Propylene glycol-mixed steam enhanced extraction for an efficient and sustainable remediation of PAHs-contaminated soil.
JOURNAL OF HAZARDOUS MATERIALS 2023;
459:132029. [PMID:
37499501 DOI:
10.1016/j.jhazmat.2023.132029]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 06/25/2023] [Accepted: 07/09/2023] [Indexed: 07/29/2023]
Abstract
An innovative thermal desorption method, propylene glycol (PG)-mixed steam enhanced extraction, is proposed for a highly efficient remediation of polycyclic aromatic hydrocarbons (PAHs)-contaminated soil. It is found that injecting PG-mixed steam into soil column could obtain > 99% removal efficiencies of PAHs either for the pyrene-spiked soil, or for the contaminated field soil with high-molecular-weight PAHs. PG is a safe and low-cost dihydric alcohol with a boiling point higher than water. When the PG-mixed steam penetrated the contaminated soil, the PG vapor preferentially condensed to form a hot liquid with concentrated PG (e.g., from 30 wt% PG in gas phase to 90 wt% PG in the liquid phase), which would significantly solubilize the PAHs and enhance their desorption from soils. The results also revealed that the effluents derived from the PG-mixed steam could be purified by removing the desorbed PAHs using a simple coagulation treatment, and the recovered PG solution could be reused. The plant assay using wheat seeds showed that the remediated soil had a good regreening potential. Our results demonstrate that PG-mixed steam injection is a promising thermal desorption method for an efficient and sustainable remediation of PAHs-contaminated soil.
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