title: Removal of polycyclic aromatic hydrocarbons from sediments using sodium persulfate activated by temperature and nanoscale zero-valent iron.
abstract: The oxidation of 16 polycyclic aromatic hydrocarbons (PAHs) compounds in sediments by sodium persulfate (Na2S2O8) simultaneously activated by temperature and nano zero-valent iron (nZVI) as the source of catalytic ferrous iron was investigated. The effect of various controlling factors, including S2O8(2-) (0.017-170 g/L), nZVI (0.01-1 g/L), and temperature (50-70 °C) were performed. The efficiency to remove PAHs was 10.7-39.1% for unactivated persulfate. The treated sample had over 50% of the persulfate still remaining from an initial persulfate dose of 170 g/L, whereas less than 1% of the persulfate remained from an initial persulfate dose of 0.017, 0.17, and 1.7 g/L. Adequate persulfate (170 g/L) must be present because it is the source of the sulfate radicals responsible for the degradation of PAHs. Results indicated that increasing temperature and the addition of nZVI into a persulfate-slurry system could enhance the persulfate oxidation process. The best removal efficiency (90%) was achieved after 24 hr while adding nZVI (0.01 g/L) to persulfate (170 g/L) at temperature of 70 °C. The results suggested that nZVI assisted persulfate oxidation without elevating temperature may be a suitable and economic alternative for the ex situ treatment of PAH-contaminated sediments.
  
  
  CONCLUSIONS
  Nano zero-valent iron (nZVI) has been successfully applied to transform/degrade contaminants in soils and water. Additionally, nZVI has been used as a catalyst to activate persulfate for the treatment of various contaminants. In this study, with the support of temperature, nZVI-persulfate oxidation system for treatment of PAH-contaminated sediments was improved significantly and the treated sediment could meet remediation goals.
authors.affiliation: a Department of Marine Environmental Engineering , National Kaohsiung Marine University , Kaohsiung , Taiwan , Republic of China.
authors.forename: Chih-Feng
authors.initials: CF
authors.lastname: Chen
authors.forename: Nguyen Thanh
authors.initials: NT
authors.lastname: Binh
authors.forename: Chiu-Wen
authors.initials: CW
authors.lastname: Chen
authors.forename: Cheng-Di
authors.initials: CD
authors.lastname: Dong
mesh_terms: D019015:Geologic Sediments / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D010084:Oxidation-Reduction; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry*; D017670:Sodium Compounds / Q000737:chemistry*; D013431:Sulfates / Q000737:chemistry*; D013696:Temperature; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000737:chemistry
chemical_list: D011084:Polycyclic Aromatic Hydrocarbons; D017670:Sodium Compounds; D013431:Sulfates; D014874:Water Pollutants, Chemical; D007501:Iron; C024625:sodium persulfate