Solubilization Parameters Research Articles

An in-depth investigation of the impact of salt nature on the formulation of microemulsion systems

Electrolytes have a wide range of technological applications. Despite the recent improvements in characterizing and predicting the phase behavior of microemulsion systems by hydrophilic-lipophilic deviation (HLD) and net-average curvature (NAC) frameworks, they are ineffective in the presence of different salts. This work seeks to bridge this gap by investigating the influence of salt nature on the microemulsion phase formulation. First, a one-dimensional salinity scan on different microemulsion systems consisting of sodium dodecyl benzene sulfonate as a surfactant, hexane as an oil and, several brines was carried out, and the effect of each salt on the phase behavior were precisely evaluated. The results for optimum salinity and solubilization parameter of different salts were consistent with the Hofmeister series. In addition, multiple linear regression model is presented to accurately predicting the optimum salinity of different salts using this research data and all the available experimental data. The results revealed that the values estimated by this model is in significant consistency with the experimental data by correlation coefficient of 0.92. Finally, the effect of salt type on the NAC parameters (length parameter, and characteristic length) were evaluated to improve the predicting ability of this equation of state in the presence of various salts. We found that salt nature has a significant impact on both these parameters. It was found that the length parameter is linearly dependent on the optimum ionic strength of salts while the salting-out capacity of each salt was predominant factor affecting the characteristic length.

Sustainable Phenylalanine-Derived SAILs for Solubilization of Polycyclic Aromatic Hydrocarbons.

The solubilization capacity of a series of sustainable phenylalanine-derived surface-active ionic liquids (SAILs) was evaluated towards polycyclic aromatic hydrocarbons-naphthalene, anthracene and pyrene. The key physico-chemical parameters of the studied systems (critical micelle concentration, spectral properties, solubilization parameters) were determined, analyzed and compared with conventional cationic surfactant, CTABr. For all studied PAH solubilization capacity increases with extension of alkyl chain length of PyPheOCn SAILs reaching the values comparable to CTABr for SAILs with n = 10-12. A remarkable advantage of the phenylalanine-derived SAILs PyPheOCn and PyPheNHCn is a possibility to cleave enzymatically ester and/or amide bonds under mild conditions, to separate polycyclic aromatic hydrocarbons in situ. A series of immobilized enzymes was tested to determine the most suitable candidates for tunable decomposition of SAILs. The decomposition pathway could be adjusted depending on the choice of the enzyme system, reaction conditions, and selection of SAILs type. The evaluated systems can provide selective cleavage of the ester and amide bond and help to choose the optimal decomposition method of SAILs for enzymatic recycling of SAILs transformation products or as a pretreatment towards biological mineralization. The concept of a possible practical application of studied systems for PAHs solubilization/separation was also discussed focusing on sustainability and a green chemistry approach.

Phosphatase activity of Phosphate Solubilizing Fungi Isolation from Rhizosphere Soil of Medicinal Plants of Shivamogga District

Phosphatases are a group of enzymes which significantly accelerate the release of inorganic phosphate from organically bound phosphate and return to the soil by phosphate solubilizing fungi. Hence for the present study, we focused on the activity of phosphatase. Total 46 fungi were isolated from 55 rhizosphere soils of medicinal plants at Malnad regions of Shivamogga district. Among them, 10 isolates were selected by screening them using their solubilization index ranging from 3.02 to 3.96 and they were further evaluated. The selected 10 isolates showed good results in phosphate solubilization parameters. Decreased pH was observed in culture broth (4.3 to 3.0) from initial pH of 6.89. Amount of acid present in the culture broth (30.01 - 38.08g/L) and concentration of phosphate (70 - 20μg/ml) were recorded. The phosphatases activity was determined on 7th, 14th, 21st and 28th days after incubation at room temperature. Among them, PSF 44 (Aspergillus awamori) showed maximum alkaline phosphatase activity of 0.81, 1.53, 2.15 and 2.38μg PNP liberated/ml/min and acid phosphatases activity of 0.71, 1.34, 2.30 and 2.34μg PNP liberated/ml/min on 7th, 14th, 21st and 28th day respectively after incubation. Hence due to the maximum phosphatase activity and phosphate solubilization capacity of Aspergillus awamori, they can be recommended as phospho-fungal bioinoculum for agricultural field.

A New Thermal Stable and Salt Tolerant Alkyl Polyether Benzyl Sulfonate Surfactant with Ultralow Interfacial Tensions for Enhanced Oil Recovery

A large variety of surfactants have been widely used in enhanced oil recovery, yet there is still a challenge for the application of surfactants in oil reservoirs with high salinity and high temperatures. Herein we report a new alkyl polyether benzyl sulfonate anionic surfactant named sodium iso-tridecanol polyoxyethylene ether benzyl sulfonate with ultralow interfacial tensions at high salinity and high temperatures synthesized through a strategy connecting the alkyl polyether with a benzyl group. Its structure was confirmed by 1H NMR. Effects of the temperature, salinity, divalent ion, and surfactant concentration on interfacial tensions and phase behaviors were investigated. The alkyl polyether benzyl sulfonate surfactant demonstrated a strong interfacial activity and excellent phase behavior with high solubilization parameters at salinities up to 18.0 wt % NaCl and temperatures up to 120 °C, which suggest that the new alkyl polyether benzyl sulfonate surfactant has good temperature resistance and salt tolerance and is promising for applications in enhanced oil recovery in high temperature and high salinity oil reservoirs.

Interaction of Victoria Blue Dye in Anionic and Cationic Micellar Media: Spectroscopic Study

This manuscript has reported the micellar interaction of cationic triphenylmethane-based dye andquot;Victoria Blue-B (VBB)andquot;. The study was conducted using ionic surfactants viz. Cetyltrimethylammonium Bromide (CTAB)] Sodium Dodecyl Sulphate (SDS), and Sodium Docusate (SD). The behavior of dye in micellar media at concentration ranges of the surfactants mentioned above was monitored by UV-vis absorption spectroscopic study. The solubilization parameters to reveal the interaction of cationic dye in micellar media were assessed. The mathematical calculations of partition constant (Kc), partition coefficient (Kx), binding coefficient (Kb), Gibb’s free energy for partition (ΔGp) and binding (ΔGb) were derived from UV–Vis absorption data. The presence of anionic surfactants caused more bathochromic shifts in the maximum absorption of the dye, which was indicative of strong interactions as compared to the cationic surfactant.

Screening and Isolation of Plant Growth Promoting, Halotolerant Endophytic Bacteria from Mangrove Plant Avicennia officinalis L. at Coastal Region of Corangi Andhra Pradesh

Background: Main objective of this study is to isolate and characterize halo tolerant plant growth promoting endophytic bacteria from leaves and pneumatophores of mangrove plant Avicennia officinalis L. Isolates were also screened for their ability to provide resistance to extreme salt tolerance and temperatures and to produce exo enzymatic activity like catalase, amylase, protease, phosphate solubilization and plant growth promoting hormone (Indole 3-acetic acid). Methods: The present study was carried out during 2020-21 to 2021-22 at field and laboratory level. Eleven endophytic bacterial isolates were obtained from mangrove Avicennia officinalis L. grown at coastal region of Corangi Wildlife Sanctuary, East Godavari. All Isolates were enumerated, purified and preserved for further studies. Result: Out of eleven isolates obtained bacteria “AOL2” isolated from leaves of Avicennia officinalis L. was found promising in production of exo enzymes, Indole 3-acetic acid (IAA) and phosphate solubilization parameters. Isolate AOL2 was a Gram’s negative, motile, moderately halophilic, rod shaped diplobacilli which grows optimally at 32°C, pH 8.3 and had a salt tolerance of 10% NaCl. Microbial identification was carried out by morphological, biochemical and by 16S rRNA sequence. Based on nucleotide homology and phylogenetic analysis isolate AOL2 showed high degree of resemblance with Salinicola salarius. On the basis of the experimental findings, strain Salinicola salarius AOL2 had a capability in producing plant growth promoting substances, exo enzymes, phosphate solubilization ability and was first reported in endophytic bacteria isolated from Avicennia officinalis L. that can be studied further.

Loading of hydrophobic drug silymarin in pluronic and reverse pluronic mixed micelles

In the presented work, pure pluronic and mixed micelles of normal pluronics (F108, F127, P85 and P84) with reverse pluronic (10R5) have been studied to enhance the solubilization of the hydrophobic drug silymarin (SLY) at different % w/v proportions (4:1, 2.5, 1:4 and 5). Solubilization capacity of SLY in the mixed micelles was found to be higher than pure pluronic micelles. Drug solubilization parameters including drug loading efficiency (DL), partition coefficient (P) and Gibbs free energy of solubilization (ΔG◦) were calculated. SLY loaded mixed micellar formulation of P84:10R5 (4:1% w/v) showed maximum solubility and drug loading efficiency as compared to other mixed micellar formulations. The cmc of pure as well as mixed micellar systems has been evaluated using fluorescence measurements. The locus of SLY in these micelles was evaluated by micropolarity measurements. After solubilization, increase in hydrodynamic size evidenced by DLS measurements confirmed the solubilization of SLY in the mixed micelles. In vitro drug release study was also performed for mixed micellar formulations with maximum SLY solubilization, and it was found to exhibit sustained release drug behavior. Different kinetics models were also applied and the best fitted model for the optimum SLY loaded mixed micellar formulation was found to be the Korsmeyer-Peppas model. To investigate the anti-oxidative potential of SLY drug and SLY loaded mixed micellar formulation of P84:10R5 (4:1% w/v),1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH·) scavenging, ferrous ions (Fe2+) chelating activities, total reducing ability determination by Fe3+ to Fe2+ transformation method, 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging and nitric oxide assay were undertaken. The SLY loaded mixed micellar formulation of P84:10R5 (4:1% w/v) exhibited appreciably enhanced anti-oxidative activity as compared to SLY alone.

Evaluation of surfactant blends for enhanced oil recovery through activity maps

Better use of already exploited oil reservoirs using Enhanced Oil Recovery techniques is becoming essential. The use of surfactant blends is a common approach when individual surfactants are not effective. However, defining the optimum conditions for application becomes very challenging due to the number of variables involved in specific cases. In this work, blends of dioctyl sulfosuccinate sodium salt with Akypo LF2 and two surfactant ionic liquids (1-decyl-3-methylimidazolium chloride and 1-dodecyl-3-methylimidazolium bromide) were evaluated for oil recovery. Activity maps, representations of the phase behavior of the surfactants as a function of blend ratio, salinity and temperature, were found to be useful tools to describe conditions leading to Winsor type III systems. Among the blends studied, mixtures with Akypo LF2 were found of interest for application at low temperatures, showing interfacial tensions close to 0.01 mN/m in a wide range of salinity concentrations. In the case of blends with ionic liquids, even though they led to more promising solubilization parameters, the high sensitivity of these mixtures to blend ratio changes discourages, in principle, their use for practical applications.

Facile synthesis of Fe3O4/Sio2/Cu nanoparticles: investigation of physicochemical attributes of interaction in cationic micellar media and photo-antibacterial impact

Solubilization of core-shell magnetic nanoparticles has gained new popularity as a versatile partitioning method with the recent growth in nanotechnology and related biotechnology applications. In this sense, Fe3O4/SiO2/Cu nanoparticles (NPs) were designed and characterized by various techniques such as Ultra-violet visible (UV-vis), Fourier transforms infrared (FTIR), X-ray diffractometry (XRD), scanning and transmission electron microscopy (SEM & TEM), energy dispersive X-ray (EDX) and thermogravimetric (TGA) analyses. The size determined by TEM analysis of Fe3O4/SiO2/Cu NPs was found in the range of 24 nm. The diffractometer results verified the impurity-free synthesis of the desired nanoparticles. Micellar solubilization and thermodynamics of micellization were determined correspondingly using a UV-Vis spectrophotometer and conductometer. The thermodynamics of micellization in terms of enthalpy, entropy and standard Gibb’s free energy was determined using electrical conductometry. The solubilization parameters viz. partition constant (Kc), binding constant (Kb), partition coefficient (Kx), and the corresponding Gibb’s free energies were estimated from the absorption spectroscopic analysis. The experimental outcomes and their computation revealed the rise in the critical micelle concentration of CTAB due to the incorporation of the nanoparticles with the micelles. Moreover, the photo-antibacterial activity of the nanoparticles in the bacteria culture environment showed effectiveness in comparison to the control group.

Study of sodium electrolytes on phase behavior of the anionic surfactant/alcohol/model oil system and its application for alkaline-surfactant flooding formulation design

In this study, the phase behavior of several anionic surfactants, i.e., one internal olefin sulfonate, the sodium dodecyl sulfate and the dodecyl benzene sulfonate, were conducted to investigate the influence of different sodium electrolytes on the optimal salinity of the anionic surfactant/alcohol/model oil system. The sodium activity at the optimal salinity was calculated by the PHREEQC software, which was found to be equal between different sodium electrolytes. Noticeably, the solubilization parameter of water or oil at the optimal salinity was not influenced by the anions, but largely dependent on the alcohol type, the oil type and the temperature. Furthermore, oleic acid was added into model oil to simulate the acid components in crude oil. The phase behavior results indicated that a larger fraction of oleic acid was active at higher pH with sodium hydroxide (NaOH), however, its solubilization parameter at optimal salinity was lower compared to that using sodium carbonate (Na2CO3). The phase behavior of alkali/crude oil was also performed by mixing different alkalis with a crude oil sample that consisted of high contents of water-soluble active soaps. It is found that the soap generated by NaOH is more lipophilic than that generated by Na2CO3. When sodium activity is used, the optimal salinity of alkali/surfactant/crude oil system can be accurately predicted by the improved mixing rule correlation. The findings of this study would be helpful for us to rapidly select the optimum formulation for alkaline/surfactant flooding process.

Interactional study of a polymeric organotin complex in micellar media

In this manuscript, a study on interactions of a polymeric derivative of Tributyltin(IV) with [(2-Methylpropanoyl)amino]propanoic acid (TMP) in micellar media is presented. The study was conducted using two surfactants viz. Sodium 2-ethylhexylsulphate (SES) and Cetyltrimethylammonium bromide (CTAB). The solubilization parameters in terms of partition constant (K c ), partition coefficient (K x ), binding constant (K b ), Gibb’s free energy of partition (ΔG p ), and binding (ΔG b ) were investigated by UV–Visible spectrophotometer. The estimation of micellization thermodynamics including entropy (ΔS m ), enthalpy (ΔH m ), and Gibb’s free energy (ΔG m ) were determined conductometrically. The compound showed more interaction with the cationic surfactant as compared to anionic participating surfactant due to comparative electrostatic interactions. The partition coefficient (K x ) in the micellar media of CTAB was significantly higher (4.22 × 107) than SES media (1.33 × 105). The Gibb’s free energies of partition. Binding and micellization were higher in CTAB as compared to SES.

Solubilization of cationic dye in single and mixed micellar media

The effect of mixed-micellization of anionic/non-ionic surfactants on the solubilization of a cationic dye (Methylene blue) is presented in this manuscript. Interactions of dye with the single anionic surfactant sodium dodecyl sulfate (SDS), and its mixture with the non-ionic surfactant (Triton X-100), were investigated. The non-ionic surfactant was initially screened, and then its concentration was kept constant at its critical micellar concentration. The critical micellar concentration, entropy, enthalpy, and free energy of micelle formation (ΔGmic°) were determined by electrical conductivity measurements. The solubilization parameters in terms of the partition coefficient (Kx) and binding constant (Kbind) were assessed by UV–Visible spectroscopy. The role of non-ionic surfactants on the electrostatic interactions of cationic dye and surfactant was also elaborated. Mixed micellization significantly enhanced the solubility of dye molecules as shown by conductivity and absorbance analysis. The disruption of structured water in the vicinal environment of hydrophobic groups of surfactants was responsible for the increase in critical micelle concentration (CMC). The negative values of energies of binding, partitioning, and micellization indicated the spontaneity and feasibility of micellar systems. The experimental outcomes supported the superiority of anionic/non-ionic mixed micellar solubilization over a single anionic surfactant. Thus, the mixed micellar system (SDS + TX-100) assured a higher degree of solubilization than the corresponding single system (SDS).

Experimental Investigation of PEG 6000/Tween 40/SiO2 NPs Stabilized Nanoemulsion Properties: A Versatile Oil Recovery Approach

The article presents a comprehensive oil recovery approach through experimental investigations and mechanistic descriptions of formulated nanoemulsion systems stabilized by {PEG 6000 (an amphiphilic polymer), Tween 40 (a non-ionic surfactant) and silica nanoparticles (SiO2 NPs)}. Initially, polymers were screened for emulsion preparation depending on their surface active properties and solubilization parameters. Oil droplets of nano-size (<500 nm) were measured by dynamic light scattering (DLS) in emulsion phase. The prolonged kinetic stabilities of nanoemulsions were inspected by zeta (ζ) potential and phase behavior studies. The mechanical barrier (steric hindrance + electrostatic repulsion) is strengthened at oil-aqueous interface by NPs inclusion occasioning augmented emulsion stability. Surface tension measurements quantified the air-emulsion interfacial behavior and lowest value of 6.42 mN/m at 343 K signifies the improved adsorption of polymer, surfactant and NPs at the interface in polymer-surfactant-NPs (PSN) nanoemulsion system. Viscosity analysis at varying temperatures concludes the pseudo-plastic behavior through fitting of flow parameters by Power law model. The hydrophobic connection of viscosification of nanoemulsion by formation of macromolecular and supramolecular structures is described mechanistically. The miscibility test infers the improved emulsification of crude oil by PSN nanoemulsion system with synergistic interactions among polymer, surfactant and nanoparticles. The core flood test yielded an additional oil recovery of 27.82% of original oil in place (OOIP) by PSN nanoemulsion, after conventional water flooding.

Surface properties and microemulsion of anionic/nonionic mixtures based on sulfonate Gemini surfactant in the presence of NaCl

The mixing properties of anionic/nonionic surfactant mixtures in the presence of inorganic salts are essential to the industrial application. The equilibrium and dynamic surface tension of the sulfonate Gemini surfactant (SGS12) and alkyl glycoside (APG0810) mixtures were examined using the plate method and drop-shape analysis. Moreover, the Winsor phase diagram and solubility properties of the microemulsion were studied using the salinity scan. Results show that the critical micelle concentration (cmc) of the SGS12/APG0810 mixtures was intermediate between those of the two single surfactants in the presence of NaCl. For the SGS12/APG0810 mixtures, the absolute value of interaction parameters increased as the APG0810 content increased at cNaCl = 0.01 or 0.1 mol/L. The formation of the mixed micelles was spontaneous. At cNaCl = 0.01 mol/L, the initial adsorption (t → 0) of surfactant molecules from the bulk phase to the surface was diffusion-controlled. The salinity scan experiments showed that the optimal solubilization parameters of the SGS12/APG0810 microemulsion decrease with the decrease of the molar fraction of SGS12. However, the concentration range of inorganic salt between the formation and disappearance of Winsor III broadened with the decline in SGS12 content. The impact of temperature on the volume fraction of the middle-phase microemulsion (MPM) was ignorable, indicating the high stability of MPM at the temperature range of 30.0 °C ~ 80.0 °C. At 30.0 ± 0.1 °C, the hydrodynamic diameter of the SGS12/APG0810 MPM was about 28.0 nm, and the number of microemulsion droplets decreased with the increase of APG0810 content. When the total mass fraction of surfactant and cosurfactant was 15%, wNaCl = 5% (brine), Km = 1:3 and Vo/Vw = 1, the interfacial tension between crude oil and the SGS12/APG0810 MPM reached the order of 10−3mN/m. At nSGS12:nAPG0810 = 7:3, the lowest interfacial tension was 9 × 10−4 mN/m. For the SGS12/APG0810 (7:3) mixture, the addition of n-butanol induced the formation of MPM. The concentration range of n-butanol between the formation and the disappearance of Winsor III first increased and then decreased with the increase of surfactant concentration.

Composition and Solubilization of the Microemulsion Systems Containing Triton X-100: Effects of Aqueous Composition and Oil-Water-Ratios

Abstract The composition and solubilization of the optimum microemulsion systems containing Triton X-100/pentan-1-ol/aliphatic hydrocarbon/water were studied with the ∊-β fishlike phase diagram method. The solubilities of the alkanol (S A), the mass fractions of the alkanol in the interfacial layer (AS ) and the optimum solubilization parameters (SP∗) of the microemulsion systems with different aqueous phases (salt, acid, alkali) and with different α values were obtained and discussed. The SP∗ values increase significantly with the cation radius of the chlorides (NaCl, KCl, CsCl), but decrease slightly with the anion radius of the sodium halides (NaCl, NaBr, NaI). However, SP∗ values decrease with the increased salinities and NaOH contents. The trend was reversed for the acid systems. When the oil-water ratio (α) increases, the S A and A S values significantly increase, while the SP∗ values increase slowly. As the length of the carbon chain of the alkane molecules increases, both the S A and A S values increase, while the SP∗ values decrease significantly.

Combustible Microemulsions with Diesel and Diesel Admixed with Rapeseed Oil

Novel results on combustible microemulsions prepared with diesel (D), blends of diesel and rapeseed oil (RSO), and mixtures of eco-friendly amphiphiles are presented. Water solubilization in oil/amphiphile systems was estimated by pseudo-ternary diagrams whereas the phase behavior by Winsor (W) diagrams. The extent of single-phase microemulsion (SPM) area depends on the amphiphile and oil phase composition. The presence of cosurfactant in the anionic-nonionic surfactant mixture increases very much the SPM area, but no effect is observed when half of D is replaced by RSO. In the pseudo-ternary phase diagram, the addition of organic electrolyte decreases the SPM areas. The microemulsions were characterized by the oil/water interfacial tension (gow), and the oil and water solubilization parameters (SPo) and (SPw). The results obtained reveal that the W III microemulsions have minimal goow values, whereas SPo and SPw are maximal. The work connects the phase behavior with the interfacial tension and the solubilization parameters of oil and water and is useful for obtaining and developing optimal microemulsions as alternative fuels.

A Comparison Study on the Phase Behavior and Solubilization between Cn(Bim)2-2Br-Butyric Acid and CnmimBr-Butyric Acid Microemulsion Systems

AbstractThe solubility, interfacial composition and solubilization ability of microemulsions containing gemini 1,4-bis(3-alkylimidazolium-1-yl) butane bromide [Cn(Bim)2-2Br]/butyric acid were studied and compared with that of microemulsions containing 1-alkyl-3-methylimidazolium (CnmimBr)/butyric acid. The solubilities of butyric acid (SA), and the mass fractions of butyric acid in the interfacial layer(AS) decrease, while the solubilization parameters (SP*) increase with the increase in the carbon chain length of the surfactants in Cn(Bim)2-2Br based and CnmimBr based microemulsions. A comparison of the gemini Cn(Bim)2-2Br microemulsions with CnmimBr microemulsions indicates that the values of SA and AS are in the order: Cn(Bim)2-2Br &lt; CnmimBr, while SP* values are Cn(Bim)2-2Br &gt; CnmimBr. With salinity increasing, the values of SA and AS decrease, while SP* values increase. With the increase in the alkyl chain length of the oil molecules, the SA values increase, AS and SP* values decrease. Temperature has less influence on the values of SA, AS and SP* of microemulsions containing Cn(Bim)2-2Br/butyric acid.

Interfacial composition and solubilization of microemulsion systems containing mixed surfactants C12mimBr and Brij35: effects of surfactant composition, temperature, and salinity

The composition of the interfacial layer and solubilization of the microemulsions containing mixed cationic and nonionic surfactants (C12mimBr-Brij35) were studied and compared based on the mass and the number of moles of the surfactants, respectively. As $$ {X}_{C_{12}\mathrm{mimBr}} $$ (mole fractions of C12mimBr in C12mimBr-Brij35 mixture) increases, the total masses of the surfactants ( $$ {m}_S^s $$ ) decrease, whereas the total number of moles of surfactants ( $$ {n}_S^S $$ ) increases in the interfacial layer. This opposite pattern of change between $$ {m}_S^s $$ and $$ {n}_S^S $$ against $$ {X}_{C_{12}\mathrm{mimBr}} $$ is due to the significant difference in the molecular mass between the two surfactants. The mass solubilization parameter of the microemulsions, $$ {\mathrm{SP}}_m^{\ast } $$ , increases and follows a curve that concaves downward as $$ {X}_{C_{12}\mathrm{mimBr}} $$ values increase. However, the molar solubilization parameter, $$ {\mathrm{SP}}_n^{\ast } $$ , would decrease as $$ {X}_{C_{12}\mathrm{mimBr}} $$ increases. The physicochemical properties of the microemulsions are less sensitive to both temperature and salinity.

Effect of amphoteric surfactant on phase behavior of hydrocarbon-electrolyte-water system-an application in enhanced oil recovery

ABSTRACTThe different techniques such as enhanced oil recovery (EOR) and improved oil recovery (IOR) have been used to enhance oil production. The surfactant flooding is a tertiary oil recovery technique that has been widely used in oil field industry. A variety of surfactant chemicals have been used in which among them the amphoteric type, which has two groups of opposite charges, needs more investigation. In this work, we use cocamidopropyl betaine as an amphoteric surfactant that is used to investigate its influence on the aquifer + hydrocarbon system. The effects of surfactant concentration, salinity, and hydrocarbon type on the phase behavior of the various saline aqueous-hydrocarbon mixtures are investigated. Moreover, the surfactant flooding is carried out using a glass micromodel. Thus, to investigate the wettability, the contact angle is also measured for the present system that it is an influential factor in oil recovery. First, by increasing salinity from 0 wt% to 20 wt% in n-hexadecane, the phase change take placed so that a Winsor formation from type I to III and then to type II occurs. However, for n-heptane upon enhancing salinity, Winsor type III is transformed to type II so that hydrocarbon (oil) recovery increases and break through occurs with a delay. By increasing salinity, water solubilization parameter decreases for both hydrocarbon and by enhancing both surfactant concentration and salinity leads to reduce the contact angle. Thus, cocamidopropyl betaine works better for the longer hydrocarbon chain.In the micromodel flooding test upon formation of Winsor II, the recovery is higher and the break through takes place with a delay. However, for the case of Winsor I, the recovery is lower and the break through occurs earlier. Finally, one can conclude that the low concentration of amphoteric surfactants needs to use that plays an important role in chemical EOR and results a higher recovery in high salinity.

Additive Effects on the Phase Behavior of Cationic Surfactant ([C16mim]Br) Stabilized Hydrophobic Ionic Liquid Based Middle-Phase Microemulsions

The e-β fishlike phase diagram of the system [C16mim]Br/[Omim]Tf2N/water was constructed in the presence of different additives (alcohol and inorganic salt). From the diagram some additive-dependent characteristic physicochemical parameters were obtained. Results show that with the increase of the alkyl chain length of alcohols, the solubility of the alcohol in [Omim]Tf2N, and the optimum solubilization parameter (SP*) decrease, while the maximum alcohol width (△e) for the phase inversion and the mass fraction of the alcohol in the balanced interfacial film (Ain) increase. For inorganic salts, an increase in [NaCl], or an increase of the radius of halides (X–) at constant [NaX], or the substitution of the divalent anion SO42– by the same molar concentration of monovalent anion Cl– makes both SP* and △e increase, but Ain decrease. Overall, the alcohol effect on the phase behavior of the microemulsion is greater than the salt effect, and the composition effect of an inorganic salt is greater than the concen...