A novel technology for remediation of PBDEs contaminated soils using tourmaline-catalyzed Fenton-like oxidation combined with P. chrysosporium

Abstract

We carried out the 70-day remediation process for soil contaminated polybrominated diphenyl ethers (PBDEs) using a novel technology, a tourmaline catalyzed Fenton-like reaction (TCFR) combined with Phanerochaete chrysosporium (TCFR+P) in field soil microcosms. The results showed that the TCFR is more efficient in removing PBDE compounds with lower numbers of bromine (Br) atoms such as BDE-28, BDE-47, BDE-99, BDE-100, while the TCFR+P is a good method to remove the PBDEs with greater number of Br atoms. For the total PBDE removal from soil, the TCFR was more efficient than that in the soil added TCFR+P. SEM analysis showed that lower PBDE removal using TCFR+P may be due to the mycelium produced by P. chrysosporium covering the humin (HM) surface, thereby decreasing the effective contact between hydroxyl radicals (OH) and PBDEs. Moreover, a systemic series of experiments on the effects of the TCFR and TCFR+P on soil pH, soil organic matter (SOM) content, humic acid (HA) and HM compositions and structure, soil fungi, and degradation pathways were designed to discuss the removal mechanisms of the TCFR and the TCFR+P. Both of the TCFR and the TCFR+P caused a decrease in the SOM contents, a decline in aromaticity, an increase in surface hydrophilicity, an improvement in the polarity index of HA and HM, and an unexpected increased ergosterol content, compared to that of the soil added H2O2, tourmaline or P. chrysosporium alone, which in turn, enhanced the removal of PBDEs. Additionally, the five and nine oxidation degradation products of BDE-47, -153, respectively, were analyzed by LC–MS/MS. To the best of our knowledge, this study is the first report demonstrating that PBDEs in soil can be removed through TCFR oxidization.