Surfactant Solutions Research Articles

Study on the effect of electrolyte on surface tension of surfactant solution and wettability of coal dust

It is valuable to study the effect of electrolytes on the surface tension and wettability of surfactant solutions for industrial production. Surface tension test, coal dust sink test, and molecular dynamics simulation are employed to investigate the influence of four electrolytes (NaCl, NaAc, Na2CO3, MgCl2) on nonionic surfactant AEO-9 and anionic surfactant SDBS. The study showed that AEO-9 had a more extraordinary ability to reduce surface tension when the surfactant was applied alone. The surface tension achieved by SDBS solution was lower when compounded with electrolytes. The influence degree of electrolytes on the surface tension of SDBS solutions was shown as MgCl2>NaCl≈Na2CO3>NaAc. In contrast, the influence on the surface tension of AEO-9 solutions was insignificant. In addition, adding electrolytes to the low-concentration surfactant solution can markedly reduce the surface tension. When selecting the electrolytes compounded with anionic surfactants, the electrolyte cation is recommended to choose elements with a larger main groups number in the same periodic element from the periodic table and electrolyte anions that can form more hydrogen bonds with water molecules. The results of the coal dust sink test are different from the results of the surface tension measurement. Regardless of whether the electrolyte is added, the sink time of coal dust in the AEO-9 solution is shorter than that in the SDBS solution, and the wettability is better at the same concentration. The results of this study may guide the selection and design of dust suppression solutions.

Treatment methodology for sludge and scale TENORM waste from petroleum industry in Egypt

In this present laboratory work, experiments have been steered to decrease the activity concentration of 226Ra in sludge and scale (TENORM) which Technically Enhanced Naturally Occurring Radioactive Materials waste samples deposited in oilfield tubes and tools, sludge and scale, Egypt, respectively. The influence of the leaching parameters on the radium dissolution mechanism using nonionic surfactant tween 20 as a leaching agent has been determined. The greatest leaching percent of radium isotopes approximated 58.31 % of the total radium percentage in bulk sludge TENORM waste sample (size < 2.5 mm) using tween 20 as surfactant solutions through three successive cycles at the optimum conditions. The greatest leaching percent of radium isotopes was 77.98 and 86.12 % of the total radium percentage in scale TENORM waste samples from two different places, the first place is the western desert area and the second place is Ras Shukeir area, respectively, (size < 1 mm) using tween 20 solutions through four successive cycles at the optimum conditions. The kinetic calculations indicated that the leaching procedure can be explained by the Shrinking Core Model with activation energy equivalent to 18.18 kJ/mol. The low value of activation energy illustrated that the diffusion process controls the sludge TENORM waste sample leaching rate. The estimated values of thermodynamics parameters (ΔG°, ΔH°, ΔS°) were appointed in this study and showed the dissolution of radium is a non-spontaneous response and temperature dependent.

Experimental studies on self-propulsion of deformable 5CB liquid crystal droplets in micellar solution

ABSTRACT The 5CB liquid crystal droplets were found to self-propel when suspended in a micellar solution of surfactant. We report experimental studies on the motion of these droplets in a quasi-two-dimensional geometry. The droplets exhibit directed, self-avoiding, or random coiling trajectories depending on the size of the droplets compared to the height of the sample cell. The flattened droplets showed smoother trajectories and with self-crossing. Interestingly, the large flattened droplets were found to exhibit deformation of their apparent cross-section during their self-propulsive motion. These unique properties of self-propulsion of 5CB liquid crystal droplets in surfactant solution can provide a new opportunity to study active biomimetic systems.

Microbubbles: Revolutionizing Biomedical Applications with Tailored Therapeutic Precision.

Over the past ten years, tremendous progress has been made in microbubble-based research for a variety of biological applications. Microbubbles emerged as a compelling and dynamic tool in modern drug delivery systems. They are employed to deliver drugs or genes to targeted regions of interest, and then ultrasound is used to burst the microbubbles, causing site-specific delivery of the bioactive materials. The objective of this article is to review the microbubble compositions and physiochemical characteristics in relation to the development of innovative biomedical applications, with a focus on molecular imaging and targeted drug/gene delivery. The microbubbles are prepared by using various methods, which include cross-linking polymerization, emulsion solvent evaporation, atomization, and reconstitution. In cross-linking polymerization, a fine foam of the polymer is formed, which serves as a bubble coating agent and colloidal stabilizer, resulting from the vigorous stirring of a polymeric solution. In the case of emulsion solvent evaporation, there are two solutions utilized in the production of microbubbles. In atomization and reconstitution, porous spheres are created by atomising a surfactant solution into a hot gas. They are encapsulated in primary modifier gas. After the addition of the second gas or gas osmotic agent, the package is placed into a vial and sealed after reconstituting with sterile saline solution. Microbubble-based drug delivery is an innovative approach in the field of drug delivery that utilizes microbubbles, which are tiny gas-filled bubbles, act as carriers for therapeutic agents. These microbubbles can be loaded with drugs, imaging agents, or genes and then guided to specific target sites. The potential utility of microbubbles in biomedical applications is continually growing as novel formulations and methods. The versatility of microbubbles allows for customization, tailoring the delivery system to various medical applications, including cancer therapy, cardiovascular treatments, and gene therapy.

The effect of corrosion inhibitor chemistry on rheology and stability of CO2 and N2 acidic foam under harsh conditions

Utilization of CO2 foam in well-stimulation operations is a realistic practice to reduce carbon emissions by injecting CO2 into subsurface formations. The viscosity and stability of CO2 and N2 acidic foamed fluid is impacted by additives such as corrosion inhibitor and chelating agent and conditions such as pressure. In this study, the apparent foam viscosity was determined using a high pressure - high temperature foam rheometer at a temperature of 150 °C, pressure ranging from 1000–4000 psi, and different shear rates 100-2000 1/s. A foam analyzer was furthermore utilized to characterize foam properties such as foamability, foam stability, and bubble structures at 100 °C and 1000 psi. Different surfactants were used due to their ability to generate stable and viscous foam; Duomeen TTM, Ethoduomeen T13, Armovis VES, and the combination of Duomeen TTM and Armovis VES. Among all surfactants, Duomeen TTM provided the highest foam viscosity with CO2 at both low and high shear rate. Once the surfactant solution was mixed with 1.5 wt% of CI, the foam viscosity dropped sharply. However, the synergic surfactants (i.e., Duomeen TTM and Armovis VES) obtained the highest viscosity once mixed with CI. Also, the effect of CO2 and N2 at different pressures on the viscosity of generated foam was investigated. When the CO2 pressure was raised to 2000 psi, the viscosity of CO2 foam increased by 55% at both low and high shear. In comparison, the N2 foam viscosity increased by 12% at 100 1/s shear rate and by 32% at 1500 1/s. According to the findings, the influence of CI increased as the pH of the foam fluid declined, and thus reduced the foam viscosity. Finally, foam properties such as foamability, foam stability, and bubble structure were determined. N2 foam generated higher foam stability than CO2 foam. The findings of this study can help for a better understanding of the effect of corrosion inhibitor on CO2 and N2 foam viscosity at high temperature and pressure.

Emergent properties of magnetic ions and nanoparticles in micellar solutions of surfactants: Use in fine technologies

Objectives. To establish expected emergent (unexpected) properties of magnetic materials when obtained in aqueous micellar solutions of surfactants (aqueous quantum materials), and their use in fine technologies.Methods. Chemical synthesis of magnetic nanoparticles in aqueous micellar solutions of surfactants of various nature. Characterization of magnetic solutions and nanoparticles by magnetic measurements, spectroscopy, diffractometry, small-angle X-ray diffraction, scanning probe microscopy, and others.Results. The term “water quantum material” refers to materials (micellar solutions) whose properties are mainly determined by the nuclear quantum effect on macroscopic scales (emergent property). Micellar solutions exhibit phenomena and functionality not always consistent with the classical theory of micellization. The article presents in detail the experimental results that suggest the manifestation of the emergent properties of magnetic materials obtained in aqueous micellar solutions of surfactants. In particular, Gd3+ ions in an aqueous micellar solution of sodium dodecyl sulfate exhibit paramagnetic properties, possibly indicating their random arrangement in solution contrary to the classical theory of micellization with an ordered adsorption layer on micelles. Hybrid Pt–Gd nanoparticles are formed in a quantum material with cetylpyridinium chloride as a matrix, although Gd3+ ions must be repelled by CP+ ions on micelles. Nanosized powders of cobalt ferrite and nickel ferrite obtained in a micellar solution of sodium dodecyl sulfate have superparamagnetic properties, although the presence of their precursor ions in the adsorption layer in classical micelles should lead to ferromagnetic properties.Conclusions. The synthesis of nanoparticles in a quantum material opens up the possibility of reducing ions of different signs in one stage during the processing of metallurgy waste, in order to obtain nanoparticles of various metals and their composites. Magnetic nanoparticles obtained in a quantum surfactant material self-assemble on various substrates, enabling the creation of materials whose residual magnetization and coercive field can be controlled at room temperatures.

Experimental investigation on the effect of nanoparticles on surfactant flooding performance in resin-based 3D printed porous media

Adding nanoparticles (NPs) into surfactant solutions represents a promising strategy for enhancing oil displacement in porous media, with significant implications for various engineering and environmental applications, including soil remediation and enhanced oil recovery from underground reservoirs. Recent investigations have focused on the integration of silica and alumina NPs into anionic surfactant solutions to mitigate interfacial tension (IFT) and reduce the contact angle between the surfactant and oil phases. However, the utilization of these injection scenarios in fractured porous media has received limited attention. In this experimental study, we employed a 3D printer to design and fabricate three distinct porous media types: single permeability (S), fractured (F), and dual permeability (D). Subsequently, we prepared the sodium dodecyl sulfate (SDS) solution by adding SDS powder into a brine solution containing 2% NaCl. Nanofluids were then produced through the dispersion of SiO2 and Al2O3 NPs in the SDS solution using a sonicator. The prepared solutions were subsequently injected into each porous medium, while the recovery process was recorded using a camera. Recovery rates for each scenario were calculated utilizing a developed Python image processing code. Furthermore, analysis of the images enabled us to demonstrate the behavior and growth of the displacing phase’s fingers within the oil phase. Findings from this study showed that SDS injection into the S medium resulted in an approximate 60% oil recovery. Adding silica and alumina NPs into the SDS solution led to enhanced total recovery rates of up to 70% and 78%, respectively. The recovery results obtained from tests conducted within the F medium exhibited a pronounced decrease, with the SDS solution sweeping a mere 25% of the medium, while the silica and alumina nanofluids recovered 43% and 47%, of the oil respectively. Notably, the silica nanofluid displayed superior performance to the alumina nanofluid during the breakthrough stage in the F medium. In the D medium, the injection of SDS, silica, and alumina nanofluids achieved total recovery rates of 49%, 53%, and 56%, respectively. These outcomes highlight the diminished effectiveness of nanofluids within the dual permeable medium.

Solubilization of Carbon Nanobelts in Aqueous Solutions: Optical and Colloidal Properties.

Carbon nanobelts (CNBs) correspond to carbon nanotube (CNT) segments and are insoluble in most common aqueous solutions, posing challenges across diverse applications. In this study, [12] CNB, which corresponds to a (6,6) CNT segment, was solubilized by aliphatic surfactant micelles through host-guest complexation, which was confirmed by comprehensive analyses involving spectrophotometry, mass spectrometry, and molecular dynamics simulations. Through this solubilization, zero-Stokes shift emission of the CNB could occur, which could be ascribed to the symmetry-allowed transition. In contrast, CNB was insoluble in non-aliphatic surfactant solutions. The mechanism by which CNB is solubilized using aliphatic surfactants is completely distinct from that of the CNT dispersion mechanism. The present finding provides knowledge of the effectiveness of aliphatic compounds in solubilizing CNBs and their derivatives (carbon nanohoops), which show significant potential for various applications in aqueous systems, including biological applications.

EXPRESS METHOD FOR CHEMICAL REAGENTS SELECTION FOR INCREASING OIL RECOVERY OF LOW-PERMEABILITY RESERVOIRS

The choice of hard-to-recover reservoir (HRR) engineering technologies is one of the actual problems facing oil companies in the Russian Federation and the World. In order to increase the efficiency of the development of such fields various methods for production intensification are used to obtain an economically profitable industrial oil inflow. It is possible to use surfactant flooding to solve this problem. The surfactant efficacy results from the fact that aqueous surfactants solutions even at low concentrations dramatically decrease the oil/water/rock interfacial tension that results to changing wettability, allowing to increase the oil inflow.The purpose of this work is to study an alternative method of testing the effect of surfactant solutions on oil recovery. The method consists in mass testing using a laboratory petrophysical centrifuge to identify the most promising solutions, followed by the classical filtration method. The method of centrifugation is based on the substitution of one fluid in the pores of the core sample by another, occurring at a pressure difference at the boundary of the two phases under the action of centrifugal force. The suggested method will allow massively and in a short time to identify the most effective solutions for specific geological conditions.To carry out this work, three surfactant solutions were selected that were tested for resistance to mineral aggression and temperature, surface tensions and phase behaviors were determined. The object of the study was the core material of the formations of the AS, BS and YuS groups of one of the deposits of Western Siberia. Two series of experiments were carried out: classical filtration tests and centrifugation of core samples under conditions of initial and residual oil saturation.The results of the experiments have shown the effectiveness and prospects of using the centrifugation method for mass testing of surfactant solutions as displacing agents. The described method is express and cannot completely replace the classical filtration experiment due to non-compliance with an important criterion – the thermobaric conditions of the reservoir.

Complete biodegradability assessment of polyoxyethylene glycerol ester non-ionic surfactant: Aerobic, anaerobic, combined biodegradation and inhibitory effects

Aerobic and anaerobic biodegradability have become one of the most relevant characteristics for all contaminants. This is especially important in case of surfactants, which are discharged in wastewater treatment plants or directly into the aquatic bodies. The aim of this study is the integral assessment of the biodegradability of the non-ionic surfactant polyoxyethylene glycerol ester PGE-OE17. The aerobic and anaerobic biodegradation of PGE-OE17 was evaluated at different initial surfactant concentrations, and the evolution of the toxicity of the surfactant and its by-products was followed during the aerobic and anaerobic processes using bacteria Vibrio fischeri. PGE-OE17 was not completely biodegradable neither aerobically nor anaerobically, and the increase in the initial surfactant concentration had a negative effect in the biodegradation. Toxicity of the surfactant solutions and degradation by-products had a first increase followed by a gradual decrease during both tests, revealing that toxic substances released can harm the microorganisms and therefore hinder the biodegradation. Additionally, combined aerobic-anaerobic biodegradation tests were performed, consisting in a first aerobic treatment of different duration and initial concentration, followed by a complete anaerobic treatment. Results showed that a balance between aerobic and anaerobic biodegradation duration can maximize the biodegradation rates in comparison with only aerobic or anaerobic tests.

Unraveling the surface activity and micellization characteristics of linear alkyl benzene sulfonate in aqueous solution

Abstract The aggregation behavior of various neutralizing agents (monovalent and diamine bases) has been investigated for linear alkylbenzene sulfonate. Measurements employing conductivity at temperature (298.15 K, 303.15 K, 308.15 K, and 313.15 K) and surface tension at 298.15 K have been determined to study micellization and surface active properties. The conductivity versus concentration plot elucidated CMC and dissociation of counterion (α). Additionally, surface active parameters ϒCMC, A min, π CMC, and τ max were investigated via tensiometry using the Wilhelmy plate procedure. The wettability characteristic of the surfactant solution was determined using contact angle analysis. Furthermore, the particle size parameters were determined using DLS measurements. The Gemini salts of LABS portrayed improved efficiency and demonstrated economical in domestic and industrial applications.

Removal of microplastics and refractory humic/fulvic – like components from landfill leachate using Coagulative Colloidal Gas Aphrons: Insights on dissolved organic matter fingerprints

Microplastics (<5 mm) are one of the most persistent and emerging pollutants found ubiquitously in the natural environment. Still, identifying the source of these pollutants is lacking. Landfill leachates are known to be a major pathway to transmit them in the environment. Yet, removing these microplastics from leachate is being another challenging task. This research work investigates the removal of microplastics, metal ions and refractory organic pollutants from landfill leachate using a unique technique known as coagulative colloidal gas aphrons (CCGA). The target microplastics chosen for this study are polyethylene terephthalate (PET), polystyrene (PST), polypropylene (PPL) and polyethylene (PEL) microplastics. The property of metastable with superior stability of CCGA was confined by various parameters such as surfactant solution, Fe (III) dosages, microplastic quantities, zeta potential, kinetics and size of microbubble. The excitation – emission matrix results help to understand the occurrence and removal of refractory humic, fulvic and tryptophan components. The removal efficiency of COD and DOC was found to be 86 and 84%, respectively. Here we show that the electrostatic attraction plays a significant role in removing microplastics and coagulation mechanism such as bridging, adsorption and sweeping performs a major role in treating ion concentration present in the leachate solution.

Colloid-chemical properties of surfactant–nitric acid–water systems

The behavior of the surfactants Tween 80, SaS and alkyl betaine in aqueous and nitric acid environments as promising additives for nitrate leaching of hard-to-process ore concentrates of non-ferrous metals was studied. The influence of surfactant concentration (0.04–1.28 g/dm3), nitric acid concentration (0.1–10 g/dm3) and temperature (295–343 K) on the surface tension, critical micelle concentration (CMC), pH and optical density of aqueous surfactant solutions and surfactant–HNO3–H2O systems was found. The critical micelle concentration of the surfactants used was estimated. A positive effect of nitric acid on the surface activity of surfactants was discovered, which manifests itself in a decrease in both the CMC and the surface tension at the liquid–gas interface. The values of surface activity and Gibbs energy of surfactant micelle formation in aqueous and nitric acid media were calculated. Associative processes in the solutions and compositions were confirmed by measuring the optical density of the systems under study.

Design of novel aqueous two-phase systems to be coupled in biological remediation processes

The ability of a biodegradable Deep Eutectic Solvent (DES) reline to induce phase segregation in aqueous solutions of polymeric non-ionic surfactants (Tween 20 and Tween 80) has been demonstrated as a preliminary step to be employed for assisting a biological degradation process of a model contaminant. The binodal curves for systems composed of (surfactants + reline + Water) have been determined at several temperatures, and the experimental data have been correlated using well-known equations. The equilibrium data have been analysed in the light of the operating temperature and the hydrophobicity of surfactants. Tie-lines of these systems have been determined, together with useful parameters such as tie-line length and tie-line slopes. Othmer-Tobias and Bancroft equations have been applied to provide an adequate description of the equilibrium data. Finally, the application of this new approach for the remediation of aqueous polluted effluent has proven to be highly efficient, with extraction percentages exceeding 99% for two model persistent contaminants (Acid Black 48 and Crystal Violet). Consequently, this ATPS is proposed as an extra-stage to enhance the remediation percentages achieved through biological methods. Furthermore, the process has been simulated using commercial software.

Research on imbibition effect of surfactant fracturing fluid in offshore reservoirs with low permeability and high temperature

Surfactant imbibition can effectively improve the development effect of fracturing technique. In order to enhance oil recovery, a temperature resistant surfactant was selected using interfacial tension and contact angle testers based on the offshore reservoir conditions of high temperature and low permeability. Experiments on spontaneous and forced imbibition with artificial columnar cores were performed to optimize parameters of imbibition processes during fracturing in high temperature and low permeability reservoirs. Results show that among the three surfactants, amphoteric Gemini surfactant had a stable molecular structure with non-compressible hydrophobic groups which significantly reduced oil-water interfacial tension, enhanced rock wettability, and demonstrated good resistance to high temperatures The maximum recovery increase during amphoteric Gemini surfactant imbibition is 16.22%. The higher the core permeability, the higher the core inside pressure, and the longer the well shut-in time, the greater the forced imbibition effect. A proper well shut-in time and injection volume should be considered when using surfactant solution as fracturing liquid.

Study Evaluates CO2 Storage Potential During CO2 Mobility-Control Optimization

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 212969, “Evaluation of CO2 Storage Potential During CO2 Mobility-Control Optimization for Enhanced Oil Recovery,” by Alvinda Sri Hanamertani, SPE, Ying Yu, SPE, and Omar El-Khatib, SPE, University of Wyoming, et al. The paper has not been peer reviewed. _ CO2 mobility control through foam technology has enabled better sweep efficiency and, consequently, better oil productivity during enhanced oil recovery (EOR) processes. Along with enhancing oil production, a sound potential exists for in-situ generated foam to enhance CO2 storage. However, the effect of the different in-situ foam generation strategies on the combined goal of maximum oil production and carbon storage is not well elucidated in the literature. In the complete paper, the authors methodically evaluate the simultaneous optimization of CO2 storage and oil recovery using multiple injection strategies. Introduction The current investigation is a continuation of two previous studies that provided a methodology for screening and using foaming agents for optimized CO2 storage in sandstone and carbonate formations. A base case of tertiary CO2 flooding was established for comparison with in-situ foam generation by two approaches: single-cycle surfactant-alternating-gas (SAG) flooding and coinjection of CO2 and surfactant. Additionally, the effect of surfactant concentration on foam efficiency, CO2 storage capacity, and oil recovery were evaluated in both approaches at reservoir conditions. Materials and Methods Fluids and Porous Medium. In this study, a synthetic brine with total dissolved solids of 20 wt% was used as blank brine and laden with a commercial zwitterionic surfactant that was used to prepare surfactant solutions with concentrations of 0.5 and 1 wt% active matter in the synthetic brine. Three core plugs were drilled from an Indiana limestone outcrop block. The cores were then cleaned and oven-dried at 95°C. Experimental Procedure. Vacuum saturation with brine was commenced for the three cores. The porosity of the cores was calculated using their dry and brine-saturated weights. Then, the 100% brine-saturated core was placed in a core holder and loaded into an oven set to 90°C. The pore pressure was fixed at 2,000 psi, and the confining pressure was controlled at 3,000 psi throughout the flooding experiment. The brine permeability of the core samples was evaluated by measuring the pressure drop across the core at different brine-injection flow rates. In the first experiment (IL1), oil drainage with a flow rate of 0.2 cm3/min was performed to establish irreducible water saturation of 46.9%. This total flow rate was kept the same throughout the three experiments. Then, a waterflooding stage was begun and the oil recovery was recorded. After reaching a plateau in oil recovery, supercritical CO2 (scCO2) was injected during the EOR process until the oil production plateaued.

Evaluation of Foaming Chemical Composition and Performance of Commonly Used Detergents

The foaming chemical composition of commonly used detergents mainly includes surfactants, auxiliaries and solvents. Surfactants are the most important components in detergents. Surfactants reduce the surface tension of water, allowing it to better contact dirt and provide a cleansing effect. This paper focuses on two commonly used detergents, alpha olefin sulfonate (AOS) and sodium dodecylbenzene sulfonate (SDS). Then the foaming properties and half-life of these two surfactant solutions at different concentrations were investigated. The results show that AOS has the best foaming property and the longest half-life at 0.7%, while SDS has the best foaming property at 0.3%. The solutions with the best foaming concentration ratios were added with sodium chloride and calcium chloride respectively. And the salt resistance of these two solutions was found to be good. Secondly, the temperature resistance of AOS and SDS decreases with increasing temperature. In addition, the two surfactants showed structured, regular and stable foams under optical microscope study.

High‐pressure high‐temperature fluid displacement by foam injection within a multiblock matrix‐fracture system

AbstractFoam injection has been suggested and demonstrated as a potential gas‐based solution for enhancing oil recovery from underground reservoirs. While the pore‐scale behavior of foam has been investigated for many years, most of those studies were done at room temperature and pressure. A high‐pressure high‐temperature (HPHT) cell was constructed to relax this contributing simplification and evaluate foam behavior under reservoir conditions. The performance of foam injection into a fractured reservoir was investigated experimentally at vertical and horizontal pathways utilizing a 2D microfluidic device. The results showed foam had a higher lamellae density in the fracture network and could direct fluids to the matrix. This was mainly attributed to the created pressure drop in the fractured media dictated by foam self‐tuning ability, which is a higher viscosity in areas with higher conductivity. Generating a viscous crossflow in horizontal tests leads to enhanced recovery relative to gas injection. But the presence of gravity in the vertical tests causes the drainage of the foam film and the segregation of the gas and surfactant solution due to gravity, which ultimately reduces the stability of the foam. Comparing the performance of gas and foam in the vertical injection scenario reveals that foam injection results in a considerably more enhanced oil recovery. The oleic phase had a detrimental impact on foam strength and reduced fluids diversion from fracture to matrix. The sizes of gas bubbles were also larger in the presence of the oleic phase.

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.

Agglomeration effect of nanoparticles on foam stability of nonionic surface-active liquid: experimental and density functional theory studies

Innovative applications of foam are the need of time which fundamentally depends on the stability of the foam. In the present research work, the static foam behavior of the nonionic surfactant Tween-20 in the presence and absence of Titanium dioxide nanoparticles (TiO2-NPs) was investigated. The role of TiO2-NPs on foaming power based on foam height and foamability was studied at different temperatures. At 29 ± 1 0C, maximum foam height for Tween 20 (5% surfactant solution in distilled water) without and with TiO2-NPs was increased from 45.60 to 60.30 cm exhibiting 32.25% increase. In view of studying foam stability, axial dye displacement rate (ADDR) test was performed without and with nanoparticles where TiO2-NPs resist liquid drainage. TiO2 -NPs and Tween-20 form intermolecular hydrogen bonding which helps to enhance the foam stability as revealed by the density functional theory (DFT) studies. However, TiO2 -NPs have tendency to agglomerate if zeta potential value is low that severely affect the foaming power and foamability.