Mechanism Of Surfactant Adsorption Research Articles

The role of adsorption of a natural surfactant at oil–water interface in enhanced oil recovery: interfacial rheology, and structural, and emulsifying analyses

The enhanced oil recovery (EOR) method is widely used for recovering residual crude oil after implementing conventional oil recovery techniques. Chemical additives, such as surfactants, are considered beneficial for EOR. Their efficacy is assessed based on their ability to reduce interfacial tension, modify wettability, and establish a stable emulsion system. Understanding the mechanism of surfactant adsorption at the oil–water interface is critical for effectively implementing surfactant flooding. In this work, we have studied the adsorption of a natural surfactant synthesized from Eichhornia crassipes at the oil–water interface using numerous interfacial analyses. The results show substantial adsorption at the oil–water interface, indicated by a 27% increase in zeta potential (i.e. −25.2 to −37.2 mV) and ∼27 times increase in film elasticity (i.e. 0.15–4.12 Pa at 0.01 Hz frequency and 0.01% strain). The synthesized natural surfactant demonstrates a noteworthy improvement in the stability of the oil-in-water emulsion and interfacial rheological properties, indicating its potential application in EOR.

Adsorption of surfactant during chemical enhanced oil recovery

AbstractSurfactant is extensively used as chemicals during chemical enhanced oil recovery (CEOR) process. Effectiveness of surfactant CEOR process depends on several parameters like formation of micro emulsion, ultra‐low interfacial tension (IFT) and adsorption of surfactant. First two parameters enhance the effectiveness while the last parameter reduces the effectiveness. Micro emulsions are highly desirable for CEOR due to its low interfacial tension (IFT) value and higher viscosity. In this research the size of the emulsions were studied with particle size analyzer to study the liquid–liquid absorption process and the entrapment of oil drops inside surfactant drop. Initially, the average surfactant drop size was found to be 100 nm, after mixing the surfactant slug with reservoir crude, the size was increase up to 10 times. It signifies the formation of micro emulsion between surfactant and oil. Another attempt was done in this research to study the adsorption mechanism of surfactant on reservoir rock. The process of adsorption was studied by Langmuir and Freundlich isotherm to understand the adsorption phenomena. In this study, it was found that the adsorption follows Freundlich isotherm and the adsorption phenomena was chemical for surfactant flooding process. In chemical adsorption phenomena, the rate of adsorption is high because, surfactant molecules are adsorbed layer after layer by the rock surface. Use of alkali along with surfactant reduces adsorption of surfactant since, alkali blocked the active clay sites before interacting with surfactant and hence the adsorption isotherm was found to be Langmuir and phenomena was physical adsorption.

Adsorption of extended anionic surfactants at the water- polymethylmethacrylate interface: The effect of polyoxyethylene groups

Wetting of solid surfaces is a typical phenomenon in daily life and manufacturing. The wettability of solid surfaces can be efficiently altered by certain surfactants. Extended surfactants, a novel class of surfactant with a unique structure, have a potent potential to convert neutral surfaces into hydrophilic surfaces. To deeply understand the influence of EO groups on the adsorption mechanism of surfactants at solid surfaces, the wettability of the extended anionic surfactants sodium cetyl (oxyethylene)3 carboxylate (C16EO3C), sodium cetyl (oxyethylene)5 carboxylate (C16EO5C), and sodium cetyl (oxyethylene)7 carboxylate (C16EO7C) on polymethylmethacrylate (PMMA) surfaces was investigated. Surface tension and contact angle experiments were used to determine adsorption characteristics such as adhesion tension, PMMA-liquid interface tension, and adhesion work. The experimental results show that the adsorption amounts of C16EOnC at the liquid-air interface are obviously larger than those at the PMMA-liquid interface. Below CMC, all three extended surfactant molecules adsorb at the PMMA-liquid interface via polar interactions and hydrophobic part towards the aqueous phase, which results in an increase of γSL. However, the decrease of γLV and the increase of γSL have opposite effects on the contact angle, resulting in almost constant values below CMC. With an increase in EO number, the hydrophobic modification ability increases because longer EO chains provide stronger polar interactions between C16EOnC molecules and the PMMA surface. Above CMC, C16EOnC molecules continue to adsorb at the PMMA-liquid interface and form a bilayer film. Conclusively, the contact angle abruptly decreased due to the hydrophilic modification of the PMMA surface. With an increase of EO number, the hydrophilic modification ability increases because surfactants with a larger EO number endow the second layer with a more hydrophilic nature.

Wettability alteration and reducing water blockage in tight gas sandstone reservoirs using mixed cationic Gemini/nonionic fluorosurfactant mixtures

AbstractThe unrecovered hydraulic fracturing fluid will invade the matrix and induce water blockage, creating formation damage and hindering the oil or gas production rate. First, the synergistic effect of cationic Gemini surfactant (MQAS) and nonionic fluorosurfactant (N‐2821) mixtures on reducing the surface tension and wettability alteration was investigated in this paper. The critical micelle concentration (CMC) of the surfactant mixture is one or two orders of magnitude lower than that of N‐2821 and MQAS, indicating that the MQAS/N‐2821 mixtures exhibit an apparent synergistic effect in reducing surface tension. Moreover, the maximal contact angle of MQAS/N‐2821 mixtures reached 83.55° at αN‐2821 = 0.5, and the total surfactant concentration of 1 × 10−4 mol/L due to the adsorption of surfactant. The adsorption mechanism of surfactants on the surface of quartz sand was then examined. The adsorption kinetics is consistent with the pseudo‐second‐order model at different surfactant concentrations, while the Freundlich model is suitable for describing the adsorption behavior of surfactants on the sandstone surface. This finding indicates that surfactant adsorption is multilayered. The MQAS/N‐2821 surfactant mixtures have excellent surfactant activity due to the relationship of the capillary pressure to the surface tension, pore radius, and contact angle; thus, the addition of surfactant mixtures can reduce the liquid saturation effectively. Furthermore, the sequential imbibition experiments indicate that MQAS/N‐2821 mixtures alter the wettability of the core plug, which results from the adsorption of surfactants. Compared with brine water, the MQAS/N‐2821 mixtures decreased the liquid saturation and increased the permeability recovery ratios of the core plug.

Simulation study of the mechanism of mesoscopic adsorption and the evolution of molecular dynamics of a surfactant/polymer composite on the surface of low rank coal

In this paper, the head group, tail group, and main chain of a single type of surfactant were constructed by a mesoscopic simulation, and the interaction between the simulated surfactant and coal dust both on its own and in a composite with polyacrylamide (PAM) was studied. The molecular adsorption behavior of cetyltrimethylammonium chloride (CTAC) surfactant mixed in different ratios with PAM was also experimentally characterized. The results showed that. From the above results, we can see that CTAC and PAM can form spherical, rod-shaped, and wormlike aggregates and a network structure as their volume fraction increases in an aqueous solution. The energy spectrum showed that when CTAC adsorbed on the surface of the coal, the content of carbon on the surface decreased from 63.8 to 50.4%, and the content of oxygen increased from 35.2 to 41.8%. The study on the adsorption mechanism of surfactants and polymers on the surface of low rank coal and the hydrophilicity of low rank coal is of great significance in developing efficient dust prevention technology for low rank coal to reduce coal dust pollution.

Effects of Hydration on the Adsorption of Benzohydroxamic Acid on the Lead-Ion-Activated Cassiterite Surface: A DFT Study.

The strategy of enhancing the surface activity by preadsorption of metal ions (surface activation) is an effective way to promote the adsorption of surfactant on surfaces, which is very important in surface process engineering. However, the adsorption mechanism of surfactant (collector) on the surface preadsorbed by metal ions in the explicit solution phase is still poorly understood. Herein, the effects of hydration on the adsorption of benzohydroxamic acid (BHA) onto the oxide mineral surface before and after lead-ion activation are investigated by first-principles calculations, owing to its importance in the field of flotation. The results show that the direct adsorption of BHA on the hydrated surface is not thermodynamically allowed in the absence of metal ions. However, the adsorption of BHA onto the lead-ion-activated surface possesses a very low barrier and a very negative reaction energy difference, indicating that the adsorption of BHA on hydrated Pb2+ at cassiterite surface is very favorable in both thermodynamics and kinetics. In addition, the adsorption of BHA results in the dehydration of hydrated Pb2+. More interestingly, the surface hydroxyl groups could participate in and may promote the coordination adsorption through proton transfer. This work sheds some new lights on understanding the roles of interfacial water and the mechanisms of metal-ion surface activation.

Impact of mineralogy, salinity, and temperature on the adsorption characteristics of a novel natural surfactant for enhanced oil recovery

Surfactants are considered as beneficial chemical additives in enhanced oil recovery due to their capability of reducing the interfacial tension and altering the wettability. However, the loss of surfactant by adsorption on the surface of the porous rock is one of the significant drawbacks of surfactant flooding. The mechanism, equilibrium, and kinetics of adsorption of a natural surfactant derived from the weed, Eichhornia crassipes, on sandstone and sand surfaces have been investigated through batch experiments at different concentrations (i.e., 1000–5000 mg dm−3), temperatures (i.e., 298–333 K), and a fixed salinity [NaCl (76.2%), CaCl2 (3.7%), MgCl2 (1.5%), and Na2SO4 (18.6%)]. The mineralogy and morphology of the adsorbent samples were examined by the XRD and SEM analyses. The mechanism of surfactant adsorption and maximum adsorption were determined by various isotherms and kinetic models. for adsorption on sandstone and sand was found to be −21.48 and −20.80 kJ mol−1, respectively.

Potential of surfactant foam stabilized by Ethylene glycol and Allyl alcohol for the remediation of diesel contaminated soil

Abstract Refined petroleum products like diesel oil enters the soil as a result of damaged pipelines and storage tanks. This constitutes a major hazard for the environment as it leads to problems associated with soil contamination. The application and impact of surfactant foam, stabilized by the use of biodegradable additives — Ethylene glycol and Allyl alcohol, for treating diesel contaminated soil is a novel concept and has not been reported so far. The aim of the current work was thus to check the diesel contaminated soil remediation potential with the usage of surfactant foam, stabilized by Ethylene glycol and Allyl alcohol. To better understand the foam properties, experiments were performed by mixing the appropriate quantities of additives and two popular surfactants — Sodium n-dodecyl sulfate (SDS), Tween 80, using Dynamic Foam Analyzer (Kruss, Germany). The stable foams produced were then utilized to treat the diesel contaminated soil and interesting results were obtained. The foam stabilized by surfactant SDS in combination with 0.3 weight% Allyl alcohol showed maximum diesel oil removal efficiency of 62%. Also, surfactant Tween 80 with 0.3 weight% of Allyl alcohol produced the most stable foam with a half-life of 18 mins and resulted in maximum diesel removal efficiency of 71%. SDS, Tween 80 foams stabilized by 0.3 weight% Ethylene glycol however produced much lower diesel removal efficiency. The mechanism of surfactant adsorption onto soil was studied. The surface tension analysis, using the different additives — Ethylene glycol, Allyl alcohol with the surfactant solutions, were performed to check on the mobilization of diesel oil from the soil.

Increase in wettability difference between organic and mineral matter to promote low-rank coal flotation by using ultrasonic treatment

Due to Van der Waals or electrostatic interactions of surfactants active to all kinds of minerals, in low-rank coal (LRC) flotation, surfactants could both adsorb on the organic and mineral matter of LRC, thus increasing the hydrophobicity of them and resulting in the increase of clean coal yield as well as the ash content. In this work, density functional theory (DFT) calculations were clarified the adsorption mechanism of surfactant (C12EO, lauryl polyoxyethylene ether) on the LRC model molecules and kaolinite surfaces (the representative of organic and mineral matter in LRC). The DFT results demonstrate that the interaction strength between C12EO and LRC model molecules is stronger than that of kaolinite. Based on the calculation results, ultrasonic treatment was selected to expand the wettability difference between organic and mineral matter that adsorbed C12EO. The microcalorimetry results show that the wetting heat of organic matter that is adsorbed C12EO is unchanged basically after 30 s ultrasonic treatment. However, there is an obvious increase trend for the wetting heat of kaolinite. Flotation experiments of artificial mixed samples proved that ultrasonic treatment is useful in decreasing the extent of ash content in LRC flotation, thus improving the quality of clean coal in LRC flotation.

Вплив рН і йонної сили розчину на колоїдно-хімічні властивості бінарних сумішей поверхнево-активних речовин

Досліджено вплив рН і йонної сили розчину на міцелоутворення і адсорбцію бінарних сумішей гексадецилпіридиній броміду (ГДПБ) і тритону Х-100 (ТХ-100.).З використанням моделі фазового поділу (підхід Рубіна-Розена) розраховані склад змішаних міцел і адсорбційних шарів, параметри взаємодії в міцелах β m і адсорбційних шарах β σ , а також надлишкові вільні енергії міцелоутворення та адсорбції. Розрахунки складу змішаних адсорбційних шарів показали, що адсорбційний шар на межі розділу розчин – повітря у всьому інтервалі досліджених об'ємних співвідношень збагачений молекулами нейонної поверхнево-активної речовини (ПАР), що має вищу поверхневу активність. Встановлено, що збільшення йонної сили розчину призводить до зниження сили взаємодій ПАР в змішаному адсорбційному шарі. Це підтверджує електростатичну природу взаємодій у сумішах катіонних і нейонних ПАР. Ключові слова : поверхнево-активні речовини, адсорбція, бінарні суміші, міцелоутворення, адсорбційний шар

Adsorption mechanisms of alcoholic additives in water at low pressure – An experimental study

Alcoholic additives are used to enhance the heat and mass transfer of the absorber, which has been widely recognized as the bounding device of an absorption chiller. Small quantities of additives in the aqueous lithium bromide solution reduce its surface tension, leading to a better wetting of the tube bundle of the absorber and triggering the Marangoni convection. Nevertheless, the enhancement mechanism relies on many parameters which have not been yet studied in details. In this work, the adsorption mechanisms of surfactants at the interface of water drops are experimentally investigated. 2-ethylhexanol, 1-octanol, 3,5,5-trimethyl-1-hexanol and 3-phenyl-1-propanol are chosen as additives and are added to water in different concentrations. The static and dynamic surface tension is measured according to the pendant drop method and the surface excess concentration is hereafter calculated with the Gibbs isotherm. Drops are generated in a saturated atmosphere without inert gases at low pressure, which represents the real working condition of an absorber. The results show that 2-ethylhexanol, 1-octanol and 3,5,5-trimethyl-1-hexanol lead to high surface tension reduction at high concentrations, and they are characterized by a fast diffusion and adsorption. Contrary, 3-phenyl-1-propanol presents a slow adsorption kinetic and is not effective in reducing the surface tension of water.

A Review of Surfactant Role in Soil Clogging Processes at Wastewater Exfiltration Locations in Sewers.

Wastewater contains significant sources of pollutants and contaminants. often the failure of a pipe, inadequate sealing or corrupt pipe-connections cause the loss of raw sewage, which percolates into the nearby soil. As a consequence, a colmation layer in conjunction with soil clogging is developing, which regulates the exfiltration rate. Recently, literature has emerged that offers findings about the effects of wastewater surfactants on the change of physical properties of the soil. A survey of published literature in this field provides information highlighting the influential mechanisms of surfactants in soil clogging through physical, chemical and biological processes. Therefore, to provide a comprehensive approach, this review describes the adsorption mechanisms of surfactants on organic and inorganic particles, at gas-bubbles and at biomass. We also provided our own input to the description of the adsorption of surfactants at fluid/fluid and fluid/solid interfaces in porous media associated with the clogging process.

Interfacial dynamic properties and dilational rheology of mixed anionic and cationic Gemini surfactant systems at air–water interface

The interfacial dynamic properties and dilational rheology of sulfonate Gemini surfactant (SGS-12), two bisquaternary ammonium dibromides with different carbon chain lengths (BQAS-12, 16), and two mixed anionic and cationic Gemini surfactant solutions (SGS-12/BQAS-12 and SGS-12/BQAS-16) air–water interface were investigated using the drop shape analysis. Results indicate that the adsorption mechanism of surfactants is diffusion-controlled at dilute concentrations, whereas the adsorption process gradually shifts to a mixed kinetic-diffusion control with increasing the surfactant concentration. The surface tension of the mixtures reaches the minimum value when the molar ratios of SGS-12/BQAS-12 and SGS-12/BQAS-16 mixtures are 6:5 and 8:5, respectively. The effects of oscillating frequency and concentration on the dilational properties were also examined. As the dilational frequency increases, the dilational modulus of these surfactants increases gradually, but the phase angle decreases. The dilational elasticity peaks at a certain concentration, which is less than the critical micelle concentration. Moreover, the effects of SGS-12 concentration on the dilational interfacial rheology of the BQAS-12/SGS-12 and BQAS-16/SGS-12 mixtures were studied. The surface activities of these mixtures show positive correlation with the phase angle. Moreover, the surface film mainly exhibits viscosity as the surface tension reaches the minimum.

Understanding the Stabilization of Single-Walled Carbon Nanotubes and Graphene in Ionic Surfactant Aqueous Solutions: Large-Scale Coarse-Grained Molecular Dynamics Simulation-Assisted DLVO Theory

Understanding the dispersion of single-walled carbon nanotubes (SWCNTs) and graphene in surfactant aqueous solutions is essential for processing of these materials. Herein, we develop the first theoretical framework, which combines large-scale coarse-grained (CG) molecular dynamics (MD) simulations with the Derjaguin–Landau–Verwey–Overbeek (DLVO) theory and Langmuir isotherm, to inform the mechanisms of surfactant adsorption and induced colloidal stability. By carrying out large-scale CG-MD simulations (∼1 million CPU h), we successfully calculated the surface coverage of the widely used ionic surfactant sodium cholate (SC) on different carbon nanomaterials at experimentally realistic SC concentrations. This was accomplished by simultaneously simulating SC micellization and adsorption in one simulation box. Our theoretical framework further allows us to quantify the surface electric potential and the potential energy barrier height that maintains colloidal stability of dispersed SWCNTs or graphene sheets ...

Synergistic effect of ZnO nanoparticles and triblock copolymer surfactant on the dynamic and equilibrium oil-water interfacial tension.

The present study reports the effects of non-ionic surfactant Pluronic F-127 on the equilibrium and dynamic oil-water interfacial tension in the presence of ZnO nanoparticles. The results show that in the presence of nanoparticles, the decrease of interfacial tension is more. The cooperative behavior of F-127 and ZnO nanoparticles especially at low concentrations increases the surfactant efficiency in lowering the interfacial tension. Statistical rate theory (SRT) and mixed diffusion-kinetic controlled model were used for modeling the dynamic interfacial tension data. The modeling results show that the mechanism of surfactant adsorption is controlled with the mixed diffusion-kinetic model. In addition, the influence of the solution pH on the interfacial tension was investigated. Finally, the effects of F-127 on the contact angle in the absence and presence of ZnO was compared.

The adsorption kinetics and thermodynamics of cationic surfactants on graphite oxide

Abstract The adsorption isotherms and structural evolution of alkyl quaternary ammonium bromide (C n TAB) on graphite oxide (GO) were measured by means of an elemental analyzer, X-ray diffraction and Fourier transform infrared spectroscopy. In order to interpret the adsorption mechanism of surfactants onto GO, the adsorption kinetics and thermodynamics were further investigated. It was found that GO is a relatively efficient adsorbent within a wide range of temperatures (297–353 K), and the C n TAB was intercalated and then agglomerated into the interlayer spacing of GO via ionic bonding and hydrophobic bonding. The saturation amount of alkyl ammonium adsorbed on GO was decreased with the rise in temperature, and the experimental data fitted well into the modified Langmuir (Langmuir-Freundlich) equation. In addition, the negative values of ΔG and ΔH showed that the adsorption process of C n TAB onto the GO was spontaneous and exothermic.

Effect of ZnO Nanoparticle and Hexadecyltrimethylammonium Bromide on the Dynamic and Equilibrium Oil–Water Interfacial Tension

The effect of ZnO nanoparticles on the dynamic and equilibrium interfacial tension in the presence and absence of cationic surfactant CTAB was investigated. The results show that nanoparticles solely have no effect on interfacial tension. However, in the presence of CTAB, both particles and surfactants are adsorbed at the interface, and by a synergistic effect decrease the interfacial tension more. The effect of ZnO nanoparticles on the contact angle and stability of emulsions was studied too. The dynamic interfacial tension data were fitted with two different models. The results show that the adsorption mechanism of surfactant from bulk to interface was controlled by the mixed diffusion-kinetic model.

Surfactants in Mechanical Alloying/Milling: A Catch-22 Situation

Mechanical alloying/milling technique is characterized by the repeated welding and fracturing of powder particles in a high-energy ball mill, which often results in excessive cold welding and agglomeration of ductile particles. To achieve the critical balance between cold welding and fracturing, the surface of the deforming particles is modified by introducing a suitable organic material, called surfactant or process control agent (PCA). However, the use of surfactants is self-contradictory by nature and requires further consideration of the milling variables and type/amount of surfactant. The current article provides a practical approach to the promises and challenges associated with surfactants in mechanical alloying/milling. An attempt has been made to address the most crucial aspects correlated with surfactants, including contamination, the morphology and size of powder particles, formation of alloy and microstructural evolution, and powder yield, as well as the physico-mechanical properties, such as magnetism, density, hardness, and compressive strength. An overview is also given on the adsorption mechanism of surfactants onto the surface of powder particles, with a special emphasis on type, amount, and the addition time of surfactants in the mechanical alloying process.

Effect of surfactant types and their concentration on the structural characteristics of nanoclay

A series of organo-modified nanoclays was synthesized using three different surfactants having different alkyl chain lengths and concentrations [0.5–5.0 cation exchange capacity (CEC)]. These surfactants were Ethanolamine (EA), Cetyltrimethylammoniumbromide (CTAB) and Tetraoctadecylammoniumbromide (TO). The obtained modified nanoclays were characterized by X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM) and compared with unmodified nanoclay. The results of XRD analysis indicated that the basal d-spacing has increased with increasing alkyl chain length and surfactant concentration. From the obtained microstructures of these organo-modified nanoclays, the mechanism of surfactant adsorption was proposed. At relatively low loading of surfactant, most of surfactant entered the spacing by an ion-exchange mechanism and is adsorbed onto the interlayer cation sites. When the concentration of the surfactant exceeds the CEC of clay, the surfactant molecules then adhere to the surface adsorbed surfactant. Some surfactants entered the interlayers, whereas the others were attached to the clay surface. When the concentration of surfactant increased further beyond 2.0 CEC, the surfactants might occupy the inter-particle space within the house-of-cards aggregate structure.

One-Pot Shear Synthesis of Gallium, Indium, and Indium–Bismuth Nanofluids: An Experimental and Computational Study

Nanofluids are often proposed as advanced heat transfer fluids. In this work, using a one-step nanoemulsification method, we synthesize gallium, indium, and indium–bismuth nanofluids in poly-alpha-olefin (PAO). The size distributions of the resulting nanoparticles are analyzed using transmission electron microscopy (TEM). X-ray diffraction (XRD) analysis of the alloy nanoparticles indicates that their composition is the same as that of the bulk alloy. It was found that oleylamine stabilizes both gallium and indium particles in PAO, while oleic acid is effective for gallium particles only. The microscopic adsorption mechanism of surfactants on gallium and indium surfaces is investigated using density functional theory (DFT) to understand why oleylamine is effective for both metals while oleic acid is effective for gallium only.