Remediation of phenanthrene-contaminated soil using a Schwertmannite activated persulfate system

Polycyclic aromatic hydrocarbons, such as phenanthrene, have become widespread environmental contaminants due to industrial and incomplete combustion, posing serious risks to soil ecosystems and agricultural safety. This study conducted a pot experiment with seven treatments to investigate the remediation performance and ecological effects of a Schwertmannite-activated persulfate system on phenanthrene-contaminated soil. The concentrations of phenanthrene, persulfate, and Schwertmannite were 20 mg·kg−1, 200 mg·kg−1, and 1 g·kg−1, respectively. The results revealed that the combined Schwertmannite-persulfate treatment was superior for soil remediation and Brassica rapa subsp. Chinensis protection. By leveraging the adsorption capability of Schwertmannite and its catalytic activation of persulfate to generate sulfate radicals (SO4−·), the system achieved 86.2% phenanthrene removal within 5 days, with the ultimate removal efficiency reaching 94.5%. Regarding plant development, the combined treatment improved B. rapa subsp. Chinensis growth, achieving a total biomass of 6.91 g per pot, and also inhibited Phe accumulation in plant tissues, reducing phenanthrene concentrations in leaves, stems, and roots to 0.2, 0.2, and 0.3 mg·kg−1, respectively. Taken together, this study demonstrates that the Schwertmannite-persulfate system was effective and environmentally compatible for remediating phenanthrene-contaminated soil, providing valuable insights for developing field-scale remediation strategies for PAH-contaminated soils.