Journal of Surfactants and Detergents最新文献

The efficacy of CO₂-switchable surfactants in reducing viscosity of heavy crude oil has received widespread attention due to its switchable surface activity for constructing reversible emulsion. However, the intricate synthesis processes of these surfactants pose a significant challenge in their practical application. The present investigation involved the preparation of surfactants that are responsive to CO₂, specifically dimer acid (DA)/tetramethylpropylenediamine (TMPDA), through a facile mixing approach. These surfactants were subsequently employed to mitigate the high viscosity of heavy crude oil. The study employed a surface tension meter to examine the surface behavior of DA/TMPDA, which demonstrated the potential for reducing viscosity. The study examined the CO₂ responsiveness of DA/TMPDA through the application of alternating CO₂ and N₂. It confirmed the reversible CO₂ responsiveness of the surface activator. The results from the emulsification and viscosity reduction assessments suggest that the amalgamation of DA and TMPDA in a 1:1 molar ratio yielded a surfactant. This surfactant demonstrated favorable stability in water and heavy crude oil emulsions, as well as low viscosity and rapid emulsion breaking upon exposure to CO₂. This investigation demonstrates that it is feasible to produce surfactants that are responsive to CO₂ and possess the ability to reduce viscosity through a straightforward mixing process. This presents a viable approach to utilizing oligomeric surfactants that are CO₂-responsive for the purposes of emulsifying and breaking down heavy crude oil.

Surfactants find utility in hydraulic fracturing operations for their ability to modify rock wettability and increase the flowback of fracturing fluid following proppant delivery. The performance of a series of nonionic and anionic surfactants was evaluated by gravity drainage displacement testing. Alkylbenzenesulfonates having alkyl chains possessing at least 16 carbons were among the best performers, yet a similar surfactant having an alkyl chain possessing only ~12 carbons performed quite poorly. These data illustrate that a critical chain length exists for this series. Lauryldimethylamine oxide also performed well. In general, those surfactants possessing the greatest ionic character outperformed nonionic surfactants. Critical micelle concentration, surface tension, contact angle, relative solubility number, and hydrophilic–lipophilic balance were determined for each surfactant studied. Unexpectedly however, few correlations between any of these physical and surface properties and performance in gravity drainage displacement tests were identified, underscoring the complexity of selecting surfactants suitable in the application. These data suggest that more real-world test methods, employing stationary phases, temperatures and pressures that better mimic the fields and individual wells being considered, are needed to better guide surfactant selection.

To develop an environment-friendly detergent for textile relics adsorbing soil/rust stains, the relationship between surfactant types and concentrations, the nature of additives and the type of textile (e.g., cotton, linen, silk or wool) were systematically investigated. Results showed that the detergent formulations of sodium montmorillonite (5 g/L) as additives were overall the best options for soil stains removal on textile relics. Specifically, the most suitable surfactant for cotton, linen, silk and wool textiles relics adsorbing soil stains was rhamnolipid (8 g/L), tea saponin (6 g/L), tea saponin (8 g/L), alkyl glycosides (10 g/L), respectively. The detergent formulations of ascorbic acid (5 g/L) as additives were more beneficial for rust stains peeling-off from the surface of the textile relics regardless of the type of surfactant and textile relics. But the optimal surfactants for different textiles relics were different. In detail, the most suitable surfactants for cotton, linen, silk and wool textiles relics adsorbing rust stains were separately rhamnolipid (10 g/L), Tea saponin (8 g/L), Tea saponin (6 g/L), Alkyl glycosides (6 g/L). This indicated that the washing effect of detergent formulation was related to the types of stains and textile relics' fiber. These findings not only demonstrated the necessity for developing detergent formulations for different textile relics, but also illustrated the complexity and diversity of the textile relics' stain-washing work. Moreover, this work also assists understanding of the washing mechanism of textile relics and help the department of textile relics protection to properly wash textile relics and extend the life of textile relics.

Amino acid surfactants (AASs) based on environmentally friendly biomasses have the characteristics of renewable, easy biodegradation, antibacterial and low toxicity, and have been widely used in daily chemicals, pharmaceuticals, and other fields. This study concerned the use of octanal and amino acids as raw materials. In addition, seven types of amino acid-based surfactants, through Collins reagents, Wittig-Hornor reaction, and aza-Micheal addition reaction, and amino acid head groups were connected with the alkyl chain by the CN bond. The structures were confirmed by infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (¹HNMR). Its surface activity and adsorption properties are evaluated. The physical properties of amino acid-based surfactants were tested by surface tension and dynamic contact angle. The results demonstrated that histidine-based amino acid surfactant (C8His) has the lowest critical micelle concentration (CMC) and surface tension at CMC (γCMC), 0.39 mmol L⁻¹ and 28.79 mN L⁻¹, respectively. Amino acid residues contribute to reducing the critical micelle concentration of surfactant. The interfacial adsorption of glycine-based amino acid surfactant (C8Gly) significantly improved with the increase in temperature, so the surface tension decreased significantly. In addition, sodium chloride could effectively enhance the interfacial adsorption, and the gas–liquid interfacial tension and contact angle of AASs decrease.

The addition of salt can irreversibly disrupt the stability of both emulsions and polymer latex. The reversible conversion of amines into organic ammonium salts can be induced by CO₂ stimulation, thereby enabling the switching of colloids. The switchable amine, tris[2-(dimethylamino)ethyl]amine (Me₆TRAN), was selected for the study. The electrical conductivity of an aqueous solution of Me₆TRAN is modulated by the introduction and removal of CO₂. The critical micelle concentration of sodium dodecyl benzene sulfonate (SDBS) was observed to decrease from 1.0 × 10⁻³ to 5.0 × 10⁻⁴ M upon the introduction of Me₆TRAN, as confirmed by surface tension measurements conducted under CO₂. The emulsion of crude oil, which comprised of SDBS and Me₆TRAN, underwent reversible destruction and restoration upon exposure to CO₂ and N₂. The PMMA latex exhibited a clear phase separation subsequent to CO₂ sparging, but attained homogeneity upon N₂ sparging. This study is anticipated to introduce a novel avenue for emulsion or polymer latex that can undergo demulsification and emulsification through CO₂ stimulation.

The demand of biosurfactants is increasing. It is of great significance to obtain nonpathogenic and high-yielding microorganisms for the industrial-scale production of biosurfactants. A biosurfactant-producing strain SL9 was isolated from oily sludge. It was identified as Bacillus tequilensis based on colonial morphology and 16S rDNA sequence analysis. The biosurfactants produced by strain SL9 was extracted by modified acid precipitation method. A mixture of C₁₂, C₁₃, C₁₄ and C₁₅ surfactin homologues was detected based on HPLC–MS analysis. The optimum production of biosurfactants occurs at pH 7.0 and in the presence of 1.0 g/L NaCl. The optimal carbon source and nitrogen source were 40.0 g/L sucrose and 4.0 g/L NaNO₃, respectively. The maximum yield of biosurfactants from strain SL9 was up to 1332.68 mg/L. Interestingly, B. tequilensis SL9 can rapidly synthesize biosurfactants with a yield of 739.36 mg/L in 12 h. The extracted biosurfactants reduced the surface tension of water from 72.1 to 27.5 mN/m with a CMC of 33 mg/L. The biosurfactants can also emulsify paraffin with a EI₂₄ value of 57.58% and keep this good emulsifying activity after 96 h. The produced biosurfactants showed antimicrobial activities against Staphylococcus aureus, Cladosporium sp. and Alternaria sp. with inhibitory rate of 75.67%, 59.07% and 22.91%, respectively. The isolated strain B. tequilensis SL9 can be a nonpathogenic producer for rapid biosynthesis of biosurfactants with a relative high yield. Strain SL9 and its biosurfactant products are promising for application in the oil exploration, bioremediation, agricultural biocontrol, and pharmaceutical industries.

The microstructure of wormlike micelles (WLM) directly affects the rheological properties of their solutions. Investigating the structure–property relationships of WLM has long been a popular topic for researchers who have developed theoretical and empirical models to describe their viscoelastic behavior. All these models rely on a collection of characteristic “length” parameters that are often difficult to estimate using relatively simple rheological tests. In particular, the micelle stiffness, as described by the persistence length, can be difficult to measure experimentally, while being very impactful on the bulk rheology of WLM solutions. Here, an array of inorganic salts (NaCl, LiCl, MgCl₂, NaBr, NaI, and Na₂SO₄) have been used to induce wormlike micelle formation in an aqueous solution of the surfactant sodium lauryl ether sulfate. Ion dissociation/association with the surfactant head groups and the hydrogen bond network of the water alters the effective stiffness of the micelles, allowing for an estimation of the stiffness using three different methods: (1) small angle neutron scattering (SANS) measurements, (2) oscillatory rheological measurements, and (3) steady rheological measurements with a thermodynamic packing parameter model. Each of these methods are then compared and shown to be consistent with each other for the micelle solutions tested. The consistency of the results across all the measurements suggests that the approach used in this study, which estimates micelle parameters using steady shear rheology and a thermodynamic model, could provide a simpler and more accessible method for estimating micelle parameters in a wide range of surfactant systems.

Surfactants play an important role in the domain of metal anticorrosion. Gemini surfactants, as corrosion inhibitors, have the advantages of strong practicality, high safety, convenient operation and fast response. In this study, a new Schiff-base cationic Gemini surfactant (named TMPA) was designed, synthesized and characterized. The mechanism of metal anticorrosion of surfactant was studied by electrochemistry and static weightlessness method. And the adsorption isotherm of TMPA shows that the behavior follows Langmuir adsorption isotherm. The anticorrosion efficiency of printed circuit board (PCB) was 92.88% and Q235 carbon steel (Q235 CS) was 97.78% with the addition of only 5 mM TMPA. The surface appearance of the PCB and Q235 CS was scrutinized by x-ray photoelectron spectroscopy and scanning electron microscopy, proving that samples have few corrosion marks in the presence of TMPA and oxidants. These results show that TMPA provides an attractive application in terms of metal corrosion inhibition.

Tetradecyltrimethylammonium (TTA+) benzoate surfactants have a range of CMC values dependent on the substituent effects of the benzoate counterions. Twenty-three TTA+/X-benzoate CMC values were determined by conductivity and surface tension. The 12 TTA+/para- and meta-benzoate and the unsubstituted benzoate CMC values yield a correlation to the hydrophobicity parameter (log P) of the benzoic acid, as the counterion. The logarithm of conductivity CMCs correlated to the log P value of the benzoic acid yields a slope of—0.4399. All 10 of the TTA+/ortho-benzoate CMC values do not yield a correlation with hydrophobicity yet the TTA+/ortho-halogenated benzoates give a strong correlation to hydrophobicity (log P). For this subset, the correlation was nearly identical to one of the TTA+/para- and meta-benzoates. The slope of the logarithm of TTA+/ortho-halogenated benzoate CMC values to the log P of benzoic acid is—0.413. Another subset is the TTA+/ortho-hydrogen bond donating benzoates which clearly show micelle formation is favored in addition to the hydrophobic effect. The surface tension data CMCs yield a similar correlation to the conductivity data. This combined data yields further insight on the structural features of the counterion contribution to micelle formation. Specifically, the benzoates show both hydrophobicity effects and when ortho-hydrogen bond donating substituents are present, micelle formation is strongly enhanced in addition to the hydrophobic effect of the anion.