Nonionic Alcohol Ethoxylate Surfactant Research Articles

Predictive Toxicity Models for Chemically Related Substances: A Case Study with Nonionic Alcohol Ethoxylate Surfactant.

Predictive toxicity models, including interspecies correlation estimation (ICE) models, are reliable alternatives to animal toxicity testing. The ICE models describe mathematical relationships facilitating toxicity prediction from one surrogate test species to a species of unknown sensitivity. The ICE models were developed from curated aquatic toxicity data for 19 nonionic alcohol ethoxylate (AE) surfactants manufactured through the same process. Comparison of AE-ICE predictions with observed values from external validation datasets indicates a reasonable predictive accuracy. Model predictions were also closer to observed values than predictions from previously published ICE models for other substance groups. Comparison of acute fifth percentile hazard concentrations (HC5s) from species sensitivity distributions enhanced with AE-ICE predictions with chronic HC5s published elsewhere produced an acute-to-chronic ratio of 5, which was used to estimate chronic HC5s. With both acute and chronic HC5s for 14 AE substances, regressions were made relative to their respective liposome-water partitioning coefficients (log K lipw ), resulting in HC5-log K lipw relationships useful in estimating HC5s for AE substances with known composition but with limited or unavailable toxicity data. The findings from this case study further demonstrate that ICE models are viable alternatives to toxicity testing and could be used as weight of evidence in hazard assessment evaluations. Environ Toxicol Chem 2021;40:2073-2082. © 2021 SETAC.

Cold Water Detergency of Triacylglycerol Semisolid Soils: The Effect of Salinity, Alcohol Type, and Surfactant Systems

AbstractCold water detergency of triacylglycerol semisolid soils is much more challenging than liquid vegetable oils due to poorer interaction between surfactants and semisolid soil. This research seeks to improve the removal efficiency of semisolid soils below their melting points using surfactant‐based formulations containing different alcohol additives. To this end, cold water detergency of solid coconut oil and solid palm kernel oil was investigated in various surfactant/alcohol systems, including single anionic extended surfactants, single nonionic alcohol ethoxylate surfactants, and a mixture of anionic surfactants. A series of alcohols (2‐butanol, 1‐hexanol, 1‐heptanol, 1‐octanol, 1‐nonanol, and 1‐decanol) were added to the surfactant formulations to investigate cold water detergency improvement. While cold water detergency using surfactants alone was poor, it was considerably improved when optimum salinity (S*) and 1‐heptanol, 1‐octanol, or 1‐nonanol were introduced to the studied surfactant formulations. The maximum detergency of solid coconut oil exceeded 90% removal in the 0.1 w/v% C14‐15‐8PO‐SO4Na/0.2 w/v% 1‐octanol/4 w/v% NaCl system (a final optimized surfactant system) at a washing temperature of 10°C versus 22.9 ± 2.2% in the surfactant alone (not at optimum salinity and no additive). Further analysis showed that improved cold water detergency using surfactant/intermediate‐chain alcohols/NaCl could be correlated with high wettability (low contact angle) as well as favorable surfactant system‐soil interaction as observed by lower interfacial tension values. In contrast, the improved cold water detergency was observed to be independent of dispersion stability. This work thus demonstrates that surfactant system design, including additives, can improve cold water detergency of semisolid soils and should be further explored in future research.

Effect of Surfactant-Bile Interactions on the Solubility of Hydrophobic Drugs in Biorelevant Dissolution Media.

Biorelevant dissolution media (BDM) methods are commonly employed to investigate the oral absorption of poorly water-soluble drugs. Despite the significant progress in this area, the effect of commonly employed pharmaceutical excipients, such as surfactants, on the solubility of drugs in BDM has not been characterized in detail. The aim of this study is to clarify the impact of surfactant-bile interactions on drug solubility by using a set of 12 surfactants, 3 model hydrophobic drugs (fenofibrate, danazol, and progesterone) and two types of BDM (porcine bile extract and sodium taurodeoxycholate). Drug precipitation and sharp nonlinear decrease in the solubility of all studied drugs is observed when drug-loaded ionic surfactant micelles are introduced in solutions of both BDM, whereas the drugs remain solubilized in the mixtures of nonionic polysorbate surfactants + BDM. One-dimensional and diffusion-ordered 1H NMR spectroscopy show that mixed bile salt + surfactant micelles with low drug solubilization capacity are formed for the ionic surfactants. On the other hand, separate surfactant-rich and bile salt-rich micelles coexist in the nonionic polysorbate surfactant + bile salt mixtures, explaining the better drug solubility in these systems. The nonionic alcohol ethoxylate surfactants show intermediate behavior. The large dependence of the drug solubility on surfactant-bile interactions (in which the drug molecules do not play a major role per se) highlights how the complex interplay between excipients and bile salts can significantly change one of the key parameters which governs the oral absorption of poorly water-soluble drugs, viz. the drug solubility in the intestinal fluids.

Polymer Film Dewetting by Water/Surfactant/Good-Solvent Mixtures: A Mechanistic Insight and Its Implications for the Conservation of Cultural Heritage.

Aqueous nanostructured fluids (NSFs) have been proposed to remove polymer coatings from the surface of works of art; this process usually involves film dewetting. The NSF cleaning mechanism was studied using several techniques that were employed to obtain mechanistic insight on the interaction of a methacrylic/acrylic copolymer (Paraloid B72) film laid on glass surfaces and several NSFs, based on two solvents and two surfactants. The experimental results provide a detailed picture of the dewetting process. The gyration radius and the reduction of the Tg of Paraloid B72 fully swollen in the two solvents is larger for propylene carbonate than for methyl ethyl ketone, suggesting higher mobility of polymer chains for the former, while a nonionic alcohol ethoxylate surfactant was more effective than sodium dodecylsulfate in favoring the dewetting process. FTIR 2D imaging showed that the dewetting patterns observed on model samples are also present on polymer-coated mortar tiles when exposed to NSFs.

Polymer Film Dewetting by Water/Surfactant/Good‐Solvent Mixtures: A Mechanistic Insight and Its Implications for the Conservation of Cultural Heritage

AbstractAqueous nanostructured fluids (NSFs) have been proposed to remove polymer coatings from the surface of works of art; this process usually involves film dewetting. The NSF cleaning mechanism was studied using several techniques that were employed to obtain mechanistic insight on the interaction of a methacrylic/acrylic copolymer (Paraloid B72) film laid on glass surfaces and several NSFs, based on two solvents and two surfactants. The experimental results provide a detailed picture of the dewetting process. The gyration radius and the reduction of the Tg of Paraloid B72 fully swollen in the two solvents is larger for propylene carbonate than for methyl ethyl ketone, suggesting higher mobility of polymer chains for the former, while a nonionic alcohol ethoxylate surfactant was more effective than sodium dodecylsulfate in favoring the dewetting process. FTIR 2D imaging showed that the dewetting patterns observed on model samples are also present on polymer‐coated mortar tiles when exposed to NSFs.

Manipulating Interfacial Polymer Structures through Mixed Surfactant Adsorption and Complexation

The effects of a nonionic alcohol ethoxylate surfactant, C(13)E(7), on the interactions between PVP and SDS both in the bulk and at the silica nanoparticle interface are studied by photon correlation spectroscopy, solvent relaxation NMR, SANS, and optical reflectometry. Our results confirmed that, in the absence of SDS, C(13)E(7) and PVP are noninteracting, while SDS interacts strongly both with PVP and C(13)E(7) . Studying interfacial interactions showed that the interfacial interactions of PVP with silica can be manipulated by varying the amounts of SDS and C(13)E(7) present. Upon SDS addition, the adsorbed layer thickness of PVP on silica increases due to Coulombic repulsion between micelles in the polymer layer. When C(13)E(7) is progressively added to the system, it forms mixed micelles with the complexed SDS, reducing the total charge per micelle and thus reducing the repulsion between micelle and the silica surface that would otherwise cause the PVP to desorb. This causes the amount of adsorbed polymer to increase with C(13)E(7) addition for the systems containing SDS, demonstrating that addition of C(13)E(7) hinders the SDS-mediated desorption of an adsorbed PVP layer.

Assessing the aquatic hazard of some branched and linear nonionic surfactants by biodegradation and toxicity

AbstractAn aquatic hazard assessment was conducted for branched and linear nonionic surfactants using toxicity and biodegradation measurements. Four nonionic alcohol ethoxylate surfactants with different degrees of branching (ranging from 0.1, essentially linear, to 4.0 internal methyl groups per hydrophobe) were evaluated for neat surfactant toxicity, degradation in laboratory sewage treatment units, and aquatic toxicity of treated effluents. Acute testing with neat surfactants showed ranges for EC50s of 1.3 to 11.6 mg/L for Daphnia, 1.6 to 6.1 mg/L for Pimephales promelas (fathead minnow), and 1.5 to 11.4 mg/L for Microtox®. Chronic testing of algae showed NOECs of 1 to 10 mg/L and maximum acceptable toxicant concentrations (MATCs) of 0.8 to 14.2 mg/L. Seven‐day chronic estimation tests showed MATCs of 0.6 to 41.4 mg/L for Pimephales promelas and 1 to 14 mg/L for Daphnia. Effluents collected from treatment units receiving a 50‐mg/L surfactant feed at 25°C showed no acute toxicity to either Daphnia or fathead minnows, with the exception of a unit containing nonylphenol ethoxylate. Chronic effluent toxicity was greatest in effluent from the nonyl‐phenol ethoxylate unit and least in the effluent from the linear alcohol ethoxylate unit. Chronic toxicity of the highly branched C13 alcohol ethoxylate effluent was greater than that for the linear alcohol ethoxylate unit effluent.

A laboratory study of the biodegradation of an alcohol ethoxylate surfactant by native soil microbes

Laboratory experiments were conducted to study the biodegradation of a nonionic alcohol ethoxylate surfactant by native microbes from a contaminated site. Three sets of experiments consisting of 13 microcosms were carried out to evaluate the rate of biodegradation and the effect of nutrients and supplementary oxygen on the degradation process. The results from these active microcosms were compared with those for controlled microcosms in which a biocide was added to inhibit biological activities. In the presence of ground water and sterilized soil, surfactant solutions with initial concentrations of 1000, 650, 250, and 180 mgl −1 were reduced to less than 5 mgl −1 in 36 days, 20 days, 17 days, and 17 days, respectively. The biodegradation rate in microcosms with added nutrients was more than twice the rate in the reactor without nutrients. The results from experiments in which various nitrogen and phosphorus nutrients were added showed that a ratio of 10 carbon:2 nitrogen:1 phosphorus was the optimum for the biodegradation of surfactant under the microcosm conditions. The addition of 5 mgl −1 of oxygen in the form of hydrogen peroxide increased the degradation rate of surfactant by 30%. The study showed that microbes indigenous to the soil and ground water at a contaminated site rapidly degrade the low levels of the surfactant that may remain at the site after soil washing, and that the degradation rate can be increased by the addition of nutrients and oxygen.

Comparison of high‐temperature gas chromatography and CO2 supercritical fluid chromatography for the analysis of alcohol ethoxylates

This work compares capillary supercritical fluid chromatography (SFC) and capillary high‐temperature gas chromatography (HTGC) for the quantitative characterization of nonionic alcohol ethoxylate surfactants. Supercritical fluid chromatographic separations of the alcohol ethoxylates were obtained with a density‐programmed carbon dioxide mobile phase and a fused silica capillary column. High‐temperature gas chromatographic separations were obtained with a high‐temperature polyimide‐coated fused silica capillary column. In addition, a procedure was developed for the quantitation of the capillary chromatographic data using flame ionization molar response factors based on the effective carbon theory. The alcohol and ethoxylate distributions, mean molecular weights and average moles of the ethylene oxide are rapidly calculated from the chromatographic data. Advantages and limitations of SFC and HTGC procedures are illustrated and discussed. Based on this work, the following conclusions can be drawn: i) For routine quality control analyses of known alcohol ethoxylates, SFC and HTGC appear to be equally applicable. ii) SFC has the advantage of time because derivatization is not required, although derivatization does improve resolution. iii) HTGC has the advantage of resolving C12 through C18 alcohol ethoxylate oligomers, avoiding ambiguous identification of components. iv)SFC and HTGC both have disadvantages. SFC has a resolution limitation and HTGC discriminates against high molecular‐weight components.

Effect of surfactants at low concentrations on the desorption and biodegradation of sorbed aromatic compounds in soil

A study was conducted to determine the effect of low concentrations of surfactants on the biodegradation of sorbed aromatic compounds in soil. The nonionic alcohol ethoxylate surfactants Alfonic 810-60 and Novel II 1412-56 increased the extent of desorption of phenanthrene from a mineral soil. Alfonic 810-60 enhanced desorption of biphenyl from this soil at one concentration tested, but Novel II 1412-56 did not. Less than 0.01{per thousand} of the added phenanthrene and biphenyl was present in solution after their introduction into an organic soil, and the surfactants did not promote desorption. The two surfactants at 10 {mu}g/g of soil markedly increased the extent of biodegradation of phenanthrene in both the mineral and the organic soil; the stimulation was greater in the organic soil. Biphenyl mineralization in the mineral soil was not affected by either surfactant, but biodegradation in the organic soil was enhanced by Alfonic 810-60 at 100 {mu}g/g. The authors suggest that surfactants at low concentrations may promote the mineralization of sorbed aromatic compounds in polluted soils, even when surfactant-induced desorption is not appreciable.

Characterization of nonionic surfactants using supercritical fluid chromatography and carbon‐13 nuclear magnetic resonance spectroscopy

AbstractCapillary supercritical fluid chromatography, using a carbon dioxide mobile phase and flame ionization detection, was employed for characterization of nonionic alcohol ethoxylate surfactants. Data from separations was used to calculate average molecular weights, degree of ethoxylation and distribution of telomers. The SFC approach was compared with carbon‐13 nuclear magnetic resonance spectroscopy for evaluation of the same samples. The faster chromatographic technique permitted information to be obtained in the presence of materials which interfered with the NMR analysis, and provided a means of identifying the minor components of mixtures. The advantages and disadvantages of the methods are discussed and the complementary nature of the techniques illustrated.