Photocatalytic degradation of H2S in the gas-phase using a continuous flow reactor coated with TiO2-based acrylic paint.

For the photocatalytic degradation of the hydrogen sulphide (H2S) in the gas-phase it was developed a rectangular reactor, coated with acrylic paint supported on fiber cement material. The surface formed by the paint coverage was characterized structural and morphologically by scanning electron microscopy with energy dispersive X-ray and X-ray diffraction analysis. The flow rate and the inlet concentration of H2S were evaluated as operational performance parameters of the reactor. Removal efficiencies of up to 94% were obtained at a flow rate of 2 L min-1 (residence time of 115 s) and inlet concentration of 31 ppm of H2S. In addition, the H2S degradation kinetics was modelled according to the Langmuir-Hinshelwood (L-H) model for the inlet concentrations of 8-23 ppm of H2S. The results suggest that flow rate has a more important influence on photocatalytic degradation than the inlet concentration. It is assumed that H2S has been oxidized to SO42- , a condition that led to a deactivation of the photocatalyst after 193 min of semi-continuous use.