Solutions Of Cationic Surfactants Research Articles

Facile On-Substrate Fabrication of Silver Coordination Polymer Nanowires for Sustainable and Efficient Water Disinfection.

Silver, as the oldest antibacterial material, has been almost replaced by other alternatives for its insufficient activity or potential side-effects on the ecosystem due to the over-release of Ag ions (Ag+). Herein, a facile and general strategy is developed to on-substrate fabricate silver coordination polymer nanowire arrays (Ag CPN) by simply immersing Ag-containing substrates into cationic surfactant solution at room temperature. Such a Ag CPN not only provides high-surface-area nano-biointerfaces for destroying microorganisms via physicomechanical interactions but also acts as a safe Ag+ reservoir, steadily releasing Ag+ at a relatively high but safe level (∼40 ppb, but lower than the safe level of 100 ppb). Taking advantage of physicomechanical and chemical effects together, the on-substrate fabricated Ag CPN allows Ag substrates or Ag-coated disposable substrates for efficient and sustainable bacterial disinfection. As a demonstration, the modified silver net shows ∼100% antibacterial activity when the bacterial water with a 1.0 × 106 CFU mL-1 of E. coli flows through in 4.0 m3 h-1 m-2 fluxes. By coating a silver film onto a wide range of cheap or disposable substrates, the present strategy opens up opportunities for reviving ancient silver materials for affordable and recoverable antibacterial applications such as water disinfection.

Flow-driven pattern formation during coacervation of xanthan gum with a cationic surfactant.

We experimentally demonstrate that the coacervation of a biopolymer can trigger a hydrodynamic instability when a coacervate is formed upon injection of a xanthan gum dispersion into a cationic surfactant (C14TAB) solution. The local increase of the viscosity due to the coacervate formation induces a viscous fingering instability. Three characteristic displacement regimes were observed: a viscous fingering dominated regime, a buoyancy-controlled "volcano" regime and a "fan"-like regime determined by the coacervate membrane dynamics. The dependence of the spatial properties of the viscous fingering pattern on the Péclet and Rayleigh numbers is investigated.

Solubilization of Artemisinin in Solutions of Cationic Surfactants

Solubilization of Artemisinin in Solutions of Cationic Surfactants

Volumetric and viscometric study on the interaction of amino acid (valine) with an aqueous solution of cationic surfactant, Cetyltrimethylammonium Bromide (CTAB), at 298.15, 303.15, 308.15, and 313.15 K

Interactions between the surfactant (CTAB) and amino acid (valine) were investigated using density and viscosity data. These data were utilized to calculate apparent molar volume, fv, and partial molar volume also known as limiting molar volume f0v and these parameters were further used to find out solute-solvent interactions between amino acid and surfactant at 298.15, 303.15, 308.15 and 313.15 K temperatures.

An ESIPT-Based Fluorescent Probe for Wash-Free Cell Membrane Imaging.

The cell membrane tracking is important for studying the membrane function and diagnosing membrane-related diseases, so the development of fluorescent molecule specifically lighting up cell membrane is highly desirable. In this work, we designed and readily prepared a fluorescent dye (BOHI) that can target cell membrane. The pH-dependent emission spectra reveal that BOHI shows fluorescence based on the excited-state intramolecular proton transfer (ESIPT) under acidic and neutral conditions, while the blue-shifted emission from the phenolate anion of BOHI was observed when pH ≥ 9. Among various solvents, the weakest fluorescence emission was observed in H2O, which is favorable to wash-free imaging. The fluorescence intensity of BOHI is greatly affected by surfactants. The anionic surfactant can induce intense green fluorescence, while very weak fluorescence was observed in the solution of cationic surfactant. Hela cells images show that BOHI can specifically targets and lights up cell membrane.

Promote or inhibit turbulence drag reduction behavior of surfactant solutions with different micelle structures by certain nanoparticle addition

The micelle structure of surfactant is easy to be destroyed in the flow process resulting in a decrease in its drag reduction (DR) efficiency; therefore, how to strengthen the stability of the micelle structure during the flow process and thus improve the drag reduction efficiency deserves intensive research. In this work, by comparing a variety of nanoparticles, hydrophobic silica nanoparticles were selected as the best additive to enhance the turbulence drag reduction efficiency of surfactant solution with spherical micelle structure. The experimental results also demonstrated that the hydrophobic silica nanoparticles had a reinforcing effect on anionic, cationic, nonionic, and zwitterionic surfactant solutions with the same concentration (dominated by spherical micelles), and the optimal nanoparticle addition concentration and maximum drag reduction rate were obtained. Meanwhile, the effect of silica nanoparticles on the turbulence drag reduction efficiency of surfactant solutions with different micelle structures was evaluated by inducing the surfactant micelle structure change. It was shown that the hydrophobic silica nanoparticles had a strengthening effect on the turbulence drag reduction performance of surfactant solutions with spherical micelle structure, while they had an inhibiting effect on the turbulence drag reduction performance of surfactant solutions with worm-like micelle structure. The change in solution viscoelasticity indicated that the decrease in viscoelasticity was the main reason for the decrease in drag reduction efficiency of surfactant solution with worm-like micelle structure when silica nanoparticles were added. A mechanism for the interaction of hydrophilic/hydrophobic silica nanoparticles with spherical micelles and wormlike micelle structures was finally discussed and proposed.

Preparation of cationic surfactant modified two-dimensional (2D) multi-layered Ti3C2Tx MXene for methyl orange removal from aqueous solution: Kinetic, equilibrium, and adsorption mechanisms

In this study, cetyltrimethylammonium bromide-modified multi-layered Ti3C2Tx MXene (CMM) was produced using a Ti3AlC2 precursor, and its capacity to remove the anionic dye, methyl orange (MO), was investigated in detail. An electrostatic combination between negatively charged Ti3C2Tx nanosheets and cationic surfactant solution (CTAB) produced this adsorbent. This triggered an exposure of the accessible active sites to further boost adsorption effectiveness by increasing the distance between the MXene nanosheets. Prepared adsorbents were characterized using some analytical techniques, including TGA, FESEM, EDX, FTIR, XRD, and N2 adsorption-desorption. Furthermore, some influencing parameters such as contact time, solution of pH, loading adsorbent, and initial dye concentration were evaluated, with findings showing that MO could adsorb CMM to its maximum capacity at an adsorbent dosage of 0.83 g/L, a contact time of 90 min, and a solution pH of 3. Adsorption results were found to be highly linked with both Langmuir isotherm (R2 = 0.9990) and the pseudo-second-order kinetic model (R2 = 0.9924). The maximum adsorption capacity of MO was obtained at approximately 213.00 mg/g. Also, hydrogen bonding, π-cation interactions, and electrostatic adsorption can all be implicated in the mechanism of MO adsorption on CMM. The fabricated CMM is presented as a prospective adsorbent for the removal of dyes from polluted water, demonstrating robust recyclability for up to the fifth iteration. All these outstanding properties indicate that cetyltrimethylammonium bromide-modified multi-layered Ti3C2Tx MXene can be considered as applicable adsorbents for textile pollutants.

Quinolin-2(1H-)-one-isoxazole dye as an acceptor for mild addition of bisulfite in cationic or zwitterionic aqueous micellar solutions

Aqueous micellar solutions of cationic and zwitterionic surfactants have been demonstrated to enable nucleophilic addition reactions of bisulfite to an activated Michael acceptor-type probe (MQI) to be performed in water under mild conditions.

Experimental study on the synergic effects of surfactants and nanoparticles on the seepage of water injected into coal seams

To study the synergic effects of surfactants and nanoparticles on the seepage of water injected into coal seams, we prepared three chip models with complex cracks using glass etching technology based on the real conformation of cracks in coal mass and set up a visual experimental platform for microscopic seepage. Based on these models, we carried out a series of seepage experiments on gas expelling with different solutions and investigated the effects of surfactants, nanoparticles, and flow velocities on seepage characteristics. The results showed that all tested anionic, non-ionic, and cationic surfactant solutions could reduce flow resistance, showing a downward trend with the rise of the mass fractions of these surfactants. The combination of nanoparticles with these surfactant solutions further reduced flow resistance, showing the best drag reduction effects with hydrophobic nanoparticles at all tested flow velocities. Moreover, all three tested surfactants could displace gas and reduce gas residue in the crack networks. The higher the mass fraction of the surfactant solution is, the more significant the gas displacement effect. Furthermore, the gas displacement effect of the surfactant solution is positively proportional to the flow velocity. The higher the flow velocity is, the more significant the gas displacement effect.

Effects of static magnetic field on the surface tension of surfactant solutions

AbstractThe magnetic field (MF) effects resulting from water or solution treatments are still of significant interest. However, a relatively small number of papers have been published dealing with the pure surfactant solutions alone. On the other hand, surfactants are applied in many industrial processes as well as in everyday life and are also present in different waste waters. Therefore, it seemed interesting to investigate whether some effects would appear after the MF treatment of pure aqueous surfactant solutions. In the earlier published papers after MF action the changes in water evaporation rate and the surface tension were found for both the cationic dodecyltrimethylammonium bromide (DTAB) and anionic sodium dodecyl sulfate (SDS) solutions. The gradient MF originated from three connected ring magnets inside which the solutions were placed. The objective of this paper is to study whether using the same magnets but in a different position the effects of the MF are observed. The given surfactant solution in a closed vessel was placed in an uniform MF when the magnets were in the “lying” position. The investigated solutions on the magnet surface remained for 24 h. In this paper, despite SDS and DTAB also the cationic hexadecyltrimethylammonium bromide (CTAB) and nonionic Triton X‐100 solutions were applied. It appeared that in the uniform MF the surface tension of cationic and anionic surfactant solutions changes. However, larger changes were observed in the gradient MF. Generally, the changes of surface tension depend on the surfactant kind and its concentration. Stronger MF influence was found for the cationic surfactant and almost no changes were observed for nonionic Triton X‐100.

Enhancement of the Texture & Morphology of Nano γ-Alumina as a Support for Naphtha Reforming Catalyst

The morphology of nano gamma alumina affects the molecule adsorption-desorption phenomena. In this case, manipulating the surface area, pore volume, and pore size by the technique of preparation to control the morphology and textural properties of gamma alumina. Washing of the synthesized boehmite gel with methanol has a significant effect. The co-precipitation method was used to prepare nano gamma alumina, which is involved by adding drop-by-drop ammonium hydroxide and aluminum nitrate nonahydrate solutions to a cetyltrimethylammonium bromide (CTAB) cationic surfactant solution at 30 C and adjust PH to 8. Nitrogen adsorption-desorption analysis (ASAP 2020), Atomic Force Microscope (AFM), and X-Ray Diffraction (XRD) were used to examine the obtained material. Surface area (362 m2/g), pore volume (0.51 cm3/g), pore size (5.2 nm), and narrow pore size distribution were obtained.

Development of a Novel Surfactant-Based Viscoelastic Fluid System as an Alternative Nonpolymeric Fracturing Fluid and Comparative Analysis with Traditional Guar Gum Gel Fluid.

Surfactant-based viscoelastic (SBVE) fluids have recently gained interest from many oil industry researchers due to their polymer-like viscoelastic behaviour and ability to mitigate problems of polymeric fluids by replacing them during various operations. This study investigates an alternative SBVE fluid system for hydraulic fracturing with comparable rheological characteristics to conventional polymeric guar gum fluid. In this study, low and high surfactant concentration SBVE fluid and nanofluid systems were synthesized, optimized, and compared. Cetyltrimethylammonium bromide and counterion inorganic sodium nitrate salt, with and without 1 wt% ZnO nano-dispersion additives, were used; these are entangled wormlike micellar solutions of cationic surfactant. The fluids were divided into the categories of type 1, type 2, type 3, and type 4, and were optimized by comparing the rheological characteristics of different concentration fluids in each category at 25 °C. The authors have reported recently that ZnO NPs can improve the rheological characteristics of fluids with a low surfactant concentration of 0.1 M cetyltrimethylammonium bromide by proposing fluids and nanofluids of type 1 and type 2. In addition, conventional polymeric guar gum gel fluid is prepared in this study and analyzed for its rheological characteristics. The rheology of all SBVE fluids and the guar gum fluid was analyzed using a rotational rheometer at varying shear rate conditions from 0.1 to 500 s-1 under 25 °C, 35 °C, 45 °C, 55 °C, 65 °C, and 75 °C temperature conditions. The comparative analysis section compares the rheology of the optimal SBVE fluids and nanofluids in each category to the rheology of polymeric guar gum fluid for the entire range of shear rates and temperature conditions. The type 3 optimum fluid with high surfactant concentration of 0.2 M cetyltrimethylammonium bromide and 1.2 M sodium nitrate was the best of all the optimum fluids and nanofluids. This fluid shows comparative rheology to guar gum fluid even at elevated shear rate and temperature conditions. The comparison of average viscosity values under a different group of shear rate conditions suggests that the overall optimum SBVE fluid prepared in this study is a potential nonpolymeric viscoelastic fluid candidate for hydraulic fracturing operation that could replace polymeric guar gum fluids.

Regression modelling for concentration dependent mass density and specific volume of aqueous surfactant solutions

ABSTRACT. In the present work, mathematical models relating mass density and specific volume of solution with concentration for aqueous solutions of anionic (sodium lauryl sulfate - SLS) and cationic (cetyltrimethylammonium bromide - CTAB) surfactants (0-10% (w/w)) have been investigated. The experimental studies were performed to study the effect of solution concentration on mass density and specific volume of solution. Mass density increases, and specific volume decreases with an increase in solution concentration for both surfactants. Linear, quadratic, cubic, quartic, quintic, and exponential models were fitted to the experimental data to check the applicability. The models were validated based on the coefficient of determination (R2) and the sum of square of error (SSE) to be unity and zero, respectively. Modelling results reveal that the quintic model was fitted to study the effect of density on solution concentration for both surfactants.
 
 KEY WORDS: Density, Surfactant, Cetyltrimethylammonium bromide, Sodium lauryl sulfate, Modelling, Regression
 
 Bull. Chem. Soc. Ethiop. 2023, 37(4), 1047-1054. 
 DOI: https://dx.doi.org/10.4314/bcse.v37i4.19

Effect of Surfactants on Reverse Osmosis Membrane Performance

The aim of this study was to evaluate the performance of a reverse osmosis (RO) membrane in surfactant removal using various surfactant model aqueous solutions. The separation tests were performed with laboratory scale units in a dead-end configuration. Cellulose Acetate (CA) and Polyamide (PA) RO membranes were used with nonionic, anionic, or cationic surfactants at a wide range of concentrations. Membrane performance was evaluated using permeate flux and total organic carbon (TOC) rejection. The effects of surfactant type and concentration on RO membranes were assessed. Permeate flux of the PA membrane depended on the surfactant type and concentration. The separation of cationic surfactant aqueous solutions yielded the lowest permeate flux, followed by nonionic and anionic surfactant aqueous solutions, respectively. Surfactant adsorption on the membrane surface occurred at very low concentration of cationic and nonionic surfactants due to electrostatic and hydrophobic interactions, respectively, which affected permeate flux, and micelles did not affect the permeate flux of PA membrane. However, for CA membrane the permeate flux was not affected by the feed solution. Both membranes exhibited satisfactory TOC rejection (92–99%). This study highlights the importance of assessing interactions between membrane material and surfactant molecules to mitigate membrane fouling and guarantee a better performance of the RO membrane.

The influence of lead ions, cationic synthetic surfactants and their combinations on the pigment composition of tissues of plant organisms in water bodies Ceratophyllum demersum and Egeria densa

The mass of man-made chemical elements entering water bodies along with wastewater is gradually increasing, causing a lot of negative consequences. Plant organisms of water bodies are among the first to experience the effects of any anthropogenic pollutants and especially heavy metals and surfactants, the amount of which increases in the water of rivers and lakes. Changes in the ratio of the pool of green and yellow enzymes in aquatic plants are considered as a reliable diagnostic indicator of the development of disorders in plant cells due to technogenic influences. Changes in the content of photosynthetic pigments in plants of two species (Ceratophyllum demersum and Egeria densa) were monitored when they were exposed to very common technogenic substances (lead ions and a solution of cationic synthetic surfactants). The changes found in the quantitative content of photosynthetic pigments in aquatic plants are caused by the appearance and development of stress and some adaptation to it. Under these conditions, the structures of proteins and lipids of thylakoid membranes change, the level of ATP decreases, free radical processes are activated and the intensity of photosynthesis is inhibited. Thus, the action of lead ions, a solution of cationic synthetic surfactants, and especially their combination have a very negative effect on the tissues of Ceratophyllum demersum and Egeria densa, which is expressed in a change in the content of photosynthetic pigments and their ratio.

The influence of toxic substances in the environment on the activity of antioxidant enzymes in the tissues of Ceratophyllum demersum and Egeria densa

In the context of a gradual increase in anthropogenic environmental pollution, detailed environmental studies become relevant. It is very important in this regard to monitor the qualitative and quantitative aspects of the influence of the pollution process on various biological objects that receive the influence of substances entering the environment. Of great practical interest are the toxic effects of technogenic discharges on various hydrobionts and the main mechanisms of their development in macrophyte plants. In this regard, this work studied the influence of heavy metal ions, cationic synthetic surfactants and their combinations on the activity of the main antioxidant enzymes in tissues of Ceratophyllum demersum and Egeria densa. To do this, an experiment was conducted to assess changes in the freshwater macrophytes Ceratophyllum demersum and Egeria densa. The dynamics of the activity of antioxidant enzymes: peroxidase, polyphenol oxidase, ascorbate oxidase and catalase were studied. Their activity was assessed basally and in response to chemical stressors (100 µmol/l lead ions, 1% solution of cationic synthetic surfactants) individually and in combination with different exposures to toxic substances. The identified features of enzymatic activity in the tissues of aquatic macrophytes indicate different levels and power of their antioxidant protection. It becomes clear that the activity of antioxidant enzymes when plants are exposed to certain types of pollutants and their combinations is determined by the chemical nature of the pollutant, the mechanism of its action on the plant organism, the duration of exposure and the localization of these enzymes in cell compartments.

ГИДРОФОБНЫЕ АРОМАТИЧЕСКИЕ ТИО(ДИТИО)СОЕДИНЕНИЯ В КАЧЕСТВЕ ХРОМОГЕННЫХ АНАЛИТИЧЕСКИХ РЕАГЕНТОВ ДЛЯ ФОТОМЕТРИЧЕСКОГО ОПРЕДЕЛЕНИЯ ТИОЛОВ ПО МЕРКАПТО-ГРУППЕ. III. АНАЛИТИЧЕСКИЕ РЕАГЕНТЫ В ВОДНО-МИЦЕЛЛЯРНЫХ РАСТВОРАХ КАТИОННЫХ ПОВЕРХНОСТНО-АКТИВНЫХ ВЕЩЕСТВ

It was discovered for the first time the ability of a number of hydrophobic aromatic azothio (dithio) compounds, chromogenic analytical reagents to the mercapto group in dipolar aprotic solvents (SH- reagents), to react in aqueous solutions of cationic surfactants with sulfhydryl compounds (SH- compounds) by the type of "thiol-thiol" substitution with manifestation of significant analytical effects (AE). Photometry of hydrophobic thiols is possible by preliminary extraction of the latter with a solution of the SH- reagent from a solution in an acyclic ultimate hydrocarbon. The "thiol-thiol" substitution products may be extracted from aqueous solutions of cationic surfactants with chloroform followed by photometry of AE in an organic medium; reducing the volume of the organic phase compared to the aqueous phase results in higher sensitivity of the assay. Appropriate analytical methods can be used to control hydrogen sulfide and thiols in natural and industrial wastewater, in hydrocarbon gases, and in biological fluids.

Effects of surfactant adsorption on the wettability and friction of biomimetic surfaces.

The properties of solid-liquid interfaces can be markedly altered by surfactant adsorption. Here, we use molecular dynamics (MD) simulations to study the adsorption of ionic surfactants at the interface between water and heterogeneous solid surfaces with randomly arranged hydrophilic and hydrophobic regions, which mimic the surface properties of human hair. We use the coarse-grained MARTINI model to describe both the hair surfaces and surfactant solutions. We consider negatively-charged virgin and bleached hair surface models with different grafting densities of neutral octadecyl and anionic sulfonate groups. The adsorption of cationic cetrimonium bromide (CTAB) and anionic sodium dodecyl sulfate (SDS) surfactants from water are studied above the critical micelle concentration. The simulated adsorption isotherms suggest that cationic surfactants adsorb to the surfaces via a two-stage process, initially forming monolayers and then bilayers at high concentrations, which is consistent with previous experiments. Anionic surfactants weakly adsorb via hydrophobic interactions, forming only monolayers on both virgin and medium bleached hair surfaces. We also conduct non-equilibrium molecular dynamics simulations, which show that applying cationic surfactant solutions to bleached hair successfully restores the low friction seen with virgin hair. Friction is controlled by the combined surface coverage of the grafted lipids and the adsorbed CTAB molecules. Treated surfaces containing monolayers and bilayers both show similar friction, since the latter are easily removed by compression and shear. Further wetting MD simulations show that bleached hair treated with CTAB increases the hydrophobicity to similar levels seen for virgin hair. Treated surfaces containing CTAB monolayers with the tailgroups pointing predominantly away from the surface are more hydrophobic than bilayers due to the electrostatic interactions between water molecules and the exposed cationic headgroups.

Structural Transitions of Anionic, Cationic, and Nonionic Surfactant Solutions Confined between Amorphous SiO2 Slabs: Molecular Dynamics Simulations

Adsorption of surfactants of a different nature on solid surfaces has found remarkable enthusiasm in many industrial processes such as enhanced oil recovery, detergency, solubilization, and flocculation/dispersion. Surfactants can interact with solid slabs and alter their surface charge and hydrophobicity, which are essential in interfacial phenomena. Interestingly, the surface charges of amorphous materials are thoroughly different from crystalline materials due to the disordered distribution of surface atoms. Therefore, we performed molecular dynamics simulations to examine the interactions of surfactant solutions with SiO2 surface in detail. To this aim, aqueous solutions of various surfactants were confined between two amorphous SiO2 walls, which were 10 nm apart. The results indicate that the structure of the amorphous solid surfaces is changed substantially due to their interactions with surfactant solutions. The simulation results indicate the presence of the nonionic surfactant aggregates in the bulk solvent, while ionic surfactants without branching, such as SDS, form aggregates that adsorb on the SiO2 surface. The interactions of the confined surfactants with glassy SiO2 slabs change the structure of the surface layer and consequently alter the surface charge density during the simulation, which leads to the separation of cationic and anionic parts of the confined surfactants in the vicinity of amorphous SiO2 slabs.

Rheological study of nanoparticle-based cationic surfactant solutions

Worm-like micelles are of special interest among the many forms of surfactant aggregates because of their usefulness in research and technology. Micelles are elongated, flexible aggregates formed by amphiphilic molecules spontaneously self-organizing in liquids. The nature of the surfactant determines its unique shape, which may be altered by mixing it with other substances or changing physicochemical variables like as temperature, pH, or salinity. The rheology of viscoelastic fluid systems is currently being modified using nanoparticles. This method, which was just introduced about 10 years ago, has shown to be highly promising, producing significant improvements in rheological properties, particularly at reservoir temperatures. The goal of this research is to investigate and assess the rheology of an aqueous cationic surfactant solution based on graphene oxide nanoparticles. The thermodynamics, structure, and rheology of nanoparticle-based cationic surfactant solutions were investigated experimentally. According to structural and thermodynamic investigations in surfactant-nanoparticle mixtures, micelle-nanoparticle interactions arise as physical crosslinks between micelles. The existence of these interactions is shown to generate considerable viscosity and viscoelasticity in wormlike micelles, even when the fluid is Newtonian in the absence of nanoparticles. The viscosity, shear modulus, and relaxation time all increase as particle concentration increases. Adding nanoparticles generates a network of micellar entanglements as a result of that. Our results demonstrate that adding nanoparticles to surfactant solutions provides for a one-of-a-kind method of altering fluid rheology under a range of circumstances.