Enhanced reductive debromination of decabromodiphenyl ether by organic-attapulgite supported Fe/Pd nanoparticles: Synergetic effect and mechanism

Effective removal of polybrominated diphenyl ethers (PBDEs) from the environment is essential for the ecosystem and human health. Reductive debromination of PBDEs by nanoscale zerovalent iron (nZVI) has become an important technology. However, the agglomeration and low persistence catalytic activity of nZVI particles have become urgent problems to be improved. Herein, we report the first application of a new organo-attapulgite (OA) supported Fe/Pd nanoparticles (OA-Fe/Pd) composite for decabromodiphenyl ether (BDE209) removal. BDE209 was efficiently removed using OA-Fe/Pd with a reaction rate that was 9.97 times greater than that of the nZVI due to the synergetic effect of support material OA and Pd loading. OA could prevent nZVI particles from agglomeration and adsorb BDE209 molecules to its surface. Pd could supply atomic hydrogen and also prevent the oxidation of nZVI particles. The degradation of BDE209 by OA-Fe/Pd was affected by many factors and followed pseudo first-order kinetics. The degradation of BDE209 by OA-Fe/Pd underwent a stepwise debromination manner with the H-transfer dominant mechanism. BDE209 (25 mg∙L-1) could be degraded to penta-BDEs to diphenyl ether (DE) by 3.0 g∙L-1 OA-Fe/Pd within 240 min under neutral condition. This study provides some inspiration for improving the removal efficiency of PBDEs with nZVI-based materials.