Biomineralization of 2′2′4′4′-Tetrabromodiphenyl ether in a Pseudomonas putida and Fe/Pd nanoparticles integrated system

Polybrominated diphenyl ethers (PBDEs) are widely used as flame retardants and challenges for water treatment due to their persistence and toxicity. In this study, the reduction of 2'2'4'4'-tetrabromodiphenyl ether (BDE-47) was investigated in a nano-bio-integrated system. Results showed that the introducing of P. putida could markedly accelerate the demineralization of BDE-47 in nZVI/Pd-P.p system; the continuous generation of acidic metaboliates by P. putida could decrease pH, which could alleviate the surface passivation to some extent, resulting in the releasing of Fe2+ and high generation of H2O2, the shift in reactive oxygen species from Fe(IV) to center dot OH. The BDE-47 was firstly debrominated to the DE by the highly reductive [Pd center dot 2H] generated by nZVI/Pd, then oxidized to bromophenol and phenol, catechol as well as hydroquinone via the P. putida strain and the Fenton-like system. The toxicity assays confirmed the combined system could avert generation of nocuous intermediates, and could be an alternative strategy for complete remediation of recalcitrant POPs. (C) 2019 Elsevier Ltd. All rights reserved.