Liquid surfactants

The second type is a stable dispersion, or foam. Separation can be extremely difficult in some cases. A pure two-component system of gas and liquid cannot produce dispersions of the second type. Stable foams can oe produced only when an additional substance is adsorbed at the liquid-surface interface. The substance adsorbed may be in true solution but with a chemical tendency to concentrate in the interface such as that of a surface-active agent, or it may be a finely divided sohd which concentrates in the interface because it is only poorly wetted by the liquid. Surfactants and proteins are examples of soluble materials, while dust particles and extraneous dirt including traces of nonmisci-ble liquids can be examples of poorly wetted materials. 

In air drilling areas, the use of air drilling technique can be prolonged when formation water enters the hole by adding a small stream of liquid surfactant to the air stream. The addition of surfactant forms foam at the contact with formation water. The foam carries out cuttings and produced water. Considerable volumes of formation water can be held using this technique. 

Liquid-liquid extraction Bulk liquid membrane transport Liquid surfactant membrane transport... 

Correlation between composition and properties of phosphate ester surfactants was exemplified by octyl phosphate with an optimum of foam inhibition and surfactant properties [301]. In separation and concentration of rare earth metals by liquid surfactant membranes 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester was used as carrier [302]. 

For the wet case, the foam enters and achieves steady state after several pore volumes. A mobility reduction compared to water of about 90% ensues. However, for the dry case, there is about a one pore-volume time lag before the pressure responds. During this time, visual observations into the micromodel indicate a catas-tropic collapse of the foam at the inlet face. The liquid surfactant solution released upon collapse imbibes into the smaller pores of the medium. Once the water saturation rises to slightly above connate (ca 30%), foam enters and eventually achieves the same mobility as that injected into the wet medium. 

Breakage of glassware allowed 92% sulfuric acid into a heating bath containing hot Synperonic NX (nearly anhydrous ethoxylated nonylphenol, a liquid surfactant). Hydrolysis of the latter lowered the flashpoint and the bath ignited (possibly from formation of dioxane, flash point 12°C). 

Juang, R. S. Jiang, J. D. Recovery of nickel from a simulated electroplating rinse solution by solvent extraction and liquid surfactant membrane. J. Memhr. Sci. 1995, 100, 163-170. 

Surfactant. Any compound that reduces the surface tension (the electrical force that keeps them apart) between two liquids or between a liquid and a solid when it is dissolved in the liquid. Surfactants can be wetting agents, emulsifiers, or detergents. 

Petro-Green, Inc., ADP-7 is a biodegradable, water-soluble, nonionic/anionic liquid surfactant concentrate that emulsifies hydrocarbons, makes them water-wet, and allows natural processes to biodegrade them in situ. Once it is an emulsion, the hydrocarbons are no longer flammable or odoriferous. ADP-7 promotes the natural biodegradation processes. 

Liquid surfactant membrane phase -Emulsion globule Internal aqueous droplets... 

Phase diagrams of water, hydrocarbon, and nonionic surfactants (polyoxyethylene alkyl ethers) are presented, and their general features are related to the PIT value or HLB temperature. The pronounced solubilization changes in the isotropic liquid phases which have been observed in the HLB temperature range were limited to the association of the surfactant into micelles. The solubility of water in a liquid surfactant and the regions of liquid crystals obtained from water-surfactant interaction varied only slightly in the HLB temperature range. 

For liquid surfactants, drug solubility can be approximated using a simple method, in which the drug is added to a Lxed amount of a liquid surfactant while stirring at room temperature until the solid... 

For the preparation of a micellar solution, the water-insoluble drug and lipophilic excipients can be dissolved in a liquid surfactant by mixing at a relatively high temperature (43S 6flntil a clear solution is obtained. If necessary, a cosolvent can be added to aid solubility in the surfactant. Then a water or buffer solution containing hydrophilic excipients is added to the desired volume while mixing. In some cases, the aqueous solution needs to be heated to the same temperature as that > the surfactant to obtain desirable results. 

Figure 11.15 Copper extraction by a liquid emulsion membrane process [52]. Feed, 200 ml, pH 2.0, 300 ppm Cu2+ membrane, 15 mL LIX 64N in kerosene, 3% Span 80 stripping solution, 15 mL H2S04. Reprinted from J. Membr. Sci. 6, W. Volkel, W. Halwachs and K. SchUgerl, Copper Extraction by Means of a Liquid Surfactant Membrane Process, p. 19, Copyright 1980, with permission from Elsevier...

N.N. Li, Permeation Through Liquid Surfactant Membranes, AIChEJ. 17, 459 (1971). 

W. Volkel, W. Halwachs and K. Schtigerl, Copper Extraction by Means of a Liquid Surfactant Membrane Process, 7. Membr. Sci. 6, 19 (1980). 

In perfumery practice solubility problems occur only at the extremes of the solvent range. At the high polarity end of the scale, the systems contain high proportions of water such as low-degree alcoholic skin lotions or after shaves, or foam baths and dishwashing liquids (surfactant-water blends) with very low surfactant levels. In the latter, salt is often added to increase viscosity. This addition further increases the polarity of the water and aggravates perfume solubility problems. 

Let us first consider an inverted W/O emulsion made of 10% of 0.1 M NaCl large droplets dispersed in sorbitan monooleate (Span 80), a liquid surfactant which also acts as the dispersing continuous phase. At this low droplet volume fraction, the rheological properties of the premixed emulsion is essentially determined by the continuous medium. The rheological behavior of the oil phase can be described as follows it exhibits a Newtonian behavior with a viscosity of 1 Pa s up to 1000 s 1 and a pronounced shear thinning behavior above this threshold value. Between 1000 s 1 and 3000 s1, although the stress is approximately unchanged, the viscosity ratio is increased by a factor of 4. 

Figure 7. Simplified representation of a bulk liquid surfactant membrane in which the membrane is composed of a surfactant-containing organic solvent.

The edges of this dodecahedron sized a - 8.5 cm. When the volume of the rubber balloon at inflation became bigger than the volume of the sphere inscribed in the dodecahedron, the balloon was deformed by the dedecahedron faces and took a shape close to the respective shape of a bubble in a monodisperse dodecahedral foam with a definite expansion ratio. The expansion ratio of the foam was determined by the volume of liquid (surfactant solution or black ink in the presence of sodium dodecylsulphate) poured into the dodecahedron. An electric bulb fixed in the centre of the balloon was used to take pictures of the model of the foam cell obtained. The film shape and the projection of the borders and vertexes on the dodecahedron face are clearly seen in Fig. 1.10. 

Form Liquid Surfactant for Light and Heavy Duty Detergents. Used in Textiles for Leveling and Scouring. 

Production of aikyibenzene suifonates [1, 2]. The alkylbenzene sulfonates, used as liquid surfactants in making the detergent slurry, are produced by the sulfonation of linear alkylates followed by the neutralization step with a caustic solution containing sodium hydroxide (NaOH). The process of sulfonation of alkylbenzenes with oleum takes... 

Teramoto M, Takihana H, Shibutani M, Yuasa T, and Hara N. Extraction of phenol and cresol by liquid surfactant membrane. Sep Sci Technol 1983 18 397 19. 

Kataoka T, Nishiki T, and Kimura S. Phenol permeation through liquid surfactant membrane—permeation model and effective diffusivity. J Membr Sci 1989 41 197-209. 

Kataoka T, Nishiki T, Kimura S, and Tamioka Y. A model for mass transfer through liquid surfactant membranes. Water Treat 1990 5 136-149. 

Yan N, Shi Y, and Su YF. Removal of acetic acid from wastewater with liquid surfactant membranes An external boundary layer and membrane diffusion controlled model. Sep Sci Technol 1987 22 801-818. 

Teramoto M, Sakai T, Yanagawa K, Ohsuga M, and Miyake Y. Modeling of the permeation of copper through liquid surfactant... 

---