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Evaluation of enhanced mobility of polynuclear aromatic compounds in soil systems

Thesis/Dissertation ·
OSTI ID:6324658

The objective of this research was to investigate the mobility of polynuclear aromatic (PNA) compounds under enhanced mobility conditions in soil systems as a function of PNA physical/chemical properties, transporting fluid properties, and soil properties. PNA compounds that were evaluated, included anthracene, fluorene, fluoranthene, benzo(a)pyrene, and indeno(1,2,3-cd)pyrene. Transporting fluids evaluated included ethanol (100 percent) and 1:1 methanol/water solutions. Two soil types, a sandy loam soil and a clay loam soil. Two sets of experiments were conducted. Adsorption isotherms were developed for each of the five PNA compounds. Column displacement experiments were conducted for anthracene, fluoranthene, and benzo(a)pyrene. Results indicated that adsorption constants have a semi-logarithmic relationship with parachor and with methanol content of the solution. This bit of relationship is useful in the assessment of the mobility of PNA for the following situations: (1) where a dissolved organic phase is present in a PNA/soil mixture; (2) PNA recovery efficiency where contaminated soils are washed with a solvent to recover PNA contaminants for treatment as an on-site remediation alternative; and (3) in the determination of adsorption constants in aqueous systems of hydrophobic compounds where solubility is below the detection limit. Column displacement experiments provided breakthrough curves (BTCs) for anthracene and fluoranthene. A mobility and degradation index (MDI) was defined as the ratio of the time needed for a pollutant front to travel through a defined critical depth at a site to the pollutant half-life based on first order degradation kinetics. The effect of enhanced PNA mobility on MDI values was evaluated for 11 compounds in the presence of methanol.

Research Organization:
Utah State Univ., Logan, UT (USA)
OSTI ID:
6324658
Country of Publication:
United States
Language:
English