Surface tension detergency

Foam low high Alkali stab Electrolyte stab Acid stab Chlorine stab Surface tension Detergent effect Hydrotropic effect Solubilizing effect Biodegrad- ability... 

Introduction of chemical sensors for water quality monitoring. This includes parameters like turbidity, color, surface tension, detergent concentrations, pH-value etc. Optoelectronic systems are used to monitor the turbidity of washing water, which then determines the number of rinsing cycles (aqua-sensor system). 

Chemical sensors for water quality determination. The parameters measured include turbidity, color, surface tension, detergent concentration, pH-value etc. 

The type of behavior shown by the ethanol-water system reaches an extreme in the case of higher-molecular-weight solutes of the polar-nonpolar type, such as, soaps and detergents [91]. As illustrated in Fig. Ul-9e, the decrease in surface tension now takes place at very low concentrations sometimes showing a point of abrupt change in slope in a y/C plot [92]. The surface tension becomes essentially constant beyond a certain concentration identified with micelle formation (see Section XIII-5). The lines in Fig. III-9e are fits to Eq. III-57. The authors combined this analysis with the Gibbs equation (Section III-SB) to obtain the surface excess of surfactant and an alcohol cosurfactant. 

In detergency, for separation of an oily soil O from a solid fabric S just to occur in an aqueous surfactant solution W, the desired condition is 730 = 7wo+7sw. Use simple empirical surface tension relationships to infer whether the above condition might be met if (a) 73 = 7w. (6) 70 = 7W, or (c) 73 = 70. 

Thus, adding surfactants to minimize the oil-water and solid-water interfacial tensions causes removal to become spontaneous. On the other hand, a mere decrease in the surface tension of the water-air interface, as evidenced, say, by foam formation, is not a direct indication that the surfactant will function well as a detergent. The decrease in yow or ysw implies, through the Gibb s equation (see Section III-5) adsorption of detergent. 

A surfactant is known to lower the surface tension of water and also is known to adsorb at the water-oil interface but not to adsorb appreciably at the water-fabric interface. Explain briefly whether this detergent should be useful in (a) waterproofing of fabrics or (b) in detergency and the washing of fabrics. 

Detergents may be produced by the chemical reaction of fats and fatty acids with polar materials such as sulfuric or phosphoric acid or ethylene oxide. Detergents emulsify oil and grease because of their abiUty to reduce the surface tension and contact angle of water as well as the interfacial tension between water and oil. Recent trends in detergents have been to lower phosphate content to prevent eutrification of lakes when detergents are disposed of in municipal waste. 

Furthermore, in a series of polyoxyethylene nonylphenol nonionic surfactants, the value of varied linearly with the HLB number of the surfactant. The value of K2 varied linearly with the log of the interfacial tension measured at the surfactant concentration that gives 90% soil removal. Carrying the correlations still further, it was found that from the detergency equation of a single surfactant with three different polar sods, was a function of the sod s dipole moment and a function of the sod s surface tension (81). 

Even if the interfacial tension is measured accurately, there may be doubt about its applicability to the surface of bubbles being rapidly formed in a solution of a surface-active agent, for the bubble surface may not have time to become equihbrated with the solution. Coppock and Meiklejohn [Trans. Instn. Chem. Engrs., 29, 75 (1951)] reported that bubbles formed in the single-bubble regime at an orifice in a solution of a commercial detergent had a diameter larger than that calculated in terms of the measured surface tension of the solution [Eq. (14-206)]. The disparity is probably a reflection of unequihbrated bubble laminae. 

Surface active agent. Any of a wide range of detergents, emulsifiers, dispersants, defoamers, etc., that tend to reduce the surface tension of water and improve its wetting power. 

The DATs present in LAB will readily sulfonate to form dialkyltetralin-sulfonate or DATS. The foam and detergency performance properties of individual C DATS homologs are very similar to that of the corresponding C j LAS homologs [21]. Thus, even at a level of 10% DATS in the LAB, no decrease in foam or detergency performance is observed. In some liquid formulations, the presence of DATS can provide a beneficial hydrotropic effect to LAS [22]. Figure 8 illustrates that DATS are indeed surfactants, as evidenced by their surface tension vs. concentration plot. 

Schulze [51] described an extensive study on C12-C14 ether carboxylic acid sodium salt (4.5 mol EO) in terms of surface tension, critical micelle concentration (CMC), wetting, detergency, foam, hardness stability, and lime soap dispersing properties. He found good detergent effect compared to the etho-xylated C16-C18 fatty alcohol (25 mol EO) independent of CaCl2 concentration, there was excellent soil suspending power, low surface tension, and fewer Ca deposits than with alkylbenzenesulfonate. 

AOS at this proportion the micelle promotion tendency of AOS in the mixture is clearly optimal. At this composition, the authors have also observed a minimum in the surface tension vs. composition plot, and maximum performance benefits in detergency tests (see below). 

In 1963, a detailed report on the various technical aspects of sodium sulfosuccinate monoesters was given [11] physical properties, stability, surface tension, and detergency. Mildness to skin and eyes are documented for the first time in this paper. 

Monoamidotriphosphate compounds have been evaluated for their combined detergent-sequestrant action [65,66]. Good surfactant properties are also attributed to organoaminodialkylenephosphonic acids. Typical compounds of this kind are the tetra- and trialkali salts of decyl-, dodecyl-, and tetradecylaminodi (methylphosphonate). Values of surface tension and detergency are given in Refs. 118 and 216-219. Wash test results, foam behavior, wetting performance, and surface tensions of aqueous solutions of phosphate esters have been tabulated [12,17,18,33,37,50,52,56,90,220]. 

In another study of the physical behavior of soap-LSDA blends, Weil and Linfield [35] showed that the mechanism of action of such mixtures is based on a close association between the two components. In deionized water this association is mixed micellar. Surface tension curves confirm the presence of mixed micelles in deionized water and show a combination of optimum surface active properties, such as low CMC, high surface concentration, and low surface concentration above the CMC. Solubilization of high Krafft point soap by an LSDA and of a difficulty soluble LSDA by soap are related results of this association. Analysis of dispersions of soap-LSDA mixtures in hard water shows that the dispersed particles are mixtures of soap and LSDA in the same proportion as they were originally added. These findings are inconsistent with the view that soap reacts separately with hard water ions and that the resulting lime soap is suspended by surface adsorption of LSDA. The suspended particles are responsible for surface-active properties and detergency and do not permit deposits on washed fabric unlike those found after washing with soap alone. 

The presence of surface active agents, such as detergents, also decreases the surface tension of water. 

It is known from laboratory tests that surface tension measurement can provide reliable information regarding existing detergent concentration. Work is being carried out in various institutes on such sensors for the commercial sector. However, for use in domestic washing machines, only sensors that are extremely inexpensive, maintenance-free and durable are suitable. How much of a breakthrough can be achieved here in the future remains to be seen. 

The basis for the foam properties is given by interfacial parameters. Although correlations have been shown between a single parameter and foam properties, there is still a lack in a general correlation between interfacial properties and the foam behavior of complex systems in detergency. The simplest approach to correlate interfacial parameters to foam properties is the comparison of the surface activity measured by the surface tension of a surfactant system and foam stability. 

The knowledge of physico-chemical parameters like surface tension, conductivity, turbidity and the pH of the washing liquor is important for the improvement of existing washing and dishwashing detergent formulations further development of new alternatives. Today s advanced physico-chemical and analytical methods make... 

Fig. 4.7 Typical behavior of a solid detergent product during the first 20 minutes in a commercially available washing machine. Relevant parameters (pH value, conductivity A, surface tension y, peroxide content ) were detected by on-line sensorics.

In the future, monitoring of surface tension could be an attractive option for measuring surfactant concentration. Automatic dosing systems could also be introduced for a controlled supply of concentrated detergents. 

Tween 20 (detergent and surface tension reducer optional)... 

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