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 H2 O2 , the shift in reactive oxygen species from Fe(IV) to •OH. The BDE-47 was firstly debrominated to the DE by the highly reductive [Pd·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.