Anionic Surfactant Research Articles

Influence of Surfactant on the Skin Permeation of Methylisothiazolinone and Methylchloroisothiazolinone.

Patch tests are often used in safety evaluations to identify the substance causing skin irritation, but the same substance can sometimes give positive or negative results depending on the test conditions. Here, we investigated differences in the skin penetration of two test compounds under different application conditions. We studied the effects of the anionic surfactant sodium dodecyl sulfate (SDS) and the nonionic surfactant polysorbate 80 (PS) on skin penetration of the preservatives methylisothiazolinone (MT) and methylchloroisothiazolinone (MCT), which are used in cosmetics such as shampoos. The skin permeation of MT was enhanced by SDS but was unchanged by PS. Skin impedance decreased in the presence of SDS whereas PS had the same effect as the control aqueous solution, suggesting that SDS reduction of the barrier function of skin affects the permeation of MT, a hydrophilic drug. Application of a mixture of MCT and MT in the presence of SDS did not affect the skin permeation of MCT whereas the permeation of MT was enhanced by SDS, indicating that the skin permeation of MCT is less affected by SDS than is MT. Thus, attention should be paid to the possible effect of co-solutes, especially hydrophilic drugs.

Study on the compounding optimization of surfactants and synergistic effects on the wettability of bituminous coal

To improve the wettability of surfactants on bituminous coal and to explore its wettability and wettability mechanism on bituminous coal, taking the Sandaogou bituminous coal as an example, a single factor experiment was carried out first. Through contact angle and surface tension experiments, three surfactants with good wettability were selected from among the nine surfactants and mixed in equal proportions two by two to determine the optimal compounding method and compounding concentration. The experimental results show that the compounding of nonionic and anionic, nonionic and zwitterionic, anionic and zwitterionic surfactants can have synergistic effects and significantly improve the wettability of bituminous coal. Among them, the 0.5 wt% SDS + 0.5 wt% CAB-50 (R2) compound surfactant had the best wettability on bituminous coal, and the contact angle and surface tension were only 15.24° and 23.62 mN/m, respectively. The surface electrostatic potential values of each material molecule were calculated by Materials Studio software based on the quantum chemistry method, and correlation analysis was carried out with wettability. The results show that the surface electrostatic potentials of CDEA, SDS and CAB-50 were greater than those of water and bituminous coal, and the region of maximum negative electrostatic potential corresponded to oxygen atoms, which are easier to adsorb on bituminous coal and water molecules. Then, through molecular dynamics simulation, the interaction energy and the distribution of contributions along the Z-axis of the water/compound surfactant/bituminous coal system at equilibrium were investigated, and finally, a spray dust reduction test was carried out in the Sandaogou Coal Mine. The results showed that the 0.5 wt% SDS + 0.5 wt% CAB-50 compound solution can be used as a water molecule adsorption carrier, prompting more water molecules to be embedded into coal molecules, increasing the relative concentration of water molecules on the surface of bituminous coal, restricting the diffusion of water molecules, and greatly improving the wettability. After the addition of 0.5 wt% SDS + 0.5 wt% CAB-50 as a spray agent, the concentration of total dust at the driver's position decreased from 65.14 to 9.11 mg/m3, the concentration of exhaled dust decreased from 30.07 to 3.35 mg/m3, and the efficiency of total and exhaled dust reduction compared with that of pure water was 86.01% and 89.35%, respectively.

Switchability and synergistic effect of a CO2-responsive surfactant with co-surfactants at an O/W interface: A molecular insight

CO2-responsive surfactants are a promising technology with potential applications in various fields. Therefore, the design of their formulations must be carefully considered to ensure their effectiveness in each specific application. Herein, we employed molecular dynamics simulations to investigate an oil/water (O/W) interface stabilized by a surfactant mixture containing a CO2-responsive cationic primary surfactant and another co-surfactant. It has been discovered that formulating the CO2-responsive cationic surfactant with a typical anionic surfactant (sodium dodecyl sulfate, SDS) can lead to a distinct CO2-responsive mechanism of the surfactant mixture. To compare, the CO2-responsive mechanism remains unchanged if the CO2-responsive cationic surfactant is formulated with a typical cationic surfactant (dodecyl trimethylammonium bromide, DTAB). A nonionic co-surfactant can enhance the interface activity of the surfactant mixture but the synergistic effect is not strong enough to lead to a different CO2-responsive mechanism. The distinct phase behavior between two surfactant mixtures suggests that the CO2-responsive mechanism is dominated by the type of surfactants formulated with the CO2-switchable surfactant.

Enzyme stability with essential oils and surfactants. Growing towards green disinfectant detergents

This study investigates the stability of α-amylase and protease in disinfectant formulations incorporating essential oils (EOs), anionic surfactants (linear alkylbenzene sulfonate), non-ionic surfactants (alkylpolyglucosides and ethoxylated fatty alcohols), and mixtures of them, analysing the influence of the composition, temperature, and time using shelf-life assays. EOs reduce α-amylase activity showing first-order deactivation kinetics, and surfactants were found not to significantly affect its activity. However, protease activity increases with the presence of EOs, and it was also observed that the use of surfactants does not significantly affect protease activity either. This work represents a step forward in the development of environmentally friendly multifunctional detergents with high disinfectant and detersive capacity.

Addressing the interaction of stem bromelain with different anionic surfactants, below, at and above the critical micelle concentration (cmc) in phosphate buffer at pH 7: Physicochemical, spectroscopic, & molecular docking study

The structural stability and therapeutic activity of Stem Bromelain (BM) have been explored by unravelling the interaction of stem BM in presence of two different types of anionic surfactants namely, bile salts, NaC and NaDC and the conventional anionic surfactants, SDDS and SDBS, below, at and above the critical micelle concentration (cmc) in aqueous phosphate buffer of pH 7. Different physicochemical parameters like, surface excess (Γcmc), minimum area of surfactants at air water interface (Amin) etc. are calculated from tensiometry both in absence and presence of BM. Several inflection points (C1, C2 and C3) have been found in tensiometry profile of surfactants in presence of BM due to the conformational change of BM assisted by surfactants. Similar observation also found in isothermal titration calorimetry (ITC) profiles where the enthalpy of micellization (ΔH0obs) of surfactants in absence and presence of BM have calculated. Further, steady state absorption and fluorescence spectra monitoring the tryptophan (Trp) emission of free BM and in presence of all the surfactants at three different temperatures (288.15 K, 298.15 K, and 308.15 K) reveal the nature of fluorescence quenching of BM in presence of bile salts/surfactants. Time resolved fluorescence studies at room temperature also support to determine the several quenching parameters. The binding constant (Kb) of BM with all the surfactants and free energy of binding (∆G0 of bile salts/surfactants with BM at different temperatures have been calculated exploiting steady state fluorescence technique. It is observed that, the binding of NaC with BM is greater as compared to other surfactants while Stern-Volmer quenching constant (KSV) is found greater in presence of SDBS as compared with others which supports the surface tension and ITC data with the fact that surface activity of surfactant(s) is decreasing with the binding of the surfactants at the core or binding pocket of BM. Circular Dichroism (CD) study shows the stability of secondary structure of BM in presence of NaC and NaDC below C3, while BM lost its structural stability even at very low surfactant concentration of SDDS and SDBS which also supports the more involvement of bile salts in binding rather than surfactants. The molecular docking studies have also been substantiated for better understanding the several experimental investigations interaction of BM with the bile salts/surfactants.

Comparative study of nanoemulsion and micelle formed by surfactants containing benzene ring for spontaneous imbibition displacement

Nanoemulsion has a wide range of applications in oilfield chemistry due to its unique nanoscale size, excellent kinetic stability and high specific surface area. In this paper, a novel nanoemulsion oil flooding system was prepared using anionic surfactant sodium dodecyl benzene sulfonate (SDBS), the nonionic surfactant alkylphenol ethoxylates (OP-10), kerosene, n-butanol and deionized water. The particle size, Zeta potential, interfacial tension (IFT) and wettability properties were evaluated in the laboratory. The displacement performance of nanoemulsion was evaluated by the spontaneous imbibition experiment. Meanwhile, it compared with the same concentration of SDBS + OP-10 + n-butanol (SOB) system. The results showed that the particle size of the nanoemulsion was 70 ∼ 100 nm. When the concentration of nanoemulsion was 0.10 %, the oil–water IFT could reach 0.091 mN/m. The spontaneous imbibition oil recovery of the nanoemulsion (0.10 wt%) could reach 33.20 %, which was 23.02 % higher than that of SOB system. We also research the spontaneous imbibition displacement mechanism of nanoemulsion and micelle in low-permeability reservoirs. This paper will help to select the best oil displacement agent for the design of enhanced oil recovery (EOR) projects and promote the application of oil displacement agent in oilfield.

Interfacial and ion-pairing catalysis for oxygen-tolerant large-scale ATRP in ab initio emulsion

A cooperative interfacial and ion-pairing catalysis, coupled with a molecular oxygen reduction reaction (ORR), to scale up an Atom Transfer Radical Polymerization of n-butyl acrylate (BA) from 20 mL to 10 L (scale-up factor = 500) in ab initio emulsion conditions is introduced. The polymerization is driven by the regeneration of [CuIL]+ through CuII/Cu0 comproportionation. [CuIL]+ simultaneously converts O2 to H2O2 (which is then degraded by sodium pyruvate) and drives the polymerization of butyl acrylate. The anionic surfactant sodium dodecyl sulfate (SDS) facilitates catalyst transport inside and outside the micelles by ion-pairing catalysis. n-Butyl acrylate polymerizations are investigated on a small scale with Cu0 wire and on a larger scale with Cu0 powder. On a 10 L scale, the polymerization yielded controlled PBA-Br (Mn = 32.3 × 103; Ð = 1.39, ∼1.64 kg) after 9 h. Chain extension of PBA-Br macroinitiators proved their livingness. An on-line electrochemical monitoring was also introduced to determine the instantaneous CuI and CuII concentrations at the Cu0 wire surface during the polymerization.

Effects of surfactants on the adsorption of norfloxacin onto ferrihydrite: comparison between anionic and cationic surfactants

ABSTRACT There is little information on how widespread surfactants affect the adsorption of norfloxacin (NOR) onto iron oxide minerals. In order to elucidate the effects of various surfactants on the adsorption characteristics of NOR onto typical iron oxides, we have explored the different influences of sodium dodecylbenzene sulfonate (SDBS), an anionic surfactant, and didodecyldimethylammonium bromide (DDAB), a cationic surfactant, on the interactions between NOR and ferrihydrite under different solution chemistry conditions. Interestingly, SDBS facilitated NOR adsorption, whereas DDAB inhibited NOR adsorption. The adsorption-enhancement effect of SDBS was ascribed to the enhanced electrostatic attraction, the interactions between the adsorbed SDBS on ferrihydrite surfaces and NOR molecules, and the bridging effect of SDBS between NOR and iron oxide. In comparison, the adsorption-inhibition effect of DDAB owning to the adsorption site competitive adsorption between NOR and DDAB for the effective sites as well as the steric hindrance between NOR-DDAB complexes and the adsorbed DDAB on ferrihydrite surfaces. Additionally, the magnitude of the effects of surfactants on NOR adsorption declined with increasing pH values from 5.0 to 9.0, which was related to the amounts of surfactant binding to ferrihydrite surfaces. Moreover, when the background electrolyte was Ca2+, the enhanced effect of SDBS on NOR adsorption was caused by the formation of NOR-Ca2+-SDBS complexes. The inhibitory effect of DDAB was due to the DDAB coating on ferrihydrite, which undermined the cation-bridging effect. Together, the findings from this work emphasize the essential roles of widely existing surfactants in controlling the environmental fate of quinolone antibiotics.

Comprehensive rheological analysis of structurally related acetan-like heteroexopolysaccharides from two Kozakia baliensis strains in surfactants and galactomannan blends

Natural biopolymers become increasingly attractive as bio-based alternatives to petrol-based rheological modifiers, especially in personal care applications. However, many polysaccharides exhibit undesired properties in cosmetic applications such as limited viscosifying characteristics, unpleasant sensory properties, or incompatibility with certain formulation compounds. Here, a comprehensive rheological analysis of non-decorated acetan-like heteroexopolysaccharides derived from two Kozakia baliensis strains was performed in selected surfactant formulations. The results were compared to native xanthan gum and a genetically engineered xanthan variant, Xan∆gumFGL, which lacks any acetyl- and pyruvyl moieties and whose rheological properties are unaffected by saline environments. All four polysaccharides displayed a highly similar rheological performance in the non-ionic surfactant lauryl glucoside, while the rheological properties differed in amphoteric and anionic surfactants cocamidopropyl betaine and sodium laureth sulfate due to minor changes in side chain composition. Polysaccharide precipitation was observed in the presence of the cationic surfactant. Nevertheless, the native heteroexopolysaccharide derived from K. baliensis LMG 27018 shows significant potential as a salt-independent rheological modifier compared to the genetically engineered Xan∆gumFGL variant. In addition, blends of heteroexopolysaccharides from K. baliensis and several galactomannans displayed synergistic effects which were comparable to native xanthan gum-galactomannan blends. This study shows that heteroexopolysaccharides of K. baliensis are capable of further extending the portfolio of bio-based rheological modifiers.

Interface engineering enabled by sodium dodecyl sulfonate surfactant for stable Zn metal batteries

Aqueous zinc-ion batteries are emerging as powerful candidates for large-scale energy storage, due to their inherent high safety and high theoretical capacity. However, the inevitable hydrogen evolution and side effects of the deposition process limit their lifespan, which requires rational engineering of the interface between anode and aqueous electrolyte. In this paper, an anionic surfactant as electrolyte additive, sodium dodecyl sulfonate (SDS), is introduced to deliver highly reversible zinc metal batteries. Unlike traditional surfactants, the solvation structure is not affected by SDS, which tends to adsorb on the (002) crystal plane of Zn with the purpose of effectively limiting the water molecules adsorption. Attributed to the natural hydrophobic part of SDS, a dynamic electrostatic shielding layer and a unique hydrophobic interface are constructed on the anode. Assisted by the above merits, the adverse surface corrosion, hydrogen evolution and dendrite growth are significantly inhibited without the sacrifice in the deposition kinetics of Zn ions. As a result, the Zn||Zn symmetric batteries demonstrate an increased cycle life of 2000 h (1 mA cm−2, 1 mA h cm−2) with the presence of SDS additive. Such strategy provides a new avenue for the developing advanced electrolytes to be applied in aqueous energy storage systems.

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

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

Liquid-phase microextraction approach using supramolecular solvent formed in aqueous systems based on di(2-ethylhexyl)phosphoric acid salt: Spectrophotometric determination of antipyrine in saliva

In this study, di(2-ethylhexyl)phosphoric acid salt was investigated as a double-chain anionic surfactant for supramolecular solvent formation in a liquid-phase microextraction procedure for the first time. Inorganic electrolytes (sodium salts) were shown to be coacervation agents, due to their salting-out property in solution of sodium di(2-ethylhexyl)phosphate, obtained by deprotonation of the acid. The physico-chemical properties of the newly synthesised solvents were studied. Sodium carbonate and sodium phosphate were found to be the most suitable coacervation agents, due to their alkaline nature and low viscosity of the supramolecular solvent phases they produce. The extraction ability of the novel solvent was demonstrated in liquid-phase microextraction of a colored derivative of antipyrine from saliva for further spectrophotometric determination. The extraction recovery was found to be 70 %. The proposed green sample preparation technique enabled the exclusion of traditional toxic solvents and reduction of reagent consumption. The satisfactory analytical performance of the procedure was validated with real sample analysis. The calibration graph was linear over the concentration range of 0.03 to 0.5 mmol/L. The limit of detection (3σ) and limit of quantification (10σ), calculated from blank tests, were 0.01 and 0.03 mmol/L, respectively.

Polymeric surfactants with high acid values for emulsion type pressure-sensitive adhesives

Low molecular weight polymers with hydrophobic-carboxyl groups have been usually used as anionic surfactants in emulsion polymerization for coatings. However, such polymeric surfactants usually have low acid values below 200, because it is difficult to make high acid-value polymeric surfactants using a normal batch reactor. In this work, we polymerized high acid value polymeric surfactant having high acid values successfully up to 380 using CSTR (continuous stirring tank reactor). The synthesized polymeric surfactant was a random copolymer of P(BA-AA) and we applied them as anionic surfactants in making emulsion-type acrylic PSAs (Pressure-Sensitive Adhesives) to investigate the effects of high acid values on the adhesive properties. This CSTR can effectively control the composition and molecular weight of polymeric surfactants through varying monomer ratios, retention time, and initiator concentrations. The surface tension analysis and emulsion stability test indicated that the synthesized polymeric surfactants exhibited a similar levels of critical micelle concentration (CMC) and emulsion stability with other conventional anionic surfactants. Also, the adhesion property analysis showed that the PSA used high acid value polymeric surfactant resulting in superior adhesive properties and heat resistance than the PSAs used low acid value polymeric surfactant or conventional low molecular weight surfactant. It was very notable that polymeric surfactants having unusually high acid values above 300 because of their high contents of carboxylic acid groups could result in superior adhesive properties and heat resistance.

Surface properties, aggregation behavior and wettability of the mixed system of fluorocarbon cationic surfactant and hydrocarbon anionic surfactant in dilute solutions

Traditional perfluorooctane sulfonic acid (PFOS) fluorocarbon surfactants endangered human health and environment. Therefore, an environmentally friendly quaternary ammonium cationic fluorocarbon surfactant (PFAS-IEt) was synthesized, and surface activities, aggregation behavior, adsorption properties and wettability of PFAS-IEt/sodium n-octyl sulfate (SOS) mixtures in dilute solutions were systematically investigated. The results demonstrated that PFAS-IEt possessed excellent surface activity in aqueous solution. Surprisingly, its surface tension was only 15.33 mN/m and critical micelle concentration (CMC) was 0.002 mol/L. It could be used as a potential substitute for PFOS. In addition, PFAS-IEt had the good synergistic effect with SOS. The PTFE plate with low surface energy could be completely wetted by the binary compound solution at low concentration (0.04 mol/L) (contact angle was 0°), which was superior to the reported long chain quaternary ammonium non-ionic fluorocarbon surfactants (MN-2C9F19 and EN-2C9F19).

Green Surfactant Assisted-Solidified Floating Organic Drop Micro-Extraction (SA-SFODME) for the Preconcentration of Trace Lead with Determination by Flame Atomic Absorption Spectrometry (FAAS)

Determination of trace lead from environmental samples was carried out by solidified floating organic drop microextraction for preconcentration before analysis by flame atomic absorption spectrometry. The determination of lead from environmental samples, even at trace levels, was possible with an ordinary flame atomic absorption spectrometer (FAAS). The lead formed a hydrophobic complex with the anionic surfactant sodium dodecyl benzene sulfonate (SDBS), and this hydrophobic complex was extracted into the 1-dodecanol drop. Parameters affecting analytical performance have been studied. The optimum pH value was 3.5. The optimum sample volume, SDBS concentration, and extraction solvent volume were 75 mL, 50 mM in dodecanol, and 75 µL, respectively. The optimum extraction time was determined as 30 min, the optimum extraction temperature was 45 °C, the optimum mixing speed was 650 rpm and the ideal extraction phase volume was 0.50 mL. Methanol has been shown to be effective when used as a diluent. Using the optimum conditions, the enhancement factor was 106, and the limit of detection (3s) and precision were 3.3 ng/mL and 2.3% (n = 9,15 ng/mL), respectively. The limit of quantification (LOQ) (10s) was 10 ng/mL and the linear working range was 15-100 ng/mL. The accuracy was evaluated by certified reference material analysis. The optimized method was applied to the determination of Pb(II) from environmental water samples. This method follows the principles of green analytical chemistry.

Synergistic effects of nonionic surfactants ethoxylated alkylamines and sodium dodecyl sulfate in mixed systems

HypothesisIn general, the performance of surfactant hybrid systems is better than that of single surfactants, so surfactant hybrid systems are widely used in various industries. As a very important class of nonionic surfactants, ethoxylated alkylamines have been widely used in industries such as washing, coating, and pesticide, but little research has been conducted on their mixed systems. In order to improve the utilization efficiency of surfactants and reduce wastage, the surface properties and aggregation behavior of ethoxylated alkylamine mixed systems should be further explored. ExperimentIn this study, the nonionic surfactant ethoxylated dodecylamine (AC-1202) and the anionic surfactant sodium dodecyl sulfate (SDS) were used to form a mixed system. The static surface tension and interaction parameters of the mixed system under the influence of inorganic salt ions were investigated using a KRÜSS K12 surface tensiometer. The diffusion process of the mixed system was investigated using a KRÜSS bubble pressure tensiometer. At the same time, the aggregate behavior of the mixed system was studied by particle size analyzer. In addition, the contact angle and rheological properties of the mixed solution were also investigated. FindingsThe SDS/AC-1202 mixture system formed a synergistic effect that could reduce the CMC value to 24.20 mN/m and the CMC value was as low as 22.89 mN/m after the addition of inorganic salts. The mixed system conforms to the kinetic mechanism of mixing and diffusion and the Ostwald de model for non-Newtonian fluids. Finally, there is a good aggregation pattern in the mixed system, and the stronger synergistic effect will lead to the reduction of the average particle size of the mixture to 45.41 nm.

Stretchable and Flexible Painted Thermoelectric Generators on Japanese Paper Using Inks Dispersed with P- and N-Type Single-Walled Carbon Nanotubes.

As power sources for Internet-of-Things sensors, thermoelectric generators must exhibit compactness, flexibility, and low manufacturing costs. Stretchable and flexible painted thermoelectric generators were fabricated on Japanese paper using inks with dispersed p- and n-type single-walled carbon nanotubes (SWCNTs). The p- and n-type SWCNT inks were dispersed using the anionic surfactant of sodium dodecylbenzene sulfonate and the cationic surfactant of dimethyldioctadecylammonium chloride, respectively. The bundle diameters of the p- and n-type SWCNT layers painted on Japanese paper differed significantly; however, the crystallinities of both types of layers were almost the same. The thermoelectric properties of both types of layers exhibited mostly the same values at 30 °C; however, the properties, particularly the electrical conductivity, of the n-type layer increased linearly, and of the p-type layer decreased as the temperature increased. The p- and n-type SWCNT inks were used to paint striped patterns on Japanese paper. By folding at the boundaries of the patterns, painted generators can shrink and expand, even on curved surfaces. The painted generator (length: 145 mm, height: 13 mm) exhibited an output voltage of 10.4 mV and a maximum power of 0.21 μW with a temperature difference of 64 K at 120 °C on the hot side.

Construction of oleogels based on emulsion gels stabilized by glycyrrhizic acid and chitosan

Liquid oils can be converted into elastic solids by preparing oleogels using an emulsion-templated approach. In this study, we prepared emulsion gels using a layer-by-layer (LBL) electrostatic deposition approach. These emulsion gels were then used as templates to prepare oleogels. Initially, oil-in-water emulsion gels were formed using glycyrrhizic acid (GA) as a natural anionic surfactant to form and stabilize the oil droplets. Cationic chitosan (CS) was then added to these emulsions to form a biopolymer coating around the oil droplets. The GA/CS ratio in these emulsion gels played a critical role in determining the physical stability of the oleogels created from them. At a sufficiently high chitosan concentration (3% CS for samples with 1% GA, 2% CS for samples with 2% GA), the emulsion gels were resistant to destabilization during drying, which was attributed to the formation of a thick chitosan coating around the oil droplets. The oil loss from the optimized oleogels (GCOs1-3, GCOs2-2, GCOs2-3) during drying was relatively low (0.41%–1.08%), indicating their strong oil binding capacity. In contrast, non-optimized oleogels (2% GA, 1% CS) were prone to droplet coalescence and oil loss (74.2% ± 1.3%) during drying. The optimized oleogels (GCOs1-3, GCOs2-2, GCOs2-3) all had relatively high storage modulus (∼150 kPa) at a frequency of 1 rad/s. Overall, the interfacial engineering strategy used in this study may be useful for converting liquid oils into semi-solid materials, which may be useful for several applications in the food and other industries.

Quaternary blended eco high performance concrete utilizing high volumes of siliceous additives

This research examines the optimal feasibility of incorporating siliceous additives as an adjunct material for cement in the formulation of environmentally sustainable high-performance concrete (Eco-HPC). Siliceous materials, including Nano silica (NS), Rice Husk Ash (RHA), and Fly Ash (FA), were fine-tuned within the cementitious system in order to achieve the amplified performance of Eco-HPC by reducing the required cement content from 370 kg/m3 to 273 kg/m3. This is achieved by employing the Modified Andreasen and Andreasen (MA&A) particle packing model, with ‘q’ (distribution factor) as ‘0.3’. The Levenberg Marquardt algorithm (curve fitting) was utilized to validate the packing density of each concrete blends. Initially, the dry NS agglomerates are synthesized into stabilized aqueous dispersion through High shear mixing (10 min/1750 rpm) followed by probe sonication (15 min/(1/3) s/s) with anionic surfactant dosage of 0.1 g/10 g. Incorporating secondary siliceous binders into the cement matrix led to an enhancement in the packing density, increasing from 0.94 (nullary) to 0.96 (quaternary) which in turn alters the reactivity and cohesiveness of the matrix. Compressive strength values for Binary (NS2), Ternary (RN15, FN20), and quaternary mix (FRN25) were observed as 57.42 MPa, 56.83 MPa, 55.34 MPa, and 52.58 MPa, respectively, for primary binder contents of 362 kg/m3, 314 kg/m3, 296 kg/m3, and 273 kg/m3 without compromising durability parameters. An assessment on reduced carbon dioxide emissions indicated that increasing the cement replacement percentages in Eco-HPC by up to 30% for binder contents of 358 kg/m3, 296 kg/m3, 259 kg/m3, and 273 kg/m3 resulted in a reduction of CO2 emissions by 2.98%, 18%, 27%, and 23.33%, respectively. Among the twelve formulated mixes, FRN25, FRN20, FRN15 and FN30 are identified as Eco-HPC mix through a computational framework which integrates the packing density, carbon emission, strength and diffusion coefficient.

USE OF ETHOXYLATED ALCOHOLS WITH ANIONIC SURFACTANTS FOR ENHANCED RECOVERY

The article is devoted to the development of surfactant compositions, including a number of known anionic surfactants, in formulations with new types of nonionic surfactants - fatty alcohols with an increased degree of ethoxylation. The solubilizing properties of new types of fatty ethoxylated alcohols have been exploited during formulation development. A conductometric method was used to control the assembly of the formulations. After evaluating the stability of the resulting compositions, physicochemical properties were evaluated, including thermal stability and corrosiveness. The freezing point of the compositions was evaluated at temperatures down to minus 40 °C. The search for stable compositions was carried out for aggressive application conditions: at 90 ° C for models of mineralized formation waters having a total amount of dissolved salts in the range of 100-300 g/l. Ranges including critical concentrations of formulations at which colloidal structures are stable and exhibit maximum surface activity were evaluated. When determining the interfacial tension at the surfactant-hydrocarbon liquid solution boundary, a number of developed compositions showed ultra-low interfacial tension (less than 0.01 mN/m). Biodegradability was evaluated for compositions showing the best properties. According to the results of the assessment, biodegradability was more than 98 %, which reduces environmental risks. The results obtained by the authors show that a number of compositions collected by conductometric method are stable under aggressive conditions and can be used in the field of chemical methods for increasing oil recovery. The resulting compositions were adapted to reduce human factors in subsequent applications. The results reflect the potential of these approaches in adapting and selecting surfactant compositions for chemical waterflooding to enhance oil recovery. The development of technologies for the ethoxylation of higher fatty alcohols allows the manufacturability of processes for the production, collection and treatment of oil and gas. The development of practices for the use of new chemical technologies will expand the capabilities of subsoil users and reduce the risks associated with the use of large-scale chemical products.