Oil dispersants

Last updated September 26, 2023

An oil dispersant is a mixture of emulsifiers and solvents that helps break oil into small droplets following an oil spill. Small droplets are easier to disperse throughout a water volume, and small droplets may be more readily biodegraded by microbes in the water. Dispersant use involves a trade-off between exposing coastal life to surface oil and exposing aquatic life to dispersed oil. While submerging the oil with dispersant may lessen exposure to marine life on the surface, it increases exposure for animals dwelling underwater, who may be harmed by toxicity of both dispersed oil and dispersant.^[1]^[2]^[3] Although dispersant reduces the amount of oil that lands ashore, it may allow faster, deeper penetration of oil into coastal terrain, where it is not easily biodegraded.^[4]

History

Torrey Canyon

In 1967, the supertanker Torrey Canyon leaked oil onto the English coastline.^[5] Alkylphenol surfactants were primarily used to break up the oil, but proved very toxic in the marine environment; all types of marine life were killed. This led to a reformulation of dispersants to be more environmentally sensitive.^{[ when? ]} After the Torrey Canyon spill, new boat-spraying systems were developed.^[5] Later reformulations allowed more dispersant to be contained (at a higher concentration) to be aerosolized.

Exxon Valdez

Alaska had fewer than 4,000 gallons of dispersants available at the time of the Exxon Valdez oil spill, and no aircraft with which to dispense them. The dispersants introduced were relatively ineffective due to insufficient wave action to mix the oil and water, and their use was shortly abandoned.^[6]

A report by David Kirby for TakePart found that the main component of the Corexit 9527 formulation used during Exxon Valdez cleanup, 2-butoxyethanol, was identified as "one of the agents that caused liver, kidney, lung, nervous system, and blood disorders among cleanup crews in Alaska following the 1989 Exxon Valdez spill."^[7]

Early use (by volume)

Dispersants were applied to a number of oil spills between the years 1967 and 1989.^[8]

Year	Spill	Country	Oil volume (L)	Dispersant volume (L)
1967	Torrey Canyon	England	119,000,000	10,000,000
1968	Ocean Eagle	Puerto Rico	12,000,000	6,000
1969	Santa Barbara	USA	1,000,000	3,200
1970	Arrow	Canada	5,000,000	1,200
1970	Pacific Glory	England	6,300,000
1975	Showa Maru	Singapore	15,000,000	500,000
1975	Jakob Maersk	Portugal	88,000,000	110,000
1976	Urquiola	Spain	100,000,000	2,400,000
1978	Amoco Cadiz	France	200,000,000	2,500,000
1978	Eleni V	England	7,500,000	900,000
1978	Christos Bitas	England	3,000,000	280,000
1979	Betelgeuse	Ireland	10,000,000	35,000
1979	Ixtoc I	Mexico	500,000,000	5,000,000
1983	Sivand	England	6,000,000	110,000
1984	SS Puerto Rican	USA		7,570^[9]
1989	Exxon Valdez	USA	50,000,000	8,000

Deepwater Horizon

During the Deep water Horizon oil spill, an estimated 1.84 million gallons of Corexit was used in an attempt to increase the amount of surface oil and mitigate the damage to coastal habitat. BP purchased all of the world's supply of Corexit soon after the spill began.^[10] Nearly half (771,000 gallons) of the dispersants were applied directly at the wellhead.^[11] The primary dispersant used were Corexit 9527 and 9500, which were controversial due to toxicity.

In 2012, a study found that Corexit made the oil up to 52 times more toxic than oil alone,^[12] and that the dispersant's emulsifying effect makes oil droplets more bio-available to plankton.^[13] The Georgia Institute of Technology found that "Mixing oil with dispersant increased toxicity to ecosystems" and made the gulf oil spill worse.^[14]

In 2013, in response to the growing body of laboratory-derived toxicity data, some researchers address the scrutiny that should be used when evaluating laboratory test results that have been extrapolated using procedures that are not fully reliable for environmental assessments.^[15]^[16] Since then, guidance has been published that improves the comparability and relevance of oil toxicity tests.^[17]

Rena oil spill

Maritime New Zealand used the oil dispersant Corexit 9500 to help in the cleanup process.^[18] The dispersant was applied for only a week, after results proved inconclusive.^[19]

Theory

Overview

Surfactants reduce oil-water interfacial tension, which helps waves break oil into small droplets. A mixture of oil and water is normally unstable, but can be stabilized with the addition of surfactants; these surfactants can prevent coalescence of dispersed oil droplets. The effectiveness of the dispersant depends on the weathering of the oil, sea energy (waves), salinity of the water, temperature and the type of oil.^[20] Dispersion is unlikely to occur if the oil spreads into a thin layer, because the dispersant requires a particular thickness to work; otherwise, the dispersant will interact with both the water and the oil. More dispersant may be required if the sea energy is low. The salinity of the water is more important for ionic-surfactant dispersants, as salt screens electrostatic interactions between molecules. The viscosity of the oil is another important factor; viscosity can retard dispersant migration to the oil-water interface and also increase the energy required to shear a drop from the slick. Viscosities below 2,000 centipoise are optimal for dispersants. If the viscosity is above 10,000 centipoise, no dispersion is possible.^[21]

Requirements

There are five requirements for surfactants to successfully disperse oil:^[5]

Dispersant must be on the oil's surface in the proper concentration
Dispersant must penetrate (mix with) the oil
Surfactant molecules must orient at the oil-water interface (hydrophobic in oil and hydrophilic in water)
Oil-water interfacial tension must be lowered (so the oil can be broken up).
Energy must be applied to the mix (for example, by waves)

Effectiveness

The effectiveness of a dispersant may be analyzed with the following equations.^[22] The Area refers to the area under the absorbance/wavelength curve, which is determined using the trapezoidal rule. The absorbances are measured at 340, 370, and 400 nm.

Area = 30(Abs₃₄₀ + Abs₃₇₀)/2 + 30(Abs₃₄₀ + Abs₄₀₀)/2 (1)

The dispersant effectiveness may then be calculated using the equation below.

Effectiveness (%) = Total oil dispersed x 100/(ρ_oilV_oil)

ρ_oil = density of the test oil (g/L)
V_oil = volume of oil added to test flask (L)
Total oil dispersed = mass of oil x 120mL/30mL
Mass of oil = concentration oil x V_DCM
V_DCM = final volume of DCM-extract of water sample (0.020 L)
Concentration of oil = area determined by Equation (1) / slope of calibration curve

Dispersion models

Developing well-constructed models (accounting for variables such as oil type, salinity and surfactant) are necessary to select the appropriate dispersant in a given situation. Two models exist which integrate the use of dispersants: Mackay's model and Johansen's model.^[23] There are several parameters which must be considered when creating a dispersion model, including oil-slick thickness, advection, resurfacing and wave action.^[23] A general problem in modeling dispersants is that they change several of these parameters; surfactants lower the thickness of the film, increase the amount of diffusion into the water column and increase the amount of breakup caused by wave action. This causes the oil slick's behavior to be more dominated by vertical diffusion than horizontal advection.^[23]

One equation for the modeling of oil spills is:^[24]

${\frac {\partial h}{\partial t}}+{\vec {\nabla }}\left(h\left({\vec {U}}+{\frac {\vec {\tau }}{f}}\right)\right)-{\vec {\nabla }}(E{\vec {\nabla }}h)=R$

where

h is the oil-slick thickness
${\vec {U}}$ is the velocity of ocean currents in the mixing layer of the water column (where oil and water mix together)
${\vec {\tau }}$ is the wind-driven shear stress
f is the oil-water friction coefficient
E is the relative difference in densities between the oil and water
R is the rate of spill propagation

Mackay's model predicts an increasing dispersion rate, as the slick becomes thinner in one dimension. The model predicts that thin slicks will disperse faster than thick slicks for several reasons. Thin slicks are less effective at dampening waves and other sources of turbidity. Additionally, droplets formed upon dispersion are expected to be smaller in a thin slick and thus easier to disperse in water. The model also includes:^[23]

An expression for the diameter of the oil drop
Temperature dependence of oil movement
An expression for the resurfacing of oil
Calibrations based on data from experimental spills

The model is lacking in several areas: it does not account for evaporation, the topography of the ocean floor or the geography of the spill zone.^[23]

Johansen's model is more complex than Mackay's model. It considers particles to be in one of three states: at the surface, entrained in the water column or evaporated. The empirically based model uses probabilistic variables to determine where the dispersant will move and where it will go after it breaks up oil slicks. The drift of each particle is determined by the state of that particle; this means that a particle in the vapor state will travel much further than a particle on the surface (or under the surface) of the ocean.^[23] This model improves on Mackay's model in several key areas, including terms for:^[23]

Probability of entrainment – depends on wind
Probability of resurfacing – depends on density, droplet size, time submerged and wind
Probability of evaporation – matched with empirical data

Oil dispersants are modeled by Johansen using a different set of entrainment and resurfacing parameters for treated versus untreated oil. This allows areas of the oil slick to be modeled differently, to better understand how oil spreads along the water's surface.

Surfactants

Surfactants are classified into four main types, each with different properties and applications: anionic, cationic, nonionic and zwitterionic (or amphoteric). Anionic surfactants are compounds that contain an anionic polar group. Examples of anionic surfactants include sodium dodecyl sulfate and dioctyl sodium sulfosuccinate.^[25] Included in this class of surfactants are sodium alkylcarboxylates (soaps).^[26] Cationic surfactats are similar in nature to anionic surfactants, except the surfactant molecules carry a positive charge at the hydrophilic portion. Many of these compounds are quaternary ammonium salts, as well as cetrimonium bromide (CTAB).^[26] Non-ionic surfactants are non-charged and together with anionic surfactants make up the majority of oil-dispersant formulations.^[25] The hydrophilic portion of the surfactant contains polar functional groups, such as -OH or -NH.^[26] Zwitterionic surfactants are the most expensive, and are used for specific applications.^[26] These compounds have both positively and negatively charged components. An example of a zwitterionic compound is phosphatidylcholine, which as a lipid is largely insoluble in water.^[26]

HLB values

Surfactant behavior is highly dependent on the hydrophilic-lipophilic balance (HLB) value. The HLB is a coding scale from 0 to 20 for non-ionic surfactants, and takes into account the chemical structure of the surfactant molecule. A zero value corresponds to the most lipophilic and a value of 20 is the most hydrophilic for a non-ionic surfactant.^[5] In general, compounds with an HLB between one and four will not mix with water. Compounds with an HLB value above 13 will form a clear solution in water.^[25] Oil dispersants usually have HLB values from 8–18.^[25]

HLB values for various surfactants
Surfactant	Structure	Avg mol wt	HLB
Arkopal N-300	C₉H₁₉C₆H₄O(CH₂CH₂O)₃₀H	1,550	17.0^[27]
Brij 30	polyoxyethylenated straight chain alcohol	362	9.7^[28]
Brij 35	C₁₂H₂₅O(CH₂CH₂O)₂₃H	1,200	17.0^[27]
Brij 56	C₁₆H₃₃O(CH₂CH₂O)₁₀H	682	12.9^[29]
Brij 58	C₁₆H₃₃O(CH₂CH₂O)₂₀H	1122	15.7^[29]
EGE Coco	ethyl glucoside	415	10.6^[28]
EGE no. 10	ethyl glucoside	362	12.5^[28]
Genapol X-150	C₁₃H₂₇O(CH₂CH₂O)₁₅H	860	15.0^[27]
Tergitol NP-10	nonylphenolethoxylate	682	13.6^[28]
Marlipal 013/90	C₁₃H₂₇O(CH₂CH₂O)₉H	596	13.3^[27]
Pluronic PE6400	HO(CH₂CH₂O)_x(C₂H₄CH₂O)₃₀(CH₂CH₂O)_28-xH	3000	N.A.^[27]
Sapogenat T-300	(C₄H₉)₃C₆H₂O(CH₂CH₂O)₃₀H	1600	17.0^[27]
T-Maz 60K	ethoxylated sorbitan monostearate	1310	14.9^[28]
T-Maz 20	ethoxylated sorbitan monolaurate	1226	16.7^[28]
Triton X-45	C₈H₁₇C₆H₄O(CH₂CH₂O)₅H	427	10.4^[29]
Triton X-100	C₈H₁₇C₆H₄(OC₂H₄)₁₀OH	625	13.6^[30]
Triton X-102	C₈H₁₇C₆H₄O(CH₂CH₂O)₁₂H	756	14.6^[27]
Triton X-114	C₈H₁₇C₆H₄O(CH₂CH₂O)_7.5H	537	12.4^[29]
Triton X-165	C₈H₁₇C₆H₄O(CH₂CH₂O)₁₆H	911	15.8^[29]
Tween 80	C₁₈H₃₇-C₆H₉O₅-(OC₂H₄)₂₀OH	1309	13.4^[30]

Comparative industrial formulations

Two formulations of different dispersing agents for oil spills, Dispersit and Omni-Clean, are shown below. A key difference between the two is that Omni-Clean uses ionic surfactants and Dispersit uses entirely non-ionic surfactants. Omni-Clean was formulated for little or no toxicity toward the environment. Dispersit, however, was designed as a competitor with Corexit. Dispersit contains non-ionic surfactants, which permit both primarily oil-soluble and primarily water-soluble surfactants. The partitioning of surfactants between the phases allows for effective dispersion.

Omni-Clean OSD ^[31]				Dispersit ^[32]
Category	Ingredient		Function	Category	Ingredient		Function
Surfactant		Sodium lauryl sulfate	Charged ionic surfactant and thickener	Emulsifying agent		Oleic acid sorbitan monoester	Emulsifying agent
Surfactant		Cocamidopropyl betaine	Emulsifying agent	Surfactant		Coconut oil monoethanolamide	Dissolves oil and water into each other
Surfactant		Ethoxylated nonylphenol	Petroleum emulsifier & wetting agent	Surfactant		Poly(ethylene glycol) monooleate	Oil-soluble surfactant
Dispersant		Lauric acid diethanolamide	Non-ionic viscosity booster & emulsifier	Surfactant		Polyethoxylated tallow amine	Oil-soluble surfactant
Detergent		Diethanolamine	Water-soluble detergent for cutting oil	Surfactant		Polyethoxylated linear secondary alcohol	Oil-soluble surfactant
Emulsifier		Propylene glycol	Solvent for oils, wetting agent, emulsifier	Solvent		Dipropylene glycol methyl ether	Enhances solubility of surfactants in water and oil.
Solvent	H₂O	Water	Reduces viscosity	Solvent	H₂O	Water	Reduces viscosity

Degradation and toxicity

Concerns regarding the persistence in the environment and toxicity to various flora and fauna of oil dispersants date back to their early use in the 1960s and 1970s.^[33] Both the degradation and the toxicity of dispersants depend on the chemicals chosen within the formulation. Compounds which interact too harshly with oil dispersants should be tested to ensure that they meet three criteria:^[34]

They should be biodegradable.
In the presence of oil, they must not be preferentially utilized as a carbon source.
They must be nontoxic to indigenous bacteria.

Methods of use

Dispersants can be delivered in aerosolized form by an aircraft or boat. Sufficient dispersant with droplets in the proper size are necessary; this can be achieved with an appropriate pumping rate. Droplets larger than 1,000 µm are preferred, to ensure they are not blown away by the wind. The ratio of dispersant to oil is typically 1:20.^[20]

Related Research Articles

An emulsion is a mixture of two or more liquids that are normally immiscible owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Although the terms colloid and emulsion are sometimes used interchangeably, emulsion should be used when both phases, dispersed and continuous, are liquids. In an emulsion, one liquid is dispersed in the other. Examples of emulsions include vinaigrettes, homogenized milk, liquid biomolecular condensates, and some cutting fluids for metal working.

<span class="mw-page-title-main">Detergent</span> Surfactants with cleansing properties

A detergent is a surfactant or a mixture of surfactants with cleansing properties when in dilute solutions. There are a large variety of detergents, a common family being the alkylbenzene sulfonates, which are soap-like compounds that are more soluble in hard water, because the polar sulfonate is less likely than the polar carboxylate to bind to calcium and other ions found in hard water.

<span class="mw-page-title-main">Surfactant</span> Substance that lowers the surface tension between a liquid and another material

Surfactants are chemical compounds that decrease the surface tension or interfacial tension between two liquids, a liquid and a gas, or a liquid and a solid. Surfactants may function as emulsifiers, wetting agents, detergents, foaming agents, or dispersants. The word "surfactant" is a blend of surface-active agent, coined c. 1950.

<span class="mw-page-title-main">Oil spill</span> Release of petroleum into the environment

An oil spill is the release of a liquid petroleum hydrocarbon into the environment, especially the marine ecosystem, due to human activity, and is a form of pollution. The term is usually given to marine oil spills, where oil is released into the ocean or coastal waters, but spills may also occur on land. Oil spills may be due to releases of crude oil from tankers, offshore platforms, drilling rigs and wells, as well as spills of refined petroleum products and their by-products, heavier fuels used by large ships such as bunker fuel, or the spill of any oily refuse or waste oil.

Emulsion polymerization is a type of radical polymerization that usually starts with an emulsion incorporating water, monomer, and surfactant. The most common type of emulsion polymerization is an oil-in-water emulsion, in which droplets of monomer are emulsified in a continuous phase of water. Water-soluble polymers, such as certain polyvinyl alcohols or hydroxyethyl celluloses, can also be used to act as emulsifiers/stabilizers. The name "emulsion polymerization" is a misnomer that arises from a historical misconception. Rather than occurring in emulsion droplets, polymerization takes place in the latex/colloid particles that form spontaneously in the first few minutes of the process. These latex particles are typically 100 nm in size, and are made of many individual polymer chains. The particles are prevented from coagulating with each other because each particle is surrounded by the surfactant ('soap'); the charge on the surfactant repels other particles electrostatically. When water-soluble polymers are used as stabilizers instead of soap, the repulsion between particles arises because these water-soluble polymers form a 'hairy layer' around a particle that repels other particles, because pushing particles together would involve compressing these chains.

Lipophilicity, refers to the ability of a chemical compound to dissolve in fats, oils, lipids, and non-polar solvents such as hexane or toluene. Such non-polar solvents are themselves lipophilic, and the axiom that "like dissolves like" generally holds true. Thus lipophilic substances tend to dissolve in other lipophilic substances, but hydrophilic ("water-loving") substances tend to dissolve in water and other hydrophilic substances.

<span class="mw-page-title-main">2-Butoxyethanol</span> Chemical compound

2-Butoxyethanol is an organic compound with the chemical formula BuOC₂H₄OH (Bu = CH₃CH₂CH₂CH₂). This colorless liquid has a sweet, ether-like odor, as it derives from the family of glycol ethers, and is a butyl ether of ethylene glycol. As a relatively nonvolatile, inexpensive solvent, it is used in many domestic and industrial products because of its properties as a surfactant. It is a known respiratory irritant and can be acutely toxic, but animal studies did not find it to be mutagenic, and no studies suggest it is a human carcinogen. A study of 13 classroom air contaminants conducted in Portugal reported a statistically significant association with increased rates of nasal obstruction and a positive association below the level of statistical significance with a higher risk of obese asthma and increased child BMI.

<span class="mw-page-title-main">Amphiphile</span> Hydrophilic and lipophilic chemical compound

An amphiphile, or amphipath, is a chemical compound possessing both hydrophilic and lipophilic (fat-loving) properties. Such a compound is called amphiphilic or amphipathic. Amphiphilic compounds include surfactants. The phospholipid amphiphiles are the major structural component of cell membranes.

The hydrophilic–lipophilic balance (HLB) of a surfactant is a measure of its degree of hydrophilicity or lipophilicity, determined by calculating percentages of molecular weights for the hydrophilic and lipophilic portions of the surfactant molecule, as described by Griffin in 1949 and 1954. Other methods have been suggested, notably in 1957 by Davies.

A dispersant or a dispersing agent is a substance, typically a surfactant, that is added to a suspension of solid or liquid particles in a liquid to improve the separation of the particles and to prevent their settling or clumping.

The Deepwater Horizon oil spill was an industrial disaster that began on 20 April 2010 off of the coast of the United States in the Gulf of Mexico on the BP-operated Macondo Prospect, considered to be the largest marine oil spill in the history of the petroleum industry and estimated to be 8 to 31 percent larger in volume than the previous largest, the Ixtoc I oil spill, also in the Gulf of Mexico. The United States federal government estimated the total discharge at 4.9 MMbbl. After several failed efforts to contain the flow, the well was declared sealed on 19 September 2010. Reports in early 2012 indicated that the well site was still leaking. The Deepwater Horizon oil spill is regarded as one of the largest environmental disasters in world history.

Corexit is a product line of oil dispersants used during oil spill response operations. It is produced by Nalco Holding Company, an indirect subsidiary of Ecolab. Corexit was originally developed by the Standard Oil Company of New Jersey. Corexit is typically applied by aerial spraying or spraying from ships directly onto an oil slick. On contact with the dispersant, oil that would otherwise float on the surface of the water is emulsified into tiny droplets and sinks or remains suspended in the water. In theory this allows the oil to be more rapidly degraded by bacteria (bioremediation) and prevents it from accumulating on beaches and in marshes.

Dispersit SPC 1000 or Dispersit is a dispersant used for oil spills, produced by U.S. Polychemical Corporation.

Paint has four major components: pigments, binders, solvents, and additives. Pigments serve to give paint its color, texture, toughness, as well as determining if a paint is opaque or not. Common white pigments include titanium dioxide and zinc oxide. Binders are the film forming component of a paint as it dries and affects the durability, gloss, and flexibility of the coating. Polyurethanes, polyesters, and acrylics are all examples of common binders. The solvent is the medium in which all other components of the paint are dissolved and evaporates away as the paint dries and cures. The solvent also modifies the curing rate and viscosity of the paint in its liquid state. There are two types of paint: solvent-borne and water-borne paints. Solvent-borne paints use organic solvents as the primary vehicle carrying the solid components in a paint formulation, whereas water-borne paints use water as the continuous medium. The additives that are incorporated into paints are a wide range of things which impart important effects on the properties of the paint and the final coating. Common paint additives are catalysts, thickeners, stabilizers, emulsifiers, texturizers, biocides to fight bacterial growth, etc.

The Health consequences of the Deepwater Horizon oil spill are health effects related to the explosion of the Deepwater Horizon offshore drilling rig in the Gulf of Mexico on April 20, 2010. An oil discharge continued for 84 days, resulting in the largest oil spill in the history of the petroleum industry, estimated at approximately 206 million gallons. The spill exposed thousands of area residents and cleanup workers to risks associated with oil fumes, particulate matter from Controlled burns, volatile organic compounds (VOCs), polycylic aromatic hydrocarbons (PAHs), and heavy metals.

The Deepwater Horizon oil spill occurred between 10 April and 19 September 2010 in the Gulf of Mexico. A variety of techniques were used to address fundamental strategies for addressing the spilled oil, which were: to contain oil on the surface, dispersal, and removal. While most of the oil drilled off Louisiana is a lighter crude, the leaking oil was of a heavier blend which contained asphalt-like substances. According to Ed Overton, who heads a federal chemical hazard assessment team for oil spills, this type of oil emulsifies well. Once it becomes emulsified, it no longer evaporates as quickly as regular oil, does not rinse off as easily, cannot be broken down by microbes as easily, and does not burn as well. "That type of mixture essentially removes all the best oil clean-up weapons", Overton said.

On May 1, 2010, a ruptured ExxonMobil pipeline in the state of Akwa Ibom, Nigeria, spilled more than a million gallons into the delta and contributed to the major environmental issues in the Niger Delta. The spill had occurred at an Exxon platform some 20–25 miles (32–40 km) offshore which feeds the Qua Iboe oil export terminal. Exxon Mobil declared force majeure on Qua Iboe oil shipments due to the pipeline damage. The leakage in the Qua Iboe oil field discharged about 232 barrels of crude into the Atlantic Ocean contaminating the waters and coastal settlements in the predominantly fishing communities along Akwa Ibom and Cross River.

Oil pollution toxicity to marine fish has been observed from oil spills such as the Exxon Valdez disaster, and from nonpoint sources, such as surface runoff, which is the largest source of oil pollution in marine waters.

Sucrose esters or sucrose fatty acid esters are a group of non-naturally occurring surfactants chemically synthesized from the esterification of sucrose and fatty acids. This group of substances is remarkable for the wide range of hydrophilic-lipophilic balance (HLB) that it covers. The polar sucrose moiety serves as a hydrophilic end of the molecule, while the long fatty acid chain serves as a lipophilic end of the molecule. Due to this amphipathic property, sucrose esters act as emulsifiers; i.e., they have the ability to bind both water and oil simultaneously. Depending on the HLB value, some can be used as water-in-oil emulsifiers, and some as oil-in-water emulsifiers. Sucrose esters are used in cosmetics, food preservatives, food additives, and other products. A class of sucrose esters with highly substituted hydroxyl groups, olestra, is also used as a fat replacer in food.

<span class="mw-page-title-main">Wetting solution</span>

Wetting solutions are liquids containing active chemical compounds that minimise the distance between two immiscible phases by lowering the surface tension to induce optimal spreading. The two phases, known as an interface, can be classified into five categories, namely, solid-solid, solid-liquid, solid-gas, liquid-liquid and liquid-gas.

References

↑ "Treating oil spills with chemical dispersants: Is the cure worse than the ailment?" . Retrieved 7 April 2014.
↑ "Dispersants EPA.gov".
↑ "Dispersants". Center for Biological Diversity. Retrieved 6 April 2014.
↑ "Study: Dispersants Can Move Hydrocarbons Faster and Deeper into Gulf Sand". 2013-05-10.
1 2 3 4 Clayton, John R. (1992). Oil Spill Dispersants: Mechanisms of Action and Laboratory Tests. C K Smoley & Sons. pp. 9–23. ISBN 978-0-87371-946-9.
↑ EPA: Learning Center: Exxon Valdez. http://www.epa.gov/oem/content/learning/exxon.htm accessed 5/23/2012
↑ "Corexit: An Oil Spill Solution Worse Than the Problem?". TakePart. Archived from the original on 5 May 2016. Retrieved 4 April 2014.
↑ Jafvert, Chad (2011-09-23). "Understanding oil dispersants" (PDF). School of Civil Engineering & Division of Environmental and Ecological Engineering. Purdue University. Retrieved 2015-03-07.
↑ "Tank from ship towed into port". Santa Cruz Sentinel. 1984-11-06. Retrieved 2015-03-08.
↑ "Less Toxic Dispersants Lose Out in BP Oil Spill Cleanup". The New York Times . Retrieved 4 April 2014.
↑ National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling. "Use of Surface and Subsea Dispersants During the BP Deepwater Horizon Oil Spill" . Retrieved 23 May 2012.
↑ GT | Newsroom - Gulf of Mexico Clean-Up Makes 2010 Spill 52-Times More Toxic
↑ "Dispersant Makes Oil 52 Times More Toxic". Live Science . 30 November 2012.
↑ Study: Mixing oil with dispersant made the BP oil spill worse | Science Recorder
↑ Coelho, Gina; Clark, James; Aurand, Don (2013-06-01). "Toxicity testing of dispersed oil requires adherence to standardized protocols to assess potential real world effects". Environmental Pollution. 177: 185–188. doi:10.1016/j.envpol.2013.02.004. ISSN 1873-6424. PMID 23497795.
↑ Bejarano, Adriana C.; Clark, James R.; Coelho, Gina M. (2014-04-01). "Issues and challenges with oil toxicity data and implications for their use in decision making: A quantitative review". Environmental Toxicology and Chemistry. 33 (4): 732–742. doi: 10.1002/etc.2501 . ISSN 1552-8618. PMID 24616123.
↑ Redman, Aaron D.; Parkerton, Thomas F. (2015-09-15). "Guidance for improving comparability and relevance of oil toxicity tests". Marine Pollution Bulletin. 98 (1–2): 156–170. doi:10.1016/j.marpolbul.2015.06.053. PMID 26162510.
↑ "Dispersants 'worse than oil'". 11 October 2011.
↑ "Cleaning up the oil spill".
1 2 Fingas, Merv (2001). The Basics of Oil Spill Cleanup. Lewis Publishers. pp. 120–125. ISBN 978-1-56670-537-0.
↑ National Research Council (U.S.) (1989). Using Oil Spill Dispersants on the Sea. Washington, D.C.: National Academy Press. p. 54.
↑ Chandrasekar, Subhashini; Sorial, George; Weaver, James (2006). "Dispersant effectiveness on oil spills – impact of salinity". ICES Journal of Marine Science. 63 (8): 1418–1430. doi: 10.1016/j.icesjms.2006.04.019 .
1 2 3 4 5 6 7 National Research Council Committee on Effectiveness of Oil Spill Dispersants: Using Oil Dispersants on the Sea, National Academy Press, 1989 pp 63-75
↑ Tkalich,P Xiaobo,C Accurate Simulation of Oil Slicks, Tropical marine science institute, Presented 2001 International Oil Spill Conference pp 1133-1135 http://www.ioscproceedings.org/doi/pdf/10.7901/2169-3358-2001-2-1133
1 2 3 4 Using Oil Spill Dispersants. National Academy Press. pp 29-32 1989
1 2 3 4 5 Butt, Hans-Jürgen. Graf, Karlheinz. Kappl, Michael. "Physics and Chemistry of Interfaces". 2nd Edition. WILEY-VCH. pp 265-299. 2006.
1 2 3 4 5 6 7 Tiehm, Andreas (January 1994). "Degradation of polycyclic aromatic hydrocarbons in the presence of synthetic surfactants". Applied and Environmental Microbiology. 60 (1): 258–263. Bibcode:1994ApEnM..60..258T. doi:10.1128/aem.60.1.258-263.1994. PMC 201297 . PMID 8117081.
1 2 3 4 5 6 Grimberg, S.J.; Nagel, J; Aitken, M.D. (June 1995). "Kinetics of phenanthrene dissolution into water in the presence of nonionic surfactants". Environmental Science & Technology. 29 (6): 1480–1487. Bibcode:1995EnST...29.1480G. doi:10.1021/es00006a008. PMID 22276867.
1 2 3 4 5 Egan, Robert; Lehninger, A.; Jones, M.A. (January 26, 1976). "Hydrophile-lipophile balance and critical micelle concentration as key factors influencing surfactant disruption of mitochondrial membranes" (PDF). Journal of Biological Chemistry. 251 (14): 4442–4447. doi: 10.1016/S0021-9258(17)33316-1 . PMID 932040.
1 2 Kim, I.S.; Park, J.S.; Kim, K.W. (2001). "Enhanced biodegradation of polycyclic aromatic hydrocarbons using nonionic surfactants in soil slurry". Applied Geochemistry. 16 (11–12): 1419–1428. Bibcode:2001ApGC...16.1419K. doi:10.1016/S0883-2927(01)00043-9.
↑ USpatent 4992213,G. Troy Mallett, Edward E. Friloux, David I. Foster,"Cleaning composition, oil dispersant and use thereof",published 1991-02-12
↑ USpatent 6261463,Savarimuthu M. Jacob, Robert E. Bergman, Jr.,"Water based oil dispersant",published 2001-07-17, assigned to U.S. Polychemical Marine Corp.
↑ "Study says oil is poison (1974)". The Capital Times. 1974-05-31. p. 50. Retrieved 2020-07-02.
↑ Mulkins-Phillips, G. J.; Stewart, J.E. (October 1974). "Effect of Four Dispersants on Biodegradation and Growth of Bacteria on Crude Oil". Applied Microbiology. 28 (4): 547–552. doi:10.1128/am.28.4.547-552.1974. PMC 186769 . PMID 4418491.