Effect Of Surfactants Research Articles

Cloud point extraction of heavy metal ions for wastewater remediation: an equilibrium and kinetic study

Abstract Surfactants offer a promising alternative for the efficient and environmentally friendly removal of organic pollutants and toxic heavy metal ions from various media. Their high efficiency and environmental compatibility make them a valuable option for remediation efforts. This study focuses on the cloud point extraction (CPE) of ions from aqueous solutions using biodegradable nonionic surfactants combined with ionic surfactants instead of chelating agents. Phase diagrams of binary surfactant/water systems were first constructed. The effects of salt, inorganic contaminants, and ionic surfactants on the cloud point (Tc) were then investigated. At temperatures above the cloud point, two distinct phenomena were observed and monitored over time: phase separation and phase clarification. The kinetic process was studied using the Turbiscan Lab Expert. Extraction results were evaluated based on four responses: extraction yield (E%), residual concentrations of solute (Xs,w) and surfactant (Xt,w) in the dilute phase, and volume fraction of coacervate at equilibrium (Φ C). Empirical modelling gives a satisfactory agreement between experimental and calculated values. The capacity of CPE to simultaneously remove an organic pollutant and a toxic heavy metal was demonstrated.

Evaluating the Extraction and Quantification of Marine Surfactants from Seawater through Solid Phase Extraction and Subsequent Colorimetric Analyses.

Surfactants are amphiphilic molecules that adsorb to interfaces and affect the interfacial tension. Surfactants in seawater can impact gas-exchange, surface properties, and the composition and fate of sea spray aerosol. The accurate quantification of surfactants and their classes is crucial to constraining the effect of surfactants in seawater and their role in air-sea exchanges. Here, we evaluate and optimize a solid phase extraction (SPE) method paired with colorimetry and UV-vis spectroscopy to quantify the concentrations of anionic, cationic, and nonionic surfactants in seawater. We compare tandem SPE with two-step SPE and different elution volumes and evaluate the impact of different interferents. Improved extraction efficiencies were obtained with an 8 mL acetonitrile elution and with separate ENVI-18 and ENVI-Carb extractions, instead of tandem. With complex surfactant mixtures, the presence of anionic surfactants interfered with the quantification of cationic surfactants and caused underestimations of up to 83%. Using a two-step extraction and analyzing each seawater SPE extract separately during colorimetric quantification help avoid the effects of interferents and ensure more representative quantification of surfactants. With this method, average seawater surfactant concentrations ranged from 0.04 to 0.06 μM. At the highest concentrations, the class composition comprised 23% anionic, 21% cationic, and 56% nonionic surfactants.

Study on the Molecular Mechanism of the Effect of Surfactants on the Fragrance Retention of Spices

Study on the Molecular Mechanism of the Effect of Surfactants on the Fragrance Retention of Spices

Effect of surfactants with different ionizing properties on dispersion stability and PCMP properties of CeO2 nanoparticle polishing slurry

Effect of surfactants with different ionizing properties on dispersion stability and PCMP properties of CeO2 nanoparticle polishing slurry

In-situ solvothermal synthesis of free-binder NiCo2S4/nickel foam electrode for supercapacitor application: Effects of CTAB surfactant

The free-binder NiCo2S4/nickel foam electrode was prepared using a two-step solvothermal method: double-layered hydroxide formation and sulfurization. The effects of cetyltrimethylammonium bromide (CTAB) on the structural, microstructural, and electrochemical properties throughout the sulfurization process were investigated using various characterization techniques. By adding the CTAB surfactant, the sheetlike morphology of NiCo2S4 material was transformed to a fine particular morphology. Using one mmol CTAB surfactant, the specific capacitance of NiCo2S4/nickel foam increased from 578 to 835 C g−1 due to the downsizing of particles, inducing the higher electroactive sites for redox reactions. An asymmetric capacitor of NiCo2S4 as positive and CuCo2S4 as negative electrodes demonstrated an energy density of 23.2 Wh kg−1 at a power density of 5040 W kg−1.

Experimental and molecular dynamics simulation studies on the effect of composite surfactants on the wettability of anthracite coal

In order to improve the wettability of coal bed water injection, the effects of several composite surfactants on the wettability of anthracite coal were investigated. Firstly, the wettability of different composite surfactants on anthracite was analysed by macroscopic experiments (surface tension and settling time) to determine the optimal concentration and optimal ratio of composite surfactants. Secondly, the effects of adsorption of different composite surfactants on the physicochemical properties of the coal dust surface were investigated by mesoscopic experiments (scanning electron microscopy, energy spectrometer analysis, infrared spectroscopy, X-ray electron spectroscopy and zeta potential), and the results showed that the content of hydrophilic functional groups (Si-O-Si, C-O-C, C-O and C=O) on the surface of anthracite coal after treatment with the composite surfactant increased significantly, and the surface potential value decreased significantly in absolute value, agglomerated large coal particles would be formed on the coal surface, and the cracks between coal particles were favourable for the penetration of aqueous solution. Finally, the synergistic mechanism of different composite surfactants was analysed from the perspective of microscopic molecular simulation. The results showed that the composite surfactants enhanced the interaction energy of the coal/composite surfactant/water system, improved the relative concentration distribution of the system, and increased the diffusion coefficient of water molecules. The results of the study can provide valuable guidance for the development of new composite surfactants with wetting effect, which has important application value for mine dust control.

A hybrid lattice Boltzmann and finite difference method for two-phase flows with soluble surfactants

A hybrid method is developed to simulate two-phase flows with soluble surfactants. In this method, the interface and bulk surfactant concentration equations of diffuse-interface form, which include source terms to consider surfactant adsorption and desorption dynamics, are solved in the entire fluid domain by the finite difference method, while two-phase flows are solved by a lattice Boltzmann color-gradient model, which can accurately simulate binary fluids with unequal densities. The flow and interface surfactant concentration fields are coupled by a modified Langmuir equation of state, which allows for surfactant concentration beyond critical micelle concentration. The capability and accuracy of the hybrid method are first validated by simulating three numerical examples, including the adsorption of bulk surfactants onto the interface of a stationary droplet, the droplet migration in a constant surfactant gradient, and the deformation of a surfactant-laden droplet in a simple shear flow, in which the numerical results are compared with theoretical solutions and available literature data. Then, the hybrid method is applied to simulate the buoyancy-driven bubble rise in a surfactant solution, in which the influence of surfactants is identified for varying wall confinement, density ratio, Eotvos number and Biot number. It is found that surfactants exhibit a retardation effect on the bubble rise due to the Marangoni stress that resists interface motion, and the retardation effect weakens as the Eotvos or Biot number increases. We further show that the weakened retardation effect at higher Biot numbers is attributed to a decreased non-uniform effect of surfactants at the interface. By comparing with the Cahn-Hilliard phase-field method, we also show that the present method conserves the mass for each fluid, improves numerical stability especially at high density ratio and Eotvos number, and does not need the selection of free parameters, thus breaking the limitations of the existing method.

Evaporation, spreading, and possible uptake of droplets on sorghum (Sorghum bicolor) and cowpea (Vigna unguiculata) leaves using an imaging-based technology.

Sprayed agrochemical droplets have a dynamic evolution on the leaf surface, undergoing changes in shape and volume due to spreading, evaporation, and adsorption. To better understand these processes, an accessible imaging-based experimental methodology is presented to precisely measure droplet spreading, evaporation, and potential uptake by a leaf within a controlled relative humidity environment. Laboratory experiments were conducted to determine the effect of hydrocarbon surfactants, accelerators (light mineral oil), and humectants (high fructose corn syrup) on droplet spread, evaporation, and potential uptake when applied to sorghum (Sorghum bicolor 'Tricker') and cowpea (Vigna unguiculata) leaves. Experiments on cowpea leaves showed uniform spreading and no change in evaporation compared to the predicted rate. In contrast, on sorghum leaves, results suggest that the volume loss rate exceeds the predicted evaporation rate (up to 23%), indicating a potential uptake by the leaves. Some accelerated dynamics on sorghum can be attributed to the lateral spreading observed on hairy leaves along the veins, increasing the contact area by an average of 65%. However, samples containing light mineral oil, typically considered an accelerant to aid in uptake, demonstrated the highest rate but exhibited minimal spreading. The study demonstrates how droplet composition affects droplet dynamics on waxy and hairy leaves by using an imaging-based methodology to measure evaporation rates, volume loss, contact angle, wetted area, and spreading behavior. The findings highlight some of the complex coupling between the crop protection product composition and droplet life cycle on a leaf. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Quartz crystal microbalance analysis of effects of surfactants on dissolution kinetics of poly(4-hydroxystyrene) partially protected with t-butoxycarbonyl group

Abstract Surfactants comprise water-repellent and water-attracting moieties and have been used to improve the lithographic performance of resist materials. However, the effects of surfactants on the dissolution kinetics of these materials are still unclear. In this study, the effects of surfactants on the dissolution kinetics of partially-protected poly(4-hydroxystyrene) (PHS) in 0.26 N tetramethylammonium hydroxide aqueous solution was investigated using a quartz crystal microbalance method. Anionic (sodium n-octanonate, sodium 1-hexanesulfonate, n-dodecylbenzenesulfonic acid, and sodium n-dodecyl sulfate), cationic (methylamine hydrochloride, dodecyltrimethylammonium chloride, and 30% ammonium lauryl sulfate solution), nonionic (sorbitan monooleate, polyoxyethylene(23)lauryl ether, and polyoxyethylene(10)hydrogenated castor oil), and amphoteric (35% lauryl dimethylaminoacetic acid solution) surfactants were examined. The surfactant significantly affected the dissolution kinetics of the PHS films. The surfactant effects were significantly reduced by protecting the hydroxyl groups of PHS. The effect of the surfactant on the dissolution kinetics depended on the surfactant rather than on the surfactant type.

Effect of water hardness and surfactant on the particle coverage and distribution of plant protection products granules

The paper presents a study done to determine how particles of different plant protection products (fungicides) are distributed onto treated surfaces when their solutions are prepared with water of different hardness and addition of surfactant. A total of fifteen plant protection products were studied, all in the same concentration of 0.3% with four type of solutions: only distilled water, distilled water plus a wetting agent – the organosilicone surfactant – Silwet L-77, very hard tap water (hardness = 196.9 ррm СаСО3, 11 °dH) and very hard tap water plus wetting agent. The observations and images were made via light microscope with magnification 200X and 3MP digital camera. The images were analyzed for a percent distribution, and spreading of particles by ImageJ software. The results showed that the distribution, and coverage of particles onto treated surfaces can be different even at application of similar plant protection products. The variations in the properties were observed when the solutions were made with waters with different hardness and a wetting agent was added to the solutions. Contrary to the common perception that hard water can reduce the effectiveness of pesticides towards pests, according to the distribution and coverage of particles onto treated surfaces, in some cases hard water can even enhance these properties of the pesticide solutions. Keywords: plant protection products, distribution, coverage, wetting agent, water hardness

Effect of Ionic Surfactants on Kinetics and Mechanism of the Bi(III) Ion Electroreduction in the Mixed Aqueous-Organic Solutions of Supporting Electrolytes.

This work presents the results of a study on the effect of ionic surfactants: cationic hexadecyltriammonium bromide (CTAB) and anionic sodium salt of sulfonic acid (1OSASS) on the Bi(III) electroreduction process in mixed aqueous-organic supporting electrolyte solutions containing methanol. This study showed that the composition of the supporting electrolyte solution, particularly the methanol and surfactant concentrations, significantly affects the mechanism and rate of the Bi(III) ion electroreduction. Analysis of the influence of the indicated factors on the mechanisms and kinetics of metal ion electroreduction can contribute not only to the optimization of industrial electrochemical processes but also to the development of innovative technological solutions, such as advanced electrochemical materials and novel sensors. In these experiments, an innovative electrode made of cyclic renewable liquid silver amalgam (R-AgLAFE) was used as a working electrode, which stands out among classic mercury electrodes (HMDE type) due to the significant reduction in mercury consumption while maintaining similar performance.

Preparation of novel polymeric surfactants based on synergistic effects and analysis of the mechanism driving the oil-displacement process and enhanced oil recovery

Polymeric surfactants have been favored by researchers due to their ability to increase the viscosity of the aqueous phase, reduce the viscosity of the oil phase, and avoid the chromatographic separation effects of polymer-surfactant binary combination flooding. However, there is little research into the oil-displacement effect of polymer surfactants, and the mechanism whereby it enhances heavy oil recovery remains unclear. To fill this theoretical gap in the research into the oil-displacement mechanism of polymer surfactants, a novel polymeric surfactant PNBM was prepared using acrylamide, acrylic acid, nonylphenol ethoxylate (NP), and 4-vinylbiphenyl (VB). The chemical structure of PNBM was validated by characterization methods such as 1HNMR, FT-IR spectroscopy and elemental analysis. The mechanism of PNBM for enhancing heavy oil recovery was systematically studied based on the displacement and profile control by thickening, reducing viscosity by emulsification, and peeling of oil films and droplets. Polymeric surfactant PNM containing NP and polymeric surfactant PBM containing VB were used as control groups. Benefiting from the synergistic effect of two viscosity-reducing monomers, PNBM has better oil displacement effect compared to PNM and PBM: (1) a tighter adsorption film can be formed at the water–oil interface due to the good interfacial activity of PNBM, so that the average viscosity reduction rate of PNBM at a low concentration reaches 85.5 %; (2) PNBM can significantly increase the viscosity of aqueous solutions (increasing to 38.2 mPa·s), decrease the water–oil mobility ratio, and expand the swept volume; (3) PNBM can reduce the contact angle of the water phase on the oil-wet surface to 62.8°, supplemented by its good viscoelasticity, thereby improving the oil-washing efficiency. Therefore, under the triple effects of displacement and profile control by thickening, reducing viscosity by emulsification, and peeling of oil films and droplets, PNBM can enhance heavy oil recovery by 17.7 %, significantly improving the beneficial industrial exploitation of heavy oil reservoirs.

Evaluating surfactant effectiveness in preventing antibody adsorption directly on medical surfaces using a novel device

Biopharmaceuticals, specifically antibody-based therapeutics, have revolutionized disease treatment. Throughout their lifecycle, these therapeutic proteins are exposed to several stress conditions, for example at interfaces, posing a risk to the drug product stability, safety and quality. Therapeutic protein adsorption at interfaces may lead to loss of active product and protein aggregation, with potential immunogenicity risks. Non-ionic surfactants are commonly added in formulations to mitigate protein-surface interactions. However, their effectiveness varies with the monoclonal antibody (mAb), and model surface material. Extrapolating findings from model surfaces to real medical surfaces is challenging due to diverse properties.This study pioneers the evaluation of surfactant effectiveness in preventing mAb adsorption directly on medical surfaces at the medical bag/formulation interface, utilizing the ELIBAG device. The adsorption of different protein modalities, mAbs and antibody-drug conjugate (ADC), using three surfactants (PS80, PS20, and P188), was examined across various medical surfaces, IV bags and manufacturing bags, and model surfaces. Our findings reveal that surfactants prevent mAb adsorption depending on the mAb modality, surfactant type and concentration, and surface material. This research underscores the importance of considering real medical surfaces in direct contact with formulations, offering insights for enhancing drug product development and ensuring material-protein compatibility in real world use.

Application and characterization of Fusarium solani lipase microemulsion used to degrade fatty

Obesity is a chronic disease with a high prevalence, now recognized as a global epidemic. Studies show a strong association between high body mass index (BMI) and various chronic diseases, including non-alcoholic fatty liver (NAFL), cardiovascular diseases, diabetes, musculoskeletal disorders, chronic kidney disease, and mental health issues. These conditions negatively impact quality of life and elevate healthcare costs (Boutari et al., 2022). Objective: This study explores exogenous lipase produced by the fungus Fusarium solani as a biotechnological alternative for aesthetic and health applications, particularly for women with excess abdominal fat. Methods: F. solani was cultivated on solid medium, followed by submerged and semi-solid fermentation. The lipolytic activity of the extracts was evaluated through pH and temperature tests, surfactant effects, and storage stability. Additionally, we assessed cell viability in normal and cancer cells, antioxidant activity, antimicrobial properties, and fat degradation. Results: Submerged fermentation with olive oil yielded Lipase F2, which exhibited significant lipolytic activity. Lipase F2 demonstrated stability at pH 8.0, maintaining an activity of 135.89 U/mg and a purity of 3.63. It remained active between 35 and 70°C, with optimal stability at 35°C, and showed resistance to various surfactants and ions. The enzyme degraded chicken fat from 10g to 0.89g in 96 hours. Conclusion: An enzymatic formulation with F. solani lipase is viable for intradermal and surface applications, proving to be safe and non-toxic for human use.

A novel electrochemical sensor for ultra-sensitive detection of nitrite based on the synergistic effect of surfactant and KTiTaO5

A novel electrochemical sensor for ultra-sensitive detection of nitrite based on the synergistic effect of surfactant and KTiTaO5

Influence of Gamma irradiation on shape memory polymer nano-composite for satellite deployment mechanism

This research investigates the impact of gamma irradiation on epoxy-MWCNT nanocomposites for satellite deployment mechanisms. Nanocomposites, enhanced with surfactants, were meticulously prepared and subjected to controlled gamma irradiation (250–1000 kGy) utilizing the Cobalt-60 facility Industrial Mega Gamma-1 at NCRRT in Egypt. Surface tension measurements explored surfactant effects on epoxy-MWCNT composites in acetone. Acetone reduced tension from 26.7 to be 24.2 (mN/m). Surfactants (Tween 80, SDS) effectively lowered tension (24.4 mN/m), while surfactant-free systems had higher tension (25.1 mN/m). Cationic surfactant (CTAB) slightly increased tension (25.4 mN/m) but aided MWCNT dispersion. Nonionic and anionic surfactants showed superior dispersing power, aligning with MWCNTs and enhancing dispersion. Thermogravimetric analysis (TGA) unveiled alterations in the thermal stability of epoxy-MWCNT nanocomposites induced by radiation, particularly evident at elevated doses (500 and 1000 kGy). Notably, surfactant-modified specimens exhibited discernible effects on various thermal stability parameters. DMA analysis revealed radiation-induced changes in viscoelastic properties. Unirradiated epoxy exhibited a Tg of 58 °C, while 250 kGy irradiation enhanced crosslinking (Tg: 64 °C). Higher doses (500 kGy, 1000 kGy) caused marginal Tg changes. Surfactant-modified samples showed varied effects, with Tween 80 emphasizing its role in phase separation. Results highlighted radiation’s influence on stiffness and energy dissipation. Shape memory behavior indicated increased recovery time with higher doses, except at 250 kGy. Epoxy-MWCNT exhibited a stable recovery time, suggesting a MWCNT stabilizing effect. Fixation rates consistently reached 100%, indicating improved shape recovery influenced by MWCNTs and surfactants. This study provides insights into optimizing nanocomposites for satellite deployment applications.

Effects of pressure depletion rate, solvent, and surfactant on non‐equilibrium reactions in foamy oil

AbstractThis research employed a visual method to explore the behaviour of foamy oil in heavy oil systems. A Hele‐Shaw cell was designed for observing the volumetric expansion of foamy oil as the system pressure decreased. This approach facilitated an examination of foamy oil's interface evolution under pressure depletion and an analysis of bubble sizes and their distribution. Using Minitab, 15 experiments were strategized, aimed at observing the distribution of bubbles and their stability during the foamy oil process. The investigation also extended to studying the influence of surfactants, solvent type, and pressure reduction rate on foamy oil. The findings suggest that a high concentration of surfactant, a high percentage of CO2 solvent, and a rapid pressure drop rate all contributed to the generation of microbubbles and enhanced volumetric expansion and stability of foamy oil. However, in light of the conducted energy analysis, a lower rate of pressure reduction is recommended. Finally, the conditions of the 15 experiments were applied to the CMG to derive two non‐equilibrium reactions for bubble generation and collapsing. The reaction rates are such that they relate bubble generation to the pressure reduction rate of the process and bubble resistance to collapsing to the surfactant concentration of the foamy oil.

Evaluating the Effectiveness of Cellulose-Based Surfactants in Expandable Graphite Wood Coatings.

This study deals with the design of modern environmentally friendly and non-toxic flame retardants based on expandable graphite 25 K + 180 (EG) modified by cellulose ethers (Lovose TS 20, Tylose MH 300, Klucel H) and nanocellulose (CNC) that are biocompatible with wood and, therefore, are a prerequisite for an effective surfactant for connecting EG to wood. The effectiveness of the formulations and surfactants was verified using a radiant heat source test. The cohesion of the coating to the wood surface and the cohesion of the expanded graphite layer were also assessed. The fire efficiency of the surfactants varied greatly. Still, in combination with EG, they were all able to provide sufficient protection-the total relative mass loss was, in all cases, in the range of 7.38-7.83% (for untreated wood it was 88.67 ± 1.33%), and the maximum relative burning rate decreased tenfold compared to untreated wood, i.e., to 0.04-0.05%·s-1. Good results were achieved using Klucel H + EG and CNC + EG formulations. Compared to Klucel H, CNC provides significantly better cohesion of the expanded layer, but its high price increases the cost of the fireproof coating.

Study on the effect of spatial adsorption orientation on the preferential selection mechanism of dust suppression surfactants

Surfactants are widely used in the field of coal dust control. However, the dust suppression effect of different surfactants varies significantly, and the preferential selection mechanism of dust suppressants for mining is not clear. In this study, the water/surfactant/lignite system was constructed by molecular simulation to investigate the adsorption behavior of surfactants with different structures on the lignite surface at the molecular level. The reasons for the differences in the wettability adsorption of sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate (SDBS), fatty alcohol polyoxyethylene ether-9 (AEO-9), and alkyl polyglycoside (APG1214) on the lignite surface were also investigated based on the quantum chemical calculations and macroscopic experimental analysis. The results showed that the adsorption orientation of surfactant molecules at the solid–liquid interface exerted a pivotal influence on the surface wettability of lignite. According to molecular orbital and electrostatic potential analysis, surfactant molecules with LUMO distributed in the tail chain were more inclined to form a positive adsorption orientation than that concentrated in the polar headgroups; and the stronger the interaction between the polar headgroups and the coal surface with the like charge, the more stable the adsorption of surfactant molecules with the positive arrangement at the interface was. Furthermore, the stronger potential difference between SDS molecules and the hydroxyl-rich structure of the APG1214 molecules are conducive to the formation of hydrogen bonds with water molecules. Wettability experiments showed that the ability of surfactants to improve the wettability of coal dust was positively correlated with the adsorption orientation.

Multi-scale evaluation of surfactant effects on asphalt desorption behavior from oil sand surfaces

This study created a hydrophobic oil sand model to investigate the impact of surfactants on the desorption behavior of asphalt from solid surface. Cationic surfactant cetyl trimethyl ammonium bromide (CTAB) and anionic surfactant sodium dodecyl benzene sulfonate (SDBS) were used to soak the model to observe the effect of surfactants on asphalt desorption. The effect of surfactant pretreatment on the wettability of the substrate was evaluated by measuring the contact angle of ultrapure water on the substrate and observing the morphological changes of the solid surface by atomic force microscopy. The results show that the contact angle of the model treated with SDBS decreases to 10° after 3 days, which significantly improves the wettability of the substrate surface and promotes the desorption of asphalt. However, CTAB has no obvious effect on asphalt desorption. The standard deviation of the gray value of the sand surface image is significantly reduced to 38.693 after the SDBS treatment, which can be seen by binarizing the image. This suggests that the asphalt and solution are evenly distributed and that there is hardly any discernible boundary. Nevertheless, neither of the two surfactants can improve the water-based extraction efficiency of oil sands after soaking treatment. The asphalt yield is less than 5% after 30 days of pretreatment with CTAB solution, while only 45% asphalt yield is obtained after 30 days of pretreatment with SDBS solution. Despite these variations, the quality of asphalt foam remains relatively the same. This may be related to the failure of surfactants to improve the surface wettability of hydrophobic sand. Therefore, the surface wettability of the sand is considered to be a key factor affecting the asphalt desorption and final yield. This study can provide a scientific basis for oil sand recovery to a certain extent.