Effect Of Surfactants Research Articles

Surfactant aggravated the antibiotic's stress on antibiotic resistance genes proliferation by altering antibiotic solubilization and microbial traits in sludge anaerobic fermentation

The excessive application of antibiotics and surfactants resulted in their massive accumulation in waste activated sludge (WAS), but the co-occurrent impacts of antibiotics and surfactants on the antibiotic resistant genes (ARGs) fates have seldom reported. This work mainly revealed the roles and critical mechanisms of sodium dodecyl benzene sulfonate (SDBS) on the sulfadiazine (SDZ) stressing for ARGs distribution during WAS anaerobic fermentation. High-throughput qPCR and metagenomic analysis revealed that SDBS aggravated the SDZ selective pressure, and accelerated the proliferation of ARGs. The total abundance of ARGs was increased from 8.81 × 1010 in SDZ to 1.17 × 1011 copies/g TSS in the SDBS/SDZ co-occurrence system. Specifically, the absolute abundances of ermF (MLSB), mefA (MLSB), tetM-01 (tetracycline), tetX (tetracycline), sul2 (sulfonamide) and strB (aminoglycoside) were risen from 4.60 × 108–7.44 × 109 copies/g TSS in the SDZ reactor to 1.02 × 109–4.63 × 1010 copies/g TSS in SDBS/SDZ reactor. SDBS was contributed to the SDZ solubilization and simultaneously effective in disintegrating extracellular polymeric substances and improving cell membrane permeability, which would facilitate the SDZ transport and its interactions with ARGs hosts. Consequently, the microbial community structure was evidently altered, and the typical ARGs hosts (i.e., Saccharimonadales and Ahniella) were greatly enriched. Also, the cell signal transduction systems (i.e., glnL, glrK and pilG), oxidative stress response (i.e., frmA and recA) and bacterial secretion systems (i.e., VirB4), which were related with ARGs propagation, were all provoked in the co-occurred SDBS/SDZ reactor compared with that of sole SDZ. PLS-PM analysis suggested that the bacterial community was the predominant factor that determined the ARGs fates, followed by mobile genetic elements and metabolic pathway. This work demonstrated the interactive effects of surfactants and antibiotics on the ARGs fates in WAS fermentation systems and gave insightful implications on the ecological risks of different exogenous pollutants.

Indirect catalytic oxidation of multi-pollutants in diesel exhaust by ozone/micro-nano bubbles system

ABSTRACT Wet oxidation absorption is an efficient and promising method of exhaust gas treatment. When the micro-nano bubbles collapse, they can generate hydroxyl radicals with strong oxidising ability, which can oxidise a variety of pollutants in diesel exhaust. Ozone has strong oxidising properties, and the coupling of ozone and micro-nano bubbles can improve the oxidation and removal effects of polluted gases. In this study, the ozone micro-nano bubbles system was used to oxidise NO x , SO2, and CO to gases that were more readily dissolved in water, such as NO2, SO3, and CO2, and the gases were removed through the absorbent solution. The effects of surfactant, catalyst, urea, pH value, and salinity on the removal efficiency of NO x , SO2, and CO from diesel exhaust were investigated. Through experiments, it was found that the removal efficiency of pollutants was enhanced and then weakened with the increasing concentrations of surfactants, catalysts, and salinity, and continued to decrease with increasing concentrations of urea. When the pH value was < 7, the removal efficiency increased first and then weakened with the increase of the pH value. When the pH value was > 7, it mainly depended on the absorption of acid gas by the alkali solution. Under optimal conditions, the removal efficiencies were 86.3% for NO, 92.1% for SO2, and 65.4% for CO. This study could provide important theoretical support for the industrial application of this technology.

Wetting behavior during impacting bituminous coal surface for dust suppression droplets of fatty alcohol polyoxyethylene ether.

The wetting behavior of droplets during impacting coal surface widely exists in the dust control process. Understanding the effect of surfactants on the diffusion of water droplets on coal surface is critical. To study the effect of fatty alcohol polyoxyethylene ether (AEO) on the dynamic wetting behavior of droplets on bituminous coal surface, a high-speed camera is used to record the impact process of ultrapure water droplets and three different molecular weight AEO solution droplets. A dynamic evaluation index, dimensionless spreading coefficient ([Formula: see text]), is used to evaluate the dynamic wetting process. The research results show that maximum dimensionless spreading coefficient ([Formula: see text]) of AEO-3, AEO-6, and AEO-9 droplets is greater than that of ultrapure water droplets. With the increase of impact velocity, the [Formula: see text] increases, but the required time decreases. Moderately increasing the impact velocity is conducive to promoting the spreading of droplets on the coal surface. Below the critical micelle concentration (CMC), the concentration of AEO droplets is positively correlated with the [Formula: see text] and the required time. When the polymerization degree increases, the Reynolds number ([Formula: see text]) and Weber number ([Formula: see text]) of droplets decrease, and the [Formula: see text] decreases. AEO can effectively enhance the spreading of droplets on the coal surface, but the increase in polymerization degree can inhibit this process. Viscous force hinders droplet spreading during droplet interaction with the coal surface, and surface tension promotes droplet retraction. Under the experimental conditions of this paper ([Formula: see text], [Formula: see text]), there is a power exponential relationship between [Formula: see text] and [Formula: see text].

Effect of Surfactant Type on Foaming Properties of Milk

The presence of low molecular weight surfactants is suspected as one of the causes of poorly foaming milk, as they can interfere with milk proteins in the formation and stabilization of foam. Here, we explore the effect of various surfactants on the foaming properties of reconstituted skim milk powders. Each surfactant is different in electrical charge and molecular weight, including cleaning O- and E-coded chemicals, Tween 80, sucrose stearate, sodium oleate, sodium dodecyl sulfate, cetyltrimethylammonium bromide, benzalkonium chloride, and lecithin. The results showed that surfactants had different effects on foamability, foam stability, and structure, due to their varied effects on milk properties (e.g., pH, zeta potential, and surface tension). E-coded chemicals and sucrose stearate markedly decreased milk foamability, while the impact of Tween 80 and lecithin was considered detrimental to foam stability, as they mostly induced the production of large air bubbles in the foam.

Experimental investigation of the development of surfactant stabilized oil-water pipe flow downstream of a choke valve

In wells and multiphase flowlines the presence of valves, pumps and other complex geometries will considerable contribute to dispersion of the phases. In combination with the droplet stabilizing effect of natural surfactants contained in the crude oil and other production chemicals, this may lead to a considerable development length of the flow. Such effects should be understood and considered by future simulation tools. In the presented work, the described scenario was experimentally tested under controlled conditions. The development of dispersed oil-water flow downstream of a valve was monitored. Surfactant was added to the mineral oil to obtain a suitable droplet stability. The near horizontal test section was 220 m long and had an inner diameter of 109 mm. The vertical phase fraction distributions were measured at six locations along the pipe with traversing gamma densitometers. The test section was further instrumented with nine pressure transducers, four optical sections, and three droplet sampling points to monitor flow development. The flow development showed a characteristic behavior of a rather sudden separation after a certain length with stable dispersed flow conditions. The degree of inlet mixing and thus initial droplet size governed by the pressure drop over the mixing valve was found to be crucial for the development length. Flow rate and initial water fraction were of minor importance. The separation behavior was coalescence controlled as it would be expected for a surfactant stabilized system. Still, even if static separation bench tests resulted in very long separation time scales, the in-flow separation happened much faster. This indicates the importance of dynamic flow conditions and associated effects such as shear and a certain mixing to be preferential for the separation. The measured pressure drop of the dispersed flow was more than 20% higher than separated flow with otherwise the same conditions. As the flow separates, the pressure drop decreases and, as expected, finally approaches the value for separated flow. The work presents a detailed data set as basis for model development.

Experimental and molecular dynamics investigations of the effects of ionic surfactants on the wettability of low-rank coal

The wetting properties of ALES (Ammonium lauryl ether sulfate), SLES (sodium lauryl ether sulfate), TD (dodecyl triethanolamine salfate) and SDS (sodium dodecyl sulfate) solutions and their adsorption capacities on coal dust surface were evaluated by surface tension, contact angle, sink time, wetting rate, and changes in the micromorphology and functional groups on coal surface. The results showed that the four surfactants share similar adhesion and spreading wettability, while they differ notably in immersion wetting. A water-surfactant-low rank coal (LRC) system was established using Materials Studio software and the Wender coal model; then quantum chemical calculations and molecular dynamics (MD) simulations were conducted. The results showed that ALES is of the widest relative concentration distribution range (25.25–60 Å), the largest overlap range (25 Å) and the largest diffusion coefficient (D = 0.318); NH4+ can easily penetrate the surfactant layer, which proves the strong modification ability of ALES to LRC. ALES/LRC/H2O has the lowest interaction energy and the most H-bonds, indicating that ALES is of a strong adsorption capacity. Based on the experimental data and simulation results, the integrated wettabilities of the four surfactants follow ALES＞SLES＞TD＞SDS, partially contributed by the hydrolytic cations and EO groups.

Revealing Surfactant Effect of Trifluoromethylbenzene in Medium-Concentrated PC Electrolyte for Advanced Lithium-Ion Batteries.

Despite wide-temperature tolerance and high-voltage compatibility, employing propylene carbonate (PC) as electrolyte in lithium-ion batteries (LIBs) is hampered by solvent co-intercalation and graphite exfoliation due to incompetent solvent-derived solid electrolyte interphase (SEI). Herein, trifluoromethylbenzene (PhCF3 ), featuring both specific adsorption and anion attraction, is utilized to regulate the interfacial behaviors and construct anion-induced SEI at low Li salts' concentration (<1m). The adsorbed PhCF3 , showing surfactant effect on graphite surface, induces preferential accumulation and facilitated decomposition of bis(fluorosulfonyl)imide anions (FSI- ) based on the adsorption-attraction-reduction mechanism. As a result, PhCF3 successfully ameliorates graphite exfoliation-induced cell failure in PC-based electrolyte and enables the practical operation of NCM613/graphite pouch cell with high reversibility at 4.35V (96% capacity retention over 300 cycles at 0.5C). This work constructs stable anion-derived SEI at low concentration of Li salt by regulating anions-co-solvents interaction and electrode/electrolyte interfacial chemistries.

Surface activity of N-graphene quantum dot in presence of CTAB surfactant

An interface can be subtly engineered utilizing nanoparticle-surfactant interactions by controlling surface activity and surface charge balancing. In this research, the effect of N-doped Graphene Quantum Dot particles (N-GQDs) and Cetyl trimethylammonium bromide surfactant (CTAB) presence in the air/water interface is explored. We found on the study of interplay of N-GQD with CTAB that N-GQDs are surface active particles. Thereafter, the effect of concentration ratio of CTAB to N-GQD on surface tension and elasticity is investigated up to critical micelle concentration (CMC). The results demonstrate the surface activity of N-GQDs when there is no surfactant molecules (1 wt% N-GQD, surface tension (ST) ∼53). In addition, the results manifest that due to CTAB molecules' attachment to the N-GQD particles, more efficient surface-active mixtures are created. At higher surfactant loadings, the excess CTAB monomers compete with CTAB/ N-GQDs mixtures to reach the interfaces, causing mixture to come back into the bulk of liquid verified by elasticity evaluations. The preparation of N-GQDs and as a result its mixture includes economical and easy experimental protocols, and according to the synergistic effects defeat the individual components constraints i.e. –at 1% N-GQD+0.25 CMC CTAB the dynamic surface tension lies below pure CTAB CMC line.

Investigating the Effects of Various Surfactants on the Emulsion and Powder of Hazelnut Oil

Investigating the Effects of Various Surfactants on the Emulsion and Powder of Hazelnut Oil

Synergistic Effect of Surfactants of Nocardia vaccinii IMV B-7405 and Essential Oils on Candida Genus Yeast

The increase in the number of resistant strains of Candida genus representatives, capable of forming biofilms on various surfaces, stimulates the search for new, alternative methods of combating them, one of which is the use of compounds of natural origin, such as essential oils. However, at the same time, their concentration should be minimal, which is due to the ability of essential oils to cause severe damage of the human’s central nervous system and aspiration pneumonia. This leads to the necessity of searching for new methods to reduce the concentration of essential oils and at the same time to preserve their properties, in particular, by their use in a mixture with other antimicrobial agents, which can be microbial surfactants. Previously, it was found that the degree of yeast biofilm destruction under the action of Nocardia vaccinii IMV B-7405 surfactants dependson the nature of the growth substrate and is the highest in the presence of preparations synthesized on purified glycerol. Aim. To study the synergism of antifungal activity and the role in the destruction of biofilms of a mixture of Nocardia vaccinii IMV B-7405 surfactants synthesized on glycerol of different quality and essential oils. Methods. N. vaccinii IMV B-7405 was grown in a medium containing purified glycerol or waste from biodiesel production at a concentration of 2% (v/v) as carbon sources. The surfactants were extracted from the supernatant of cultural liquid by a modified Folch mixture. The antimicrobial activity of essential oils, surfactants, and their mixtures was determined by the index of the minimum inhibitory concentration. To assess the synergistic effect of a mixture of surfactants with essential oils, the fractional inhibitory concentration index was used. The degree of biofilm destruction (%) was determined as the difference between the cell adhesion in untreated and treated with surfactants, essential oil, or their mixture wells of the polystyrene microplates. Results. It was found that the surfactants synthesized by N. vaccinii IMV B-7405 on both purified glycerol and waste from biodiesel production showed synergistic antifungal activity in mixtures with cinnamon and lemongrass essential oils. Thus, the minimum inhibitory concentrations against Candida albicans D-6, Candida utilis BVS-65, and Candida tropicalis RE-2 of a mixture of surfactants synthesized on purified glycerol with cinnamon and lemongrass essential oils were 1.8—7.5 and 3.7— 15 μg/mL, respectively, and were lower than in the case of using surfactants (30-60 μg/mL), cinnamon or lemongrass essential oil (156—312 μg/mL) alone. The use of a mixture of surfactants obtained on waste from biodiesel production and cinnamon or lemongrass essential oils made it possible to reduce the minimum inhibitory concentrations of the latter against studied yeast test cultures by 14—56 times. At the same time, the index of fractional inhibitory concentration did not exceed 0.5, which indicates the synergism of the antifungal activity of the mixture of these compounds. The destruction of Candida yeast biofilms under the action of surfactants synthesized on both purified glycerol and waste from biodiesel production in a mixture with cinnamon or lemongrass essential oils reached 60—67 and 67—77%, respectively, which is an average of 25—35% higher compared to the use of each monopreparation separately. Conclusions. The results presented in this paper confirm the previously obtained data that N. vaccinii IMV B-7405 surfactants, synthesized on both traditional substrates and toxic industrial wastes, have antimicrobial and antiadhesive synergistic action with essential oils, which allows us to consider them as potential components of the so-called «antifungal locks» in the fight against of Candida genus representatives.

Microscopic Insights into the Effects of Anti-Agglomerant Surfactants on Surface Characteristics of Tetrahydrofuran Hydrate

The formation of clathrate hydrates in pipelines is potentially threatening to exploration and gas transportation in the petroleum industry. To reduce such risks, various surfactants have been explored as anti-agglomerants to prevent the aggregation of hydrate particles. However, the anti-agglomeration mechanisms are not yet fully understood. In this study, modified atomic force microscopy is first developed to investigate the effects of two surfactants, namely, 1-naphthaleneacetic acid and dodecylbenzenesulfonic acid, on the surface of a tetrahydrofuran (THF) hydrate. The surfactants have remarkable effects in terms of changing the grain size and decreasing the grain boundary depth and surface roughness of the THF hydrate. In addition, the surfactants reduce the quasi-liquid layer (QLL) thickness of the THF hydrate and the adhesion forces between the hydrate and the microsphere probe. This phenomenon may be caused by the changes induced by surfactant molecules on the water–guest molecule structure near the gas/water interface. Thus, hydrate growth is enhanced in the QLL. The adhesion forces decrease linearly with QLL thickness after adding the surfactants. These findings indicate that surfactants reduce the adhesion forces by reducing the QLL thickness at higher temperatures. The effects of surfactants on the QLL thickness and surface morphology of the hydrate are investigated, providing critical information on the cohesive behaviors among hydrate particles or between hydrate particles with other materials. Our work provides new insights into the underlying mechanism of how surfactants prevent hydrate aggregation, which is crucial in hydrate-related safety management.

Assessment of the Effect of Various Catalysts on the Destruction of Food Waste during Their Processing

The process of destruction of solid household waste occurs mainly under the action of microflora and leads to mass loss due to mineralization of organic matter, with separation of filtrate and gases. Considering the basic principles of the action of enzyme preparations, it is promising to create conditions for fermentation of the nutrient solution by a consortium of microorganisms, for example, existing in the soil. Another promising direction may be to stimulate the growth and development of native microflora (microorganisms and fungi) due to the effects of surfactants and/or providing preliminary hydrolysis of the substrate. The effect of stimulating catalyst additives on the weight loss of food waste samples was evaluated and compared. The effect was recorded in the form of a loss of substrate mass and a decrease in its volume. Variants of catalysts (honey syrup, protein hydrolysate, potassium hydrophosphate), their combinations, as well as a commercial drug and water as a comparison were investigated. Under anaerobic conditions, it was shown that the losses due to the release of gases were small, while the option with a commercial catalyst showed the greatest efficiency. Under aerobic conditions, when using a combination of molasses and an alkaline medium as a catalyst, a faster mass loss was shown, which slowed down by the end of the experiment. At the same time, an additional amount of alkali (2.8% of the substrate weight) had a significant effect on the substrate due to the alkaline hydrolysis of the components, which made them more accessible for further microbiological destruction.

Investigating the effects of surfactants on Chlorella pyrenoidosa in the hydrolysis acidification liquor by integrated physiochemical and transcriptome analyses

In our two recently published articles, we investigated the effects of Tween 80, sodium lignosulfonate (LS), sodium dodecyl sulfate (SDS), and rhamnolipid (RL) on the co-conversion of endogenous carbon (C) and nitrogen (N) of dairy wastewater in the hydrolytic acidification coupled microalgae culture system. Although the effects of surfactants on the microalgae (Chlorella pyrenoidosa) growth from the perspective of enhancing the accumulation of the volatile fatty acids (VFAs) were investigated, the question regarding the effect of surfactants themselves on microalgae growth and mechanism remains to be addressed. In this work, we extend our discussion to clearly demonstrate the effects of these four surfactants on microalgae growth, nutrient removal, and the output of the culture system in artificial hydrolysis-acidification liquor (HAL). Furthermore, de novo transcriptome profiling and the metabolic pathway analysis of C. pyrenoidosa cells in response to these four surfactants were also performed. The results showed that SDS inhibited while the other three surfactants promoted microalgae growth (promotion order of dry weight: Tween 80 > RL > LS). The maximum ammonia nitrogen removal rate followed Tween 80 80.90 % > RL 78.32 % > LS 75.23 % > control 67.08 % > SDS 34.74 %. Surfactants enhanced the C assimilation followed Tween 80 > RL ≈ LS > control. Tween 80, RL, and LS treatment groups achieved higher yield of protein, carbohydrates, and lipid. The differential transcriptome analysis revealed that the number of down-regulated differential expression of unigenes (DEUs) more than that of up-regulated in SDS group, while the opposite was true for the other 3 surfactants. KEGG enrichment analysis revealed that Tween 80 mainly affects lipid metabolism in the early stage of microalgae growth, RL mainly affects lipid metabolism and membrane transport, SDS mainly affects energy metabolism, lipid metabolism, and transport and catabolism, while no DEUs significant enriched KEGG in LS group.

Electrochemical Noise of SCC Inhibition of a Supermartensitic Stainless Steel in Sour Solution

In this work, the inhibition effect of a non-ionic gemini surfactant, named bis(2-((2-palmitoamidoethyl)amino)ethyl)1H-imidazole4,5-dicarboxylate, on the stress corrosion cracking (SCC) behavior of a supermartensitic stainless steel (SMSS) was studied in sour environment. The slow strain rate stress tests (SSRT) results and fractographic analysis revealed that the corrosion inhibitor was able to inhibit the SCC process using a concentration above than 5ppm. At concentrations of 0 and 5 ppm, the steel showed a brittle fracture with susceptibility to SCC, whereas at concentrations of 25 and 100 ppm, the fracture was ductile, and the steel was practically immune to SCC. The EN measurements showed transients associated with pits and microcracks, which were confirmed by SEM examination. The EN analysis using the shot noise theory indicated that localized corrosion was the dominant corrosion process at the concentrations of inhibitor in which the SMSS was susceptible to SCC.

Synergistic effects of Gemini cationic surfactants with multiple quaternary ammonium groups and anionic surfactants with long EO chains in the mixed systems

In this study, two different anionic surfactants containing long polyoxyethylene chains involving sodium fatty alcohol ether carboxylates (AE9C) as well as isomeric sodium fatty alcohol ether sulfates (iso-AE9S) are mixed with a new Gemini cationic surfactant bearing four quaternary ammonium groups (TC-GS). Then, the surface properties and aggregation behavior of the two mixed systems were investigated. The effect of the long polyoxyethylene chains on the conformation and hydration of the hydrophilic head group of AE9C and iso-AE9S weakened their negative charge density, thus hindering their excessive electrostatic adsorption with TC-GS and improving the stability of the mixed systems. The positive synergistic effects of TC-GS/AE9C and TC-GS/iso-AE9S exhibited significantly lower critical micelle concentration, faster diffusion rates, and superior wetting capability compared to single surfactants. The micellization process of both mixed systems is spontaneously enthalpy-driven, and the diffusion-adsorption process is consistent with the mixed diffusion-kinetic mechanism. Finally, both mixed systems are capable of forming complex and interesting aggregate morphologies, with TC-GS/AE9C can form multilayer spherical vesicles and TC-GS/iso-AE9S can form multicompartment concentric spherical vesicles.

A review on nanofluids coupled with extended surfaces for heat transfer enhancement

Recently, due to the increasing demands for effective and efficient devices, the thermal sections of modern machinery deserve considerable attention. Researchers in the field of thermal engineering have since devised strategies of combined passive methods for further heat transfer enhancement. From the available literature, the employment of nanofluids, coupled with extended surfaces is scarce, with limited studies optimizing both techniques. The current investigation summarizes the combined effects of nanofluids coupled with various types of extended surfaces, within numerous applications. Parameters involving the nanofluid type, volume concentration, fin geometry, and flow conditions were examined, whereby their respective effects were investigated on the thermal performances. It was deduced that the effects of surfactants, nanoparticle volume concentration, and Reynolds number significantly contributed to the heat transfer enhancement. The review presents a trend finding that nanoparticle volume concentration would positively contribute to heat transfer enhancement, up to an extent. Surpassing the optimal concentration would lead to lower Brownian motions associated with higher viscosity and density. In terms of extended surfaces, the state-of-the-art review denoted that each fin design possesses a unique attribute that alters the thermal and hydraulic performances. Nevertheless, researchers fabricating novel fin designs should highly prioritize the effects on pressure drop when employing fins. Combining both techniques, the nanofluids and extended surfaces achieved remarkable results. The outstanding results could potentially achieve the standards of active methods, for a fraction of the operational cost. Concluding, the information surrounding the present review may be of aid to researchers developing new approaches utilizing nanofluids and extended surfaces.

Effect and Mechanism of Different Surfactants on the Stability of the Al/JP-10 Nanofluid Fuel System

Effect and Mechanism of Different Surfactants on the Stability of the Al/JP-10 Nanofluid Fuel System

Surfactant effect on mass transfer characteristics in the generation and flow stages of gas–liquid Taylor flow in a microchannel

The understanding of surfactant effect on mass transfer behaviors in microchannel devices remains insufficient even though it has been frequently added into gas–liquid systems to promote process stability. Accordingly, this work concentrates on the surfactant effect on mass transfer performances by decoupling the whole process as bubble generation and flow stage. The results show that the role of gas absorption during bubble generation process always exceeds 30 % of the total amount in the microdevice. The surfactant concentration remarkably influences the mass transfer in the bubble generation stage but slightly affects the flow stage. Importantly, the mass transfer coefficient in the generation stage is dozens of times that in the flow stage, and the inherent mechanism is revealed. Finally, the semi-empirical correlations containing the surfactant content are developed for mass transfer coefficients in two stages. This work provides some indispensable information about the selection of surfactants in microfluidic technology.

The influence mechanism and the contribution of capillary force and gravity to recovery in spontaneous imbibition in low permeability reservoirs

Spontaneous imbibition is one of the important means to enhance oil recovery in low permeability reservoirs, and it has good field application effects. Through the interfacial tension (IFT), contact angle (CA), and adsorption experiments, the effects of SDBS surfactant on IFT and reservoir wettability were studied, and the adsorption rule of SDBS at the mineral surface was obtained. On this basis, the imbibition recovery and mechanism of cores with different permeability are studied. The study showed that in low permeability reservoir, gravity and capillary force are the main controlling factors of imbibition. In the early stage, gravity determines the recovery, because the imbibition rate is 2.75 times that dominated by capillary force. The capillary force can continue to produce oil in small pores, and the imbibition time is twice that of gravity, which determines the recovery in the late imbibition stage. Therefore, the synergistic effect of gravity and capillary force can optimize the imbibition recovery, in low permeability reservoirs. When the concentration of SDBS solution is CMC (0.1%), due to the mineral interface adsorbs, the capillary force decreases by 10.76%, and the adhesion work increases by 3.42 times, resulting in a decrease in the imbibition recovery. The imbibition driving force is different for different reservoir properties, which can be adjusted by adding a surfactant to change IFT and CA.

Effect of cationic and anionic surfactants on the wettability and interfacial tension of oil-brine systems in analogous rocks from the Chicontepec Paleochannel, Mexico

The chemical enhanced oil recovery (cEOR) uses substances to improve the mobility of petroleum in reservoirs. Among these substances are the surfactants, whose purpose is to change the wettability and interfacial tension (IFT). We focus on experiments of surfactants in rocks from Chicontepec Paleochannel. CTAB, DTAB and SDS surfactants in brines of NaCl and KCl and mineral oil were investigated for reduction of IFT and contact angle alteration. The sessile and pendant drop methods were used to determine the IFT. The electrical affinity of the rock surface, dissolved ions, and the surfactant molecules, play key roles in the alteration of wettability and IFT. Thus, one scheme of interactions between the electrical charges is proposed on the basis of the rocky characterization and the following results: the lowest contact angle was 106° with CTAB at 0.01 wt% in brines at 9.25 g/L NaCl, and 108° with SDS at 0.01 wt% in brines at 20 g/L NaCl. The smallest IFT was 0.813 dyn/cm with CTAB at 0.5 wt% in brines at 5 g/L KCl. This work serves as first assessments of these surfactants to enhance the production in Chicontepec, employing cheap tensoactives to increase the applicability. Besides, these results will guide future displacement tests as cEOR lab simulation.