Thermal Remediation of Soil Contaminated with Polycyclic Aromatic Hydrocarbons: Pollutant Removal Process and Influence on Soil Functionality

• Published in: Toxics (Basel) Vol. 10; no. 8; p. 474
• Main Authors: Liu, Chenfeng, Shi, Huading, Wang, Chen, Fei, Yang, Han, Ziyu
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.08.2022; MDPI
• Subjects: Aging; Aging (natural); basic soil properties; Benzo(a)pyrene; Bioavailability; Causes of; Chemical properties; Control; Decomposition; desorption; Environmental aspects; Experiments; Factories; Fourier transforms; Gravimetry; Heat treatment; Laboratories; Low temperature; Methods; Organic matter; Organic soils; Particle size; PCB; Phenanthrene; Physical properties; Pollutant removal; Pollutants; Polychlorinated biphenyls; Polycyclic aromatic hydrocarbons; Pyrene; Quartz; Remediation; removal efficiency; Sediment pollution; Soil contamination; Soil pollution; Soil properties; Soil remediation; Soil temperature; Soil treatment; Soils; Temperature; Temperature requirements; Thermal desorption; thermal kinetics; Thermal properties; VOCs; Volatile organic compounds; China; United States > US
• ISSN: 2305-6304; 2305-6304
• 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.