Sodium Lauryl Ether Sulfate Research Articles

Experimental Study on Mechanical and Thermal Behavior of Foamed Concrete

Foamed concrete possesses characteristics such as high strength-to-weight ratio and low density. Foamed concrete reduces dead loads on the structure,saves energy and lowers the labour cost during construction. Foam concrete consists of cement, fly ash, water and air voids. The foaming agent used to generate foam is sodium lauryl ether sulphate. Foam concrete can have 10% to 70% air, which results in a material that is light-weight but may compromise the compressive strength and durability properties. Although it has been shown in the research that less connected air voids yield a lower reduction in compressive strength, with the increase in air voids the thermal resistance in increased. The properties like compressive strength and thermal resistance are studied. Six batches of Foamed concrete were prepared with varying air content 15%, 17%, and 20%. The foamed concrete cube and slab are used for compression and thermal testing. The dry density of foamed concrete varies from 860 kg/m3 to 1245 kg/m3, and the compressive strength varies from 2.5 - 6.5 MPa. In this research, the Dry density, compressive strength and thermal conductivity of foamed concrete is compared with the clay bricks. If foamed concrete blocks are used instead of clay bricks, almost 50% of the dead load of the building can be reduced. The thermal conductivity of foamed concrete varies from 0.021 - 0.035 W/mK. Key outcomes revealed that foamed concrete has good potential to be used for lightweight structural applications for low-rise buildings owing to its evolution of mechanical properties, transport properties and thermal resistance.

Dosimetric effect of the gantry rotations of a novel trunk phantom using an area integration algorithm

Background: Treatment planning systems (TPSs) have proved to be a useful tool in predetermining how a treatment outcome will be in radiotherapy. The accuracy of any TPS to calculate dose to any arbitrary point within a material is largely dependent on the mathematical algorithm used. Aims: The purpose of this study was to design a local trunk phantom and use the phantom to check the percentage dose accuracy of the Area Integration Algorithm of a Precise PLAN 2.16 TPS if it is in agreement with results obtained from manufacturer's verification by varying the gantry angle and whether it is within ± 5% International Commission on Radiation Units and Measurements (ICRU) minimal limit. Materials and Methods: The study was executed with a locally designed phantom made of Plexiglas with six insert and an ionization chamber port. The phantom was simulated using a HiSpeed NX/i computed tomography scanner and Precise PLAN 2.16 TPS for application of beam setup parameters. The mimicked organs for the inserts were: 25%–75% Glycerol-Water for liver, pure carboxyl methyl cellulose was used for lungs, 30%–70% Glycerol-Water for muscle, 40%–60% Glycerol-Water was used for adipose, pure Sodium hypochlorite was used for bone and pure sodium laureth sulfate (Texapon) for kidney. Results: The maximum percentage (%) deviation with a large field for six inhomogeneous inserts and with bone only homogeneous inserts were 3.4% and 2.9%, respectively. The maximum % deviation with a small field for six inhomogeneous inserts was 3.2%. The % deviation between the solid water phantom and the locally designed phantom was 3.5%. Conclusion: The Area Integration Algorithm has shown an overall accuracy of 4% below 5% ICRU minimal limit. There was no statistically significant difference in field sizes and in inhomogeneity/homogeneity, respectively. Variation exists in % deviation for small field size with parallel opposed field between our verification and the manufacturers.

A bioassay battery for the ecotoxicity assessment of soils conditioned with two different commercial foaming products

Alkylethoxysulfate (AES) surfactants are the main component of most commercial products used for soil conditioning in the excavation industry, in particular as lubricants for mechanized tunnelling. Huge amounts of soil debris are produced during the excavation process and their possible re-use as by-products (e.g. land covering) or discharge as waste is a critical question in civil engineering. There can be an environmental impact from the potential ecotoxicity of the residual chemical mixture occurring in the foam-conditioned excavated soil. Chemical analyses are not able on their own to assess the potential hazards for the ecosystem ascribable to inadequate management of this kind of conditioned soil. Ecotoxicological tests, on the other hand, provide useful overall information about the potential effects of conditioned debris on soil and aquatic biota, including synergic ones, whether or not there is a detailed knowledge of the chemical composition of all the components of the commercial foaming products.In this context, the objective of this work was to evaluate the overall ecotoxicity of excavated soil conditioned with two common foaming products containing sodium lauryl ether sulphate (SLES) as the main component, in order to verify their possible re-use as by-products. For this purpose, two soils with different geopedological characteristics were conditioned with the commercial foaming agents at the concentrations utilised for mechanized tunnelling and then used for microcosm laboratory experiments. Soil sub-samples were collected at different times (0, 7, 14, 28 days) of incubation and soil elutriates were produced to assess the effects of the foaming agents on five test species (Pseudokirchneriella subcapitata, Daphnia magna, Danio rerio, Vibrio fischeri and Lepidium sativum). The results of the tests were then compared with SLES residual concentrations in the elutriates, determined with the MBAS (methylene blue active substances) spectrophotometric method. Finally, the data were combined in a battery index, which proved effective at evaluating the overall ecotoxicity in a real-life situation of two different excavated soils conditioned with the two products analysed.

Competition between surfactants and apolar fragrances in micelle cores

The impact of surfactant structure and composition on the micellar partitioning of hydrophobic fragrance molecules was studied. Based on molecular diffusion coefficients derived from self-diffusion NMR spectroscopy the partition coefficient KM between water and micellar phases turned out to be directly proportional to the octanol-water partition coefficient PO/W of the fragrance molecules. By partially replacing the main surfactant sodium laureth sulfate with low- and high-molecular weight co-surfactants a shift of the fraction of fragrance molecules towards the water phase could be observed. The shift is related to a change in the hydrophobic environment inside the micelles as evidenced by fluorescence spectroscopy. A micellar affinity factor was defined and free energy differences were calculated that take into account the compatibility between solute and micellar core. A variation of micellar affinity of up to a factor of 10 was observed between various surfactant systems and mixtures, affecting significantly the proportions of the fragrance molecules in micellar and water phases. According to the Henry’s law constant, the availability of volatile fragrance molecules in the aqueous phase has a direct impact on the headspace concentration in a liquid-gas equilibrium. The shift of fragrance molecules towards the water phase and a subsequent concentration increase in the gas phase was experimentally confirmed by dynamic headspace measurements. The selection of type and composition of surfactant has thus a direct consequence on the concentration of volatiles in the gas phase and on the final perceived fragrance intensity.

A review of shampoo surfactant technology: consumer benefits, raw materials and recent developments.

Surfactants form the core of all shampoo formulations, and contribute to a wide range of different benefits, including cleansing, foaming, rheology control, skin mildness and the deposition of benefit agents to the hair and scalp. The purpose of this review was to assist the design of effective, modern, shampoo surfactant technologies. The mechanisms through which surfactants help deliver their effects are presented, along with the appraisal techniques through which surfactant options can be tested and screened for product development. The steps that should be taken to select the most appropriate blend of surfactants are described, and useful information on the most widely used surfactants is provided. The review concludes with an examination of recent developments in 'greener' surfactants, 'sulphate-free' technologies and structured liquid phases for novel sensory properties and for suspending benefit agents.

Effect of Low–surface Tension EDTA Solutions on the Bond Strength of Resin-based Sealer to Young and Old Root Canal Dentin

IntroductionThe purpose of this study was to evaluate the effect of low–surface tension EDTA solutions on the push-out bond strength of resin-based sealer to young and old root canal dentin. MethodsRoot canals from 64 (n = 32 age <30 years old and n = 32 >60 years old) extracted, decoronized, single-rooted human teeth were prepared with ProTaper rotary instruments (Dentsply Maillefer, Ballaigues, Switzerland) up to size F4 using 3 mL 2.5% sodium hypochlorite (NaOCl) between each file. Each group was divided into 4 subgroups as follows: 3 mL EDTA, REDTA (17% EDTA + 0.84 g cetyltrimethylammonium bromide; Sigma-Aldrich, St Louis, MO), EDTA-T (17% EDTA + 1.25% sodium lauryl ether sulfate, Sigma-Aldrich), and saline as the control (n = 8). The final irrigation was completed with 3 mL saline after 3 mL NaOCl in the experimental groups and 3 mL saline in the control group. After root canal filling with gutta-percha (GP) cones/AH Plus sealer (Dentsply, Petropolis, RJ, Brazil), samples were stored at 37°C and 100% humidity for 2 weeks. One-millimeter-thick horizontal sections from the coronal and midthirds of each root were sliced, and push-out bond strength values were measured using a universal testing machine. Data were analyzed using 2-way analysis of variance followed by the Bonferroni test (P < .05). ResultsEDTA-T, REDTA, and EDTA significantly increased the bond strength values of GP/AH Plus to the root canal dentin compared with saline in both young and old groups (P < .05). EDTA-T treatment provided higher bond strength values in young dentin compared with EDTA and EDTA-T–treated old dentin (P < .05). ConclusionsThe bond strength values of GP/AH Plus could be altered depending on age and the type of EDTA compounds.

Synergism and Physicochemical Properties of Anionic/Amphoteric Surfactant Mixtures with Nonionic Surfactant of Amine Oxide Type

The physicochemical properties of initial formulation, that is anionic/amphoteric surfactants mixture SLES/AOS/CAB (sodium lauryl ether sulfate (SLES), α-olefin sulfonates (AOS) and cocamidopropyl betaine (CAB) at ratio 80 : 15 : 5) with nonionic surfactant of amine oxide type (lauramine oxide (AO)) in various concentration (1–5%) were studied. To characterize the surfactants mixture, the critical micelle concentration (CMC), surface tension (γ), foam volume, biodegradability and irritability were determined. This study showed that adding of AO in those mixtures lowered both γ and CMC as well as enhanced SLES/AOS/CAB foaming properties, but did not significantly affect biodegradability and irritability of initial formulation. Moreover, an increase in AO concentration has a meaningful synergistic effect on the initial formulation properties. All those results indicates that a nonionic surfactant of amine oxide type significantly improves the performance of anionic/amphoteric mixed micelle systems, and because of that anionic/amphoteric/nonionic mixture can be used in considerably lower concentrations as a cleaning formulation.

Rheological characterization of the exopolysaccharide Paenan in surfactant systems

Rheology-controlling agents are of importance for numerous products in a variety of industries. Replacement of synthetic chemicals with natural additives is desired in light of current environmental awareness and limited fossil resources. This study investigates the rheological features of Paenan, an exopolysaccharide produced by Paenibacillus polymyxa. Paenan exhibits highly shear-thinning flow behavior at concentrations ≥0.1% in 0.5% NaCl. Because of its pronounced intermolecular network, it forms stable, weak gels, thereby delivering elasticity as well as thixotropy. Application-relevant flow behavior is obtained with 60–65% less polymer as compared to the benchmark commercial products Xanthan and Gellan. In mixtures with surfactants (sodium lauryl ether sulfate, cetrimonium chloride, cocamidopropyl betaine, or lauryl glucoside), Paenan displays outstanding compatibility with every class of surfactant, making it superior to the partially incompatible Xanthan and Gellan. The weak-gel character of Paenan/surfactant systems is retained with three out of four surfactants, rendering Paenan highly interesting for various applications.

Control of surfactant solution rheology using medium-chain cosurfactants

The rheological properties of surfactant solutions play an important role in their applications. Here we study systematically how different cosurfactants affect the rheological properties of mixed solutions of the anionic surfactant sodium laurylether sulfate (SLES) and the zwitterionic cocoamidopropyl betaine (CAPB). Mixed SLES+CAPB solutions are used in various formulations due to their excellent foaming and cleaning properties. These solutions possess nearly Newtonian behavior and low viscosity. However, the addition of cosurfactants in low concentrations may significantly increase the viscosity of these solutions and even transform them into viscoelastic gels. Here we study systematically a wide range of ionic and nonionic cosurfactants with different head-groups, chain-lengths and structures of the hydrophobic tails (linear, branched, double bonded). We reveal an optimal chain-length of 8–10 carbon atoms of the cosurfactant molecules which ensures the highest viscoelasticity of the triple SLES+CAPB+cosurfactant solutions. Cationic cosurfactants and nonionic ones with small head-group (e.g. fatty alcohols and fatty acids) are most efficient in increasing the solution viscoelasticity. There is a hierarchy in the parameters of the cosurfactant molecules which govern this behavior − most important is the head-group charge, then the chain-length and, finally, the presence of branching and double bonds in the hydrophobic tails. The observed trends are explained with the effect of the cosurfactant molecules on the properties of the entangled wormlike micelles formed in these solutions.

Study of interaction between chitosan and sodium lauryl ether sulfate

Chitosan is a biopolymer that has many potential applications in the industry because of its unique physicochemical properties. Many of these properties depend on its ability to interact with surfactants. The purpose of this study was to investigate interactions between chitosan (Ch), a cationic polysaccharide, and sodium lauryl ether sulfate (SLES), an anionic surfactant with ethylene oxide groups in the polar part of the molecule, in aqueous solution. Changes in the Ch/SLES mixtures were monitored by turbidity, surface tension, electrophoretic mobility, and viscosity measurements. Obtained results show that electrostatic interactions that occur at low SLES concentrations were less pronounced than hydrophobic. The region of hydrophobic interactions was linearly dependent on the concentration of the polymer, so that it ends at Ch/SLES mass ratio 1:3 by forming neutral complexes, which were completely precipitated as a coacervate phase. The research also demonstrates that small variations in structure of anionic surfactant (SDS and SLES) can lead to significant differences in interactions with cationic polymer-chitosan.

Electromagnetic induction of foam-based nanoscale zerovalent iron (NZVI) particles to thermally enhance non-aqueous phase liquid (NAPL) volatilization in unsaturated porous media: Proof of concept

Nanoscale zerovalent iron (NZVI) is a promising remediation agent for volatile organic compound (VOC) contamination in saturated sub-surfaces, but is rarely applied to the vadose zone as there are not enough water molecules in the unsaturated zone to participate in reductive dechlorination. In this study, we evaluated the possibility of using foam as a carrying vehicle to emplace NZVI in unsaturated porous media followed by the application of low frequency-electromagnetic field (LF-EMF) to enhance VOC volatilization in laboratory batch reactors. We found that the optimal condition for generating foam-based NZVI (F-NZVI) was using sodium lauryl ether sulfate (SLES) at a concentration of 3% (w/w) and a N2 flow rate of 500 mL/min. Also, F-NZVI could carry as much as 41.31 g/L of NZVI in the liquid phase of the foam and generate heat to raise ΔT to 77 °C in 15 min under an applied LF-EMF (150 kHz and 13 A). Under these conditions, F-NZVI together with LF-EMF enhanced trichloroethylene (TCE) volatilization from TCE-dense non-aqueous phase liquid (DNAPL) in unsaturated sand by 39.51 ± 6.59-fold compared to reactors without LF-EMF application. This suggested that using F-NZVI together with LF-EMF could theoretically be an alternative to radio frequency heating (RFH) as it requires a much lower irradiation frequency (336-fold lower), which should result in significantly lower capital and operational costs compared to RFH.

Direct Spectrophotometric Determination of Lead (II) in Industrial Samples using 1, 3-Benzenediamine, N, N'-bis(2-furanylmethylene) in Presence of Surfactant

Schiff's base are one of the excellent chelating agents that used for the spectrophotometric determination of metal ions. It was observed that 1, 3-Benzenediamine, N,N'-bis(2-furanylmethylene) (BDFM) formed a brown colored complex with lead (II) at 620 nm. Lead (II) was chelated with the Schiff's base (BDFM) in acidic medium at pH = 3.5 using acetate buffer in presence of sodium laureth sulfate (SLS) as a surfactant. The effect of time, temperature and foreign ions were studied. The stoichiometric composition of the formed complex was found to be 1:2 (metal: ligand) by Job's method of continuous variation. Beer's law was obeyed in the range of 10-110 μg mL-1 with molar absorptivity 10.16×103 L mol-1cm-1. The proposed method was applied for the determination of lead in gasoline, solders, gutters and wastewater.

Wetting and adhesion evaluation of cosmetic ingredients and products: correlation of in vitro-in vivo contact angle measurements.

The aim of this work was to use the contact angle measurement in order to predict the behaviour of ingredients and finished cosmetic products on skin to improve skin feel and product texture. Different classes of cosmetic ingredients and formulations were evaluated. The contact angle measurements were carried out by the sessile drop method using an apparatus, designed and set up in laboratory. Glass, Teflon and human skin were the reference substrates. In a preliminary phase, TEWL parameter, sebum content and hydration of human skin were measured to set up method. Data demonstrated that glass substrate may be used as replacement of the skin:critical surface tension of skin and glass were about of 27 and 31 dyne cm-1 , respectively. Non-ionic surfactant with increasing HLB was evaluated: a correlation between contact angle measured and HLB was not observed because of different and complex molecular structure. In detail, ethylhexyl hydroxystearate (θglass = 17.1°) showed lower contact angle value with respect to Polysorbate 20 (θglass = 28.1°). Sodium laureth sulphate and stearalkonium chloride were also evaluated: anionic molecule showed more affinity for glass with respect to Teflon (θglass = 21.7° and θTeflon = 52.3°). Lipids and silicones showed different affinity for substrate according to hydrophilic groups and hydrocarbon chain: contact angles of silicones remained unchanged independently from substrate. Finished cosmetic products (O/W, W/O emulsions, cleansing oil, dry skin oil) showed different profiles according to surfactant and its affinity for continuous phase of the formulation. Comparing the values of the contact angle on skin of non-ionic surfactants, as ethylhexyl hydroxystearate and Polysorbate 20, they showed values lower (near to zero) than ones of sodium laureth sulphate and Stearalkonium Chloride (21.7° and 66.8°, respectively). Finally, finished cosmetic products tested on human skin showed different profile: corresponded contact angle values were less than 20°. The product tended to be quickly adsorbed on human skin. Systematic study carried out by evaluating the wettability of single cosmetic ingredients on different substrates allowed to find correlations between the use of certain ingredients and the final performance of a cosmetic product.

Sodium lauryl ether sulfate (SLES) degradation by nitrate-reducing bacteria

The surfactant sodium lauryl ether sulfate (SLES) is widely used in the composition of detergents and frequently ends up in wastewater treatment plants (WWTPs). While aerobic SLES degradation is well studied, little is known about the fate of this compound in anoxic environments, such as denitrification tanks of WWTPs, nor about the bacteria involved in the anoxic biodegradation. Here, we used SLES as sole carbon and energy source, at concentrations ranging from 50 to 1000 mg L−1, to enrich and isolate nitrate-reducing bacteria from activated sludge of a WWTP with the anaerobic-anoxic-oxic (A2/O) concept. In the 50 mg L−1 enrichment, Comamonas (50%), Pseudomonas (24%), and Alicycliphilus (12%) were present at higher relative abundance, while Pseudomonas (53%) became dominant in the 1000 mg L−1 enrichment. Aeromonas hydrophila strain S7, Pseudomonas stutzeri strain S8, and Pseudomonas nitroreducens strain S11 were isolated from the enriched cultures. Under denitrifying conditions, strains S8 and S11 degraded 500 mg L−1 SLES in less than 1 day, while strain S7 required more than 6 days. Strains S8 and S11 also showed a remarkable resistance to SLES, being able to grow and reduce nitrate with SLES concentrations up to 40 g L−1. Strain S11 turned out to be the best anoxic SLES degrader, degrading up to 41% of 500 mg L−1. The comparison between SLES anoxic and oxic degradation by strain S11 revealed differences in SLES cleavage, degradation, and sulfate accumulation; both ester and ether cleavage were probably employed in SLES anoxic degradation by strain S11.

The Effect of Passive-Active Interaction Method on Drag Reduction Performance in Rotating Disk Apparatus

Objectives:Turbulent Drag Reduction (DR) efficacy of diesel fuelin a Rotating Disk Apparatus (RDA) using anionic surfactant of Sodium Lauryl Ether Sulfate (SLES) was investigated with smooth andSV-groove disks(riblets height of 900 and 3100 μm). Methods: The DR efficacy indicates how the torque is being reduced with a tiny amount of additives under a turbulent flow at a Reynolds number (Re) range of 302227 to 453341. The effects of different variables such as rotary disk type (smooth or structured), surfactant concentration, and Reynolds number were also studied. Findings: SLES shows a good ability to reduce the frictional drag forces with smooth and SV-groove of height 3100μm. In contract, there is no drag reduction can be observed by using this surfactant with SV-groove of height 900 μm. Application/Improvements: The passive-active interaction method can be used to improve petroleum liquid flow in pipelines.

Detection of sulfate surface-active substances via fluorescent response using new amphiphilic thiacalix[4]arenes bearing cationic headgroups with Eosin Y dye

New ammonium-containing derivatives of p-tert-butylthiacalix[4]arene in 1,3-alternate stereoisomeric form were synthesized via copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction of corresponding azides with N-propargyl-N,N,N-triethylammonium bromide. Critical aggregation concentration (CAC) of new amphiphilic thiacalixarenes 1-3 (with butyl, octyl and tetradecyl substituents) determined by pyrene micellization method are 91, 59 and 33μM, respectively. According to DLS data the diameter of these aggregates is around 130nm. Anionic dye Eosin Y (EY) forms the associates with positive charged thiacalixarenes 1-3, shifts CAC to the low concentration region (2μM) and decreases nanoaggregates size up to 90nm. Thiacalixarene/EY associates were investigated as fluorescent probe for the determination of different surface active substances (SAS) in the solution. It was found that only sodium dodecyl sulfate (SDS) and sodium laureth sulfate (SLES) causes EY release, while other anionic, cationic and zwitterionic SAS form only mixed aggregates. Fluorescent response of thiacalixarene/EY associates is considerable from 3.5μM concentration of SDS.

Synthesis and Application of Palm Fatty Acid Distillate Based Alkyd Resin in Liquid Detergent

AbstractPalm fatty acid distillate (PFAD) is the by‐product obtained during physical refining of crude palm oil, which mainly consists of free fatty acids along with minor amounts of glycerides, bioactive compounds such as tocopherols, tocotrienols, phytosterols, squalene, other hydrocarbons. In the present work, an eco‐friendly alkyd resin was prepared using sustainable feedstock such as PFAD along with rosin. The various physico‐chemical properties of PFAD‐based alkyd resin (PFAD‐AR) such as acid value, saponification value, viscosity and volatile matter were determined and compared to palm oil based alkyd resin (PO‐AR). The structural properties of the alkyd resins were investigated using Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (1H NMR) spectroscopic techniques. The study presents the utilization of PFAD‐based alkyd resin with sodium lauryl sulfate (SLS) and sodium lauryl ether sulfate (SLES) in the liquid detergent formulation. The performance properties of the PFAD‐based alkyd resin liquid detergent formulations such as surface tension, wetting power and detergency were comparable with palm oil based alkyd resin liquid detergent formulations and with commercial liquid detergent (CLD). Surface tensions of liquid detergent formulations varied from 20 to 30 mN/m with decrease in concentration. The foaming properties of alkyd resin based liquid detergents are reduced with the increase in the amount of alkyd resin polymer in the formulations. Therefore, it has potential application as a foam reducer in detergent for washing machines.

Synergistic Growth of Giant Wormlike Micelles in Ternary Mixed Surfactant Solutions: Effect of Octanoic Acid.

The synergistic growth of giant wormlike micelles in ternary mixed solutions composed of an anionic surfactant (sodium laurylethersulfate, SLES), a zwitterionic surfactant (cocamidopropyl betaine, CAPB), and octanoic acid (HC8) is studied. Rheological data and their analysis in terms of Cole-Cole plots and micellar characteristic times are presented, and the micellar structures behind the observed rheological behavior are revealed by cryo-TEM micrographs. The surfactant composition is fixed near the maximal micelle size of the binary SLES + CAPB system, whereas the concentration of HC8 is varied. At a given HC8 concentration, the viscosity of the ternary micellar solutions exhibits a very high and sharp peak. Polarized-light optical microscopy indicates that all investigated solutions are isotropic rather than liquid-crystalline. The cryo-TEM imaging shows complex phase behavior: wormlike micelles to the left of the peak, giant entangled wormlike micelles at the peak, and long wormlike micelles coexisting with multiconnected micellar aggregates to the right of the peak. The formation of multiconnected micelles leads to a drop in viscosity at the higher concentrations. The results contribute to a better understanding of the structure-rheology relations in micellar surfactant solutions and could be useful for controlling the properties of formulations in personal-care and house-hold detergency.

Mobilization of arsenic from contaminated sediment by anionic and nonionic surfactants

The increasing manufacture of surfactants and their wide application in industry, agriculture and household detergents have resulted in large amounts of surfactant residuals being discharged into water and distributed into sediment. Surfactants have the potential to enhance arsenic mobility, leading to risks to the environment and even human beings. In this study, batch and column experiments were conducted to investigate arsenic mobilization from contaminated sediment by the commercial anionic surfactants sodium dodecylbenzenesulfonate (SDBS), sodium dodecyl sulfate (SDS), sodium laureth sulfate (AES) and nonionic surfactants phenyl-polyethylene glycol (Triton X-100) and polyethylene glycol sorbitan monooleate (Tween-80). The ability of surfactants to mobilize arsenic followed the order AES>SDBS>SDS≈Triton X-100>Tween 80. Arsenic mobilization by AES and Triton X-100 increased greatly with the increase of surfactant concentration and pH, while arsenic release by SDBS, SDS and Tween-80 slightly increased. The divalent ion Ca2+ caused greater reduction of arsenic mobilization than Na+. Sequential extraction experiments showed that the main fraction of arsenic mobilized was the specifically adsorbed fraction. Solid phase extraction showed that arsenate (As(V)) was the main species mobilized by surfactants, accounting for 65.05%–77.68% of the total mobilized arsenic. The mobilization of arsenic was positively correlated with the mobilization of iron species. The main fraction of mobilized arsenic was the dissolved fraction, accounting for 70% of total mobilized arsenic.

A NOVEL POLYMER-SURFACTANT COMPLEX MIXTURE TO IMPROVE DIESEL FUEL FLOW IN A ROTATING DISK APPARATUS

This paper introduces a novel complex system to decrease the polymer degradation using polyisobutylene (PIB) and sodium lauryl ether sulfate (SLES). These materials are tested individually and as a complex mixture in a rotating disk apparatus (RDA) at various concentrations and rotational speeds (rpm). From the experimental results, it can be observed that the drag reduction for the complex mixture of cationic polymer with anionic surfactant has a better performance than the reduction of individual polymer or surfactant, respectively. This can be as a result of the important role played by complex mixtures that are highly dependent on alkyl chain in the surfactant. The maximum %DR observed in laminar flow was 38.42% for complex mixture at 1000rpm, while the %DR of polyisobutylene and sodium lauryl ether sulfate at the same condition were 27.36% and 28.42%, respectively.