Photocatalytic oxidation of H₂S in the gas phase over TiO₂-coated glass fiber filter

Abstract

To promote the photocatalytic oxidation (PCO) of hydrogen sulfide (H2S) in the gas phase, TiO2-coated glass fiber filters were packed in an annular photoreactor. Glass fibers coated with TiO2 thin films were characterized structurally and morphologically by field emission gun scanning electron microscopy (FEG-SEM), scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS) and X-ray diffractometry (XRD). Flow rate and H2S inlet concentration were evaluated to determine the performance of the reactor. Removal efficiencies up to 99% were achieved for flow rate of 25 L h(-1) (residence time of 121 s) and H2S inlet concentration from 12 to 14 ppmv. The long-term experiment presented H2S removal of 89% for 16 h. After 28 h of continuous use, H2S degradation was observed at 64%, which suggests that the photocatalyst was losing activity due to deactivation. Moreover, the kinetics of the PCO of H2S according to the Langmuir-Hinshelwood (L-H) approach along with the mass balance of a plug-flow reactor was modeled. The reaction constant (k) was calculated at approximately 10.5 μmol m(-3) s(-1) and the adsorption constant (K) of approximately 5263 m(-3) mol with linearity (R2) of 0.98.

Mitigation of Odor and Gaseous Emissions from Swine Barn with UV-A and UV-C Photocatalysis

“…Therefore, O 3 reduction could not be investigated, but neither was it generated. In our earlier research on the lab-and pilot-scales, we reported up to complete (100%) mitigation of O 3 that was naturally in the unirradiated samples [1,2,11].…”

“…It is challenging to make an accurate comparison within previous research due to the differences in the TiO 2 coating thicknesses and I (averaging over one vs. three dimensions). Several papers proved the mechanism of H 2 S oxidation with UV-A photocatalysis based on TiO 2 coating [9][10][11]. However, it is not easy to propose an accurate UV dose to mitigate H 2 S based on the currently collected data.…”

Mitigation of Odor and Gaseous Emissions from Swine Barn with UV-A and UV-C Photocatalysis

“…Therefore, O3 reduction could not be investigated, but neither was it generated. In our earlier research on the lab-and pilot-scales, we reported up to complete (100%) mitigation of O3 that was naturally in the unirradiated samples [1,2,11].…”

“…It is challenging to make an accurate comparison within previous research due to the differences in the TiO2 coating thicknesses and I (averaging over one vs. three-dimensions). Several papers proved the mechanism of H2S oxidation with UV-A photocatalysis based on TiO2 coating [9][10][11]. However, it is not easy to propose an accurate UV dose to mitigate H2S based on the currently collected data.…”

“…In the lab-scale experiments, the percent reduction varied depending on the coating's thickness, the coating material, temperature, relative humidity, dust accumulation, and the UV wavelength. Statistically significant mitigation of NH3, H2S, N2O, O3, and VOCs was shown [1,6,[11][12][13][14]. Pilotscale studies with UV-A photocatalysis showed effective mitigation of measured odor (~63%), p-cresol (~49%), skatole (~49%), indole (~66%), H2S (~40%), butan-1-ol (~41%), O3 (~100%), N2O (~14%), and NH3 (~11%) in the swine and poultry barn [2,[15][16][17][18][19].…”