Feasibility of microwave remediation of simulative crude oil-contaminated soil assisted by bluecoke-based modifiers

Microwave (MW) remediation of organics-contaminated soil technology offers the advantages of high efficiency and minimal damage, representing a new approach of soil thermal remediation. However, soil, being a weak MW-absorbing medium, struggles to convert MW energy into thermal energy, thus failing to attain the necessary temperature for thermal remediation. This paper prepared two new bluecoke (BC)-based modifiers (KHCO3@BC and KHCO3/MnO2@BC) to address temperature problem of MW remediation, as well as enhance soil quality. Their composition, structure and electromagnetic properties were analyzed to investigate their role in assisting with the MW remediation of an artificially crude oil-contaminated soil were investigated. Additionally, the industrial feasibility of MW remediation was addressed for the first time. The results showed that the KHCO3 and MnO2 particles in the two modifiers were covered on the BC surface and exhibited local agglomeration. Their carbon crystalline grain size increased, and the electromagnetic properties were weaker than those of the BC. Following 10 min of MW remediation assisted by KBC or KMnBC, the remediation temperatures exceeded 300 °C, with the removal rates of PHs reaching 76.16% and 88.31%, respectively. The organic matter content, soil potassium and mechanical fraction of the remediated soil were improved, but soil acidification still needed to be further addressed. The industrial application analysis indicated that the technical process and techno-economics of MW remediation of crude oil-contaminated soil were feasible, suggesting significant potential for the large-scale industrial application. © 2024 Elsevier Ltd