Eggshell and plant ash addition during the thermal desorption of polycyclic aromatic hydrocarbon-contaminated coke soil for improved removal efficiency and soil quality.

Thermal desorption (TD) technology is the preferred treatment technology for treating soil contaminated by organic compounds. Under laboratory conditions, eggshell and plant ash were studied as additives during thermal desorption to further improve the soil thermal desorption efficiency and the quality of soil after thermal desorption. The results showed that temperature was still an important factor affecting the soil quality and removal efficiency of PAHs (polycyclic aromatic hydrocarbons). The efficiency of the thermal desorption of soil was significantly improved (from 91.7 to 96.6%) by adding two additives, and the agglomeration of the soil was alleviated to some extent according to the decreased amount of large soil particle (100-400 μm). Moreover, the TOC (total organic carbon) and CEC (cation exchange capacity) of the soil were increased. This work suggested that the addition of similar alkaline additives to the soil during thermal desorption might have a positive impact on both thermal desorption behavior and soil quality.