Journal of Surfactants and Detergents最新文献

Green and stimuli-responsive surfactants have become a major research focus in recent years. Herein, a bio-based pH-responsive gemini surfactant (DA-CYS) containing a rigid skeleton was synthesized from dehydroabietic acid and L-cystine. The structure of DA-CYS was characterized by Fourier-transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy. The critical micelle concentration (CMC), surface tension, and foam properties of DA-CYS were evaluated. The results showed that DA-CYS demonstrated superior foam stability performance compared to sodium dodecyl sulfate (SDS) at the same concentration. The foam stability of DA-CYS could be precisely controlled via pH modulation. At pH 11.56, DA-CYS formed an ultra-stable foam with a half-life of 2704 min. Whereas acidification to pH 6.33, the foam stability was drastically reduced, yielding a half-life of only 90 min. Remarkably, reversible switching between stable and unstable states was demonstrated over at least five pH cycles (pH 11–6), confirming excellent pH-responsive recoverability. This rosin-based gemini surfactant exhibits pH-responsive recoverability from solution with high recovery rates. This strategy simplifies synthesis processes, aligns with green chemistry principles, and provides new opportunities for developing sustainable surfactant recovery technologies.

The utilization of bio-surfactants in heat transfer enhancement studies remains underexplored compared to synthetic surfactants. This study investigates the effects of Rhamnolipid, a bio-surfactant, on the thermal performance of distilled water (DW) and Al₂O₃ water-based nanofluids (NFs). Rhamnolipid concentrations ranging from 200 to 600 ppm and nanoparticle (NP) concentrations from 0.02 to 0.5 wt.% were studied. The addition of Rhamnolipid to distilled water resulted in the maximization of Thermal Conductivity (TC) at 300 ppm, which aligns with the critical micelle concentration (CMC), leading to a 19.46% improvement in the heat transfer coefficient (HTC). Al₂O₃ NPs alone showed a 32.07% HTC enhancement at 0.05 wt.% concentration, although the performance declined after a few hours due to particle sedimentation. When Rhamnolipid and NPs were combined, HTC increased with Rhamnolipid concentrations up to 550 ppm, after which the performance declined. The combined addition resulted in maximum enhancement of 92.88% HTC at 0.1 wt.% concentrated nanofluid with 550 ppm RHL. These findings demonstrate that eco-friendly bio-surfactants, such as Rhamnolipid, can serve as effective surfactants for enhancing heat conduction performance in NFs.

Wormlike micelles, which are flexible elongated aggregates formed by the self-assembly of surfactant molecules in aqueous solutions, have been widely applied in various fields because of their unique morphology and dynamic characteristics. However, the studies on the unsaturation of tails, particularly in solutions of double-tailed surfactants, remain limited. This study examines the influence of the chemical structure of hydrophobic tails on the formation and rheological properties of wormlike micelles. Two types of double-tailed surfactants with distinct tail structures, one containing double bonds and the other without, were designed and synthesized. The results show that introducing double bonds into the tail significantly affects the formation mechanism and physicochemical properties of wormlike micelles. Wormlike micelles formed from surfactants with double bonds exhibit enhanced rheological properties and viscoelastic behavior. This study enhances the understanding of the relationship between surfactant tail structure and micelle behavior. It provides theoretical and experimental support for the future design of efficient surfactants and offers new perspectives and technical guidance for their application in enhanced oil recovery, drug delivery, and environmental remediation. Future studies could explore the behavior of structurally diverse double-tailed surfactants in more complex solutions, thus expanding their potential applications across broader fields.

This study investigated the effect of non-ionic surfactants in developing the structure of an oxide during preparation by precipitation method using Polysorbate 20 as a surfactant. Effects of surfactant concentration and structure, pH, aging temperature, and zinc doping on oxide properties were investigated. Zinc-doped samples were evaluated for thiophene adsorption in a down-flow packed bed reactor at ~30°C. The use of surfactant modified the structure of aluminum oxide, increasing the fraction of mesopores as well as surface area and pore volume at all concentrations of surfactant. However, the variation of surface area with surfactant concentration was not significant. Bayerite was observed as the predominant phase in all samples. Alkaline pH improved surfactant–hydroxide interaction, increasing average pore size. The surface area of the samples did not differ significantly, but the pore volume increased from 0.6 to 1.1 cc/g as aging temperature increased. A more uniform and narrower mesopore distribution was observed for the oxide prepared in the presence of Polysorbate 20 compared to that prepared using Polysorbate 60 or Polysorbate 80, suggesting higher interaction with the former. Zinc (30 wt%) supported on Polysorbate 20-modified aluminum oxide showed greater thiophene removal than zinc on unmodified oxide, highlighting the effectiveness of surfactant-modified supports for adsorptive applications.

The quality and safety of dairy products is guaranteed mainly by the thorough cleaning of dairy production equipment. A new green and efficient composite cleaning agent is the direction of development. In this publication, response surface optimization design was used to optimize the detergent formulation comprising five surfactants. The cleaning performance of the optimum formula and the antimicrobial activity of nisin and oregano essential oil (OEO) incorporated in the formula were determined. The cleaning agent can dissolve milk residue quickly, be environmentally friendly, safe, non-toxic, and provide excellent cleaning results, which had initially met the actual production needs and is expected to achieve industrialization.

Using compounds such as methyl laurate, monoethanolamine, and glucose as raw materials, a new type of glycosylated nonionic surfactant containing amide groups, laurate aminoethyl-β-glucose, was synthesized. Through a series of characterization methods, its structure and surface properties were tested. The critical micelle concentration (CMC) of the glycosylated surfactant was measured at 0.888 mmol/L, with remarkable surface-tension-reducing ability (γ_CMC: 32.75 mN/m), a minimum molecular adsorption area (A_min 0.332 nm²), and good emulsification performance. After about 40 min, the water separation rate was 0.84%. Glycosylated surfactants have better foaming and foam stability, with 79% foam stability obtained after 5 min. The bio-based surfactant lauric acid amide ethyl-β-glucose was applied to the nanoemulsion. After being compounded with Tween-80 and Span-80, it had certain stability. The prepared emulsion had a smaller particle size and a more uniform distribution. The particle size was 118 nm, the PDI was 0.182, and the clearance rate of DPPD free radicals could reach 75%. This suggests that glycosylated surfactants have potential applications in the field of cosmetics.

Asymmetric amphoteric Gemini surfactants (PAHC and PAOC) were synthesized from cashew phenol, epichlorohydrin, dimethyl tertiary amine vis etherification and quaternization reactions. The structures were determined by FTIR and ¹H NMR. The prepared asymmetric amphoteric Gemini surfactants, sodium salicylate, and potassium chloride were optimized to obtain the systems PSP-C₁₆ and PSP-C₁₈. The experimental results showed that the two systems can reduce the interfacial tension to 2.37 × 10⁻² and 1.81 × 10⁻² mN/m, respectively, so that the crude oil can better break off from the rock. With the increase of system concentration, the adsorption capacity increased first and then changed little. The maximum splitting times of PSP-C₁₆ and PSP-C₁₈ at a concentration of 0.5 wt% were 540 and 585 s, respectively, resulting in good emulsification properties. PSP-C₁₆ can reduce the oil-contact antenna from 98.3° to 15.6°, and PSP-C₁₈ can reduce the oil-contact antenna from 96.4° to 14.3°, leading to good wettability transition. The single core flooding test results showed that the average enhanced oil recovery of the two systems was 9.42% and 10.21%, respectively, and the double core flooding test results showed that the average enhanced oil recovery of the two systems was 10.56% and 12.34%.