Induction and Coverage Times for Crude Oil Droplets Spreading on Air Bubbles

Hydrophobic oil droplets, particles and air bubbles can be dispersed in water as kinetically stabilized dispersions. It has been established since the 19th century that such objects harbor a negative electrostatic potential roughly twice larger than the thermal energy. The source of this charge continues to be one of the core observations in relation to hydrophobicity and its molecular explanation is still debated. What is clear though, is that the stabilizing interaction in these systems is understood in terms of electrostatic repulsion via DLVO theory. Recent work [Carpenter et al., PNAS 116 (2019) 9214] has added another element into the discussion, reporting the creation of bare near-zero charged droplets of oil in water that are stable for several days. Key to the creation of the droplets is a rigorous glassware cleaning procedure. Here, we investigate these conclusions and show that the cleaning procedure of glassware has no influence on the electrophoretic mobility of the droplets, that oil droplets with near-zero charge are unstable, and provide an alternative possible explanation for the observations involving glass surface chemistry.

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Multiple air-bubble enhanced oil rupture on nanostructured cellulose fabric for easy-oil cleaning fouled in a dry state

Scientific Reports ◽

10.1038/s41598-019-51216-7 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 1

Author(s):

Min-Sung Kim ◽

Tae-Jun Ko ◽

Seong Jin Kim ◽

Young-A. Lee ◽

Kyu Hwan Oh ◽

...

Keyword(s):

Aspect Ratio ◽

Solid Fraction ◽

High Aspect Ratio ◽

Air Bubbles ◽

Oil Droplets ◽

Water Contact ◽

Air Bubble ◽

Cellulose Fabric ◽

Oily Water ◽

Oil Fouling

Abstract Nanostructured cellulose fabric with an air-bubble-enhanced anti-oil fouling property is introduced for quick oil-cleaning by water even with the surface fouled by oil before water contact under a dry state. It is very challenging to recover the super-hydrophilicity because once the surface is oil-fouled, it is hard to be re-wetted by water. Anti-oil-fouling under a dry state was realized through two main features of the nanostructured, porous fabric: a low solid fraction with high-aspect-ratio nanostructures significantly increasing the retracting forces, and trapped multiscale air bubbles increasing the buoyancy and backpressure for an oil-layer rupture. The nanostructures were formed on cellulose-based rayon microfibers through selective etching with oxygen plasma, forming a nanoscale open-pore structure. Viscous crude oil fouled on a fabric under a dry state was cleaned by immersion into water owing to a higher water affinity of the rayon material and low solid fraction of the high-aspect-ratio nanostructures. Air bubbles trapped in dry porous fibers and nanostructures promote oil detachment from the fouled sites. The macroscale bubbles add buoyancy on top of the oil droplets, enhancing the oil receding at the oil-water-solid interface, whereas the relatively smaller microscale bubbles induce a backpressure underneath the oil droplets. The oil-proofing fabric was used for protecting underwater conductive sensors, allowing a robot fish to swim freely in oily water.

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The enhanced stability and biodegradation of dispersed crude oil droplets by Xanthan Gum as an additive of chemical dispersant

Marine Pollution Bulletin ◽

10.1016/j.marpolbul.2017.03.001 ◽

2017 ◽

Vol 118 (1-2) ◽

pp. 275-280 ◽

Cited By ~ 13

Author(s):

Aiqin Wang ◽

Yiming Li ◽

Xiaolong Yang ◽

Mutai Bao ◽

Hua Cheng

Keyword(s):

Crude Oil ◽

Xanthan Gum ◽

Oil Droplets ◽

Chemical Dispersant ◽

Enhanced Stability

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CHARACTERIZATION OF THE INITIAL WEATHERING OF PETROLEUM HYDROCARBONS BY FTIR SPECTROSCOPY AND SUPERCRITICAL FLUID CHROMATOGRAPHY

International Oil Spill Conference Proceedings ◽

10.7901/2169-3358-1989-1-427 ◽

1989 ◽

Vol 1989 (1) ◽

pp. 427-431 ◽

Cited By ~ 1

Author(s):

Lamya Mansur ◽

Alan Williams ◽

Keith D. Bartle ◽

Mark W. Raynor

Keyword(s):

Molecular Weight ◽

Crude Oil ◽

Ftir Spectroscopy ◽

Supercritical Fluid ◽

Supercritical Fluid Chromatography ◽

Hydrocarbon Composition ◽

Oil Droplets ◽

Weathering Processes ◽

Chemical Measurements ◽

Single Droplets

ABSTRACT Chemical changes resulting from the weathering processes of oils have been investigated on a bench scale weathering apparatus. A multicomponent oil simulating crude oil was developed for this purpose. Hydrocarbon concentrations resulting from evaporation and dissolution were measured using Fourier transform infrared (FTIR) spectroscopy and interpreted by a computer program (CIRCOM), which uses the method of principal components regression for multicomponent quantitative analysis. This method could be fast and accurate for quantitative assessments of changes in chemical and physical properties of an oil. However, this study outlines only the chemical measurements of saturated and aromatic hydrocarbon composition. Experiments were also undertaken to study weathering processes on oil droplets. In this technique single droplets of crude oil were suspended in water, the trends of dissolution were studied, and the behavior of the remaining heavy fraction assessed by FTIR spectroscopy and capillary column supercritical fluid chromatography (SFC). SFC was used to identify compounds, especially high molecular weight alkanes, and their changes in concentration with time in suspension in water. The results show that the main changes in the composition of oil droplets in stagnant waters are loss of low molecular weight material and differential loss of high boiling n-alkanes compared to their isoprenoid counterparts. FTIR spectroscopy and SFC proved powerful techniques for detecting minimal weathering processes, including oxidation, dissolution, and microbial degradation.

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PAHS AND OTHER CONTAMINANTS IN EFFLUENTS FROM ARTIFICIALLY WEATHERED OIL ON GRAVEL

International Oil Spill Conference Proceedings ◽

10.7901/2169-3358-2005-1-197 ◽

2005 ◽

Vol 2005 (1) ◽

pp. 197-200

Author(s):

Walter H. Pearson

Keyword(s):

Crude Oil ◽

Aromatic Hydrocarbons ◽

Anaerobic Biodegradation ◽

North Slope ◽

Pacific Herring ◽

Fish Eggs ◽

Oil Droplets ◽

Developmental Abnormalities ◽

Polycyclic Aromatic ◽

Oil Toxicity

ABSTRACT Several recent studies report that low parts per billion (ppb) concentrations of petroleum polycyclic aromatic hydrocarbons (PAH) are toxic to marine fish embryos and that crude oil toxicity increases as it weathers. Such claims for Pacific herring embyros derive from two experiments by Carls et al. (1999) in which herring eggs were exposed to seawater passed through gravel coated with artificially weathered Alaska North Slope crude oil. The experiments differed in the extent of weathering of the oil on gravel. Carls et al. reported that developmental abnormalities in herring embryos occur during chronic exposure to PAH levels as low as 0.4 ppb in seawater passed through the oiled gravel. Earlier studies had shown that effects are observed at low PAH levels only when oil droplets or films adhered to the herring eggs. To better understand Carls et al. experiments, we examined effluent from a gravel bed prepared following Carls et al. and report that ammonia, sulfides, and oil droplets were present in the effluent from oiled gravel generators that were shut down between two 16-day trials (as was done by Carls et al.). Oil droplets (0.5 to 1 mm) were intermittently present in effluent from oiled gravel generators even when the flow was continuous. Two hours after restarting flow, low dissolved oxygen, ammonia, and sulfides were present in the generators and in the effluent. Droplets, ammonia, and sulfides all induce developmental abnormalities of the types seen by Carls et al. The presence of ammonia and sulfide in the effluent after shutdown is a laboratory artifact and constitutes clear evidence of anaerobic biodegradation of the oil on gravel. Evidence of anaerobic biodegradation suggests that the exposure regime of Carls et al. did not effectively simulate field conditions. Our results demonstrate that the presence of confounding toxicants in the Carls et al. experiments cannot be dismissed. There is no basis to conclude that aqueous exposure to low ppb PAH levels affects herring eggs or that weathering increases oil toxicity to fish eggs without additional experiments that specifically account for the potential confounding factors and all chemicals in effluents from oiled gravel columns.

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Unexpected Interaction with Dispersed Crude Oil Droplets Drives Severe Toxicity in Atlantic Haddock Embryos

PLoS ONE ◽

10.1371/journal.pone.0124376 ◽

2015 ◽

Vol 10 (4) ◽

pp. e0124376 ◽

Cited By ~ 40

Author(s):

Elin Sørhus ◽

Rolf B. Edvardsen ◽

Ørjan Karlsen ◽

Trond Nordtug ◽

Terje van der Meeren ◽

...

Keyword(s):

Crude Oil ◽

Severe Toxicity ◽

Oil Droplets

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Effects of Chemical Dispersant on the Surface Properties of Kaolin and Aggregation with Spilled Oil

10.21203/rs.3.rs-671319/v1 ◽

2021 ◽

Author(s):

Wenxin Li ◽

Yue Yu ◽

Deqi Xiong ◽

Zhixin Qi ◽

Sinan Fu ◽

...

Keyword(s):

Crude Oil ◽

Surface Properties ◽

Oil Spills ◽

Size Ratio ◽

Small Scale ◽

Oil Droplets ◽

Mineral Aggregate ◽

Chemical Dispersant ◽

Dispersed Oil ◽

Spilled Oil

Abstract After oil spills occur, dispersed oil droplets can collide with suspended particles in the water column to form the oil-mineral aggregate (OMA) and settle to the seafloor. However, only a few studies have concerned the effect of chemical dispersant on this process. In this paper, the mechanism by which dispersant affects the surface properties of kaolin as well as the viscosity and oil-seawater interfacial tension (IFTow) of Roncador crude oil were separately investigated by small scale tests. The results indicated that the presence of dispersant impairs the zeta potential and enhances the hydrophobicity of kaolin. The viscosity of Roncador crude oil rose slightly as the dosage of dispersant increased while IFTow decreased significantly. Furthermore, the oil dispersion and OMA formation at different dispersant-to-oil ratio (DOR) were evaluated in a wave tank. When DOR was less than 1:40, the oil enhancement of dispersant was not significant. In comparison, it began to contribute when DOR was over 1:40 and the effect became more pronounced with the increasing DOR. The adhesion between oil droplets and kaolin was inhibited with the increasing DOR. The size ratio between oil droplets and particles is the significant factor for OMA formation. The closer the oil-mineral size ratio is to 1, the more difficultly the OMA forms.

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Impact of the Hydrophobicity of the Particles on the Formation and Behavior of Oil Particle Aggregates (OPA)

International Oil Spill Conference Proceedings ◽

10.7901/2169-3358-2021.1.689143 ◽

2021 ◽

Vol 2021 (1) ◽

Author(s):

Wen Ji ◽

Lin Zhao ◽

Kenneth Lee ◽

Thomas King ◽

Brian Robinson ◽

...

Keyword(s):

Contact Angle ◽

Crude Oil ◽

Marine Environment ◽

Bottom Layer ◽

Trapping Efficiency ◽

Oil Droplets ◽

Particle Aggregates ◽

And Behavior

ABSTRACT Oil droplets in marine environment interact with particles to form oil particle aggregates (OPA). As it was argued that the hydrophobicity of particles impacts the formation of OPA and subsequently the entrapment of oil and the transport of OPA, this study altered the hydrophobicity of kaolinite through the addition of chitosan and the contact angle was increased from 28.8° to 57.3°. Modified kaolinite was mixed with 500 mg/L crude oil in 200 rpm for 3 hours, then bottom layer was separated and extracted. Observations of the settled OPA microscale structure and calculations of oil trapping efficiency (OTE) were accomplished. Results indicated that with higher hydrophobicity of kaolinite, oil droplets were maintained in larger sizes in OPAs. This could increase the buoyancy of formed OPAs, thus decrease the amount of settled OPAs.

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Microscale Interactions of Surfactant and Polymer Chemicals at Crude Oil/Water Interface for Enhanced Oil Recovery

SPE Journal ◽

10.2118/198574-pa ◽

2020 ◽

Vol 25 (04) ◽

pp. 1812-1826

Author(s):

Subhash Ayirala ◽

Zuoli Li ◽

Rubia Mariath ◽

Abdulkareem AlSofi ◽

Zhenghe Xu ◽

...

Keyword(s):

Crude Oil ◽

Oil Recovery ◽

High Salinity ◽

Interfacial Shear ◽

Experimental Techniques ◽

Water Interface ◽

Oil Droplets ◽

Interfacial Film ◽

Chemical Eor ◽

Oil Water

Summary The conventional experimental techniques used for performance evaluation of enhanced oil recovery (EOR) chemicals, such as polymers and surfactants, have been mostly limited to bulk viscosity, phase behavior/interfacial tension (IFT), and thermal stability measurements. Furthermore, fundamental studies exploring the different microscale interactions instigated by the EOR chemicals at the crude oil/water interface are scanty. The objective of this experimental study is to fill this existing knowledge gap and deliver an important understanding on underlying interfacial sciences and their potential implications for oil recovery in chemical EOR. Different microscale interactions of EOR chemicals, at crude oil/water interface, were studied by using a suite of experimental techniques, including an interfacial shear rheometer, Langmuir trough, and coalescence time measurement apparatus at both ambient (23°C) and elevated (70°C) temperatures. The reservoir crude oil and high-salinity injection water (57,000 ppm total dissolved solids) were used. Two chemicals, an amphoteric surfactant (at 1,000 ppm) and a sulfonated polyacrylamide polymer (at 500 and 700 ppm) were chosen because they are tolerant to high-salinity and high-temperature conditions. Interfacial viscous and elastic moduli (viscoelasticity), interface pressures, interface compression energies, and coalescence time between crude oil droplets are the major experimental data measured. Interfacial shear rheology results showed that surfactant favorably reduced the viscoelasticity of crude oil/water interface by decreasing the elastic and viscous modulus and increasing the phase angle to soften the interfacial film. Polymers in brine either alone or together with surfactant increased the viscous and elastic modulus and decreased the phase angle at the oil/water interface, thereby contributing to interfacial film rigidity. Interfacial pressures with polymers remained almost in the same order of magnitude as the high-salinity brine. In contrast, a significant reduction in interfacial pressures with surfactant was observed. The interface compression energies indicated the same trend and were reduced by approximately two orders of magnitude when surfactant was added to the brine. The surfactant was also able to retain similar interface behavior under compression even in the presence of polymers. The coalescence times between crude oil droplets were increased by polymers, while they were substantially decreased by the surfactant. These consistent findings from different experimental techniques demonstrated the adverse interactions of polymers at the crude oil/water interface to result in more rigid films, while confirming the high efficiency of the surfactant to soften the interfacial film, promote the oil droplets coalescence, and mobilize substantial amounts of residual oil in chemical EOR. This experimental study, for the first time, characterized the microscale interactions of surfactant-polymer chemicals at the crude oil/water interface. The applicability of several interfacial experimental techniques has been demonstrated to successfully understand underlying interfacial sciences and oil mobilization mechanisms in chemical EOR. These techniques and methods can provide potential means to efficiently screen and optimize EOR chemical formulations for better oil recovery in both sandstone and carbonate reservoirs.

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