Liu Chenfeng, Shi Huading, Wang Chen, Fei Yang, Han Ziyu
Technical Centre for Soil, Agriculture and Rural Ecology and Environment, Ministry of Ecology and Environment, Beijing 100012, China.
Toxics. 2022 Aug 16;10(8):474. doi: 10.3390/toxics10080474.
Thermal remediation has been widely used for the removal of polycyclic aromatic hydrocarbon (PAH) from contaminated soil. The method has a high removal rate for semi-volatile organic pollutants; however, soil functionality is affected by the method because of the alteration of the soil properties. In this study, experimental soil was impregnated with phenanthrene (Phe), pyrene (Pyr), and benzo(a)pyrene (BaP); after natural air-dry aging, the thermal remediation experiment was carried out, using a tube-furnace and thermal gravimetry-Fourier transform infrared (TG-FTIR) equipment. More than 84% of the Phe and Pyr were lost in the aging stage, whereas the BaP was stable with 41% retention in the soil. After the thermal treatment, the desorption and decomposition of the pollutants and organic matter led to the removal of the PAHs; about 1% of the PAHs remained in the soil treated at 400 °C. The presence of the PAHs can promote the thermal reaction by slightly reducing the reaction activation energy by ~7-16%. The thermal remediation had a significant influence on the physical properties of the soil and destroyed the bioavailability by reducing the organic matter content. Therefore, a comprehensive consideration of effective PAH removal while preserving soil functionality may require a low temperature (100 °C) method for thermal remediation.
热修复已被广泛用于从污染土壤中去除多环芳烃（PAH）。该方法对半挥发性有机污染物具有较高的去除率；然而，由于土壤性质的改变，土壤功能会受到该方法的影响。在本研究中，将菲（Phe）、芘（Pyr）和苯并[a]芘（BaP）浸渍到实验土壤中；自然风干老化后，使用管式炉和热重-傅里叶变换红外（TG-FTIR）设备进行热修复实验。在老化阶段，超过84%的Phe和Pyr损失，而BaP稳定，在土壤中的保留率为41%。热处理后，污染物和有机物的解吸和分解导致PAHs的去除；在400℃处理的土壤中约1%的PAHs残留。PAHs的存在可通过将反应活化能略微降低约7-16%来促进热反应。热修复对土壤的物理性质有显著影响，并通过降低有机质含量破坏生物有效性。因此，在保留土壤功能的同时全面考虑有效去除PAHs可能需要采用低温（100℃）热修复方法。
