- Degradation of PCB153 by sulfidated nanoscale zero-valent iron
- Abstract：Sulfidated nanoscale zero-valent iron (S-nZVI) is the latest modification technology in recent years. Many studies showed that S-nZVI has a good effect on the removal of pollutants such as heavy metals, however, its reactivity with polychlorinated biphenyls (PCBs) has not been reported yet. In this study, the reduction reaction kinetics of PCB153 by S-nZVI prepared by using dithionite as a sulfidation agent, nanoscale zero-valent iron (nZVI) and carboxymethylcellulose stabilized nanoscale zero-valent iron (CMC-nZVI) were compared, the effects of pH, anion and humic acid (HA) on the degradation of PCB153 were studied. The surface properties of three materials before and after the reaction were analyzed, and the dechlorination pathway and reaction mechanism were investigated. The results showed that the degradation of PCB153 by three materials was well described by a pseudo-first-order kinetics model and the degradation mechanism was similar. The degradation efficiency decreased in the order of CMC-nZVI>nZVI>S-nZVI. The sulfidation suppressed the reactivity of nZVI to degrade PCB153. The iron sulfide on the surface of S-nZVI was not directly involved in the degradation reaction of PCB153. The low reactivity of S-nZVI may be attributed to the formation of iron sulfide, which decrease the reductive ability of Fe0. In addition, different from CMC-nZVI and nZVI, high pH will help the degradation of PCB153 by S-nZVI, and the effects of anion and HA on three nZVI were similar. The results can provide theoretical basis and technical support for the application of S-nZVI on the degradation of persistent organic pollutants.