Water -non-ionic surfactant

Strey, R. (1996) Water-non-ionic surfactant systems, and the effect of additives. Ber. Bunsenges. Phys. Chem., 100, 182. 

Dorfler et al [82] systematically studied the phase behaviour of quaternary systems, consisting of water, non-ionic surfactants, a co-surfactant and a hydrocarbon, with regard to possible applications in the textile-cleaning sector. As an example, Fig. 8.14 shows the... 

Kunieda, H., and Miyajima, A. (1989) The effect of the mixing of oils on the hydrophile-lipophile-balanced (H LB) temperature in a water/non-ionic surfactant/oil system. /. Colloid Interface Sci, 128, 605-607. 

In contrast to the small effects which temperature change has on the phase behaviour of ionic surfactants [38] there is a very pronounced change in the appearance of phase diagrams of oil-water-non-ionic surfactant systems with increase in temperature. Changes induced by temperature in the relative positions and extent of isotropic and liquid crystal phases present in the ascorbic acid-water-polysorbate 80 system have been recorded by Nixon and Chawla [39] (Fig. 2.21). Temperature increase decreases the width of the liquid crystal band the most pronounced effect occurring between temperatures of 25 and 30° C where the polysorbate concentration at which liquid crystals first appear (Li + LC) is increased from about 35 to 36% to 44% polysorbate in the presence of ascorbic acid. 

In media of low dielectric constant, electrostatic stabilization is of little importance. Colloidal dispersions in non-aqueous media are thus more likely to be stabilized by steric barriers formed by adsorbed surfactants and polymers. Relatively little work has been done on the adsorption of surfactants on to solids from non-aqueous solvents, a limiting factor of course being the insolubility of many surfactants in solvents other than water. Non-ionic surfactants tend to be soluble in both aqueous and non-polar solvent systems. Rupprecht [6] has made a series of investigations of adsorption of non-ionic alkyl polyethers on to silica in various organic solvents. Fig. 9.20 shows some of the adsorption isotherms for nonylphenol Eg. 5 from dichloromethane, n-butanol, n-propanol, ethanol, 1,4-dioxan and DMSO. As might be expected, adsorption is greatest from the dichloromethane and the effect of increasing polarity is clearly seen with the three alcohols. 

The study of the mechanism of cloud point micellar extractions by phases of non-ionic surfactant (NS) is an aspect often disregarded in most literature reports and, thus, is of general interest. The effective application of the micellar extraction in the analysis is connected with the principled and the least studied problem about the influence of hydrophobicity, stmcture and substrate charge on the distribution between the water and non-ionic surfactant-rich phase. 

SG sols were synthesized by hydrolysis of tetraethyloxysilane in the presence of polyelectrolyte and surfactant. Poly (vinylsulfonic acid) (PVSA) or poly (styrenesulfonic acid) (PSSA) were used as cation exchangers, Tween-20 or Triton X-100 were used as non- ionic surfactants. Obtained sol was dropped onto the surface of glass slide and dried over night. Template extraction from the composite film was performed in water- ethanol medium. The ion-exchange properties of the films were studied spectrophotometrically using adsorption of cationic dye Rhodamine 6G or Fe(Phen) and potentiometrically by sorption of protons. 

The substitution of water-borne versions of these primers is increasing as environmental restrictions on the use of organic solvents become stricter. These are generally aqueous emulsions of epoxy novolac or phenolic based resins stabilized by surfactants [34]. Non-ionic surfactants are preferred, as they are non-hygroscopic in the dried primer films. Hygroscopic ionic surfactants could result in excessive water absorption by the primer film in service. 

As alternatives to amphiphilic betaines, a wide range of cationic, anionic, and non-ionic surfactants including environmentally benign sugar soaps have been successfully used as colloidal stabilizers [201]. Electrochemical reduction of the metal salts provides a very clean access to water soluble nanometal colloids [192]. 

Gutfelt et al. (1997) have evaluated various ME formulations as reaction media for synthesis of decyl sulphonate from decylbromide and sodium sulphite. The reaction rate was fast both in water-in-oil and in bicontinuous ME based on non-ionic surfactants. A comparison was made with this reaction being conducted in a two-phase. system with quats as phase-transfer catalyst but was found to be much less efficient. However, when two other nucleophiles, NaCN and NaNOj, were used the PTC method was almost as efficient as the ME media. It seems that in the case of decyl sulphonate there is a strong ion pair formation between the product and the PTC. The rate in the ME media could be further increased by addition of a small amount of a cationic surfactant. 

It is important that any method for surfactant analysis maintains the same oligomer distribution in the extracted samples. LLE and SPE are generally combined with chromatographic methods for separation and resolution of non-ionic surfactants into their ethoxamers. An alternative is the use of SPME-HPLC, recently reported by Chen and Pawliszyn [141]. Alkylphenol ethoxylate surfactants such as Triton X-100 and various Rexol grades in water were determined by means of SPME-NPLC-UV (at 220 nm) [142]. Detection limits for individual alkylphenol ethoxamers were at low ppb level. 

Some of the reports are as follows. Mizukoshi et al. [31] reported ultrasound assisted reduction processes of Pt(IV) ions in the presence of anionic, cationic and non-ionic surfactant. They found that radicals formed from the reaction of the surfactants with primary radicals sonolysis of water and direct thermal decomposition of surfactants during collapsing of cavities contribute to reduction of metal ions. Fujimoto et al. [32] reported metal and alloy nanoparticles of Au, Pd and ft, and Mn02 prepared by reduction method in presence of surfactant and sonication environment. They found that surfactant shows stabilization of metal particles and has impact on narrow particle size distribution during sonication process. Abbas et al. [33] carried out the effects of different operational parameters in sodium chloride sonocrystallisation, namely temperature, ultrasonic power and concentration sodium. They found that the sonocrystallization is effective method for preparation of small NaCl crystals for pharmaceutical aerosol preparation. The crystal growth then occurs in supersaturated solution. Mersmann et al. (2001) [21] and Guo et al. [34] reported that the relative supersaturation in reactive crystallization is decisive for the crystal size and depends on the following factors. 

Favretto and co-workers [198,206-208] have described direct spectrophoto-metric methods for non-ionic surfactants based on the formation of a sodium picrate surfactant adduct. This method has been applied to seawater. A mean value of 93 1% was obtained in recovery experiments on C12E9 (at an aqueous concentration of 0.10 mg/1) extracted from synthetic sea water by means of this... 

Crisp et al. [212] has described a method for the determination of non-ionic detergent concentrations between 0.05 and 2 mg/1 in fresh, estuarine, and seawater based on solvent extraction of the detergent-potassium tetrathiocyana-tozincate (II) complex followed by determination of extracted zinc by atomic AAS. A method is described for the determination of non-ionic surfactants in the concentration range 0.05-2 mg/1. Surfactant molecules are extracted into 1,2-dichlorobenzene as a neutral adduct with potassium tetrathiocyanatozin-cate (II), and the determination is completed by AAS. With a 150 ml water sample the limit of detection is 0.03 mg/1 (as Triton X-100). The method is relatively free from interference by anionic surfactants the presence of up to 5 mg/1 of anionic surfactant introduces an error of no more than 0.07 mg/1 (as Triton X-100) in the apparent non-ionic surfactant concentration. The performance of this method in the presence of anionic surfactants is of special importance, since most natural samples which contain non-ionic surfactants also contain anionic surfactants. Soaps, such as sodium stearate, do not interfere with the recovery of Triton X-100 (1 mg/1) when present at the same concentration (i.e., mg/1). Cationic surfactants, however, form extractable nonassociation compounds with the tetrathiocyanatozincate ion and interfere with the method. 

The surface active agents (surfactants) may be cationic, anionic or non-ionic. Surfactants commonly used are cetyltrimethyl ammonium bromide (CTABr), sodium lauryl sulphate (NaLS) and triton-X, etc. The surfactants help to lower the surface tension at the monomer-water interface and also facilitate emulsification of the monomer in water. Because of their low solubility surfactants get fully dissolved or molecularly dispersed only at low concentrations and at higher concentrations micelles are formed. The highest concentration where in all the molecules are in dispersed state is known as critical micelle concentration (CMC). The CMC values of some surfactants are listed in table below. 

The non-ionic surfactants do not produce ions in aqueous solution. The solubility of non-ionic surfactants in water is due to the presence of functional groups in the molecules that have a strong affinity for water. Similarly to the anionic surfactants, and any other group of surfactants, they also show the same general property of these products, which is the reduction of the surface tension of water. 

L.S. Clesceri, A.E. Greenberg and A.D. Eaton (Eds), Standard Methods for the Examination of Water and Wastewater. 20th Edition, American Public Health Association, Washington, DC, 1998, pp. 5-47 (5540 C, Anionic Surfactants as MBAS) and pp. 5-49 (5540 D, Non-ionic Surfactants as CTAS). 

Some surfactants were found to be hardly degradable in the biological wastewater treatment process. Therefore, non-ionic surfactants are observed not only in wastewater and surface water but also in drinking water [7,8] and other environmental samples. In addition, they could be... 

The experimental evaluation [4] of the stability of non-ionic surfactants (nonylphenol ethoxylates, NPEOs, and alcohol ethoxylates, AEOs) during sample storage showed that aqueous samples can be stored at 4°C without addition of any preservative only for a short time (a maximum of 5 days). The most often used preservative is formaline (1-8% (v/v) of 37% solution of formaldehyde in water). 

Stability of surfactants in a water matrix, even using different preservation agents, is poor and serious, quantitative and qualitative changes in sample integrity occur if the storage exceeds 7 days. The most suitable preservation additive is formaldehyde (minimum 3%) for non-ionic surfactants and LAS, and acidification to pH < 3 for benzene and naphthalene sulphonates. However, storage for longer than 7 days is not recommended. 

An overview of non-ionic surfactant concentrations in saline waters can be found in Table 6.4.1. 

Reported concentrations of non-ionic surfactants and their metabolites in marine and estuarine waters... 

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