Kinetic Study of the Pyrolytic Treatment of Petroleum-Contaminated Soils

This study presents a systematic approach to determine the kinetics of pyrolytic remediation of petroleum-contaminated soils. Two clean soils with different compositions were spiked with oil crudes to prepare petroleum-contaminated soils. Thermogravimetry with evolved gas analysis (TG–IR and TG–MS) was used first to identify the mineral transformations taking place as the clean soils were heated in an anoxic atmosphere. The same analytical techniques were applied to study the pyrolysis of contaminated soils and identify the temperature ranges over which soil mineral transformations overlap with hydrocarbon desorption and pyrolysis. We then employed distributed activation energy models with multiple pseudocomponents to quantify the kinetics of thermal processes involving only components of the clean soils. Finally, the same approach was used to obtain the full kinetics for the pyrolytic treatment of soil–petroleum mixtures and to accurately characterize the temperature dependence of hydrocarbon desorption and pyrolysis rates. The presented results emphasize the importance of soil composition, provide new insights into the pyrolysis of oil–soil mixtures, and elucidate the trade-off between hydrocarbon removal and soil fertility observed in an earlier study.