Effect Of Surfactants Research Articles

Electrochemical reduction of CO2 to C2 products—effect of surfactant on copper electrodeposition

Electrochemical reduction of CO2 to C2 products—effect of surfactant on copper electrodeposition

Fat crystallization and physical characteristics of mung bean protein-based frozen whipped emulsions: Effect of lipophilic surfactants and quinoa hydrolysate

Yogurt ice cream (acid frozen whipped emulsion) is a complex frozen emulsion-foam system. The study investigated the impact of three lipophilic surfactant emulsifiers [glyceryl monostearate (GMS), polyglycerol ester (PGE), and sucrose ester 970 (S970)] and quinoa hydrolysate (QH) on fat crystallization, physical properties, and morphology of frozen whipped emulsions containing fermented mung bean protein. QH serves as a sustainable and health-conscious alternative to traditional emulsifiers. pH12-shifting treatment was utilized to modulate fermentation performance of mung bean protein. Yogurt-like ice creams (10% coconut oil) were formulated using pre-whipped emulsions comprising fermented pH12-treated mung bean protein (FMP12) or native mung bean protein (NFMP), along with 0.5% (w/w) emulsifiers or QH. Pre-whipped FMP12 emulsions exhibited significantly higher emulsification stability (P < 0.05) compared to NFMP emulsions, owing to the better-balanced hydrophilic-lipophilic nature of FMP12. The individual addition of surfactants and QH promoted fat crystallization and improved the stability and viscous of FMP12 emulsion by competitively adsorbing with FMP12 at the O/W interface. Upon freezing, all three surfactants in whipped creams resulted in uniform and fine ice crystals with a moderate accumulation of oil droplets, showing a comparable effect to QH. Consequently, FMP12 frozen whipped emulsions with surfactants or QH both exhibited superior hardness and overrun, attributed to the presence of fine ice crystals and a stable fat crystal skeleton structure. These findings indicate the prospective utility of QH as a substitute for conventional small chemical emulsifiers, thereby enhancing the quality attributes of plant-based yogurt ice cream.

The Surfactant Role on a Droplet Passing through a Constricted Microchannel in a Pressure-Driven Flow: A Lattice Boltzmann Study.

The role of surfactants in the flow of a droplet driven by a pressure gradient through a constricted microchannel is simulated by using our recently developed lattice Boltzmann method. We first study the surfactant role on a droplet flowing through a microchannel with a shrunken square section under different surfactant concentrations and capillary numbers (i.e., imposed pressure gradients). As the surfactant concentration increases, the droplet flow regime first changes from the flow regime I of the droplet getting stuck at the entrance of the constricted channel to the flow regime II of the droplet flowing through the constricted channel with breakup, and then to the flow regime III of the droplet flowing through the constricted channel without breakup. As the capillary number increases, the surfactant role on the number of mother droplets breaking up and the time of mother droplets completely flowing through the constricted section tend to decrease, suggesting that the surfactant effects are gradually weakened. Then, a phase diagram describing how the surfactant concentration and capillary number affect the droplet flow regime is presented. As the surfactant concentration increases, the critical capillary number that distinguishes droplet flow regimes I from II gradually decreases, while the critical capillary number that distinguishes droplet flow regimes II from III first increases and then decreases.

Effect of Multifactor on the Stability of Glucose Solution Emulsified Heavy Fuel Oil.

Water emulsified heavy fuel oil (HFO) has been a promising alternative fuel for reducing oil consumption and preventing environmental pollution. However, the intrinsic challenges such as fuel formula, emulsion stability, and preparation process normally limit its further applications in energy-saving and emission reduction applications. In this study, the glucose obtained from biomass was added to a dispersed-phase aqueous solution of water emulsified HFO to prepare a novel alternative emulsified fuel. First, based on the preliminary experimental design, the effects of glucose and surfactant on the stability of the HFO emulsion were systematically evaluated through the appearance of emulsion separation, droplet size distribution, and rheological characteristics. It indicated that the surfactant ratio, hydrophilic-lipophilic balance value, solution ratio, and glucose/water ratio had significant impacts on emulsion stability. Subsequently, the optimum range of influencing factors of emulsion stability was determined by a single factor experiment and determined by the response surface methodology based on the Box-Behnken design; the optimal values of the above factors were 2.439 v/v%, 5.807, 26.462 v/v%, and 35.729%, respectively. Under these conditions, an optimal glucose solution emulsified HFO with a uniform brown color and long-term stability was obtained, making the unseparated emulsion ratio reach 98% (lasting for 7 days at 85 °C). Meanwhile, it emerged that the influence of multifactor on emulsion stability was not a simple linear correlation, and there were significant interactions between the solution ratio and the surfactant ratio, as well as between the glucose/water ratio and the surfactant ratio.

A facile approach to disperse metakaolin for promoting compressive strength of cement composites

Metakaolin (MK), a highly reactive supplementary cementitious material, is extensively employed in cement composites to improve their compressive strength. Nevertheless, MK suffers from extremely poor dispersion, resulting in agglomerating in the cement-based materials, thus failing to exhibit its positive effects fully. To overcome this drawback, for the first time, this work elaborately developed a facile graphene quantum dots (GQDs)-assisted ultrasonic dispersion approach to improve the dispersity of MK effectively. Furthermore, it investigated effect of as-obtained MK (GMK) on compressive strength of cement composites. More specifically, GMK owned a smaller size and a larger specific surface area and presented a higher dispersity than UMK (namely, MK was identically treated by ultrasonic dispersion only without GQDs) and original MK. And in light of the characteristics of three types of MKs, the dispersing mechanism of MK caused by GQDs-assisted ultrasonic treatment was rationally ascribed to intercalation, exfoliation and surfactant effects of GQDs. Crucially, GMK purely by the incorporation of 1.0 wt.% (by weight of cement) demonstrated a significant enhancement of 31.03% for the 28-day compressive strength of mortar; While UMK had little influence on the compressive strength of mortar under the identical conditions. And based on the comprehensive analyses of hydration heat, phase composition and microstructure of different cement pastes, the most significant positive effect of highly dispersed GMK purely by a dosage of 1.0 wt.% on the compressive strength of cement composites was accredited to the fact that GMK was able to accelerate hydration process, boost the formation of C−(A)−S−H and refine the microstructure. This study firstly provided a facile, efficient and low-cost method to fabricate high-dispersity GMK, and verified its remarkable promotion effect on compressive strength of cement composites. These observations would improve the benefits and reduce the cost of MK-like materials applied to cement-based materials.

Benchmarking Cationic Monolayer Protected Nanoparticles and Micelles for Phosphate-Mediated and Nucleotide-Selective Proton Transfer Catalysis.

Both micelles and self-assembled monolayer (SAM)-protected nanoparticles are capable of efficiently hosting water-immiscible substrates to carry out organic reactions in aqueous media. Herein, we have analyzed the different catalytic effect of SAM-protected cationic nanoparticles and cationic surfactants of varying chain length towards base-catalyzed proton transfer mediated ring-opening reaction of 5-nitrobenzisoxazole (NBI) (also known as Kemp Elimination (KE) reaction). We use inorganic phosphate ion or different nucleotide (phosphate-ligated different nucleoside) as base to promote the reaction on micellar or nanoparticle interface. We find almost 2-3 orders of magnitude higher concentration of surfactants of comparable hydrophobicity required to reach the similar activity which attained by low cationic head group concentration bound on nanoparticle. Additionally, at low concentration of nanoparticle-bound surfactant or with high surfactant in micellar form, nucleotide-selectivity has been observed in activating KE reaction unlike free surfactant at low concentration. Finally, we showed enzyme-mediated nucleotide hydrolysis to generate phosphate ion which in situ upregulate the KE activity much more in GNP-based system compared to CTAB. Notably, we show a reasonable superiority of SAM-protected nanoparticles in activating chemical reaction in micromolar concentration of headgroup which certainly boost up application of SAM-based nanoparticles not only for selective recognition but also as eco-friendly catalyst.

A Computational Fluid Dynamics Enhanced Oil Recovery Formulation Based on the Volume Average Procedure on the Full Momentum Equation: Effects of Polymer Solution Injection in Real Reservoirs with Anisotropic Permeability

Summary In this work, we propose a new methodology to simulate the process of enhanced oil recovery (EOR) in a 3D domain, considering a non-Newtonian fluid phase. The mass balance for the two phases and the balance of momentum are based on the volume averaging theory, which upscales the information on the microscale to make viable the solution in a real case. The full balance of momentum is used in place of the usually adopted Darcy’s law, and the equations are written for each phase in terms of porosity and fluid saturation. The equations are introduced in a new numerical solver developed for the OpenFOAM toolbox, which is an open-source C++ library created to simulate problems of computational fluid dynamics (CFD). First, the methodology is verified by comparing the results obtained from the volume averaging theory equations with Darcy’s law. Then, Newtonian and non-Newtonian cases for Buckley-Leverett, 2D, and 3D meshes are presented. We also present cases with a 3D mesh in a domain extracted from a real reservoir and properties of real injector fluids. The present approach is able to accommodate anisotropic permeability, heterogeneity, and non-Newtonian effects. We compare fluid saturation over time for the different cases as well as the accumulated volume of oil over time and the flow output of the domain. The simulations performed were able to demonstrate the effectiveness of polymeric solutions, comparing polyacrylamide (PAA) and polymeric surfactant (PS) cases with different concentrations, for better use in the production of available resources in reservoirs. In the five-spot cases with polymeric solutions, lower flow rates are achieved when the concentration is increased and the oil production until breakthrough is up to 45% higher when compared with water injection.

Soil Contaminants and Their Removal through Surfactant-Enhanced Soil Remediation: A Comprehensive Review

This review provides a comprehensive analysis of the effectiveness of surfactants in enhancing the remediation of contaminated soils. The study examines recent and older research on the use of effluent treatment techniques combined with synthetic surface-active agents, bio-surfactants, and various categories of surfactants for soil reclamation purposes. The main purpose of this review is to evaluate the effectiveness of surfactants in enhancing the remediation of contaminated soils. The research question is to explore the mechanisms through which surfactants enhance soil remediation and to assess the potential benefits and limitations of surfactant-based remediation methods. This review was conducted through an extensive literature search of relevant articles published in scientific databases. The articles were selected based on their relevance to the topic and their methodological rigor. Types of possible soil pollutants and the requirements of specific surfactants were discussed. Structural relationships between pollutant and surfactants were described thoroughly. Extensive study revealed that surfactants have shown great potential in enhancing the remediation of contaminated soils. Surfactants can improve the solubility and mobility of hydrophobic contaminants and facilitate their removal from soil. However, the effectiveness of surfactant-based remediation methods depends on several factors, including the type of contaminant, the soil properties, and the surfactant concentration and type. Surfactant-enhanced soil remediation can be an effective and sustainable method for addressing soil contamination. However, the optimal conditions for using surfactants depend on the specific site characteristics and contaminant properties, and further research is needed to optimize the use of surfactants in soil remediation.

Effects of Surfactants on the Chemical Mechanical Polishing Performance of a-Plane Sapphire Substrates

The effects of four different types of surfactants, cetyltrimethylammonium bromide (CTAB, cationic type), sodium dodecyl benzene sulfonate (SDBS, anion type), N-Laurylaminoacetic acid (NL, amphoteric type) and primary alcohol ethoxylate (AEO, non-ionic type), on the chemical mechanical polishing (CMP) performance of a-plane sapphire substrates in the range of pH 6–12 were investigated using colloidal silica as abrasive particles. The results demonstrated that cationic surfactants promoted the material removal of the sapphire substrate in the range of pH 9–12, while anionic, amphoteric, and non-ionic surfactants inhibited the material removal of the sapphire substrate in the range of pH 6–10. The mechanism of material removal in sapphire CMP was discussed through AFM observations, zeta potential measurements, particle size distribution tests, and friction behavior analysis.

The Effect of Surfactants on the Removal of Ceria Particles in the Buff Clean Process

In this work, we have established a new buff clean method, using deionized water (DIW) with 2000 ppm surfactants to remove ceria particles from the surface of SiO2 after chemical mechanical polishing (CMP). Six kinds of surfactants have been compared. The SEM and AFM results show that with CAO and LAPAO, the ceria particles can be fully removed in the buff clean process. The molecular activity and adsorption energy of surfactants are calculated based on the density functional theory (DFT) to clarify the mechanism of the buff clean process. The surfactants adsorbing on the SiO2 surface can be fully removed after the buff clean process.

Lipopeptide and glycolipid assisted growth of ZnO micro-/nano-structures: Evaluating the role of chemical and microbial green surfactant

Micro-/nano-structured biomaterials with tuneable architectures and functionalities have found promising applications and facile fabrication strategies play a key role in controlling the morphological aspects. Here, green surfactants, rhamnolipid and surfactin were used to cap and stabilize zinc oxide at basic pH and compared with that synthesized using a synthetic surfactant, i.e., sodium dodecyl sulphate. The surfactant@ZnO was characterized by XRD, TGA, FTIR, SEM-EDS, TEM, XPS, AFM, DLS, UV–Vis and PL tests. The XRD, FTIR and XPS data show the successful formation of surfactant@ZnO. The SEM and TEM studies have revealed the various morphologies of ZnO. The UV–Vis and PL studies established the optical characteristics of the surfactant@ZnO. The AFM and DLS were used to examine the effect of surfactant on the size and stability of the ZnO micro- and nanostructures. It is found that the green surfactant@ZnO are more effective in controlling the crystallite size to as low as 13 nm. It is observed that the bio-surfactants meet the bare minimum criteria of a green template to control the size, morphology and optical properties of zinc oxide through a characteristic self-assembly route, essential for the rational development of nano-biomaterials which are anticipated to be widely used in industrial applications.

Effects of surfactants on bubble-induced turbulence

We use experiments to explore the effect of surfactants on bubble-induced turbulence (BIT) at different scales, considering how the bubbles affect the flow kinetic energy, anisotropy and extreme events. To this end, high-resolution particle shadow velocimetry measurements are carried out in a bubble column in which the flow is generated by bubble swarms rising in water for two different bubble diameters (3 and 4 mm) and moderate gas volume fractions (0.5 %–1.3 %). We use tap water as the base liquid and add 1-Pentanol as an additional surfactant with varying bulk concentration, leading to different bubble shapes and surface boundary conditions. The results reveal that with increasing surfactant concentration, the BIT generated increases in strength, even though bubbles of a given size rise more slowly with surfactants. We also find that the level of anisotropy in the flow is enhanced with increasing surfactant concentration for bubbles of the same size, and that for the same surfactant concentration, smaller bubbles generate stronger anisotropy in the flow. Concerning the intermittency quantified by the normalized probability density functions of the fluid velocity increments, our results indicate that extreme values in the velocity increments become more probable with decreasing surfactant concentration for cases with smaller bubbles and low gas void fraction, while the effect of the surfactant is much weaker for cases with larger bubble and higher void fractions.

Recent Advances in the Support Layer, Interlayer and Active Layer of TFC and TFN Organic Solvent Nanofiltration (OSN) Membranes: A Review.

Although separation of solutes from organic solutions is considered a challenging process, it is inevitable in various chemical, petrochemical and pharmaceutical industries. OSN membranes are the heart of OSN technology that are widely utilized to separate various solutes and contaminants from organic solvents, which is now considered an emerging field. Hence, numerous studies have been attracted to this field to manufacture novel membranes with outstanding properties. Thin-film composite (TFC) and nanocomposite (TFN) membranes are two different classes of membranes that have been recently utilized for this purpose. TFC and TFN membranes are made up of similar layers, and the difference is the use of various nanoparticles in TFN membranes, which are classified into two types of porous and nonporous ones, for enhancing the permeate flux. This study aims to review recent advances in TFC and TFN membranes fabricated for organic solvent nanofiltration (OSN) applications. Here, we will first study the materials used to fabricate the support layer, not only the membranes which are not stable in organic solvents and require to be cross-linked, but also those which are inherently stable in harsh media and do not need any cross-linking step, and all of their advantages and disadvantages. Then, we will study the effects of fabricating different interlayers on the performance of the membranes, and the mechanisms of introducing an interlayer in the regulation of the PA structure. At the final step, we will study the type of monomers utilized for the fabrication of the active layer, the effect of surfactants in reducing the tension between the monomers and the membrane surface, and the type of nanoparticles used in the active layer of TFN membranes and their effects in enhancing the membrane separation performance.

Exploring Surfactant Electrolyte-Porous Electrode Interactions

Microemulsions are an alternative to aqueous organic electrolytes for redox flow batteries (RFB) that can be modified without synthesis. Water, oil, and emulsifiers, when combined using optimized chemistries and compositions, produce stable mixtures with aggregate structures (microemulsions). Design limitations imposed by the interdependency of redox solubility and electrolyte conductivity are circumvented by solubilizing redox active molecules in the oil phase and supporting ions in the aqueous phase. While macroscopically homogeneous, microemulsions are biphasic at the nanometer scale, effectively decoupling solubility from conductivity. Recently, the first microemulsion RFB was demonstrated using ferrocene solubilized in an anionic surfactant system. Polarization curve analysis revealed performance limitations seemingly arising from electrolyte interactions with the cell components including porous electrodes. Further optimization requires a deeper understanding of microemulsion-porous electrode interactions.Due to the complexity of microemulsion electrochemistry, a first step towards understanding these interactions is made by investigating the relationship between surfactants and porous electrodes. Vanadium redox flow battery (VRFB) electrolytes with surfactant additives are used as a model system to explore fundamental interactions, in situ, between a surfactant-containing electrolyte and a porous electrode. Transport and kinetics are evaluated as a function of electrode, electrolyte, and surfactant properties. Redox species transport is quantified through mass transfer coefficients, using a generalization of an existing porous electrode model fit to experimental polarization curve data. Electrochemical impedance spectroscopy, interpreted using existing kinetic models, is also employed to gain insight into the effects of surfactant on electron transfer rates.

Significant improvement of catalytic performance for the Fischer−Tropsch synthesis over the cobalt catalysts supported on γ‑Al2O3 granules: simultaneous effects of glucose surfactant and promoter

Significant improvement of catalytic performance for the Fischer−Tropsch synthesis over the cobalt catalysts supported on γ‑Al2O3 granules: simultaneous effects of glucose surfactant and promoter

Functionalized Amphiphilic Block Copolymers and Complex Emulsions for Selective Sensing of Dissolved Metals at Liquid-Liquid Interfaces.

Increasing contamination in potable water supplies necessitates the development of sensing methods that provide the speed and selectivity necessary for safety. One promising method relies on recognition and detection at the liquid-liquid interface of dynamic complex emulsions. These all-liquid materials transduce changes in interfacial tensions into optical signals via the coupling of their chemical, physical, and optical properties. Thus, to introduce selectivity, it is necessary to modify the liquid-liquid interface with an interfacially stable and selective recognition unit. To this end, we report the synthesis and characterization of amphiphilic block copolymers modified with metal chelators to selectively measure the concentrations of dissolved metal ions. We find that significant reduction in interfacial tensions arises upon quantitative addition of metal ions with high affinity toward functionalized chelators. Furthermore, measurements from UV-vis spectroscopy reveal that complexation of the block copolymers with metal ions leads to an increase in surface excess and surfactant effectiveness. We also demonstrate selective detection of iron(III) cations (Fe3+) on the μM levels even through interference from other mono-, di-, or trivalent cations in complex matrices of synthetic groundwater. Our results provide a unique platform that couples selective recognition and modulation of interfacial behaviors and demonstrates a step forward in the development of the multiplexed sensing device needed to deconvolute the complicated array of contaminants that comprise real-world environmental samples.

Synergistic Effect of Salt and Anionic Surfactants on Interfacial Tension Reduction: Insights from Molecular Dynamics Simulations.

Surfactants are commonly utilized in chemical flooding processes alongside salt to effectively decrease interfacial tension (IFT). However, the underlying microscopic mechanism for the synergistic effect of salt and surfactants on oil displacement remains ambiguous. Herein, the structure and properties of the interface between water and n-dodecane are studied by means of molecular dynamics simulations, considering three types of anionic surfactants and two types of salts. As the salt concentration (ρsalt) increases, the IFT first decreases to a minimum value, followed by a subsequent increase to higher values. The salt ions reduce the IFT only at low ρsalt due to the salt screening effect and ion bridging effect, both of which contribute to a decrease in the nearest head-to-head distance of surfactants. By incorporating salt doping, the IFTs can be reduced by at most 5%. Notably, the IFTs of different surfactants are mainly determined by the hydrogen bond interactions between oxygen atoms in the headgroup and water molecules. The presence of a greater number of oxygen atoms corresponds to lower IFT values. Specifically, for alkyl ethoxylate sulfate, the ethoxy groups play a crucial role in reducing the IFTs. This study provides valuable insights into formulating anionic surfactants that are applicable to oil recovery processes in petroleum reservoirs using saline water.

Effect of surfactant on urease-producing flora from waste activated sludge using microbially induced calcite precipitation technology to suppress coal dust

The wettability of microbially induced calcite precipitation (MICP) is a challenge in dust suppression. Herein, the tolerance of urease-producing flora to surfactants was investigated. The optimal tolerance concentrations of the urease-producing flora to sodium dodecylbenzene sulfonate (SDBS, anionic surfactant), alkyl polyglycoside (APG, non-ionic surfactant), and cocamidopropyl betaine (CAB, zwitterionic surfactant), and were 0.2%, 0.1%, and 0.05%. The cetyltrimethylammonium bromide (CTAB, cationic surfactant) inhibited urease production by urease-producing flora. The mineralization products of SDBS, APG, and CAB treatments were all transformed into calcite. The wind resistance test showed that the mass loss of all samples is less than 0.1%. The rain resistance and hardness tests showed that 0.2% SBDS had the best effect, followed by 0.1% APG and 0.05% CAB, and finally, No surfactants. Microbiome analysis showed that the abundance of Sporosarcina and Unclassified_bacillaceae reduced, and the intense competition between Paenalcaligenes and Sporosarcina are essential reasons for reducing urease activity. SDBS and APG could reduce the pathogenic risk of microbial dust suppressants. This study will facilitate the practical application of microbial dust suppressants.

Effects of SDBS and BS-12 on functional groups/wettability of multicomponent acidified lignite

In order to explore the influence mechanism of different surfactants on the wettability of coal samples acidified with multi-component acid solutions, the effects of multi-component acid solutions and surfactant composite acid solutions on the functional groups and microcrystalline structures of coal samples were studied. In this paper, a multicomponent acid solution consisting of sodium dodecyl benzene sulfonate (SDBS), dodecyl dimethyl betaine (BS-12), hydrofluoric acid (HF), and citric acid (C6H8O7) was used to acidification and contact angle experiments on coal samples. Fourier transform infrared spectroscopy (FTIR) results show that acidification can promote the formation of CO and CO, and the synergistic effect of surfactant BS-12 on multi-component acid solution is more prominent. X-ray diffraction (XRD) results show that the variation trend of aromatic lamellar diameter La of coal samples is consistent with the aromatic layer spacing d002. Surfactants can slow down the damage of multi-component acid solution to the microcrystalline structure of coal samples. The change of contact angle shows that the instantaneous synergistic wetting effect of BS-12 is better than that of SDBS. At the same time, molecular dynamics simulation technology was used to verify the effect of surfactants on the wettability of multi-component acid solutions. Therefore, this study provides a feasible method and theoretical guidance for improving the efficiency of coal production and utilization through chemical means.

The effect of surfactants on the in vitro behaviour of suppositories: spontaneous structure formation effects solubility

The effect of surfactants on the <i>in vitro</i> behaviour of suppositories: spontaneous structure formation effects solubility