Remediation of Marine Sediments Contaminated with PAHs Using Sodium Persulfate Activated by Temperature and Nanoscale Zero Valent Iron

The oxidation of 16 polycyclic aromatic hydrocarbons compounds (PAHs) in sediments by sodium persulfate (Na2S2O8) activated by temperature and nanoscale zero−valent iron (nZVI) as the source of catalytic ferrous iron was investigated. The effect of various controlling factors including S2O82− (0.017–170 g/L), nZVI (0.01–1 g/L), and temperature (50–70°C) were performed. The efficiency to remove PAHs was not too high as 10.7–39.1% for unactivated persulfate. Results from experiments indicate that increasing temperature or the addition of nZVI into a persulfate-slurry system could enhance the persulfate oxidation process. The best removal efficiency (86.3%) was attained after 24 hr while adding nZVI (0.5 g/L) to persulfate (170 g/L) at temperature of 25°C. The results of our study suggest that nZVI assisted persulfate oxidation without elevating temperature is a suitable and economic alternative for the ex–situ treatment of PAHs contaminated sediments.