Characterization and degradation mechanism of bimetallic iron-based/AC activated persulfate for PAHs-contaminated soil remediation

In this research, a novel iron based bimetallic nanoparticles (Fe-Ni) supported on activated carbon (AC) were synthesized and employed as an activator of persulfate in polycyclic aromatic hydrocarbons (PAHs) polluted sites remediation. AC-supported Fe-Ni activator was prepared according to two-step reduction method: the liquid phase reduction and H-2- reduction under high temperature (600 degrees C), which was defined as Fe-Ni/AC. Characterizations using micropore physisorption analyzer, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron microscopy (HR-TEM) showed that the synthetic material had large specific surface area, nano-size and carbon-encapsulated metal particles, moreover, the lattice fringes of metals were clearly defined. The PAH compound types and their concentrations were determined by gas chromatography mass spectrometry (GC-MS) with SIM mode, the method detection limit (MDL) was estimated to about 0.21 mu g/kg for PAHs, and the average recovery of PAHs was 96.3%. Mechanisms of PAH oxidation degradation with the reaction system of Fe-Ni/AC activated persulfate were discussed, the results showed that short-life free radicals, such as SO4-center dot, OH center dot, and OOH center dot were generated simultaneously, which acted as strong oxidizing radicals, resulting in the oxidation and almost complete opening of the PAH rings. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

A novel iron-based bimetallic nanoparticles supported on activated carbon were synthesized and employed as an activator in persulfate oxidation for PAH remediation. Characterizations of the synthetic material indicated excellent properties, and mechanisms of PAH oxidation were discussed in the reaction system of Fe-Ni/AC activated persulfate.