. For this, TiO2 was loaded with Pd in different contents: 0.4%, 0.7%, and 1.0%. The samples were characterized, and the photodegradation experiments were conducted by Pd/TiO2/UV process. The characterization analyses showed that the metal presence did not change the catalyst structure or its surface area; however, it reduced the bandgap energy. The photocatalytic results proved that palladium improved n-octane degradation from 62% (pure TiO2) to 92.6% (0.4%Pd/TiO2) and, iso-octane degradation enhanced from 59% (pure TiO2) to 90.6% (0.7%Pd/TiO2); all results were obtained in the space time of 39 s. Therefore, 0.4%Pd/TiO2 and 0.7%Pd/TiO2 showed better oxidation results to degradation n-octane and iso-octane, respectively. The kinetic model of pseudo-first order showed a good fit for the data of both VOCs. Heterogeneous photocatalysis with Pd/TiO2 showed to be an adequate technique to reduce VOCs emission.

Toluene degradation by heterogeneous photocatalysis assisted with ozone in a tubular reactor: analysis over the reactor length.

Volatile organic compounds (VOCs) are atmospheric pollutants that can affect human healthy and intensify some environmental problems. Among different techniques to degrade VOCs, heterogeneous photocatalysis has been highlighted. The aim of this research was to obtain high toluene degradation using heterogeneous photocatalysis in the ozone presence (TiO2/O3/UV) and analyze VOC degradation over the reactor length comparing with ozone concentration also over the reactor length. Ozone concentration has influence on toluene degradation; 75% of VOC degradation was reached with 69.0 mgL-1 of O3 meanwhile a degradation of 91% was obtained with 96.2 mgL-1 of O3. Toluene degradation reached a plateau over reactor length at flowrate of 565 mL min-1, which indicates the reactor was oversized in this case. However, it was not observed at 1425 mL min-1. In addition, it was evaluated that O3 concentration and toluene reaction rate decreased over the reactor length.