Flow of surfactant anions

The aim now is to derive an equation for the flow of surfactant anions to the surface of a rising bubble. To do so, we have to calculate the integral on the right hand side of Eq. (7.22)... 

Eq. (9.38) should be used in the case when condition (7.29) is fulfilled on the main part of the bubble surface. Then, the adsorption flow of surfactant anions calculated in accordance with... 

This technique of MEUF has also been successfully employed for the recovery of thuringiensin [258], removal of cresols [262], extraction of chromate anion [257], removal of dissolved organic pollutants [256], removal of -alcohols [263],preconcentration and removal of iron [260], and preconcentration of aniline derivatives [261].Kandori and Schechter [264] have given a detailed account of selecting surfactants for MEUF. The design characteristics of micellar enhanced utrafilters and cross-flow ultrafiltration of micellar surfactant solutions have been described by Markets et al. [265]. 

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. 

The calculation of the total desorption flow in the case of electrostatic retardation of desorption kinetics follows from Eq. (7.36). The density of the surfactant anions flux within the stagnant cap can be estimated by... 

In [259] results are obtained when using foams for EOR in oil fields in China. Many oil fields in China contain up to 80% water as result of water flooding, and the oil recovery does not exceed 20%. The main reason of the low reservoir recovery is a strong heterogeneity of the reservoir which causes the injected water to channel through only the high-permeability zones. Injection of foams in the water-oil front can improve the profiles of injected liquids in view of a drastic difference in flow properties between foam and water, so that the efficiency of oil production can be increased. Anionic surfactants (petroleum sulfonates, a-olefin sulfonates, alkylsulphates) as well as their mixtures with nonionic surfactant and polyacrylamide were tested under laboratory conditions. Data are presented concerning one of the projects accomplished in one of the oil fields in China. Within the period from May 1971 to June 1973 (26.6 months) 933 of 1% solution of surfactant mixture and 8082 m air has been injected which is equivalent to about 5% of the reservoir volume. The water cut decreased by 27.7% while the recovery factor increased by 6%-8%. 

As demonstrated (cf. Fig. 15.1 and 15.2) with the results of ionisation observed in the spectra of the non-ionic surfactant mixtures of AEOs or APOs or for ionisation of the anionic surfactant mixture of AES (cf Fig. 15.3), if APCl or ESI interfaces were applied, both API interface types presented considerable differences in the ionisation processes. These differences were in both the type of ions and the efficiency of ionisation, i.e., either high molecular or low molecular compounds were favoured in ionisation and no ionisation takes places with the one interface whereas the other interface type ionises the compounds with high sensitivity. Obviously ESI is the interface which handles the very polar, partly charged compounds with low as well as high molecular weights in the best way, while the APCl interface can be used successfully for the more lipophilic compounds contained in water samples, e.g. phenol compounds. With the improved flexibility of ESI handhng low and high flow rates of eluents ESI-CEz-MS became a powerful tool to separate complex mixtures with an improved separation efficiency never previously observable with any kind of LC (see Eig. 15.6) [395]. 

Quaternary alkylammonium salts, used as flow reverser additives in the separation of small anions, will fall technically into the EKC definition, since the surfactant micellization is anticipated due to the electrolyte ionic strength in which the separation is conducted vide section on small ions analysis). 

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