Surfactants sediment

Surfactant solubility determination Solubility limits of surfactants in brine solutions in the presence of alcohol cosurfactants were determined from visual observations of the surfactant solutions and by a spectroturbidimetric method similar to the one described by Frances et al. (2). The visual observation consisted of centrifuging surfactant solutions in a table-top centrifuge at room temperature and measuring the amount of the surfactant sediment at the bottom of the tube. Surfactant was not considered soluble in a given brine if any surfactant sediment was observed. 

The spectroturbidimetric method confirmed the results obtained from visual observations as the turbidity of solutions measured at 436 nm disappeared for solutions producing no surfactant sediment when centrifuged. 

Additionally, mechanical (primarily shear), freeze—thaw, and thermal stabiHty the tendency to form sediment on long-term standing and compatibiHty with other dispersions, salts, surfactants, and pigments of acryHc dispersions are often evaluated. Details on the determination of the properties of emulsion polymers are available (60). 

Salts of alkyl phosphates and types of other surfactants used as emulsifiers and dispersing agents in polymer dispersions are discussed with respect to the preparation of polymer dispersions for use in the manufactoring and finishing of textiles. Seven examples are presented to demonstrate the significance of surfactants on the properties, e.g., sedimentation, wetting behavior, hydrophilic characteristics, foaming behavior, metal adhesion, and viscosity, of polymer dispersions used in the textile industry [239]. 

Marches JR, SA Owen, GF White, WA House, NJ Russell (1994) SDS-degrading bacteria attach to riverine sediment in response to the surfactant or its primary degradation product dodecan-l-ol. Microbiology (UK) 140 2999-3006. 

Marches JR, NJ Russel, GF White, WA House (1991) Effects of surfactant adsorption and biodegradability on the distribution of bacteria between sediments and water in a freshwater microcosm. Appl Environ Microbiol 57 2507-2513. 

Experiments have been conducted in a contaminated aquifer to examine the effect of Triton X-100 on increasing the release of TCE from sediments (Sahoo et al. 1998). The increase was rather modest (ca. 30%), and is consistent with the limited effect of surfactants in increasing the availability of PAHs, which has been discussed in Part 2 of this chapter. 

Surfactants Soil amended with PLE (MeOH/H20 90 10, v/v) and SPE (RP-Clg) LC-MS/MS Marine sediments Soil amended with sludge [33]... 

Consequently, Europe has historically been a hotspot of environmental pressures because of the contamination caused by agricultural, municipal, and industrial activities and high population densities [5, 6], Such contamination has led to poor water quality in many European river basins [7-12], In addition, this pollution can cause the accumulation in river sediments of toxic compounds such as pesticides [13], surfactants [14], and alkyl polycyclic aromatic hydrocarbons (PAHs) [15], These can in turn act as a source to biota [16] and as a potential risk for entire ecosystems [17] if the compounds bioaccumulate, and thereby enter the food chain [18],... 

Interaction of POCs with oil products and synthetic surfactants in water <- Factors increasing the ecological risk of contamination of river waters entering into the Caspian Sea by POCs Secondary contamination of river waters by POCs from bottom sediments... 

Suppliers of visible spectrophotometers are reviewed in Table 1.1. Spectroscopic methods are applicable to the determination of phenols, chlorophenols, amines, mixtures of organics, boron, halogens, total nitrogen and total phosphorus in soils, cationic surfactants, carbohydrates, total nitrogen, phosphorus and sulphur in non-saline sediments, boron, total organic carbon, total sulphur and arsenic in saline sediments, cationic surfactants, adenosine triphosphate and total organic carbon in sludges. 

Aliphatic hydrocarbons, triazine, substituted urea type and phenoxyacetic acid types of herbicides, Fluazifop and Fluazifop-butyl herbicides, ethylene diamine tetracetic acid salts in soil, aliphatic and polyaromatic hydrocarbons, phthalate esters, various organosulphur compounds, triazine herbicides, optical whiteners, mixtures of organic compounds and organotin compounds in non-saline sediments, aromatic hydrocarbons, humic and fulvic acids and mixtures of organic compounds in saline sediments and non-ionic surfactants and cobalamin in sludges. 

This technique has been used for the determination of polychlorobiphenyls, polychlorodibenzo-p-dioxins, polychlorodibenzofurans, alkyl phosphates, chlorinated insecticides, organophosphorus insecticides, triazine herbicides. Dacthal insecticide, insecticide/herbicide mixtures, mixtures of organic compounds and organotin compounds in soils, and polyaromatic compounds, polychlorobiphenyls, chlorinated insecticides and organotin compounds in non-saline sediments and anionic surfactants in sludges. 

This technique has been applied to the determination of heteroaromatic compounds, anthropogenic hydrocarbons, polymers, haloaromatic compounds in soils, polyaromatic hydrocarbons, cationic surfactants and polychlorobiphenyls and mixtures of organic compounds in non-saline sediments and bacteria identification in sludges. 

Fernandez et al. [9] used supercritical fluid extraction combined with ion pair liquid chromatography to determine quaternary ammonium in digested sludges and marine sediments. Carbon dioxide modified with 30% methanol was used as the extractant at an operating pressure of 380atm. Between 0.2 and 3.7g kg-1 surfactant was found in Swiss works effluent sludges, determined with a relative standard deviation of 7%. 

Smith, J.A., Tuck, D.A., Jaffe, P.R. and Mueller, R.T. (1991). Effect of Surfactants on the mobility of nonpolar organic contaminants in porous media, in Organic Substances and Sediments in Water. Vol. 1 (ed. R.Baker), Lewis Publishers, Chelsea, MI, pp. 201-203. 

Residues of incompletely degraded surfactants can also enter the aquatic environment via WWTP effluents, and these can follow various fates. More hydrophobic species with low water solubilities are prone to bind to suspended particles or to sediments (see Chapter 6.2.1) [58-60] and in very rare cases may cross the water-gas phase boundary to enter the atmosphere [61]. 

Figure 2.1.1 shows the most common derivatisation methods for anionic surfactants reported in the literature [1]. The first method of LAS determination by GC consisted of a microdesulfonation procedure in which LASs were desulfonated in boiling phosphoric acid at high temperature [2-4] and the corresponding alkylbenzenes analysed. The microdesulfonation method was further improved by introducing additional concentration and clean-up steps [5—11], which allowed the determination of LAS in influent, effluent and river water samples at low qg L-1 levels [7,8] and sediment and sludge samples [8] at pg g-1. In addition to the desulfonation procedure, several derivatisation techniques have been used to make LAS analysis amenable to GC. 

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