Removal of indoor α-pinene with a fiber optic illuminated honeycomb monolith photocatalytic reactor

This study was undertaken to investigate the influencing factors including gas flow rate, inlet α-pinene concentration and relative humidity on the removal of α-pinene in a Degussa P25 supported honeycomb monolith reactor. We used the fiber optic illumination to enhance the intensity of UV-light irradiating on the Degussa P25 photocatalyst. The α-pinene conversion increased with the increase of gas flow rate indicating that the reaction rate was associated with the gaseous phase mass transfer. The α-pinene conversion varied between 91% and 96% in the range of inlet α-pinene concentration (400-2400 ppb) and relative humidity (30-70%) examined. The kinetics fits the Langmuir-Hinshelwood model. The rate coefficient (k) of α-pinene under RH30%, 50% and 70% was 0.82, 0.24, and 0.18 mol m ^-2s^-1, respectively. The competitive Langmuir adsorption constants for α-pinene under RH30%, 50% and 70% were 0.17, 0.56 and 1.74 ppm^-1, respectively. The effect of relative humidity on α-pinene conversion depends on the inlet α-pinene concentration and raising relative humidity in sum has a positive effect on the reduction of partially oxidized intermediates within the range investigated.