Synergic remediation of polycyclic aromatic hydrocarbon-contaminated soil by a combined system of persulfate oxidation activated by biochar and phytoremediation with basil: A compatible, robust, and sustainable approach

A new remediation strategy for polycyclic aromatic hydrocarbon (PAH)-contaminated soil was proposed using a combination of ammonium persulfate (APS) oxidation activated by iron-modified biochar (FBC) and phytoremediation with the aromatic plant, basil. After the 105-day pot experiment, the removal rates of soil total Σ₁₆ PAHs by this combined system reached 61.6%-69.5%. In the combined system, basil grew the best among all treatment groups because the addition of FBC and APS increased the contents of available potassium and nitrogen in soil. The essential oils extracted from basil were deemed free of PAH contamination. High-throughput sequencing of soil bacteria and fungi after 105 days revealed that the advanced oxidation process substantially reduced the richness and diversity of soil microbes, which were restored to the original state by basil. Results indicate that the combined system can remediate the contaminated soil in a synergy by pronouncing the degradative capacity of FBC-APS while mitigating its adverse effects, which is suggested to be an effective, robust, and sustainable approach that holds promise for future site applications.