Surfactant Water Research Articles

Кинетические и активационные параметры реакции биохимического разложения додецилсульфата натрия в природной воде

The method of laboratory modeling was used to determine the rate constants, half-transformation periods, temperature coefficient, and free activation energy and activation enthalpy of the reaction of biochemical decomposition of sodium dodecyl sulfate in the water of the Petrozavodsk Bay of Lake Onega at different temperatures. The reaction rate constants increase from 0.064 ± 0.005 to 0.089 ± 0.006 day -1 with an increase in temperature from 10 to 20 °C, and the half-life periods respectively decrease from 10.8 ± 0.8 to 7.8 ± 0.6 days. Kinetic and activation parameters make it possible to calculate the rate of decomposition of synthetic linear anionic surfactants in natural water under changes in environmental conditions.

The influence of anionic surfactant in water on the quenching process

Understanding the patterns of heat transfer during quenching is important for many technical applications. Of particular interest is the boiling regime, which is characterized by high intensity and occurs at surface temperatures exceeding the temperature of attainable liquid superheat. This work is aimed at studying the effect of surfactants on the onset of intense heat transfer during quenching. For this, experiments were carried out on quenching spheres made of different metals (nickel, stainless steel and zirconium) in water with different concentrations of surfactants. The surfactant was alkylbenzene sulfonate, the concentration of which varied from 0.1 to 2%. The analysis of the obtained cooling thermograms revealed the influence of not only the surfactant concentration on the beginning of the intensive cooling mode, but also the state of the heat transfer surface.

Experimental study on the characteristics of temperature dependent surface/interfacial properties of a non-ionic surfactant aqueous solution at quasi-thermal equilibrium condition

The surface/interfacial properties of liquid at elevated temperatures are fundamental issues for wide applications where the surface force matters. The dynamic characteristics of wetting behavior and surface tension (ST) of surfactant solutions remain unclear at thermal equilibrium, especially at high temperature. Utilizing a quasi-thermal equilibrium setup, the temperature dependence of the surface/interfacial properties of liquids (ultra-pure water and aqueous surfactant solutions) at temperature ranging from 10 to 90 °C (1 atm) are studied, by the sessile drop method and pendant drop method, respectively. A decreasing trend of the initial ST and contact angle (CA) is observed with the increase of temperature. During evaporation, the increase of the local relative humidity around the droplet has a crucial influence on CA. The obtained ST and CA are based on the thermodynamic model with modified coefficients, which can well describe the general trends for different temperatures and concentrations. For the ultra-pure water, the droplets will be pinned suddenly on the heating surface, until a sudden contraction occurs with evaporation. However, the surfactant-laden droplet shows different dynamical behaviors from ultra-pure water. Three different stages, named spreading-controlled Stage I, evaporation-controlled Stage II, and depinning-controlled Stage III are found for the dynamic evolution of surfactant-laden droplet. In what follows, the different droplet behaviors are also analyzed for surfactant solution and ultra-pure water.

Interfacial properties of novel surfactants based on maleic and succinic acid for potential application in personal care

Hemiesters and Hemiamides of maleic and succinic acid viz. sodium lauryl succinate (C12SE), sodium lauryl maleate (C12ME), sodium lauryl succinamide (C12SA), sodium lauryl maleamide (C12MA), sodium hexadecyl succinate (C16SE) and sodium hexadecyl maleate (C16ME) were synthesized and investigated as surfactants in the pure water and aqueous hydrotrope [sodium p-toluene sulfonate (NaPTs)] solution. The chemical structures of the prepared surfactants were established by FTIR and 1H NMR spectroscopy. The surface tension measurements depicted low CMC and a high adsorption efficiency (pC20) which is highly beneficial for creating personal care formulations. The dynamic light scattering (DLS) technique indicated the formation of larger micelles which was important for skin care as larger micelles cannot penetrate the skin layer. Moreover, these surfactants depicted good foamability and stability attributed to faster monomer adsorption and small bubble size which was preferred for cleansing application. Additionally, low protein/lipid solubilization by these surfactants indicated its mild behaviour on skin as compared to other commonly used conventional anionic [sodium lauryl sulfate (SLS)], zwitterionic [cocamidopropyl betaine (CAPB)] and nonionic [decyl glucoside (DG)] surfactants. Viscosity measurements suggested decent thickening ability of surfactants in the presence of co-surfactant like lauramine oxide. Basis of all the properties discussed, these novel hemiesters and hemiamides seem promising as surfactants for improving various characteristics in potential personal care formulations.

Silicon Foliar Spray and Substrate Drench Effects on Plant Growth, Morphology, and Resistance to Wilting with Container-Grown Edible Species

The objective of this study was to evaluate silicon (Si) foliar spray and substrate drench effects on plant growth and morphology for container-grown edible crops during greenhouse production, as well as resistance to plant wilting during post-production. In the first greenhouse experiment, basil received Si foliar sprays at 0, 50, 100, 200, and 400 mg∙L–1 Si. In the second greenhouse experiment, Si was applied as either a foliar spray (500 mg∙L–1 Si) or substrate drench (100 mg∙L–1 Si) with six edible crop species. Supplemental Si increased shoot Si levels but had minimal effects on plant growth and morphology, except for parsley, which resulted in distorted growth and phytotoxicity. In the first experiment, 200 and 400 mg∙L–1 Si foliar sprays increased plant resistance to wilt by 2.2 and 2.5 d, respectively; however, this was not observed in the second experiment. All species accumulated Si with the control (no Si) treatments, indicating trace amounts of Si were taken up from the substrate, fertilizer, spray surfactant, and irrigation water. Only cucumber was classified as a Si “accumulator” with a high capacity for Si uptake. Results emphasize the need to conduct preliminary trials with supplemental Si to avoid issues of phytotoxicity.

Study on the Flow Mechanism of Shale Oil with Different Injection Media

Chinese shale oil has high recoverable resources and great development potential. However, due to the limitation of development technology, the recovery rate of shale oil is not high. In this paper, the effects of different injection media on the development of shale oil reservoirs in Dongying formation, Qikou depression, Huanghua depression, and Bohai bay basin, were studied by means of imbibition and nitrogen flooding. Combining nuclear magnetic resonance (NMR) technology with imbibition and gas displacement experiments, the mechanism of shale injected formation water, active water (surfactant), and nitrogen was reproduced. The displacement process of crude oil under different injection media and injection conditions was truly demonstrated, and the relationship between different development methods and the pore boundaries used was clarified. A theoretical basis for the effective development of shale oil was provided. At the same time, Changqing tight oil cores with similar permeability to Dagang shale oil cores were selected for comparison. The results showed that, as the imbibition time of shale samples increased, the imbibition efficiency increased. Pores with T2 < 10 ms contributed the most to imbibition efficiency, with an average contribution greater than 90%. 10 ms < T2 < 100 ms and more than 100 ms pores contributed less to imbibition efficiency. Active water can change the wettability of shale, increase its hydrophilicity, and improve the efficiency of imbibition. The imbibition recovery ratio of injected active water was 17.56% higher than that of injected formation water. Compared with tight sandstone with similar permeability, the imbibition efficiency of shale was lower. As the nitrogen displacement pressure increased, the oil displacement efficiency also increased. The higher the shale permeability was, the greater the displacement efficiency would be. T2 > 100 ms pore throat of shale contributed to the main oil displacement efficiency, with an average oil displacement efficiency contribution of 63.16%. And the relaxation interval 10 < T2 < 100 ms pore throat displacement efficiency contributed to 28.27%. T2 < 10 ms pore throat contributed the least to the oil displacement efficiency, with an average oil displacement efficiency contribution of 8.58%. Compared with tight sandstone with similar permeability, shale had lower oil displacement efficiency. The findings of this study can help for better understanding of the influence of different injection media on shale oil recovery effect.

Microfluidic study of heavy oil emulsification on solid surface

Sandpack experiments cannot fully describe the microcosmic mechanism of oil/water emulsification. In this study, we used a microfluidic chip that can generate a heavy oil drop on the surface to investigate its flow behavior under both surfactant flooding and water flooding conditions. We recorded the images of the dynamic processes by a microfluidic platform and analyzed the effects of different influencing factors on the shape of the emulsion droplet. The findings indicated that the heavy oil drop advances slowly along the solid surface during water flooding while it could be emulsified as a tadpole-shaped droplet by surfactant. The surfactant adsorption could lead to a decrease in the adhesion force and friction force. Experiments further demonstrated that the shape of the emulsion droplet is related with surfactant flow rate, thickness, and viscosity of heavy oil. This work presents detailed mechanisms for heavy oil emulsification at the pore scale.

First-principles prediction of critical micellar concentrations for ionic and nonionic surfactants

The concentration of surfactant in solution for which micelles start to form, also known as critical micelle concentration is a key property in formulation design. The critical micelle concentration can be determined experimentally with a tensiometer by measuring the surface tension of a concentration series. In analogy with experiments, in-silico predictions can be achieved through interfacial tension calculations.We present a newly developed method, which employs first principles-based interfacial tension calculations rooted in COSMO-RS theory, for the prediction of the critical micelle concentration of a set of nonionic, cationic, anionic, and zwitterionic surfactants in water. Our approach consists of a combination of two prediction strategies for modelling two different phenomena involving the removal of the surfactant hydrophobic tail from contact with water. The two strategies are based on regular micelle formation and thermodynamic phase separation of the surfactant from water and both are required to take into account a wide range of polarity in the hydrophilic headgroup.Our method yields accurate predictions for the critical micellar concentration, within one log unit from experiments, for a wide range of surfactant types and introduces possibilities for first-principles based prediction of formulation properties for more complex compositions.

Evidence of formation of dye–surfactant ion pair micelle in the anionic surfactant mediated alkaline fading of methyl violet carbocation

AbstractIn the submicellar solution of anionic surfactants sodium dodecyl sulfate (SDS) and dioctyl sodium sulfosuccinate (AOT), the alkaline fading of methyl violet (MV+) carbocation has been studied spectrophotometrically in the temperature range 293–308 K. The interaction behavior of the dye carbocation with the anionic surfactant and the observed submicellar rate retardation is consistent with the ion pair and subsequent ion‐pair micelle formation. The change in the spectral pattern along with a change in the peak intensity and shoulder intensity with increasing surfactant concentrations indicates the shifting of the equilibrium between the helical and distorted helical isomers of MV+ owing to the existence of dye–surfactant ion pair, ion‐pair micelles, and dye‐embedded micelles. This dynamic dye–surfactant ion‐ion interaction has been corroborated by the tensiometric studies. The decrease in the fading rate and the change in the spectral pattern in the presence of anion, especially I–, support the existence of the dye–anion interaction. The premicellar rate inhibition and the corresponding interaction have been accounted for by the use of two kinetic models namely, Olson–Simonson and Piszkiewicz cooperativity models. The cooperativity index value suggested a 1:1 dye–surfactant association in both the surfactants. The ratio of the concentration of the premicellar complex and the free dye cation indicates appreciable binding. The kinetic and thermodynamic parameters associated with the dye–surfactant complex have been explained in terms of dye–surfactant, dye–water, and surfactant–water interactions.

Investigation on the formation and stability of microemulsions with Gemini surfactants: DPD simulation

To study the formation and stability of the O/W and reverse W/O microemulsion, dissipative particle dynamics (DPD) simulation was utilized to investigate the system composed of oil, water and Gemini surfactants. The effects of oil-water ratio, temperature, inorganic salt and shear rate were discussed in the simulation. Controlled of the formation process and stability of microemulsions by analyzing the interfacial tension of oil and water interfaces, end-to-end distance of Gemini surfactants and the translucent three-dimensional structures of formed aggregates. Two types microemulsions could form and mutually transform with changing the oil-water ratio. In conclusion, the O/W microemulsion has better temperature, salt and shear tolerance comparing to the reverse W/O microemulsion. The results of the research using DPD simulation expanded the theoretical knowledge of microemulsion on the molecular level, which is of great importance to develop new microemulsion systems with other surfactants and provided better theoretical guidance for the application of microemulsions.

Hot Compressed Water Pretreatment and Surfactant Effect on Enzymatic Hydrolysis Using Agave Bagasse

Agave bagasse is a residual biomass in the production of the alcoholic beverage tequila, and therefore, it is a promising raw material in the development of biorefineries using hot compressed water pretreatment (hydrothermal processing). Surfactants application has been frequently reported as an alternative to enhance monomeric sugars production efficiency and as a possibility to reduce the enzyme loading required. Nevertheless, the surfactant’s action mechanisms in the enzymatic hydrolysis is still not elucidated. In this work, hot compressed water pretreatment was applied on agave bagasse for biomass fractionation at 194 °C in isothermal regime for 30 min, and the effect of non-ionic surfactants (Tween 20, Tween 80, Span 80, and Polyethylene glycol (PEG 400)) was studied as a potential enhancer of enzymatic saccharification of hydrothermally pretreated solids of agave bagasse (AGB). It was found that non-ionic surfactants show an improvement in the conversion yield of cellulose to glucose (100%) and production of glucose (79.76 g/L) at 15 FPU/g glucan, the highest enhancement obtained being 7% regarding the control (no surfactant addition), using PEG 400 as an additive. The use of surfactants allows improving the production of fermentable sugars for the development of second-generation biorefineries.

Phase Behavior and Aggregate Transition in Aqueous Mixtures of Negatively Charged Carbon Dots and Cationic Surfactants

To prepare supramolecular structures with interesting dimensions and morphologies using nanometer-sized building blocks is highly challenging. Herein, negatively charged carbon dots (n-CDs), which bear carboxy and hydroxyl groups on the surfaces, are mixed, respectively, with two cationic surfactants in water, i.e., 1-tetradecyl-3-methylimidazolium bromide (C14mimB) and tetradecyltrimethylammonium bromide (TTAB). The phase behavior and aggregate transition in n-CDs/C14mimB and n-CDs/TTAB mixtures were investigated in detail. At a fixed concentration of n-CDs (cn-CDs, 0.1 mg·mL–1), both systems exhibit a phase sequence of an isotropic phase (I1), a turbid phase (T1), a precipitated phase (P), a second turbid phase (T2), and a second isotropic phase (I2) with increasing concentration of the surfactant (cs). While only vesicles were observed in the T1 phase, hexosomes were also detected in the T2 phase in addition to vesicles. The phase transition obtained by the experiments gains solid support from computer simulations using a dissipative particle dynamics method, which give structural details of the hexosomes and evidence of anion−π interaction in an n-CDs/C14mimB system. The results obtained in the current study reinforce the conclusion that CDs/surfactant is a good combination for facile construction of supramolecular structures. The aggregates with diverse morphologies open up the possibility of a variety of future applications.

Review on Applications of Non-ionic and Anionic Surfactants in Water Based Drilling Fluids

In recent times, with the advent of exploSration activities in deeper hydrocarbon reserves, drilling of wells in HPHT conditions is one of the most studied field in the upstream oil and gas industry. Water-based fluids are the most common and frequently used drilling fluids oil and gas well construction. Although, water-based drilling fluids are environment friendly and relatively in-expensive, it is often associated with many problems when used in HPHT conditions. In order to overcome these problems in such viable conditions, modified surfactants are used with the mud to counteract the problems associated with it. This paper discusses the different applications of anionic and non-ionic surfactants in water-based drilling fluids both in laboratory and field scales. The paper also discusses the mechanisms of the surfactants and the effect on various mud properties to overcome hole problems like wellbore instability, rheology and filtration loss, foaming and flocculation of mud.

Association of ionic surfactant in binary water—ethanol media as indicator of changes in structure and properties of solvent

Association of ionic surfactant in binary water—ethanol media as indicator of changes in structure and properties of solvent

Phase Equilibria and the Extraction of Metals in Oxyethylated Alkylamine–Anionic Surfactant–Water Systems

Phase Equilibria and the Extraction of Metals in Oxyethylated Alkylamine–Anionic Surfactant–Water Systems

ECOLOGICAL EFFICIENCY OF SURFACE WATER PURIFICATION BY THE METHOD OF STRUCTURING CONTAMINATED BY THE ACTIVITIES OF THE AGROINDUSTRIAL COMPLEX

Biochemical oxygen consumption for five days in water without structuring is 5.0 mgO2/dm3, which is 1.7 MPC. With the structuring of water, the indicator of biochemical oxygen consumption decreased by 20%, to 4.0 mgO2/dm3, which was 1.3 MPC. The pH of water without structuring was 7.27, and in structured water it decreased by 0.7% or by 0.5 pH to 7.22 pH. The concentration of suspended solids in unstructured water was 180.0 mg/dm3, while the maximum permissible concentration (MPC) of suspended solids in surface waters was 15 mg/dm3. This indicates a strong pollution of the reservoir with suspended substances, 12 times higher than the permissible limits. With the structuring of water, the concentration of suspended solids decreased by 50.6%, to 89.0 mg/dm3, but this was 5.9 times higher than the MPC. The actual concentration of chlorides in water without structuring was 108.92 mg/dm3, and with structuring of water, the concentration of chlorides increased by 14.7%, to a level of 127.64 mg/dm3. In comparison with the maximum permissible concentration of chlorides in the reservoir, in both cases the actual chloride content was significantly less than the MPC and amounted to 0.3 and 0.4 MPC, respectively. The content of ammonium nitrogen in the reservoir without structuring was 6.63 mg/dm3, which was 4.4 times higher than the permissible limits. The structuring of water contributed to a decrease in the concentration of ammonium nitrogen in surface waters by 16%, to 5.57 mg/dm3. This concentration of ammoniacal nitrogen in water also exceeded the maximum permissible value by 3.7 times. The nitrate content in water without structuring was 5.18 mg/dm3. The structuring of water contributed to a decrease in the concentration of nitrates by 24.7%, to a level of 3.9 mg/dm3. This concentration of nitrates in the reservoir is significantly lower than the permissible limits and amounts to 0.52 and 0.39 MPC, respectively. The actual concentration of surfactants in the reservoir without structuring was 0.01 mg/dm3. After structuring, the concentration of surfactants in water was less than 0.01 mg/dm3, which is less than the technical sensitivity of the measuring device. Therefore, the ecological efficiency of structuring water to reduce the concentration of synthetic surfactants is more than 10%. Since the maximum permissible concentration of synthetic surfactants in water bodies is 0.2 mg/dm3, their actual concentration was much less than this indicator. Permanganate oxidizability of water without its structuring was 10.67 mgO2/dm3. With the structuring of water, permanganate oxidation decreased by 27.6% and amounted to 7.73 mgO2/dm3. Without structuring water, the permanganate oxidizability was 1.1 MPC, which was more than the permissible level, and when using a structurant, it was 0.8 MPC, which ensures acceptable limits. The transparency of the water without structuring was 2.5 cm. The structuring of the water led to an increase in the transparency of the reservoir by 44.4%, up to 4.5 cm. The minimum permissible transparency of surface waters should be 10 cm. This indicates that the water from both experimental variants is very contaminated with an excess of the permissible limits by 4 and 2.2 times, respectively.

Surfactant Adsorption to Different Fluid Interfaces

Surfactant adsorption to fluid interfaces is ubiquitous in biological systems, industrial applications, and scientific fields. Herein, we unravel the impact of the hydrophobic phase (air and oil) and the role of oil polarity on the adsorption of surfactants to fluid interfaces. We investigated the adsorption of anionic (sodium dodecyl sulfate), cationic (dodecyltrimethylammonium bromide), and non-ionic (polyoxyethylene-(23)-monododecyl ether) surfactants at different interfaces, including air and oils, with a wide range of polarities. The surfactant-induced interfacial tension decrease, called the interfacial pressure, correlates linearly with the initial interfacial tension of the clean oil-water interface and describes the experimental results of over 30 studies from the literature. The higher interfacial competition of surfactant and polar oil molecules caused the number of adsorbed molecules at the interface to drop. Further, we found that the critical micelle concentration of surfactants in water correlates to the solubility of the oil molecules in water. Hence, the nature of the oil affects the adsorption behavior and equilibrium state of the surfactant at fluid interfaces. These results broaden our understanding and enable better predictability of the interactions of surfactants with hydrophobic phases, which is essential for emulsion, foam, and capsule formation, pharmaceutical commodities, cosmetics, and many food products.

Interactions between an Associative Amphiphilic Block Polyelectrolyte and Surfactants in Water: Effect of Charge Type on Solution Properties and Aggregation.

The study of interactions between polyelectrolytes (PE) and surfactants is of great interest for both fundamental and applied research. These mixtures can represent, for example, models of self-assembly and molecular organization in biological systems, but they are also relevant in industrial applications. Amphiphilic block polyelectrolytes represent an interesting class of PE, but their interactions with surfactants have not been extensively explored so far, most studies being restricted to non-associating PE. In this work, interactions between an anionic amphiphilic triblock polyelectrolyte and different types of surfactants bearing respectively negative, positive and no charge, are investigated via surface tension and solution rheology measurements for the first time. It is evidenced that the surfactants have different effects on viscosity and surface tension, depending on their charge type. Micellization of the surfactant is affected by the presence of the polymer in all cases; shear viscosity of polymer solutions decreases in presence of the same charge or nonionic surfactants, while the opposite charge surfactant causes precipitation. This study highlights the importance of the charge type, and the role of the associating hydrophobic block in the PE structure, on the solution behavior of the mixtures. Moreover, a possible interaction model is proposed, based on the obtained data.

Bursting the bubble: A molecular understanding of surfactant-water interfaces.

Surfactant science has historically emphasized bulk, thermodynamic measurements to understand the microemulsion properties of greatest industrial significance, such as interfacial tensions, phase behavior, and thermal stability. Recently, interest in the molecular properties of surfactants has grown among the physical chemistry community. This has led to the application of cutting-edge spectroscopic methods and advanced simulations to understand the specific interactions that give rise to the previously studied bulk characteristics. In this Perspective, we catalog key findings that describe the surfactant-oil and surfactant-water interfaces in molecular detail. We emphasize the role of ultrafast spectroscopic methods, including two-dimensional infrared spectroscopy and sum-frequency-generation spectroscopy, in conjunction with molecular dynamics simulations, and the role these techniques have played in advancing our understanding of interfacial properties in surfactant microemulsions.

Investigation of nonlinear optical properties of Eosin-B nanoparticles painted ‎

In this study the nonlinear optical properties of Eosin-B dye nanoparticles were studied using the ‎scanning-fluorescence spectrophotometer and fluorometer method. The nano water droplet in the ‎oil medium is prepared by a combination of hexane and surfactant water, which is painted inside ‎the drop by Eosin-B. The droplet size was studied on a nonlinear refractive index using a 532 nm ‎laser with a scanning power of 80 mW. The results show that the surface effects on the nano-‎droplets cause the droplets to have a larger nonlinear refractive index. This change was due to a ‎decrease in the accumulation of dyes inside the droplet as well as a decrease in the polarity of the ‎drop solvent relative to the water solvent.