Surfactant power

The power of optical spectroscopies is that they are often much better developed than their electron-, ion- and atom-based counterparts, and therefore provide results that are easier to interpret. Furtlienuore, photon-based teclmiques are uniquely poised to help in the characterization of liquid-liquid, liquid-solid and even solid-solid interfaces generally inaccessible by other means. There has certainly been a renewed interest in the use of optical spectroscopies for the study of more realistic systems such as catalysts, adsorbates, emulsions, surfactants, self-assembled layers, etc. 

Carboxylate, sulfonate, sulfate, and phosphate ate the polar, solubilizing groups found in most anionic surfactants. In dilute solutions of soft water, these groups ate combined with a 12—15 carbon chain hydrophobe for best surfactant properties. In neutral or acidic media, or in the presence of heavy-metal salts, eg, Ca, the carboxylate group loses most of its solubilizing power. 

Gas turbine fuels can contain natural surfactants if the cmde fraction is high in organic acids, eg, naphthenic (cycloparaffinic) acids of 200—400 mol wt. These acids readily form salts that are water-soluble and surface-active. Older treating processes for sulfur removal can leave sulfonate residues which are even more powerful surfactants. Refineries have installed processes for surfactant removal. Clay beds to adsorb these trace materials are widely used, and salt towers to reduce water levels also remove water-soluble surfactants. In the field, clay filters designed as cartridges mounted in vertical vessels are also used extensively to remove surfactants picked up in fuel pipelines, in contaminated tankers, or in barges. 

In hair coloring a light ash blond shade may require as Httie as 0.5—1% of intermediates, whereas a tme black may require up to about 5%. In principle, the formulator blends precursors that yield red, blue, and yellow dyes. The base in which the components are dissolved or suspended is similar to that used in simple bleaches and may include alkanolamides, various types of surfactants, thickening agents, and solvents. Removal of undesirable dyes is achieved by treating the discolored hair with a powerful reductant of the sulfite family. 

The gravity measurements of the pelobischofite and appropriate compositions detergency showed the essential increase of this parameter for pelobischofite-surfactant mixtures. Thus the washing power of pelobischofite-surfactant solutions with concentration 0,1% was 90%. Erom another hand, similar detergency of bischofite-surfactant mixtures was reached for 1% solutions only. 

An explosion and fire (March 13, 1991) occurred at an ethylene oxide unit at Union Carbide Chemicals Plastics Co. s Seadrift plant in Port Lavaca, TX, 125 miles southwest of Houston. The blast killed one, injured 19, and idled the facility, that also produces ethylene, ethylene glycol, glycol ether ethanolamines, and polyethylene. Twenty-five residents were evacuated for several hours as a safety precaution. The plant lost all electrical power, for a few days, because its cogeneration unit was damaged. The Seadrift plant, with 1,600 workers, is capable of making 820 million lb per year of ethylene oxide which is one-third of Carbide s worldwide production of antifreeze, polyester fibers, and surfactants Seadrift produces two thirds of Carbide s worldwide production of polyethylene. 

Q Flux of absorbed surfactants p Rate of surface renewal by eddies P Power input to impeller P Flux of desorbed surfactants P0 Power input to impeller, no-gas condition... 

FIG. 3 Lime soap dispersing power of some alkyl ether carboxylates compared to other surfactants (DIN 53903). AEC, alkyl ether carboxylate AMEC, amidether carboxylate CAPB, cocamidoproplylbetaine OEC, oleyl ether carboxylate SLES, sodium lauryl ether sulfate. % surfactant soap = % surfactant calculated on the soap needed to disperse the lime soap. (From Refs. 61 and 64.)... 

Gafa and Lattanzi [6] determined the foaming power of commercial surfactants including AOS, LAS, AS, and SAS in 1 g/L solutions at 40°C according to a modified Ross-Miles method [66]. Their data, shown in Table 24, show that the best foaming products are the AOS and AS compounds followed by LAS and SAS. 

TABLE 24 Foaming Power of AOS and Reference Surfactants According to a Modified Ross-Miles Test at 40°C and 1 g/L Surfactant Concentration... 

LDL compositions containing AOS, a sulfosuccinic acid ester, a zwitterionic and a nonionic surfactant have been described by Noguera et al. [76]. Such compositions have good cleaning and foaming power and are useful too for shampoo and laundry-cleaning purposes. 

The applications of a-sulfo fatty acid esters are widely spread as for other surfactants. They can be used in detergents, cleansers, and cosmetic products as well as in the building industry and for the production of synthetic materials and agrochemicals. The main properties for these applications are surface activity, wetting ability, hard water stability, lime soap dispersion power, and good human and environmental safety profiles. 

Fig. 18. Comparison of results from various particle systems for stirred vessel with baffles and bubble columns Activity a/ao of Acylase resin after t = 300 h, equilibrium drop diameter dg of silicon oil-water-surfactant emulsion and reference floe diameter dpv of floe system in dependency on specific power P/V H/D = 1 D = 0.15 m 0.4 m...

In contrast to this, the enzyme resin is stressed less by gas sparging than by stirring (see Fig. 18 and 20). The same activity losses were observed first with 1 to 8 times greater specific adiabatic compression power Pj/ V than the maximum power density necessary for stirring. As in the case of the smooth disc, the effects of power input are only weak. The type of gas sparger and therefore the gas exit velocity are of no recognisable importance. The behaviour of the enzyme resin particles is thus completely different from that of the clay min-eral/polymer floes and the oil/water/surfactant droplet system, which are particularly intensively stressed by gas sparging. 

The molecular collective behavior of surfactant molecules has been analyzed using the time courses of capillary wave frequency after injection of surfactant aqueous solution onto the liquid-liquid interface [5,8]. Typical power spectra for capillary waves excited at the water-nitrobenzene interface are shown in Fig. 3 (a) without CTAB (cetyltrimethy-lammonium bromide) molecules, and (b) 10 s after the injection of CTAB solution to the water phase [5]. The peak appearing around 10-13 kHz represents the beat frequency, i.e., the capillary wave frequency. The peak of the capillary wave frequency shifts from 12.5 to 10.0kHz on the injection of CTAB solution. This is due to the decrease in interfacial tension caused by the increased number density of surfactant molecules at the interface. Time courses of capillary wave frequency after the injection of different CTAB concentrations into the aqueous phase are reproduced in Fig. 4. An anomalous temporary decrease in capillary wave frequency is observed when the CTAB solution beyond the CMC (critical micelle concentration) was injected. The capillary wave frequency decreases rapidly on injection, and after attaining its minimum value, it increases... 

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