Degradation of the polybrominated diphenyl ethers by nanoscale zero-valent metallic particles prepared from steel pickling waste liquor

Abstract

Due to the increasing levels of polybrominated diphenyl ethers (PBDEs) in the environment and their persistent toxicity, methods of removing PBDEs from the environment have become a necessary. Nanoscale zero-valent metallic particles (S-NZVI) were prepared from steel pickling waste liquor by chemical deposition and used to remove BDE209 in a water/tetrahydrofuran (4/6, v/v) solution. Nanoscale zero-valent iron particles (NZVI), nanoscale zero-valent and Ni/Fe particles were also prepared. These particles were characterized by BET, TEM, SEM, XRD, and EDS. The crystalline structure of S-NZVI was different from NZVI. However, the BET surface area of S-NZVI was the same as that of NZVI. The degradation rate of BDE209 by S-NZVI followed a pseudo-first order kinetics. The removal efficiency increased with increasing metal dosage but decreased with increasing initial BDE209 concentration. High reaction rate was observed at more water content solvent, indicating that hydrogen ion was the driving force of reaction. Comparing different nanoscale Fe-based materials, the removal of BDE209 by S-NZVI was found more effective than NZVI. By evaluating the cost and the significance of reclaimable iron resource, S-NZVI was found to give better compensation compared to other metals. Thus, the degradation of BDE209 by S-NZVI is both feasible and efficient.