Modeling the Influence of Ozone in a Fixed Bed Reactor for the Treatment of Petroleum Contaminated Soils

In this study, the influence of the parameters affecting the ozone diffusion into the oil compound polluted soil was investigated. The soil was polluted with anthracene, which is a multi-ring aromatic hydrocarbon, was sieved, and its humidity was removed. It was then kept in vessels with closed caps in dark conditions for one week. The considered parameters were soil column height, soil particles size, the amount of pollutant, ozonation time, and humidity. The pilot employed in this study included a vessel containing phosphoric acid diluted by deionized water (pH=2) followed by a cylindrical reactor in Plexiglas type with a diameter of 3 cm and a height of 25 cm. To inject ozone into the soil uniformly, a glass distributor was inserted at the bottom of the reactor. The maximum amount of diffusion and removing efficiency were 83% and 92% respectively. According to the experimental design, it was observed that any changes in the size of the soil did not have any considerable effect on the amount of diffusion, while any changes in the amount of pollutant, the height of the soil column, and humidity had a significant influence on the diffusion. It was also observed that the highest diffusion rate was happened in the initial 10 minutes of the ozonation process. In the next step, by obtaining the equations dominant on the ozone decomposition by pollutants, organic and inorganic compounds, active sites of the soil, and ozone self decomposition, it has been tried to present a model for the investigation of the ozone diffusion into the soil. This model was obtained by comparing the experimental results with the results obtained from the speed coefficients model of the kinetic reactions of ozone with pollutants, organic, and inorganic compounds, active sites of the soil, and ozone self-decomposition.