TY - JOUR
T1 - Formation of oil-particle aggregates
T2 - Impacts of mixing energy and duration
AU - Ji, Wen
AU - Boufadel, Michel
AU - Zhao, Lin
AU - Robinson, Brian
AU - King, Thomas
AU - An, Chunjiang
AU - Zhang, Baiyu (Helen)
AU - Lee, Kenneth
N1 - Funding Information:
This work was made possible by the Oceans Protection Plan from Fisheries and Oceans Canada through the Multi-Partner Research Initiative. However, no official endorsement of the work by this entity is implied.
Publisher Copyright:
© 2021
PY - 2021/11/15
Y1 - 2021/11/15
N2 - Spilled oil slicks are likely to break into droplets offshore due to wave energy. The fate and transport of such droplets are affected by suspended particles in local marine environment, through forming oil particle aggregates (OPAs). OPA formation is affected by various factors, including the mixing energy and duration. To evaluate these two factors, lab experiments of OPA formation were conducted using kaolinite at two hydrophobicities in baffled flasks, as represented by the contact angle of 28.8° and 37.7° (original and modified kaolinite). Two mixing energies (energy dissipation rates of 0.05 and 0.5 W/kg) and four durations (10 min, 30 min, 3 h, and 24 h) were considered. Penetration to the oil droplets was observed at 3–5 μm and 5–7 μm for the original and modified kaolinite by confocal microscopy, respectively. At lower mixing energy, volume median diameter d50 of oil droplets increased from 45 μm to 60 μm after 24 h mixing by original kaolinite; for modified kaolinite, d50 decreased from 40 μm to 25 μm after 24 h mixing. The trapped oil amount in negatively buoyant OPAs decreased from 35% (3 h mixing) to 17% (24 h mixing) by original kaolinite; and from 18% to 12% after 24 h mixing by modified kaolinite. Results indicated that the negatively buoyant OPAs formed with original kaolinite at low mixing energy reaggregated after 24 h. At higher mixing energy, d50 decreased from 45 μm to 17 μm after 24 h mixing for both kaolinites. And the trapped oil amount in negatively buoyant OPAs increased to 72% and 49% after 24 h mixing for original and modified kaolinite, respectively. At higher mixing energy, the OPAs formed within 10 min and reached equilibrium at 3 h by original kaolinite. For modified kaolinite, the OPAs continued to form through 24 h.
AB - Spilled oil slicks are likely to break into droplets offshore due to wave energy. The fate and transport of such droplets are affected by suspended particles in local marine environment, through forming oil particle aggregates (OPAs). OPA formation is affected by various factors, including the mixing energy and duration. To evaluate these two factors, lab experiments of OPA formation were conducted using kaolinite at two hydrophobicities in baffled flasks, as represented by the contact angle of 28.8° and 37.7° (original and modified kaolinite). Two mixing energies (energy dissipation rates of 0.05 and 0.5 W/kg) and four durations (10 min, 30 min, 3 h, and 24 h) were considered. Penetration to the oil droplets was observed at 3–5 μm and 5–7 μm for the original and modified kaolinite by confocal microscopy, respectively. At lower mixing energy, volume median diameter d50 of oil droplets increased from 45 μm to 60 μm after 24 h mixing by original kaolinite; for modified kaolinite, d50 decreased from 40 μm to 25 μm after 24 h mixing. The trapped oil amount in negatively buoyant OPAs decreased from 35% (3 h mixing) to 17% (24 h mixing) by original kaolinite; and from 18% to 12% after 24 h mixing by modified kaolinite. Results indicated that the negatively buoyant OPAs formed with original kaolinite at low mixing energy reaggregated after 24 h. At higher mixing energy, d50 decreased from 45 μm to 17 μm after 24 h mixing for both kaolinites. And the trapped oil amount in negatively buoyant OPAs increased to 72% and 49% after 24 h mixing for original and modified kaolinite, respectively. At higher mixing energy, the OPAs formed within 10 min and reached equilibrium at 3 h by original kaolinite. For modified kaolinite, the OPAs continued to form through 24 h.
KW - Baffled flask
KW - Energy dissipation rate
KW - Oil droplet size distribution
KW - Oil particle aggregate
KW - Oil trapping efficiency
KW - Volume median diameter
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U2 - 10.1016/j.scitotenv.2021.148781
DO - 10.1016/j.scitotenv.2021.148781
M3 - Article
C2 - 34252767
AN - SCOPUS:85110064752
SN - 0048-9697
VL - 795
JO - Science of the Total Environment
JF - Science of the Total Environment
M1 - 148781
ER -