Effects of physical parameters and chemical dispersant on the formation of oil-particle aggregates (OPAs) in marine environments

Yu, Yue; Qi, Zhixin; Li, Wenxin; Fu, Sinan; Yu, Xinping; Xiong, Dangsheng

doi:10.1016/j.marpolbul.2019.07.069

Cited by 21 publications

(6 citation statements)

References 25 publications

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“…The extent of OPA formation changes abruptly with increasing particle concentration ( C par ; Figure 7b). When C par is above a certain threshold, the free oil is consumed by sediments at a fixed ratio, although more oil can be captured, which is consistent with the findings of our previous work (Qi et al., 2020; Yu et al., 2019).…”

Section: Discussionsupporting

confidence: 91%

“…Environmental conditions such as salinity and temperature are also known to affect OPA formation. The effect of temperature on OPA formation is mainly attributed to its influence on oil viscosity and interfacial tension (Sørensen et al., 2014; Yu et al., 2019). OPA formation can be significantly promoted with increasing salinity in the range of 0–4 ppm but tends to stabilize above this threshold (Le Floch et al., 2002).…”

Section: Introductionmentioning

confidence: 99%

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Effects of Oil and Sediment Properties and Mixing States on the Formation and Settling of Oil‐Particle Aggregates

Xiong

et al. 2022

JGR Oceans

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Understanding the interaction of oil droplets with suspended particulate matter is important not only for sunken oil modeling but also for emergency response. In this study, the effects of mixing time and energy, oil type, and sediment concentration and size on the oil content, morphology, and density of oil‐particle aggregates (OPAs) were investigated through a series of wave tank experiments and sedimentation tests. The results showed that loads of oil and particles in OPAs are high under high mixing energy. Under turbulent hydrodynamics, moderately viscous oils form OPAs more easily and sink rapidly to the seabed. Moreover, an increase in the density and oil capacity of OPAs is observed at a higher sediment concentration. More oil is captured by finer sediments. However, the corresponding oil‐sediment aggregates generally show lower density compared with those formed by larger sediments. The oil‐seawater interfacial tension (IFTow) diminishes with the addition of sediments, further promoting oil dispersion. The increasing duration and mixing energy produce more flake OPAs and multiple‐droplet OPAs. Oil droplets tend to be surrounded by several small particles but attach to the surface of large particles. Regardless of oil type and sediment concentration, the structure of OPAs does not change significantly.

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Section: Discussionsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Effects of Oil and Sediment Properties and Mixing States on the Formation and Settling of Oil‐Particle Aggregates

Xiong

et al. 2022

JGR Oceans

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“…The impact of oil viscosity R vis is resulted from two aspects: oil with lower viscosity is more favorable for OPA formation, resulting in more particles penetrating the oil droplets and a higher possibility for breakup; on the other hand, the low viscosity is not able to provide strong enough resistance to OPA breakup. Therefore, the breakage is supposed to be proportional to oil viscosity μ c , normalized by the water viscosity μ w . R normalv normali normals = ( μ o μ o + μ w ) m …”

Section: Methodsmentioning

confidence: 99%

Modeling the Breakup of Oil–Particle Aggregates in Turbulent Environments for Projectile Penetration

Liu

Lee

et al. 2023

Langmuir

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After an oil spill incident, the spilled oil slicks are observed to migrate to the shoreline area. Under the turbulent conditions, they break into small droplets and are suspended in the water column. The dispersed droplets are expected to interact with the suspended particles and form the oil–particle aggregates (OPAs), which significantly changes the transport of the oil. Instead of an earlier assumption that particles cover the oil surface, thus preventing further breakage or aggregation of OPAs, recent studies demonstrated that particles act like projectiles penetrating the oil droplets, resulting in the breakage of OPAs over a longer period of time. A model looking into the OPA breakup through two breakup mechanisms was proposed for the first time. The first method depicted the breakup of one large OPA into two daughter droplets owing to the turbulent nature, while the second method demonstrated the tear of the OPA surface layer caused by particle uprooting. The model was then calibrated by an experimental study targeting crude oil with varied viscosities, along with previous experimental investigations. Three key factors were identified accounting for the breakage of OPAs, where the increase in particle concentration in the natural environment and the increase in turbulent energy of the surrounding flows benefited the breakage of OPAs, and the increase in oil viscosity suppressed the breakage due to large resistance to shear stress. Besides these elements, the impact of the particle shape on the penetration depth was discussed. The model serves as a fundamental theory to describe the evolution of OPAs for fragmentation behavior.

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“…Several investigations were carried out to understand the various mechanisms involving the formation of aggregates  generally termed Oil Particle Aggregates (OPAs) ,  when oil interacts with suspended particles (including both organic − and inorganic matter , ), whereby it was observed that such aggregation processes are mainly caused by the hydrophobic adsorption between the sediments and the crude oil’s polar compounds (i.e., asphaltenes and resins). − Therefore, crude oils with a relatively high fraction of polar compounds are more inclined to form OPAs, and hydrophobic sediments, such as bentonite and kaolinite, are mostly investigated. ,− …”

Section: Introductionmentioning

confidence: 99%

Post-Formation of Oil Particle Aggregates: Breakup and Biodegradation

Abou-Khalil

Jayalakshmamma

et al. 2023

Environ. Sci. Technol.

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Spilled oil slicks are likely to break into droplets in the subtidal and intertidal zones of seashores due to wave energy. The nonliving suspended fine particles in coastal ecosystems can interact with the dispersed oil droplets, resulting in the formation of Oil Particle Aggregates (OPAs). Many investigations assumed that these aggregates will settle due to the particles’ high density. Recent studies, however, reported that some particles penetrate the oil droplets, which results in further breakup while forming smaller OPAs that remain suspended in the water column. Here, we investigated the interaction of crude oil droplets with intertidal and subtidal sediments, as well as artificial pure kaolinite, in natural seawater. Results showed that the interaction between oil droplets and intertidal sediments was not particularly stable, with an Oil Trapping Efficiency (OTE) < 25%. When using subtidal sediments, OTE reached 56%. With artificial kaolinite, OPA formation and breakup were more significant (OTE reaching up to 67%) and occurred faster (within 12 h). Oil chemistry analysis showed that the biodegradation of oil in seawater (half-life of 485 h) was significantly enhanced with the addition of sediments, with half-lives of 305, 265, and 150 h when adding intertidal sediments, subtidal sediments, and pure kaolinite, respectively. Such results reveal how the sediments’ shape and size affect the various oil–sediment interaction mechanisms, and the subsequent impact on the microbial degradation of petroleum hydrocarbons. Future studies should consider investigating the application of fine (several microns) and sharp (elongated-sheeted) sediments as a nondestructive and nontoxic technique for dispersing marine oil spills.

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Effects of physical parameters and chemical dispersant on the formation of oil-particle aggregates (OPAs) in marine environments

Cited by 21 publications

References 25 publications

Effects of Oil and Sediment Properties and Mixing States on the Formation and Settling of Oil‐Particle Aggregates

Effects of Oil and Sediment Properties and Mixing States on the Formation and Settling of Oil‐Particle Aggregates

Modeling the Breakup of Oil–Particle Aggregates in Turbulent Environments for Projectile Penetration

Post-Formation of Oil Particle Aggregates: Breakup and Biodegradation

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