Experimental Study On Nano-TiO2Photolytic And Photocatalytic Degradation Of Hydrogen Sulfide Odor Gas

Sulfocompound gaseous pollutants in both municipal and industrial waste treatment facilities have become a growing concern because they are a nuisance to the ambient environment and a human health risk. Comparing with the heterogeneous traditional techniques that mitigate the sulfocompound contamination problem, titanium dioxide (TiO2)-mediated photocatalytic reactions have attracted great attention in the air treatment field because of their mild reaction conditions, low cost and energy consumption, and harmless by-products. Indeed, the destruction of volatile organic compounds (VOCs) in the gas phase using TiO2/UV has been actively and widely investigated. However, the photodestruction of inorganic compounds, including sulfur-containing ones, has yet to be fully explored.In the research described in the current paper, optimization of the photolytic and photocatalytic destruction of hydrogen sulfide (H2S) in the gas-phase was studied. The contaminant destruction was performed under laboratory conditions, and the results demonstrated that photolytic and photocatalytic oxidation (PCO) processes could degrade H2S gas.A foam nickel support was coated with TiO2sols containing anatase particles. The malodorous compound, hydrogen sulfide (H2S), was removed via photolytic and photocatalytic oxidation processes under ambient conditions using a self-made photoreactor with185-nm ozone (O3) lamp illumination. The reactor degraded H2S with high removal efficiency. Important parameters affecting the reaction, such as the effects of the initial H2S concentration, ultraviolet light wavelength, relative humidity (RH), oxygen content, photocatalyst support, catalyst deactivation and regeneration, on contaminant degradation were investigated. The highest activity for pollutants destruction were achieved with80%RH,21%oxygen content, approximately200mg/m3H2S initial concentration and185-nm O3lamp illumination, resulting in higher conversion. Lessening the thickness of supports might probably improve H2S elimination ratio of specific surface area of catalyst. Sulfur (S0) and sulfate ion (SO42-) were detected as byproducts via the XPS technique during the H2S degradation process. The catalytic activity was improved by SO42-promotion, but reduced by S0accumulation on the photocatalyst surface. In addition, by increasing the amount of SO42-generated, the yield of S0and catalyst poisoning could be controlled in the reaction.