Surfactants indicators

The third step expresses the decomposition of the surfactant indicated by the formation of CO2. This rather simple relation between mass loss and decomposition event cannot be made for D41, where CO2 is detected over the whole temperature range to a changing extent. 

Replacement of alkyl chains by an ester increases the values of k in the case of the (Cn)2Me2N+ cationic surfactants, indicating that hydrolysis is a more rapid biodegradation pathway than co-P-Oxidation. However, comparison of the k -values of C12S04 with that of DEEDMAC demonstrates that other structural moieties also have significant influence on biodegradability. The available data do not allow conclusions as to which factors are involved. 

Studies on structure-activity relationships between herbicides and homologous series of surfactants indicate that definite relationships exist between the herbicide and surfactant structure for maximum herbicide penetration. The length of the molecular chains (either hydrophilic or lipophilic) of a surfactant molecule appears to have considerable influence on herbicide penetration, and the surfactant concentration also influences this process markedly. 

Comparison of the concentrations corresponding to formation of black spots for emulsion and foam films, obtained from solutions of the same surfactants, indicate that Cbi for foam films are considerably lower than Cbi.f for emulsion films. This means that stable foam films (usually black) form at lower surfactant concentrations than emulsion films even from apolar organic phase. With the increase in the polarity of the molecules of the organic phase Cbi.f for emulsion aqueous films increases [507] which is analogous to the increase in Cbi for hydrocarbon emulsion films [509],... 

Figure 10. Surface-tension data for the polyoxyethylene sorbitan monooleate surfactant indicate that the surfactant dose required to attain aqueous-phase CMC in the presence of soil is about 0.2% (v/v).

An early indication that a widely used agricultural chemical might be metabolized to a nonpolar conjugate in plants came from an in vitro enzyme study with C-labeled surfactants of the Triton family. A crude particulate enzyme preparation from com shoots catalyzed the formation of fatty acid ester conjugates from the two 1"c-labeled polyethoxylated surfactants indicated below (Equation 32). The ester conjugates were formed primarily from palmitic and linoleic acids 0851). They were identified by mass spectrometry and by GLC analysis of hydrolysis products (J48). In vljro, rice and... 

LABs. Despite of their potential as anionic surfactants indicators , there is little information on then-recovery from the dissolved phase of wastewaters. According to onr results, LLE is an efficient extraction technique for wastewaters (Table 1), but for large sample volumes open porous PUF can still be nsed. LABs coelute with aliphatic hydrocarbons in the fractionation procednre used, thus their quantitation shonld be performed by HRG-EI MS, unless further fractionation is carried out for GC FID analysis ". 

Equation 3.15 predicts the effect of electrolyte on the CMC of ionic surfactants, indicating that the log of the CMC will decrease linearly with log C which is in accordance with experimental findings (equation 3.3). It also indicates that the CMC of ionic surfactants will decrease with increase in the extent of binding of the counterion to the micelle since that decreases the charge density on the micellar surface. Organic additives that decrease the dielectric constant of the solvent will increase the CMC of the surfactant, both of which are consistent with the experimental results discussed previously. The effect of temperature on the CMC of ionic surfactants is difficult to predict from equation 3.15. An increase in the temperature should cause a direct decrease in the CMC, but since an increase in temperature causes a decrease in the dielectric constant er of the solvent and may also affect a, the overall effect of an increase in temperature is not readily determinable from the equation alone. 

Give structural formulas for three different types of low-foaming surfactants, indicating the structural characteristics that cause them to foam poorly. 

A part of the base surfactant mixture, for instance 0.5 wt.% of the total 2 wt.%, that is 25%, is substituted by the unknown surfactant, indicated by subscript 3 in what follows. A scan is carried out by mixing the two base surfactants, i.e. by changing only a part of the three surfactant mixture, since the unknown surfactant content is constant, i.e. in... 

Note that the AOT and T 20 were not readded in the reactions with SSENDs catalyst (but they were present in the preparation due to addition before lyophilization). The surfactants indicated below were added (postlyophilization) only in the experiment with the native SC. The standard deviation for the SSEND samples is for duplicate experiments. 

The highest profits for clinoptilolite seem to be achieved in the field of cat litter, animal bedding, and odor absorbents. With increasing environmental conscious applications in pollution abatement gain importance, in particular, if large amounts of ion exchanger or absorber are needed. The versatility of surface modified clinoptilolite is not fully explored yet. As the recent example of sorption [52,53] on the surfactant indicates, many other applications seem possible where the advantages of the porous bulk structure are combined with specific properties of well-chosen surfactants. 

In a similar study, Ebeltoft et al. mixed surfactants (sodium dodecyl sulfate, eetyltrimethylammonium bromide, or cetylpyridinium ehloride) with PSAA and studied the pressiue-area isotherms (70). All the surfaetants appeared to interact with the PSAA and in similar ways. It was concluded that PSAA monolayers are good models for emulsion-stabilizing monolayers in Norwegian crude oils. Monolayers of both PSAA and cmde oil interfacially active fractions responded similarly to the presence of ionic surfactants, indicating analogous dissolution mechanisms. 

Interfacial tension measurement, both static and dynamic, provide clues about the usefulness of the surfactant as an emulsifier for a given system of oil and water. Not only is the sharp decrease in interfacial tension desirable, but it is also important to produce the minimum tension possible from a given surfactant. In fact the results of interfacial tension measurements can provide information about the effectiveness and efficiency of surfactants for a given system. A sharp decrease in interfacial tension with the increase in concentration of surfactant indicates that the surfactant is effective, whereas one that causes minimum interfacial tension although not with a sharp rate would be considered efficient. Depending on the requirements, one can use the effective or the efficient surfactant for a given formulation of paints, inks, and polishes. Interfacial data of surfactants can be used as the main criteria for quality by the users of surfactants. 

Surface tension measurements for this surfactant indicate a range of CMC values between 0.1 and 1 wt%. This is reasonable because of the distribution of molecular... 

ORION 9342BN surfactant Indicating electrode in potentiometric titration... 

Esumi et al [68] used dispersions of a-alumina as well to study the interaction between anionic fluorocarbon and hydrocarbon surfactants. The anionic fluorocarbon surfactants used were LiFOS and NFIOO, the anionic hydrocarbon surfactants were SDS and LiDS, and the nonionic surfactant was NP7.5. Like the flocculation behavior of iron hydroxide, a low concentration of an anionic surfactant precipitates alumina. A further addition of a surfactant, different from the first one, forms mixed bilayers and redisperses alumina. Measurements of zeta potentials, the size of adlayers, and the amounts of adsorbed surfactants indicated that mixed bilayers consisting of anionic hydrocarbon-nonionic hydrocarbon surfactants or anionic fluorocarbon-nonionic hydrocarbon surfactants are formed preferentially to hydrocarbon-fluorocarbon surfactant bilayers. 

Fluorinated surfactants lower the surface tension of stimulation fluids more than hydrocarbon surfactants and are stable in aqueous stimulation fluids at 100°C. Drainage of salt solution (2% KCl) from sand packs is inversely related to the surface tension. Fluorinated surfactants enhance drainage more than hydrocarbon surfactants. Flow rates of fluids through sand packs or low-permeability sandstone cores were unaffected by the fluorinated surfactant, indicating that formation blockage by a fluorinated surfactant is improbable. Aqueous fluorinated surfactant solutions do not form emulsions of kerosine. 

A sample containing 5-50 mg ethoxylate in about 90 mL water is mixed with 10 mL of 0.1 M barium chloride solution and titrated with 0.01 M aqueous sodium tetraphenylborate solution (prepared with 10 g polyvinyl alcohol and 10 mL 0.1 M NaOH per liter of titrant). The titration is made potentiometrically, using the Metrohm surfactant indicating electrode and a silver/silver chloride reference electrode (NaCl filling solution). The electrode must be rinsed free of precipitate after every few titrations using methanol. An electrode... 

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