Fatty Alcohol Ethoxylates Research Articles

Addressing the non‐ideality of an application relevant surfactant mixture within the hydrophilic–lipophilic‐deviation concept

AbstractIn cleaning products, selecting the right surfactants for the specific soil or contamination is crucial. The hydrophilic–lipophilic deviation (HLD) concept serves as a useful formulation tool by describing the interactions between surfactants, oil and water. However, for mixtures of ionic and non‐ionic surfactants, the HLD concept assumes ideal mixing behavior, which does not hold true. Therefore, interactions between different surfactants must be considered. This can be achieved by introducing the interaction term GEX/RT. Evaluating this interaction term using a set of equilibrated surfactant/oil/water (SOW) systems under various conditions is both time‐consuming and resource intensive. This work aims to demonstrate the rapid determination of this interaction term using the dynamic phase salinity inversion (DSPI) method. We determined the phase behavior of a ternary surfactant system, consisting of sodium dioctyl sulfosuccinate, alkyl polyglucoside, and fatty alcohol ethoxylate, through both equilibrated systems and the DSPI method. Differences between the theoretical HLD calculations and actual experiments allowed us to access interaction terms. To validate GEX/RT obtained by DSPI, we employed net‐average‐curvature concept to model the interfacial tension under different conditions. Spinning drop measurements showed excellent agreement between theoretical and measured values, confirming the applicability of DSPI for determining interactions in this surfactant system.

Scaled-up production and recovery of lipopeptide biosurfactant and its application for washing petroleum-contaminated drill cuttings

A simple and efficient fermentation strategy using chitosan-immobilized Bacillus subtilis GY19 was developed for large-scale lipopeptide production from waste glycerol and palm oil. When a fed-batch fermentation approach was employed, excessive foaming was minimized, while lipopeptide production was greater than that of conventional batch fermentation. When a 700L stirred tank fermenter with a 400L working volume was used, a lipopeptide concentration and yield of 7.55g/L and 0.190g/g of substrate, respectively, were achieved. The pilot-scale recovery process involved sequential bacterial cell removal via centrifugation, elimination of impurities through acidification of the cell-free broth, and partial purification and concentration of the lipopeptides via ultrafiltration. A 5kDa stabilized cellulose-based membrane maintained a constant permeate flux and resulted in 67.2% lipopeptide recovery. The concentrated lipopeptide retentate contained 16.8g/L lipopeptides and a surface tension of 28.82 mN/m. A biobased washing agent for the treatment of petroleum-contaminated drill cuttings was later formulated with the retentate and various vegetable oil-based surfactants via the simplex−lattice mixture design methodology. The mixture of 1% retentate and 4% fatty alcohol ethoxylate 5EO presented the greatest removal efficiency of 83.2% for drill cuttings containing 15% (w/w) total petroleum hydrocarbons. The formulation also mobilized petroleum hydrocarbons into a distinct free oil layer, which would be easy to separate and subsequently recycle. These findings demonstrate the scalability of the lipopeptide production and recovery process, while the biobased washing agent offers an environmentally friendly approach for petroleum remediation.

Polymer-modified mortar flexibility of the masonry-concrete structure interface

High crack occurrences at the masonry-infilled wall partition-reinforced concrete structure interface is a problem that challenges the Brazilian construction process. Improving the mortar’s flexibility is suggested as a potential solution, but it's still not widely known. This paper evaluates industrialized mortar properties modified with four polymers and one plasticizer additive. The research methodology consisted of an experimental investigation related to the mortar properties using styrene-acrylic copolymer (SAE), polyvinyl acetate copolymer (PVAc), styrene-butadiene copolymer (SBR), white glue PVA (polyvinyl acetate), and a sulfated ethoxylated fatty alcohol salt plasticizer additive. The polymers were used in addition to (4%, 5% and 8%) and instead of (4% and 5%) the amount of water established by the manufacturer of the reference mortar, while the amount of additive used was 0.08%. The investigation characterization considered the fresh and hardened conditions, especially, the flexibility evaluation, and tests of elasticity modulus and transverse deformation were carried out, in addition to scanning electron microscopy (SEM). The results showed that there was an elasticity modulus reduction of all mixtures compared with the reference mortar without modification. The transverse deformation results range from a minimum of 0.23 mm (SBR) to a maximum of 0.94 mm (SAE). Regarding SEM, the tests with polymers have smoother and less porous surfaces. The mortar flexibility performance with different additive contents is the main contribution of this research.

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.

Biological and Synthetic Surfactants Increase Class I Integron Prevalence in Ex Situ Biofilms.

The role of biocides in the spread of antimicrobial resistance (AMR) has been addressed but only a few studies focus on the impact of surfactants on microbial diversity and AMR, although they are common constituents of cleaners, disinfectants, and personal care products and are thus released into the environment in large quantities. In this study, we used a static ex situ biofilm model to examine the development of four biofilms exposed to surfactants and analyzed the biofilms for their prevalence of class I integrons as a proxy for the overall abundance of AMR in a sample. We furthermore determined the shift in bacterial community composition by high-resolution melt analysis and 16S ribosomal RNA (16S rRNA) gene sequencing. Depending on the initial intrinsic prevalence of class I integrons in the respective ex situ biofilm, benzalkonium chloride, alkylbenzene sulfonate, and cocamidopropyl betaine increased its prevalence by up to 6.5× on average. For fatty alcohol ethoxylate and the biosurfactants sophorolipid and rhamnolipid, the mean increase did not exceed 2.5-fold. Across all surfactants, the increase in class I integrons was accompanied by a shift in bacterial community composition. Especially benzalkonium chloride, cocamidopropyl betaine, and alkylbenzene sulfonate changed the communities, while fatty alcohol ethoxylate, sophorolipid, and rhamnolipid had a lower effect on the bacterial biofilm composition.

Emerging pollutants in textile wastewater: an ecotoxicological assessment focusing on surfactants.

Water and several chemicals, including dyestuffs, surfactants, acids, and salts, are required during textile dyeing processes. Surfactants are harmful to the aquatic environment and induce several negative biological effects in exposed biota. In this context, the present study aimed to assess acute effects of five surfactants, comprising anionic and nonionic classes, and other auxiliary products used in fiber dyeing processes to aquatic organisms Vibrio fischeri (bacteria) and Daphnia similis (cladocerans). The toxicities of binary surfactant mixtures containing the anionic surfactant dodecylbenzene sulfonate + nonionic fatty alcohol ethoxylate and dodecylbenzene sulfonate + nonionic alkylene oxide were also evaluated. Nonionic surfactants were more toxic than anionic compounds for both organisms. Acute nonionic toxicity ranged from 1.3mg/L (fatty alcohol ethoxylate surfactant) to 2.6mg/L (ethoxylate surfactant) for V. fischeri and from 1.9mg/L (alkylene oxide surfactant) to 12.5mg/L (alkyl aryl ethoxylated and aromatic sulfonate surfactant) for D. similis, while the anionic dodecylbenzene sulfonate EC50s were determined as 66.2mg/L and 19.7mg/L, respectively. Both mixtures were very toxic for the exposed organisms: the EC50 average in the anionic + fatty alcohol ethoxylate mixture was of 1.0mg/L ± 0.11 for V. fischeri and 4.09mg/L ± 0.69 for D. similis. While the anionic + alkylene oxide mixture, EC50 of 3.34mg/L for D. similis and 3.60mg/L for V. fischeri. These toxicity data suggested that the concentration addition was the best model to explain the action that is more likely to occur for mixture for the dodecylbenzene sulfonate and alkylene oxide mixtures in both organisms. Our findings also suggest that textile wastewater surfactants may interact and produce different responses in aquatic organisms, such as synergism and antagonism. Ecotoxicological assays provide relevant information concerning hazardous pollutants, which may then be adequately treated and suitably managed to reduce toxic loads, associated to suitable management plans.

Study on the Performance Mechanism of Polyformaldehyde Glycol Ether Polymer for Crude Oil Recovery Enhancement.

The demand for energy continues to increase as the global economy continues to grow. The role of oilfield chemicals in the process of oil and gas exploration, development, and production is becoming more and more important, and the demand is rising year by year. The support of national policies and the formulation of environmental protection regulations have put forward higher requirements for oilfield chemical products, which has promoted the innovative research and development and market application of oilfield chemicals. Polyformaldehyde glycol ether polymer (PGEP) is simple to synthesize, easily biodegradable, green and environmentally friendly, and in line with the development trend of chemicals used in oil and gas development. The interfacial tension performance of PGEP after compounding with different surfactants can reach as low as 0.00034 mN/m, which meets the requirements of the oilfield (interfacial tension ≤ 5 × 10-3 mN/m). The best oil washing efficiency performance of PGEP compounded with different surfactants reached 78.2%, which meets the requirements of the oilfield (oil washing efficiency ≥ 40%). The fracturing fluid drainage efficiency of PGEP after compounding with different surfactants reaches 22%, which meets the requirements of the oilfield (drainage efficiency ≥ 15%). The surface interfacial tension of the system remains constant after the concentration exceeds 0.2% and decreases with lower concentrations. The drainage efficiency increases with increasing concentrations in the range below 0.6%. It was determined that PGEP can be used as a surfactant instead of fatty-alcohol ethoxylates (FAE) in oilfield development.

Mild but effective skin cleansing-Evaluation of laureth-23 as a primary surfactant.

Skin cleansing products are among the main reasons for the development of hand eczema. Therefore, a mild but effective skin cleansing product is of particular interest, especially in the work place, where various contaminations frequently have to be removed from hands. In this study, the potential of laureth-23 as a primary surfactant was evaluated and compared to other fatty alcohol ethoxylates (FAEO). Also, different laureth-23 surfactant combinations were compared to each other. Therefore, transepidermal water loss, erythema and visual scoring were measured after occlusive patch testing in 24 healthy subjects (aged 18-55). Afterwards, the results were ranked from low to high irritant potential and an irritation score was calculated. Furthermore, the cleaning performance was tested using an automated cleansing device in 10 healthy subjects (aged 18-55). The results confirmed the low irritant potential of laureth-23 and blends thereof. Within the different laureth-23 surfactant combinations, the combination of laureth-23 with a mild amphoteric and a mild anionic surfactant was superior to other laureth-23 surfactant combinations like laureth-23/anionic/anionic regarding skin compatibility as well as cleaning performance. In conclusion, laureth-23 showed very good performance as a primary surfactant. Especially, the combination of laureth-23, cocamidopropyl betaine and disodium laureth sulfosuccinate was mild to the skin while also showing good cleansing performance.

Optimizing Excipient Properties to Prevent Aggregation in Biopharmaceutical Formulations.

Excipients are included within protein biotherapeutic solution formulations to improve colloidal and conformational stability but are generally not designed for the specific purpose of preventing aggregation and improving cryoprotection in solution. In this work, we have explored the relationship between the structure and antiaggregation activity of excipients by utilizing coarse-grained molecular dynamics modeling of protein-excipient interaction. We have studied human serum albumin as a model protein, and we report the interaction of 41 excipients (polysorbates, fatty alcohol ethoxylates, fatty acid ethoxylates, phospholipids, glucosides, amino acids, and others) in terms of the reduction of solvent accessible surface area of aggregation-prone regions, proposed as a mechanism of aggregation prevention. Polyoxyethylene sorbitan had the greatest degree of interaction with aggregation-prone regions, decreasing the solvent accessible surface area of APRs by 20.7 nm2 (40.1%). Physicochemical descriptors generated by Mordred are employed to probe the structure-property relationship using partial least-squares regression. A leave-one-out cross-validated model had a root-mean-square error of prediction of 4.1 nm2 and a mean relative error of prediction of 0.077. Generally, longer molecules with a large number of alcohol-terminated PEG units tended to interact more, with qualitatively different protein interactions, wrapping around the protein. Shorter or less ethoxylated compounds tend to form hemimicellar clusters at the protein surface. We propose that an improved design would feature many short chains of 5 to 10 PEG units in many distinct branches and at least some hydrophobic content in the form of medium-length or greater aliphatic chains (i.e., six or more carbon atoms). The combination of molecular dynamics simulation and quantitative modeling is an important first step in an all-purpose protein-independent model for the computer-aided design of stabilizing excipients.

Cascade Kinetic Model on Ethoxylation of Iso/Sec/n-Octanol Catalyzed by Alkali Hydroxides/Alkoxides and Its Experimental Verification

BackgroundEthoxylation kinetics of isomeric and secondary alcohols are crucial to the ethylene oxide (EO) distribution of alcohol ethoxylates, which might be influenced by basicity intensity of catalysts, similar as the ethoxylation of linear alcohols in the presence of alkali hydroxides/alkoxides catalysts; but may be affected by the steric hindrance caused by the branch chains of the ethoxylates. MethodsA kinetic model is derived based on SN2 mechanism of base-catalyzed ethoxylation of fatty alcohols, and experimentally verified with the initial kinetic characteristics in ethoxylation of 2-ethylhexanol (2-EH), 2-octanol (2-OT) and 1-octanol (1-OT) catalyzed by alkali hydroxides/alkoxides, CH3OK, CH3ONa, KOH and NaOH by GC monitoring the yields of each monodisperse oligo (ethylene glycol) iso/sec/n-octyl ethers. Significant findingsWith same catalyst, the ethoxylation rate constants of mono- (k0′) and di-adduction (k1′) products of iso/sec/n-octanol are dominated by the steric hindrance of the octanols, resulting higher k1′/k0′ for 2-EH and 2-OT than that of 1-OT; but the effect of the steric hindrance on initial EO distribution could be eliminated by stronger catalyst basicity. This finding suggests that the stronger catalyst basicity is beneficial to suppress the adverse steric hindrance of branch octanols (2-EH and 2-OT) on initial adduction rates, therefore resulting in a narrower EO distribution profile of the ethoxylates.

Surface and thermodynamics properties of commercial fatty-alcohol ethoxylate surfactants

The present study provides the surface and thermodynamic properties data of commercial fatty-alcohol ethoxylate surfactants (FAEs) at different temperatures (25–60 °C). These compounds are a mixture of fatty-alcohol ethoxylate oligomers with different degree of ethoxylation (2.6–11) and length of the alkyl chain (C10-C18). In this work, we analyzed determinate the water content by the Karl-Fisher method and measured the surface tension using the Wilhelmy plate method. In addition, we studied the effect of their structural parameters (degree of ethoxylation and length of alkyl chain) and the temperature on the changes of the thermodynamic functions (Gibbs free energy, enthalpy, and entropy) for the processes of adsorption and micellization. It was found an exponential decrease of the critical micellar concentration (CMC) in molar scale with the length alkyl chain of the fatty-alcohol ethoxylate surfactants, and the CMC values and thermodynamic parameters agree with those values found in literature for pure compounds. Moreover, the micellization entropy increases with the degree of ethoxylation of the surfactant.

Synergy Effect between Sodium Oleate and Alcohol Ethoxylates on the Reverse Flotation of Quartz

In this study, an optimized method was presented for the reverse quartz flotation in iron ore purification where sodium oleate (NaOL) was always selected as the collector due to its accessibility and economic benefits. Three alcohol ethoxylates, octylphenol ethoxylate (OP-10), nonylphenol ethoxylate (NP-10) and fatty alcohol ethoxylates (AEO-9) were introduced to improve the collecting performance of NaOL in the reverse flotation of quartz. It turned out that the addition of alcohol ethoxylates was helpful to increase the recovery of quartz in the flotation with the order of OP-10 > NP-10 > AEO-9. To characterize the adsorption of NaOL on activated quartz in different surfactant systems, Fourier-Transform Infrared Spectroscopy (FTIR) and Quartz Crystal Microbalance with Dissipation (QCM-D) were employed. Furthermore, the contact angles of the quartz surface that interacted with different surfactant systems were measured to investigate the synergy effect of NaOL and alcohol ethoxylates on the hydrophobicity of quartz. It turned out that alcohol ethoxylates promoted the adsorption of NaOL on the activated quartz, resulting in an increase in the hydrophobicity of quartz also in the order of OP-10 > NP-10 > AEO-9, which well explained the flotation results. Regular Solution Theory (RST) and the dilution effect based on the surface tension analysis were utilized to elucidate the synergy mechanism between NaOL and the alcohol ethoxylate.

Identification and Quantification of Organic Contaminants and Evaluation of Their Effects on Amine Foaming in the Natural Gas Sweetening Industry.

Contamination is a leading cause of corrosion, foaming, and amine-absorption capacity limitation, predominantly foaming. There is currently an urgent need to identify the sources of amine foaming and eliminate them or reduce their impacts. Gas chromatography-mass spectrometry (GC-MS) and a sample pretreatment method were developed to identify and quantify the organic contaminants. Linear hydrocarbons (C12-C22), long-chain carboxylic acids and esters, alcohol ethoxylates, and benzene derivatives were detected, characterized, and quantified in amine solutions. Furthermore, the effects of the contaminant concentrations on foaming behavior were also investigated by adding those contaminants. The results reveal that the main issue of foaming is due to the presence of unsaturated fatty acids and alcohol ethoxylates, even with a small amount of 10 ppm, whereas benzene derivatives like methylpyridine, quinoline, methyl naphthalene, benzyl alcohol, octahydroacridine, and linear hydrocarbons have little effect on amine foaming, even with an amount up to 2000 ppm. Therefore, it is necessary to monitor the existence and content of these surface-active contaminants.

Efficacy of Metribuzin Doses on Physiological, Growth, and Yield Characteristics of Wheat and Its Associated Weeds.

Weeds cause a serious constraint to wheat productivity. Chemical weed control is considered the most effective method to control weeds; however, a suitable dose and combination of herbicide with adjuvants play a vital role in controlling weeds and producing maximum wheat production. A field study was conducted to investigate the effectiveness of various doses of metribuzin alone or in combination with adjuvants [Bio-power (alkyl ether sulfates and sodium salts) and Ad-500 (fatty alcohol ethoxylate)] on the growth and yield of wheat and its associated weeds. Metribuzin at 175, 140, and 105 g a.i ha–1, each in combination with adjuvants (Bio-power or Ad-500) at 400 ml ha–1, were sprayed. A weedy check was also included as a control treatment. The wheat crop was infested with Fumaria indica, Melilotus indica, Anagallis arvensis, and Phalaris minor, and metribuzin with or without adjuvant was sprayed at two- to four-leaf stage of the weeds. The photosynthetic activity, weed population of each weed, and biomass of each weed was significantly affected by all herbicides along with the adjuvant. However, maximum inhibition of tested weeds was observed where metribuzin at 175 g a.i ha–1 + Bio-power at 400 ml ha–1 were sprayed. Metribuzin sprayed at 175 g a.i ha–1 with or without Bio-power recorded a maximum 1,000-grain weight, biological yield, and grain yield. Conclusively, metribuzin sprayed at 175 g a.i ha–1 + Bio-power at 400 at ml ha–1 have the potential to improve wheat yield by inhibiting weed growth, and Bio-power was superior to Ad-500 in improving the efficacy of metribuzin against weeds of wheat crop.

Determination of degree of ethoxylation of fatty alcohol ethoxylates by FTIR/ATR spectroscopy and multivalibrate calibration

Abstract The aim of the present work is to develop a fast and simple methodology of analysis of the degree of ethoxylation (ethylene oxide content – EO) of linear C12–C15 fatty alcohol ethoxylates using Fourier transform infrared spectroscopy with attenuated total reflectance accessory. The spectra were recorded in the range of 2000 cm−1 to 600 cm−1, with 64 scans and a resolution of 4 cm−1. The calibration of a linear model using the partial least square regression method applied to the spectral data allowed determination of the ethylene oxide content of the samples. The regression coefficient obtained for the model was R 2 = 0.9948 and the precision of the model was 0.014. The methodology is an important tool for quality control of non-ionic surfactants used in manufacturing of a broad range of final products in the chemical industry.

Recovery of Water from Textile Dyeing Using Membrane Filtration Processes

The aim of the work was to purify model textile wastewater (MTW) using a two-stage membrane filtration process comprising nanofiltration (NF) and reverse osmosis (RO). For this purpose, a nanofiltration membrane TFC-SR3 (KOCH) and reverse osmosis membrane AG (GE Osmonics) were used. Each model wastewater contained a selected surfactant. The greatest decrease in flux in the initial phase of the process occurred for the detergents based on fatty-acid condensation products. An evident decrease in performance was observed with polysiloxane-based surfactants. No fouling effect and high flux values were observed for the wastewater containing a nonionic surfactant based on fatty alcohol ethoxylates. During RO, a significantly higher flux and lower resistance were observed for the feed that originally contained the anionic agent. For the MTW containing the nonionic surfactant, the conductivity reduction ranged from 84% to 92% depending on the concentrate ratio at the consecutive stages of RO. After treatment, the purified wastewater was reused in the process of dyeing cellulose fibers with reactive dyes. The research confirmed that textiles dyed with the use of RO filtrates did not differ in quality of dyeing from those dyed in pure deionized water.

Rheology Control Using Nonionic Cosurfactants and pH Titration in an Amino Acid-Derived Surfactant Composition.

Sulfate-based formulations can be easily thickened by adding salt or amphoteric cosurfactants. However, sulfate-free and amino acid-based surfactants cannot. We explored an alternative thickening mechanism by studying the thickening effect of adding nonionic cosurfactants to a mixture of an amino acid-based surfactant, sodium lauroyl sarcosinate (SLSar), and a zwitterionic cosurfactant, cocamidopropyl hydroxysultaine (CAHS) at a 6:9 weight ratio. To characterize the formulations, we combined traditional rheometry with a state-of-the-art mesoscopic analysis of micelle dynamics obtained via diffusing wave spectroscopy. In addition, the formulations were characterized by cross-polarized light microscopy and dynamic light scattering. The cosurfactants studied included fatty alcohols, alkanediols, a fatty acid, and fatty alcohol ethoxylates (CnE3 and CnE6). Adding the nonionic cosurfactants increased the zero-shear viscosity up to 350 times the viscosity of the no-additive system at neutral pH. When pH titration was incorporated as a second thickening mechanism, the viscosity maximum was lower than the no-additive mixture. Furthermore, the pH of the viscosity maximum was shifted to higher pH for all systems except for CnE6, which shifted the maximum to lower pH. The nonionic amphiphiles also broadened the viscosity maximum, particularly in the C10OH system. Consequently, the C10OH system had a more favorable profile for development as a practical thickening system for an amino acid-based cleanser. Analysis according to the Zou and Larson micelle dynamics model revealed that the broadening effect was associated with substantially longer breakage times for the C10OH system (4-208 ms) compared to the no-additive system (4-38 ms).

Influence of Blending of Nonionic Emulsifiers Having Various Hydrophilic Head Sizes on Lipid Oxidation: Investigation of Antioxidant Polarity Interfacial Characteristics Relationship.

The purpose of this study was to deliver insights into the effect of interfacial composition and antioxidant polarity on the lipid oxidation of emulsions. Emulsions were created using blends of nonionic ethoxylated fatty acid alcohol surfactants with different hydrophilic head sizes, and lipophilic (TBHQ) and amphiphilic (lauryl gallate) antioxidants were incorporated into the emulsions. At the same surfactant concentration, emulsion stabilized with surfactant with a smaller hydrophilic head was more susceptible to lipid oxidation than that stabilized with surfactant with a larger hydrophilic head. When surfactants with a similar hydrophilic head size were used, lipid oxidation in emulsion containing more surfactant was slightly faster than that containing less surfactant. When emulsions were created with a 1:1 molar ratio mixture of surfactants with small and large hydrophilic heads, surfactant concentration (1.00 and 2.932 mM) had little effect on lipid peroxide generation rate. However, the concentration of thiobarbituric acid-reactive substances (TBARSs) in the emulsion prepared at 1.00 mM increased faster than that prepared at 2.93 mM. Alteration of interfacial composition and surfactant concentration did not affect antioxidant ability, regardless of antioxidant polarity, to inhibit lipid peroxide generation. However, the ability of lauryl gallate and TBHQ to prevent TBARS generation was elevated by mixing surfactants with small and large hydrophilic heads and by decreasing surfactant concentration. In most emulsions, lauryl gallate showed a more effective antioxidant ability than TBHQ.

Synthesis and Characterization of Novel Fatty Alcohol Ethoxylate Surfactants for Corrosion Inhibition of Mild Steel

Novel fatty alcohol ethoxylate surfactants (NFAES) C1:(C12–C14–EO30) and C2:(C16–C18–EO30) were synthesized and characterized, and the effect of an increase of the hydrocarbon chain length at the same numbers of ethoxylated groups of these surfactants on the corrosion of mild steel (MS) in 1 M HCl was studied by different methods. These have revealed that the inhibition efficiency (IE%) increases with increasing the dose and the hydrocarbon chain length at the same number of ethoxylated groups in the surfactants (NFAES). The surfactants (NFAES) have a perfect performance as corrosion inhibitors. The results revealed that C2 > C1 in the IE% at the same studied dose of each surfactant, The IE% reached 85% at the very low dose of 30 ppm. Potentiodynamic measurements (PP) revealed that the NFAES surfactants are working as mixed type of inhibitors for both cathodic (reduction) and anodic (oxidation) reactions. The critical micelle dose for C1 is 350 ppm while for C2 it is 30 ppm. IE% acquired from PP, electrochemical impedance spectroscopy, and electrochemical frequency modulation are approximatly the same. The surface morphology was analyzed and is discussed.

Oil recovery from polymer-containing oil sludge in oilfield by thermochemical cleaning treatment

Polymer-containing oil sludge inevitably was produced during oilfield exploitation, which caused serious environmental pollution and resource waste. In this study, thermochemical cleaning method was firstly applied to treat oil sludge from Shengli Oilfield to solve environmental pollution, recover crude oil and achieve resource utilization. Through preliminary screening of cleaning agents, such as hexadecyl trimethyl ammonium bromide (CTMAB), sodium dodecyl benzene sulfonate (SDBS), fatty alcohol polyoxyethylene sulfate (AES), rhamnolipid, fatty alcohol ethoxylate (AEO-9), polyoxyethylene castor oil ether (EL100), polyoxypropylene polyoxyethylene propylene glycol ether (SP169), Tween 80, and Na2SiO3, three cleaning agents including Na2SiO3, SP169 and rhamnolipid were more effective than others. The optimized conditions of three cleaning agents were determined by measuring oil recovery rate. Afterwards, the ratio of Na2SiO3, SP169, and rhamnolipid in the mixed cleaning agent was 10:1:0.5. Under the cleaning conditions with an agent content of 1.1 %, a liquid-solid ratio (L/S) of 7:1, a temperature of 70 °C, a stirring speed of 400 rpm, a cleaning time of 60 min, the highest oil recovery rate could reach 98 %. Compared with a single cleaning agent, the average oil recovery rate was increased by 20 %. The mechanism of thermochemical cleaning treatment of oil sludge was further discussed. This research provided a theoretical foundation and technical support for the efficient treatment and resource recovery of polymer-containing oil sludge in oilfields.