Journal of Surfactants and Detergents最新文献

Cashew nut shell liquid (CNSL), an abundant agro-industrial byproduct, was valorized into nonionic and anionic surfactants. Oxyacetic acid derivatives were synthesized with high yields (94%) and assessed for their physicochemical properties. Sodium oxyacetate from crude CNSL exhibited a critical micelle concentration at 25°C (CMC) of 0.0146 wt.%, while the one from pure anacardic acid showed a CMC of 0.0468 wt.%. The hydrophilic lipophilic behavior of surfactants was quantified by determining the change of the phase inversion temperature of a reference system (PIT-slope method). These results confirmed that the CNSL derivatives are less hydrophilic than those obtained from pure anacardic acid, likely due to the presence of cardanol-based compounds in CNSL, which contain only a single carboxyl group. Emulsions stabilized with CNSL oxyacetic acid remained stable for over 21 days. In addition, the foaming properties of sodium oxyacetate from CNSL were comparable to those of the benchmark Texapon N70 (sodium laureth sulfate), with 73.2% foam stability after 1200 s and smaller bubble sizes at similar concentrations. These results highlight the potential of crude mixture CNSL-derived surfactants as cost-effective, sustainable alternatives to petrochemical surfactants for formulation applications in detergents and personal care products, contributing to waste valorization and circular economy strategies.

Poor aqueous solubility remains a significant challenge in the formulation of liquid dosage forms for photothermal dyes. Among various technological strategies explored, the encapsulation of dye molecules within polymeric micelles has emerged as a promising approach in recent years. In this context, particular attention has been given to soluplus, an amphiphilic graft copolymer composed of polyvinyl caprolactam, polyvinyl acetate, and polyethylene glycol, which is capable of forming stable nanomicelles. The objective of the present study was to develop and characterize soluplus-based nanomicelles to enhance the apparent solubility of the hydrophobic photothermal dye IR-780 (IRSMs). Dye-loaded soluplus micelles were successfully prepared using the thin-film hydration method, resulting in nanoparticles with an average size of approximately 50–55 nm. The formulations were systematically evaluated for their mean particle size, zeta potential, dye encapsulation efficiency, and physical stability under storage and dilution conditions. Upon exposure to 808 nm laser irradiation, the micellar formulations exhibited a pronounced photothermal heating effect, with a significant increase in temperature, confirming their potential as effective photothermal agents for use in photothermal therapy (PTT). Moreover, the IRSMs showed significant stability with respect to long-term storage and dilution and hence can be an ideal candidate for in vivo PTT application.

For all applications in which interfaces play a significant role, surface-active agents (surfactants) can play an essential role. The selection of the most suitable surfactant is essential but it is not a simple task. Depending on the type of applications, a certain surface coverage by surfactant molecules or a reduction in surface tension down to a defined value is required. Moreover, the formation of micelles above a certain concentration in a solution can be essential for the optimized application of a surfactant. Hence, the classification of surfactants according to their surface activity is necessary and has to take into account a variety of characteristic parameters. This can be the critical micelle concentration (CMC), the corresponding surface tension ($�\; ��\; �{\gamma }_{\mathrm{CMC}}��$), the maximum number of adsorbed surfactant molecules per interfacial area ($�\; ��\; �{\Gamma }_{\infty }��$) or the concentration required to reduce the surface tension by a certain amount. Different interfacial parameters are discussed with respect to their application and possible interrelations between these parameters are analyzed.

Steady-state and time-resolved fluorescence spectroscopy of 7-(diethylamino)-3-(2,3-dihydrofuro[3,2-c]quinolin-4-yl)-2H-chromen-2-one (DDQC) in aerosol OT (AOT) microemulsion revealed that the DDQC molecule diffuses into the core water pool from the nonpolar region of the micelle. The present study highlights the diffusion of DDQC into the core water pool from the nonpolar region of the reverse micelle of AOT microemulsion using a detailed steady-state and time-resolved spectroscopic analyses. The formation of cationic species of DDQC inside the core of the reverse micelle was evidenced by the redshift in the absorption and emission spectra and the decrease in the fluorescence quantum yield from 0.4 to 0.12 with the increase in $�\; ��\; �w_0��$ (ratio of water and surfactant concentration). Furthermore, fluorescence correlation spectroscopy (FCS) was used to probe the diffusion dynamics of DDQC into the water pool of the micellar environment at the single-molecular level. The result ascertained that DDQC experienced a more constrained environment with increasing $�\; ��\; �w_0��$.

Achieving a low interfacial tension (IFT) is a crucial parameter for making nanofluids effective for various applications, including oil recovery and thermal fluid applications. ZnO nanoparticles are promising nanomaterials that demonstrate robust chemical properties. However, the continuous sedimentation of particles in the fluids rendered the ZnO nanofluids less effective. Five surfactants were selected to stabilize ZnO nanoparticles in terms of colloidal stability, viscosity, and IFT, which included sodium dodecyl benzene sulfonate (SDBS), polyvinylpyrrolidone (PVP), polymethyl methacrylate (PMM), oleic acid, and cetyltrimethylammonium bromide (CTAB). Zeta potential measurements and FESEM micrographs revealed moderate electrostatic stabilization and good particle distribution. The viscosity varied from 1.10 to 1.70 cP, indicating that the rheological behavior of the fluids relies on the nanoparticle dispersion. The IFT reduction trend ranged from 5.88% to 35.29%, demonstrating that surfactants can alter the performance of ZnO nanofluids. The ZnO-SDBS nanofluids exhibited the highest reduction trend of 35.29%. ZnO-CTAB showed a significant reduction in IFT (29.41%) with low viscosity (1.10 cP), indicating that the surfactant is more suitable for low-resistance flow applications. ZnO-PMM nanofluids unveiled poor interaction, making them insignificant. These findings are consequential in selecting surfactants for ZnO, making them ideal for enhanced oil recovery (EOR) and thermal fluids technology.

CO₂ cyclic gas injection is an effective method for enhanced oil recovery in shale reservoirs, yet the stimulation effectiveness and CO₂ utilization/storage efficiency of pure CO₂ injection remain limited. In this study, systematic solubility tests were conducted under Jimsar shale reservoir conditions to screen and optimize three nonionic CO₂-soluble surfactants. The optimal surfactant with a concentration of 0.1 wt% was selected for CO₂ cyclic gas injection experiments. By integrating nuclear magnetic resonance (NMR) T₂ spectrum characterization, the pore-scale mechanisms were elucidated. Experimental results demonstrate that although the surfactant only moderately reduced the CO₂/Jimsar shale oil interfacial tension from 3.26 to 1.09 mN/m, LF-NMR monitoring revealed its remarkable differential effects on oil recovery from pores of varying sizes: small-pores (0.01 ms < T ₂ < 10 ms) showed a maximum recovery increase of 8.19% per cycle, while meso-pores (10 ms <T ₂ < 100 ms) achieved an 11.14% enhancement in the second cycle. Physical modeling using matrix-fracture systems under simulated reservoir conditions confirmed that the surfactant primarily improves recovery by altering fluid distribution characteristics at the pore scale. GC/MS analysis further verified the effective production of C₂₀ ⁺ heavy components. This study provides novel insights into the pore-scale displacement mechanisms of CO₂-soluble surfactants in shale reservoirs, offering new perspectives for unconventional oil recovery optimization.

The aim of this study is to determine the potential of using ethoxylated alcohols as surfactants, which improve the sedimentation rate of CaCO₃ in tap water and are applicable for flotation separation of plastics obtained from the WEEE (waste electrical and electronic equipment). Another goal is to determine a surfactant that will not form hard and difficult-to-mix crystals in contact with CaCO₃. Moreover, estimation of the effect of ethoxylated alcohols on the CaCO₃ suspension sedimentation rate in tap water was made. 30% CaCO₃ suspensions in tap water were prepared. Then different kinds of surfactants in that suspension were tested and the stabilities of dispersions were examined. Densities, surface tensions, and sedimentation rates were determined. Moreover, the XRD analyses were performed to characterize differences before and after adding surfactants to the calcium carbonate suspensions. As follows from the research, some ethoxylated alcohols do not form hard-to-mix crystals and exhibit better stabilities of dispersion. The best result is a 1.4 improvement of TSI, which proves that ethoxylated alcohols ameliorate the sedimentation rate and can be used as additives in the flotation separation of plastics.

Rhamnolipid (RL) biosurfactants are biodegradable and widely used in various industries due to their bioavailability. However, their recovery and purification from fermentation broth can be costly and often require the use of additional chemicals or solvents. In this study, RL produced from Pseudomonas aeruginosa RS6 using biodiesel side-stream waste glycerol as a substrate was recovered and enhanced using the foam fractionation method. Crucial factors in the gas–liquid adsorption process, including air flow rates, initial feed concentrations, and feed flow rates in batch and continuous stripping modes, were examined. In batch mode, a low air flow rate of 20 mL/min achieved a maximum RL enrichment of 1.49, indicating a 1.49-fold increase in RL concentration in the foamate compared to the feed, with a recovery rate of 81%. This finding confirms the importance of foam residence time in drainage activity, which is closely related to both enrichment and recovery. Additionally, a specified threshold level of enrichment was identified at 13 g/L of feed solution concentration, beyond which further increases were found to be impractical. In contrast, the continuous mode demonstrated a higher RL enrichment of 2.5 with a recovery rate of 51%, indicating its greater effectiveness for concentrating RL in less time. This study provides valuable insights into the gas–liquid interface's adsorption behavior under different operation modes, which is crucial for optimizing RL's recovery systems. The results contribute to the development of more efficient and sustainable biosurfactant recovery processes, particularly in simulating the early stage of industrial applications.

The hydrophilic–lipophilic difference (HLD) equation has been explored as a guide to help formulate for maximum cleaning in commercial laundry detergents. A short review shows that, with anionic surfactants, there is a range roughly between HLD = 0 and HLD = −3 where detergency is maximum. New work occurred using three different soils: sebum, meat gravy, and coconut oil. One anionic (alcohol ether sulfate, AES) and three nonionic surfactants (alcohol ethoxylates, AEs) were included on two different substrates: cotton and a 65/35 polyester/cotton mix. To our knowledge, a correlation between HLD and detergency for nonionic surfactants has never been explored. For the AES and two of the soils, sebum and coconut oil, a range between HLD = 0 and −5 and HLD = 0 and −2 for optimal cleaning was found respectively for the soils, while the HLD did not affect cleaning efficiency for meat gravy. Our work with nonionic surfactants is not inconsistent with an optimal range, but neither does the data clearly support an optimal range either. Much of the reason is due to the limited HLD range available with nonionic surfactants because the equation for nonionics has a linear salt term while that for ionics has a logarithmic salt term.

The surface activity and a series of application properties of the mixture of anionic surfactant sodium dodecyl diphenyl ether disulfonate (2A1) and amphoteric surfactant cocamidopropyl betaine (CAB) were studied by measuring surface tension, contact angle, foamability and foam stability, zeta potential, as well as the chelation efficiency of trisodium methylglycine diacetate (MGDA) to Cu²⁺. The interaction parameters and thermodynamic micellization parameters of the CAB/2A1 complex system were calculated. The results show that the CAB/2A1 complex system behaves good synergistic effect, such as giving higher surface activity, smaller contact angle, and better foaming performance than the individual surfactants. The CAB and 2A1 molecules show strong interactions in both mixed micelles and mixed monolayer at air-water interface, and thermodynamic parameters calculated confirm that the micellization process is entropy-driven. The mixture gives the smallest contact angle or the best wetting performance at X _(CAB) = 0.9, and shows the best foamability and foam stability at X _(CAB) = 0.78. In addition, the mixture can significantly enhance chelation of the MGDA to Cu²⁺.