Deep desulfurization of model oil by photocatalytic air oxidation and adsorption using Ti(1−x)MxO2 (M=Zr, Ce)

Efficient solar light facilitated photo-oxidative detoxification of gaseous 2-chloroethyl ethyl sulfide on ZrO2-doped g-C3N4 under dry and humid air

Photo-oxidation of chemical warfare agents is considered a promising strategy to cope with threats from accidental or intentional release. In this study, heterostructure photocatalysts comprising different amounts of zirconium oxide (ZrO₂) over carbon nitride (CN) were synthesized via simple thermal exfoliation, followed by a precipitation method. The successful photocatalytic detoxification activity of the as-prepared photocatalyst was analyzed against 2-chloroethyl ethyl sulfide (CEES) under simulated solar light and natural sunlight irradiation in dry and humid air. As the CN/ZrO₂ demonstrated a high surface area and oxygen doping, the addition of small amounts of the ZrO₂ phase could lead to enhanced photoreactivity in surface chemistry. The as-prepared (CN/ZrO₂-II) degraded 95% of CEES under simulated solar light and 70% under natural sunlight within 90 min. The photo-detoxification of CEES was associated with the generation of holes (h⁺) and activation of oxygen to superoxide radicals (•O₂). Based on analysis results, a reaction mechanism was suggested. The activity of the used photocatalyst could be recovered to 90% of the fresh photocatalyst activity via simple water washing. However, as sulfurous compounds were accumulated on the surface in subsequent cyclic tests, solvent washing was also suggested to maintain high detoxification performance.

Deep desulfurization of sintering flue gas in iron and steel works based on low-temperature oxidation

The deep desulfurization method of sintering flue gas based on the low-temperature oxidation method is studied. Based on the analysis of the main principle of deep desulfurization of sintering flue gas, a deep desulfurization system of sintering flue gas is constructed, which is composed of an absorption washing unit and a washing solution treatment unit. Sodium hydroxide solution is used as the desulfurizing absorbent to mix with the sintering flue gas entering the reaction tower. Sulfur dioxide in the sintering flue gas reacts with sodium hydroxide to generate sodium sulfite, and sodium sulfite is oxidized to produce sodium sulfate; ozone is produced by ozone generator, nitrogen oxide compounds are oxidized by ozone to generate oxyacid, which is easy to be removed by sodium hydroxide washing solution, and the detergent is the same as that used to remove sulfur dioxide and dust. The experimental results show that the highest desulfurization rate and denitrification rate of the proposed method are 90% and over 22%, and the reaction efficiency and economy are significantly better than that of the comparative method, which shows that the method is reasonable and effective.