Bio-based carbon foams assembled with Fe nanoparticles for simultaneous remediation of As, Hg and PAHs in co-contaminated industrial soils

Abstract

Although numerous amendments show well-defined efficiencies for the remediation of soils contaminated with metals, metalloids, and organic compounds separately, few technologies have been developed capable of remediating multi-contaminated soils. In this study, carbon foams prepared from sucrose with and without impregnation with iron species were applied at a 10% dose to immobilize As on two industrial soils co-contaminated with Hg and PAHs. The results obtained by the toxicity characteristic leaching procedure (TCLP) test showed that the application of the sucrose foam loaded with iron nanoparticles decreased the leachability of As in both soils (15–20%), being statistically significant only in the case of T soil, whereas the availability of Hg was considerably reduced with both sucrose foams (50–60%). With regard to the bioavailable fraction of PAHs determined by a non-exhaustive technique, the treatment with the carbon foams caused a significant decrease of PAH content (90–96%). The macro-, meso- and microporosity of the sucrose foams (S_BET ∼300 m² g⁻¹), their structure based on condensed aromatic sheets, and the possibility of depositing iron nanoparticles on their surface (FeOOH and Fe₃O₄) make them promising new amendments for the sustainable remediation of multi-contaminated soils.