Mechanistic investigation into sunlight-facilitated photodegradation of pyrene in seawater with oil dispersants.
This study investigated the effects of 3 model oil dispersants (Corexit EC9500A, Corexit EC9527A and SPC 1000) on photodegradation of pyrene under simulated sunlight. Both Corexit dispersants enhanced photodegradation of pyrene, while SPC1000 slightly inhibited the reaction. Span 80 and Tween 85 were the key ingredients causing the effects, though the underlying mechanisms differed. Span 80 enriches pyrene in the upper layer of water column, whereas Tween 85 induces a photosensitization process. Two reactive oxygen species,1O2and O2-, were found responsible for pyrene photodegradation, though the presence of EC9500A suppressed the1O2pathway. In terms of photodegradation products, EC9500A enhanced generation of polyaromatic intermediates, i.e., phenaleno[1,9-cd][1,2]dioxine, 1-hydroxypyrene, and 1,8-pyrenequinone, but did not alter the classical photodegradation pathway. The Corexit dispersants were more prone to photochemical decomposition, with multiple by-products detected. The information aids in our understanding of the effects of dispersants on photochemical weathering of oil compositions.
Environmental Engineering Program, Department of Civil Engineering, Auburn University, Auburn, AL 36849, United States; Department of Environmental Science & Engineering, Fudan University, Shanghai 200433, China.
Jie
J
Fu
Environmental Engineering Program, Department of Civil Engineering, Auburn University, Auburn, AL 36849, United States.
Yanyan
Y
Gong
Environmental Engineering Program, Department of Civil Engineering, Auburn University, Auburn, AL 36849, United States.
Zhengqing
Z
Cai
U.S. Department of the Interior, Gulf of Mexico OCS, Office of Environment, New Orleans, LA 70123, United States.
S E
SE
O'Reilly
Environmental Engineering Program, Department of Civil Engineering, Auburn University, Auburn, AL 36849, United States. Electronic address: zhaodon@auburn.edu.
Dongye
D
Zhao
D008962:Models, Theoretical; D010578:Petroleum / Q000032:analysis* / Q000528:radiation effects; D059392:Petroleum Pollution / Q000032:analysis; D010782:Photolysis; D011721:Pyrenes / Q000032:analysis* / Q000737:chemistry / Q000528:radiation effects; D017382:Reactive Oxygen Species / Q000032:analysis; D012623:Seawater / Q000737:chemistry*; D013472:Sunlight; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry / Q000528:radiation effects
D010578:Petroleum; D011721:Pyrenes; D017382:Reactive Oxygen Species; D014874:Water Pollutants, Chemical
Dispersant; Oil spill; Oil weathering; Photodegradation; Polycyclic aromatic hydrocarbons; Surfactant