Photocatalytic degradation of hydrogen sulfide using TiO2 film under microwave electrodeless discharge lamp irradiation

• Anatase appeared in the TiO2 film with the mean crystalline size of 24 nm.
• When irradiating with MEDL, the TiO2 film coated reactor could generate ROS in air.
• TiO2 film under MEDL irradiation was effective in removing H2S in air atmosphere.

A titanium dioxide (TiO2) film-coated reactor was prepared through sol–gel and heat treatment and was characterized by X-ray diffractometry, X-ray photoelectron spectroscopy, and scanning electron microscopy. Anatase-type TiO2 with a mean crystalline size of 24 nm was deposited onto the surface of the reactor. The photocatalytic degradation of hydrogen sulfide (H2S) was examined with the TiO2 film-coated reactor with a self-made microwave electrodeless discharge lamp (MEDL) as the light source. The intensity of the MEDL light was largely dependent on the microwave (MW) output power. The reactive oxygen species (ROS) generated during the photocatalytic process were determined. Results showed that this technique can generate a number of ROS in an air atmosphere, and the amount of ROS increased with the increase in MW output power. The effects of atmosphere and MW output power in the photocatalytic degradation of H2S were investigated. Results indicate that the proposed technique is effective in removing H2S in an air atmosphere with SO42- as the main product. The removal efficiency of H2S increased with an increase in MW output power but decreased dramatically with an increase in the initial H2S concentration.