Aqueous tension data

Fig. Ill-IS. Surface tension data for aqueous alcohol illustration of the use of the Gibbs equation. (1) -butyl (2) -amyl (3) -hexyl (4) -heptyl (5) -octyl. (Data from Ref. 126).

Kakiuchi and Senda [36] measured the electrocapillary curves of the ideally polarized water nitrobenzene interface by the drop time method using the electrolyte dropping electrode [37] at various concentrations of the aqueous (LiCl) and the organic solvent (tetrabutylammonium tetraphenylborate) electrolytes. An example of the electrocapillary curve for this system is shown in Fig. 2. The surface excess charge density Q, and the relative surface excess concentrations T " and rppg of the Li cation and the tetraphenylborate anion respectively, were evaluated from the surface tension data by using Eq. (21). The relative surface excess concentrations and of the d anion and the... 

The surface tension data given in Figure 3.5 was obtained for aqueous solutions of a trivalent cationic surfactant (C0RCI3) in both water and in 150 mM NaCl solution. Use the data and the Gibbs adsorption isotherm to obtain estimates of the minimum surface area per molecule adsorbed at the air/water interface. 

Figure 3.5 Surface tension data for aqueous solutions of a trivalent surfactant C0RCI3.

The view that the monomers are confined to the reverse micellar pseudophase is supported by interfacial tension data (67), which demonstrate that in a two-phase octane/water system, partially hydrolyzed TEOS species partition preferentially into the aqueous phase. The interfacial tension determined at the octane/water interface for samples prepared with precursor ethanolic solutions of different water-to-TEOS molar ratios (h - 0, 0.29, and 0.55) are presented in Figure 2.2.14 (67). As can be seen, for TEOS concentrations below about 4 X 10- 1 M, the octane/water interfacial tension is independent of the concentration of TEOS species in the organic phase... 

From the surface tension data obtained for different electrolyte concentrations, the relative ionic surface excesses can be determined. Thus, for the cell Hgl KC1 (aqueous)IHg2Cl2lHg, from Eq. (1.69), the cation excess is given by... 

Correct 99.5 cc. of air for pressure, temperature, and aqueous tension from the following data —... 

Figure 1. Surface-tension data indicate that micelle formation in the soil-aqueous system occurs at a surfactant dose of 0.09% (v/v) for the Cl2E4 nonionic...

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).

The effective surfactant dose upon dilution was not inhibitory, and is less than the CMC in the soil-water systems. This dose to attain the CMC is nominally about 0.06% (v/v) or about 0.001 mol/L for Triton X-100 for a soil water ratio of 1 8 g/mL, as shown in Figure 3 for solubilization data or in reference 52 for surface-tension data. Therefore, the data in Figure 10 demonstrate recovery of phenanthrene biomineralization upon dilution of surfactant to sub-CMC aqueous-phase concentrations in soil-water systems. 

Standard free energies at the aqueous solution-air interface can be calculated from surface tension data in the vicinity of the CMC, where such data are commonly and conveniently taken, by use of equation 2.32 (Rosen, 1981),... 

As mentioned above, the value of t, has been shown to be related to the coverage of the air-aqueous solution interface by the surfactant and to its apparent diffusion coefficient, Dap (equation 5.7). To calculate the values of Dap at short times, equation 5.8 (Bendure, 1971), based upon the short-time approximation equation of Ward and Tordai (equation 5.6), and using dynamic short-time surface tension data, may be used ... 

The composition dependence of the surface tension of binary mixtures of severed compounds with water is given in this table. The data are tabulated as a function of the mass percent of the non-aqueous component. Data for methanol, ethanol, 1-propanol, and 2-propanol are taken from Reference 1, which also gives values at other temperatures. 

FIGURE 6.12 Model predictions and experimental dynamic surface tension data for 1.7 x 10 kmol/m aqueous decanol drops growing into decanol-free air. The equilibrium value is 35 mN/m. Reprinted from MacLeod and Radke (1994) with permission from Elsevier. 

Density, viscosity and interfacial tension data of the equilibrated phases corresponding to an aqueous to oil ratio of 1 1 are presented in Table 1. Table 2 is the summary of the number of equilibrium phases present at 35 C for different aqueous to oil ratios and sodium chloride concentrations. It should be noted that the 1 1 system having 2% NaCl at 35°C represents a three phase system. However, at 25°C the same system gave only two phases. 

The complexation of the surfactant viologens by the cyclodextrins was also clearly demonstrated with surface tension data. Figure 2 shows the surface tension of 50 mM NaCl aqueous solutions also containing 1.0 mM Cj6VBr2 as a function of the concentration of added ACD. In the absence of ACD, the surface tension is... 

From the surface tension measurements of the interface between the aqueous solution of LiCl and the nitrobenzene solution of TBATPB, the zero-charge potential difference was estimated as A cpp c 0.020 V [14] on the basis of the standard potential difference Ao tba+ = —0.248 V [37] for the reference tetrabutylammonium cation. If the corrected value zero-charge potential difference becomes Aosurface tension data for the system of NaBr in water and tetraalkylammonium tetraphenylborate in nitrobenzene also indicate that A cpp c is zero [11,13]. 

To overcome the difficulties of measuring the surface tension decrease accurately at very low surfactant concentration, a new method for calculating AG d at the aqueous solution-air interface was suggested by Rosen and Aronson [11]. The method enables the use of surface tension data in a region of larger concentrations, where surfactants show... 

The following table shows experimental surface tension data for an aqueous solution of nonylphenyl ethoxylate NPEis at 20 °C (the subscript 15 indicates that we have 15 oxyethylene groups) ... 

The effect of an inhibiting electrolyte on bubble coalescence is to extend the lifetime of the thin aqueous film separating two bubbles. Even for a strongly inhibiting electrolyte, the thin film separating two bubbles will rupture in less than ten seconds and in the absence of electrolyte, this rupture typically occurs in less than one second. It should therefore be remembered that coalescence is a dynamic process and hence equilibrium values of the surface tension may not be appropriate. Currently, there is no dynamic surface tension data available for electrolyte solutions. The acquisition of such data would be challenging as the influence of electrolytes on surface tension is small (and the dynamic influence will be... 

The influence of electrolytes on bubble coalescence in both aqueous and non-aqueous systems is ion specific. The available evidence suggests that ion specific effects at the air-water interface are strongly correlated with the partitioning of ions in the interfacial region. Ion partition coefficients determined from surface tension data correlate well with the empirically assigned a and parameters used to predict bubble coalescence inhibition. Bubble coalescence is inhibited when there is an accumulation of both ions at the interface or a removal of both ions from the interface, though the precise mechanism of inhibition remains elusive. 

A 1.5% by weight aqueous surfactant solution has a surface tension of 53.8 dyn/cm (or mN/m) at 20°C. (a) Calculate a, the area of surface containing one molecule. State any assumptions that must be made to make the calculation from the preceding data, (b) The additional information is now supplied that a 1.7% solution has a surface tension of 53.6 dyn/cm. If the surface-adsorbed film obeys the equation of state ir(o - 00) = kT, calculate from the combined data a value of 00, the actual area of a molecule. 

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