Abstract:

Using phenanthrene and pyrene as the model PAHs, we carried out a series of batch kinetic tests to investigate photochemical evolution and atmospheric ozone degradation of the PAHs under controlled dosages of UV irradiation, ozone and dispersant concentrations.

Suggested Citation:

Zhao, Don, et al.. 2015. Mesocosm studies of photochemical degradation and ozonation of persistent BP oil compounds in the spill-affected Alabama coast water and sediment. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7X63JW8

Purpose:

The specific objectives were to: 1) Test the photochemical degradation rates of PAHs of the South Louisiana sweet oil in the Alabama Gulf coast seawater under simulated Alabama solar irradiation and in the presence of various concentrations of Corexit EC9500A; and 2) Determine the ozonation rates of the oil hydrocarbons in the seawater under the atmospheric conditions of Alabama shoreline and in the presence of the oil dispersants.

Data Parameters and Units:

Ozone concentration: 1.0-1.2 mg/L, UV light intensity: 7.7 W/m2, TiO2 concentration: 0.2 g/L, Corexit EC9500A concentration: 18 mg/L, Initial phenanthrene concentration: 400 µg/L, Initial pyrene concentration: 60 µg/L, solubility of pyrene and phenanthrene (microgram per liter) at different Corexit 9500A concentrations (milligram per liter), ozone concentration (milligram per liter) over time (minutes), degradation (C/C0) over time (minutes)

Methods:

Photochemical degradation kinetic tests were carried out in a well controlled glass photo-reactor with a surface area of 78 cm2 and a volume of 650 mL. Ozonation of PAHs was tested in the same glass reactor.

Instruments:

The UV light is irradiated from a 4 W UV lamp operated at a wavelength of 253.7 nm. Ozone is generated through an A2Z lab ozone generator to simulate atmospheric ground level ozone, which is introduced over the reactor at a flow rate of 0.5 nL/min through a Teflon tube.

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