Anionic surfactant, used experiment

Applications Useful 2D NMR experiments for identification of surfactants are homonuclear proton correlation (COSY, TOCSY) and heteronuclear proton-carbon correlation (HETCOR, HMQC) spectroscopy [200,201]. 2D NMR experiments employing proton detection can be performed in 5 to 20 min for surfactant solutions of more than 50 mM. Van Gorkum and Jensen [238] have described several 2D NMR techniques that are often used for identification and quantification of anionic surfactants. The resonance frequencies of spin-coupled nuclei are correlated and hence give detailed information on the structure of organic molecules. 

All the results we obtained are qualitative in nature. The materials used in the experiments are mostly not 100% pure but should be usable in comparing performance result of industrial applications. And the conclusions we obtained do not have the limitation of a pure oil (or surfactant) or a particular oil (or surfactant). One important factor we have not discussed is the electrical effect. This may contribute significantly in anionic surfactant solubilization with polar oil. We have neither discussed the mechanism of solubilization nor the specific effect of a certain oil to a certain surfactant. To understand clearly such specific effects and to derive more quantitative relations governing the result of solubilization, we are planning to conduct future experiments with pure sample. 

Zhong et al. (2003) studied the apparent solubility of trichloroethylene in aqueous solutions, where the experimental variables were surfactant type and cosolvent concentration. The surfactants used in the experiment were sodium dihexyl sulfo-succinte (MA-80), sodium dodecyl sulfate (SDS), polyoxyethylene 20 (POE 20), sorbitan monooleate (Tween 80), and a mixture of Surfonic- PE2597 and Witconol-NPIOO. Isopropanol was used as the alcohol cosolvent. Eigure 8.20 shows the results of a batch experiment studying the effects of type and concentration of surfactant on solubilization of trichloroethylene in aqueous solutions. A correlation between surfactant chain length and solubilization rate may explain this behavior. However, the solubilization rate constants decrease with surfactant concentration. Addition of the cosolvent isopropanol to MA-80 increased the solubility of isopropanol at each surfactant concentration but did not demonstrate any particular trend in solubilization rate of isopropanol for the other surfactants tested. In the case of anionic surfactants (MA-80 and SDS), the solubility and solubilization rate increase with increasing electrolyte concentration for all surfactant concentrations. 

The common gangue material quartz (silica) is naturally hydrophilic and can be easily separated in this way from hydrophobic materials such as talc, molybdenite, metal sulphides and some types of coal. Minerals which are hydrophilic can usually be made hydrophobic by adding surfactant (referred to as an activator ) to the solution which selectively adsorbs on the required grains. For example, cationic surfactants (e.g. CTAB) will adsorb onto most negatively charged surfaces whereas anionic surfactants (e.g. SDS) will not. Optimum flotation conditions are usually obtained by experiment using a model test cell called a Hallimond tube . In addition to activator compounds, frothers which are also surfactants are added to stabilize the foam produced at the top of the flotation chamber. Mixtures of non-ionic and ionic surfactant molecules make the best frothers. As examples of the remarkable efficiency of the process, only 45 g of collector and 35 g of frother are required to float 1 ton of quartz and only 30 g of collector will separate 3 tons of sulphide ore. 

Of the many experiments run in the PS micromodel, only Test 11-19A is described here (see Table II). It was a gas-drive of surfactant solution (GDS), in which the pressure drop across the micromodel was measured and analyzed in terms of the flow behavior recorded simultaneously on videotape. It was also of interest to examine bubble formation and breakup processes in the PS model, where the large and fairly regular pores might give a different behavior than the smaller, more variable pores of the RS model. The surfactant used in the PS model was an anionic-nonionic blend in a 10 wt.% (weight percent active) solution, and nitrogen was the gas used in the GDS test. Conditions were 1000 psi back pressure and ambient temperature. 

Many surfactants have been used to formulate microemulsions (1). They were of three types anionic surfactants such as petroleum sulfonates, sodium octyl benzene sulfonate, sodium dodecyl sulfate, alkaline soaps cationic surfactants such as dodecyl ammonium and hexadecyl eimmonium chlorides or bromides and nonionic surfactants such as polyoxyethylene glycols. Furthermore, many exhibit liquid-crystalline properties (2) and in some cases the structure of the mesophases has been established (3). Nevertheless, nearly nothing is known about their compatibility with blood and tissues, and, from our own experience, some exhibit a high lytic power for red cells... 

Regarding the surfactant type and rock type, nonionic surfactants have much higher adsorption on a sandstone surface than anionic surfactants (Liu, 2007). However, Liu s initial experiments indicated that the adsorption of nonionic surfactant on calcite was much lower than that of anionic surfactant without the presence of NaaCOs and was of the same order of magnitude as that of anionic surfactant with the presence of Na2C03. Thus, nonionic surfactants might be candidates for use in carbonate formations from the adsorption point of view. The role of salinity is much less important, but the temperature effect is much more important for nonionics than for anionics (Salager et al 1979a). More factors that affect adsorption were discussed by Somasundaran and Hanna (1977). 

The third alternative to determine a component characteristic parameter is to interpolate between known systems. If for instance the EACN of a crude oil has to be estimated, the best way is to carry out base experiments with a few -alkanes for instance from heptane to tetradecane as in Fig. 3.8, in order to plot the variation of the optimum value of the scanned variable (S) versus ACN, then to carry out a scan with the unknown oil and to identify the alkane mixture that matches the optimum formulation. Figure 3.8 illustrates the determination of the EACN of an unknown crude oil by scanning the salinity of an anionic surfactant system. Such technique could also be used by extrapolating instead of interpolating, provided that the trend is linear and the extrapolation is not too far away, as for unknown paraffinic oil in Fig. 3.8. 

In addition to a generalized medium effect, micelles also have a charge effect that seems to be related to the reaction mechanism. Most of the experiments were made by using CTAX as the cationic and SDS as the anionic surfactant, and the rate constants for reaction of fully micellar bound substrates are designated k+ and k that is, k+ and k are values of k M in cationic and anionic micelles, respectively (54, 55). 

The order of component addition is important. The mixing of concentrated anionic and nonionic surfactants must be avoided because it produces gels that dissolve very slowly. Typically, a master batch of nonionic surfactant, initiator, and LMA was prepared for use with all the solutions of a series of experiments. This approach ensures that the small concentration components are all at the same concentration. To a portion of this well-mixed master batch was added more nonionic surfactant if necessary, propanamide (if used), water to about 80 g, anionic surfactant, mercaptoethanol, and water to 100 g, with stirring as appropriate. 

MEKC separation and online concentration of bisphenol A and alkyl phenols has been approached in a series of experiments using SDS and other alkyl chain anionic surfactants, bile salts, and TTAB in organic solvent and CD-modified buffers. ... 

Similar types of experiments using similar experimental setup have been reported Srivastava and co-workers [49], using a membrane which is bipolar in nature. A cationic surfactant was used in compartment A while an anionic surfactant was used in compartment B. In the oil-phase, 2,2 -bipyridine was added to reduce the impedance for diminishing the external noise. Oscillations are observed on exposure to amines and pheromones (cw-8-dodecenyl acetate and franx-10-dodecenyl acetate). Similar type of mechanism as discussed earlier holds good for Srivastava s oscillator also. 

Anionic Surfactant onto Kaolinite. The adsorption of a petroleum sulfonate surfactant, TRS 10-80, onto Na-kaolinite was conducted in batch experiments at low-to-medium salinity and under conditions in which liquid-crystal suspensions formed in alcohol-containing brines [60]. TRS 10-80 was described as not being very brine-soluble. The adsorption studies were conducted at 30 °C with pH values ranging from 7 to 13. The alcohol used was 2-butanol and its concentration was held constant at 30 g/1. 

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