In-depth investigation of Sodium percarbonate as oxidant of PAHs from soil contaminated with diesel oil

• Published in: Environmental pollution (1987) Vol. 268; no. Pt B; p. 115832
• Main Authors: Cavalcanti, Jorge Vinicius Fernandes Lima, Fraga, Tiago José Marques, Loureiro Leite, Mirella de Andrade, dos Santos e Silva, Daniella Fartes, de Lima, Valmir Félix, Schuler, Alexandre Ricardo Pereira, do Nascimento, Clístenes Williams Araújo, da Motta Sobrinho, Maurício Alves
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.01.2021
• Subjects: Advanced oxidation processes; Brazil; Carbonates; Diesel oil; Fenton oxidation; Hydrogen Peroxide; Oxidants; Photolysis; Polycyclic aromatic hydrocarbons; Polycyclic Aromatic Hydrocarbons - analysis; Sodium percarbonate; Soil; Soil Pollutants - analysis; Soil remediation; Brazil; Advanced oxidation processes; Soil remediation; Sodium percarbonate; Polycyclic aromatic hydrocarbons; Diesel oil; Fenton oxidation
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2020.115832

Sodium percarbonate (SPC, 2Na2CO3∙3H2O2), is a compound that can be used under multiple environmental applications. In this work, SPC was employed as oxidant in the treatment of soil contaminated with diesel oil. The soil samples were collected during the earthmoving stage of RNEST Oil Refinery (Petrobras), Brazil. Then, the samples were air-dried, mixed and characterized. Subsequently, raw soil was contaminated with diesel and treated by photo-Fenton reaction (H2O2/Fe2+/UV). SPC played a significant role in the generation of hydroxyl radicals under the catalytic effect of ferrous ions (Fe2+), hydrogen peroxide (H2O2) and radiation. These radicals provoked the photodegradation of polycyclic aromatic hydrocarbons (PAHs), in the soil remediation. A factorial design 33 was carried out to assess the variables which most influenced the decrease in total organic carbon (TOC). The study was performed with the following variables: initial concentration of [H2O2] and [Fe2+], between 190.0 and 950.0 mmol L−1 and 0.0–14.4 mmol L−1, respectively. UV radiation was supplied from sunlight, blacklight lamps, and system without radiation. All experiments were performed with 5.0 g of contaminated soil in 50.0 mL of solution. The initial concentration of Fe2+ showed the statistically most significant effect. The oxidation efficiency evaluated in the best condition showed a decrease from 34,765 mg kg−1 to 15,801 mg kg−1 in TOC and from 85.750 mg kg−1 to 20.770 mg kg−1 in PAHs content. Moreover, the sums of low and high molecular weight polycyclic aromatic hydrocarbons (LMW-PAHs and HMW-PAHs) were 19.537 mg kg−1 and 1.233 mg kg−1, respectively. Both values are within the limits recommended by the United Sates Environmental Protection Agency (USEPA) and evidenced the satisfactory removal of PAHs from contaminated soil, being an alternative to classic oxidation protocols. [Display omitted] •Soil collected from refinery area was artificially contaminated with Diesel oil.•Sodium Percarbonate (SPC)-assisted Fenton was highly efficient in PAHs mineralization.•Diesel-contaminated soil was successfully remediated by SPC-assisted Fenton reaction.•The parameters of the treated soil complied with USEPA and Brazilian legislation.