Volatilization behavior of polycyclic aromatic hydrocarbons from the oil-based residues of shale drill cuttings

Shale gas, an emerging oil-bearing and pillar industry at home and abroad, has a very large impact on economic development and industry, but the resulting emerging pollutants pose a serious threat to the environment. Drilling cuttings, the primary byproduct of the exploration and mining of shale gas, are potentially hazardous types of waste that seriously deplete land resources and pose environmental safety problems. In this paper, a long-term static volatilization experiment was conducted to study the volatilization of polycyclic aromatic hydrocarbons (PAHs) in the oil-based residue of shale gas drill cuttings. Furthermore, the effects of some relevant environmental factors controlling the volatilization behavior were evaluated, including different particle sizes, temperatures and illuminances. The results showed that (1) the volatilization concentrations of PAHs gradually increased with prolonged volatilization time. PAHs with smaller ring numbers were present at the highest concentrations among the detected PAHs, and they were more readily volatilized and could be detected earlier. (2) The C-history method was found to significantly describe the kinetic process of the volatilization of PAHs. (3) Different environmental factors had different effects on the volatilization of PAHs. We found that increasing the temperature and illuminance and decreasing the particle size increased volatility. Through canonical correspondence analysis, PAHs volatilization was found to be a complex process, so volatilization tests under simulated environmental conditions are of scientific and environmental interest.

Automated summary

Shale gas, as an emerging oil-bearing and pillar industry both domestically and internationally, has a significant impact on economic development and industry, but the resulting emerging pollutants pose a serious threat to the environment. Drilling cuttings, the primary byproduct of shale gas exploration and mining, are potentially hazardous waste types that seriously deplete land resources and pose environmental safety problems. Through a long-term static volatilization experiment, it was found that polycyclic aromatic hydrocarbons (PAHs) in the oil-based residue of shale gas drill cuttings exhibited increasing volatilization concentrations over time, with smaller ring numbers of PAHs being more readily volatilized. The study also showed that different environmental factors had varying effects on the volatilization of PAHs, with temperature, illuminance, and particle size playing key roles in increasing volatility.