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

ABSTRACT

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 ${\text{SO}}_4^{2-}$, a condition that led to a deactivation of the photocatalyst after 193 min of semi-continuous use.

KEYWORDS:

• Photocatalytic paint
• heterogeneous photocatalysis
• fiber cement
• reaction kinetics
• TiO₂-rutile

Disclosure statement

No potential conflict of interest was reported by the authors.