Photocatalytic Degradation of VOC Waste Gas in Petrochemical Sewage Fields

The large amount of waste gas containing volatile organic compounds (VOCs) discharged from petrochemical sewage plants will cause air pollution and seriously endanger the safety of human beings and the ecological environment. In this paper, we proposed a photocatalytic oxidation degradation technique of VOCs and designed a photocatalytic reaction device loaded with TiO2/SnO2 catalyst. Under UV light irradiation, there is an energy level difference in the conduction band between TiO2 and SnO2, which makes the photogenerated electrons (e(-)) migrate to SnO2 and reduces the surface electron density of TiO2. Thus, the recombination of photogenerated electron-hole pairs (e(-)-h(+)) is inhibited and the catalyst activity is improved. Meanwhile, the synergistic effect of the oxidation of hydroxyl radicals ((OH)-O-center dot) and ozone greatly improves the conversion rate. In addition, in the industrial side line, by studying the influence of inlet gas volume, inlet gas concentration, and gas humidity (RH) on the conversion rate of the VOCs, we revealed the operation law of the photocatalytic technique in industrial applications. Under the best working conditions, the purification rate of the VOCs was as high as 92.73%. This technique can not only effectively avoid the damage to the environment caused by polluting VOCs but also promote the low-carbon and green development of enterprises in the industry.