Interfacial molecular array behaviors of mixed surfactant systems based on sodium laurylglutamate and the effect on the foam properties

Study on anionic-nonionic mixed surfactant for enhanced oil recovery in a hypersaline reservoir

Hypersaline reservoirs are characterized by high salinity and high calcium and magnesium concentration. In order to enhance oil recovery of the hypersaline reservoirs, a specialized ternary mixed surfactant system composed of nonionic alkanolamide surfactants and anionic surfactant was developed in this study. Through careful analysis and optimization, lauric acid diethanolamide (LDEA), octanoic acid diethanolamide (ODEA), and sodium dodecyl sulfonate (SDS) were identified as promising candidates for the surfactant compounding system, and formed a ternary surfactant system composed of LDEA, ODEA, and SDS with the mass ratio of 4.64 : 0.66 : 1.00. Experimental results revealed that the interfacial tension of the system was consistently below 10-2 mN m-1 and could even reach ultra-low levels (10-3 mN m-1) under conditions of calcium and magnesium ion content of 2000 mg L-1, surfactant concentrations ranging from 0.05 to 0.3 wt%, temperature ranging from 50 to 80 °C, and salinity ranging from 20 000 to 50 000 mg L-1. Furthermore, the mixed surfactant system exhibited favorable wetting capacity and emulsifying power. The static adsorption capacities of the mixed surfactant on oil sands were less than 2 mg g-1. This study offered a novel strategy for the actual exploitation of reservoirs with high calcium-magnesium and high salinity.

Rheological Properties of Gel Foam Co-Stabilized with Nanoparticles, Xanthan Gum, and Multiple Surfactants

Gel foam has the advantages of gel and foam and shows good prospects for applications in the fields of fire prevention and extinguishing. Rheology has a significant impact on the application of gel foam, but there is little related research. In the present study, hydrophilic silica nanoparticles (NPs) and water-soluble polymer xanthan gum (XG) were combined with fluorocarbon surfactant (FS-50) and hydrocarbon surfactant (APG0810) to create gel foam. The foaming ability and foam drainage were evaluated. The gel foam's rheology, including its flow behavior and viscoelasticity, was systematically investigated. The results show that the foaming of the FS-50/APG0810 mixture decreases but the foam drainage increases in the presence of NPs and/or XG. All of the foams belong to the category of non-Newtonian fluids with shear thinning behavior. The flow curves of the foams are consistent with the Cross model. The presence of XG/NPs enhanced the foam viscoelasticity of the FS-50/APG0810 mixture. The silica NPs showed a better ability to enhance foam viscoelasticity but a worse ability to stabilize the foam compared to XG. This research can offer theoretical support for the industrial usage of gel foam.

Study on the Properties of the Sodium Lauroyl Glycinate and Sodium Lauroyl Lactylate Composite System

The scientific community has shown a great deal of interest in sodium lauroyl glycine (SLG) and sodium lauroyl lactylate (SLL), two sustainable and eco-friendly substances that are considered as potential bio-friendly alternatives for petrochemical-based amphiphiles. In the present work, the formation of mixed micelle for SLG and SLL surfactant in water was investigated. Meanwhile, the surface interaction and thermodynamic parameters were calculated according to the surface tension curves. The results indicated that at certain ratios, SLG/SLL surfactant mixtures had synergistic effects that could yield higher surface activity and improve application performance. When the mole fraction of SLL (α_SLL) was 0.4, γ_cmc achieved a minimum of 22.6 mN m^-1 and displayed the best foaming properties. The mixed solution exhibited the best wetting ability when α_SLL was 0.6. While α_SLL was 0.8, the mixed solution showed the optimum dynamic adsorption properties. And it was found that the antibacterial property of SLG and SLL could be partially preserved after compounding. These results demonstrated for the first time that the mixed environmentally friendly surfactant SLG and SLL has a promising prospect for use in the personal care, detergent, and cosmetic industries.