Polycyclic aromatic hydrocarbons (PAHs) are major pollutants in air, soils and sediments. PAH-polluted soils can be cleaned rapidly by thermal treatment. PAH volatilization is considered as the main process explaining PAH removal at low temperature, yet other processes may occur. Particularly, we hypothesize that thermal transformation can also explain PAH removal, where transformation refers to both degradation and formation of bound PAHs. We thus studied the removal of spiked benzo[a]pyrene at 0.5 mg/g in bauxite soil, fluvo-aquic soil, chernozem soil, montmorillonite, humin, and quartz sand as control, from 100 to 200 °C. We measured concentrations of benzo[a]pyrene in the volatilized fraction and solid residues by high-performance liquid chromatography. We identified transformation products by gas chromatography–mass spectrometry. Results show that the contribution of thermal transformation to the removal of benzo[a]pyrene increased from 24.7 to 58.4 wt% for bauxite soil, from 4.4 to 38.2 wt% for fluvo-aquic soil, and from 11.5 to 35.9 wt% for chernozem soil, with temperature increasing from 100 to 200 °C. Transformation such as oxidation occurred in all samples except in benzo[a]pyrene-spiked quartz sands. Transformation of benzo[a]pyrene was thus partly explained by the presence of clay minerals, as evidenced for the montmorillonite assay where transformation contributed 74.6 wt% to the total removal of benzo[a]pyrene at 200 °C. Overall, our findings demonstrate a major overlooked contribution of transformation to PAH removal at low temperature.

多环芳烃（PAHs）是空气，土壤和沉积物中的主要污染物。PAH污染的土壤可以通过热处理快速清洁。PAH挥发被认为是解释在低温下去除PAH的主要过程，但其他过程也可能发生。特别地，我们假设热转化也可以解释多环芳烃的去除，其中转化是指结合的多环芳烃的降解和形成。因此，我们研究了从100到200°C在铝土矿土壤，潮水土壤，黑钙土，蒙脱土，腐殖质和石英砂中以0.5 mg / g的浓度除去加标的苯并[a] re。我们通过高效液相色谱法测定了挥发分和固体残留物中苯并[a] py的浓度。我们通过气相色谱-质谱法鉴定了转化产物。结果表明，热转化对去除苯并[a] a的贡献从铝土矿土壤的24.7％增加到58.4 wt％，潮水土壤从4.4％增加到38.2 wt％，黑钙土从11.5％增加到35.9 wt％温度从100升至200°C。除苯并[a] py掺石英砂外，所有样品均发生诸如氧化的转化。因此，由粘土矿物的存在部分解释了苯并[a] py的转化，这是蒙脱石测定所证明的，其中在200°C下转化占苯并[a]]的总去除量的74.6 wt％。总体而言，我们的发现表明，低温下转化对去除PAH的贡献被忽略了。铝土矿土壤为4 wt％，潮土土壤为4.4至38.2 wt％，黑钙土为11.5至35.9 wt％，温度从100升高至200°C。除苯并[a] py掺石英砂外，所有样品均发生诸如氧化的转化。因此，由粘土矿物的存在部分解释了苯并[a] py的转化，这是蒙脱石测定所证明的，其中在200°C下转化占苯并[a]]的总去除量的74.6 wt％。总体而言，我们的发现表明，低温下转化对去除PAH的贡献被忽略了。铝土矿土壤为4 wt％，潮土土壤为4.4至38.2 wt％，黑钙土为11.5至35.9 wt％，温度从100升高至200°C。除苯并[a] py掺石英砂外，所有样品均发生诸如氧化的转化。因此，由粘土矿物的存在部分解释了苯并[a] py的转化，这是蒙脱石测定所证明的，其中在200°C下转化占苯并[a]]的总去除量的74.6 wt％。总体而言，我们的发现表明，低温下转化对去除PAH的贡献被忽略了。因此，由粘土矿物的存在部分解释了苯并[a] py的转化，这是蒙脱石测定所证明的，其中在200°C下转化占苯并[a]]的总去除量的74.6 wt％。总体而言，我们的发现表明，低温下转化对去除PAH的贡献被忽略了。因此，由粘土矿物的存在部分解释了苯并[a] py的转化，这是蒙脱石测定所证明的，其中在200°C下转化占苯并[a]]的总去除量的74.6 wt％。总体而言，我们的发现表明，低温下转化对去除PAH的贡献被忽略了。