Experimental investigation of the effects of oil asphaltene content on CO_(2) foam stability in the presence of nanoparticles and sodium dodecyl sulfate

Foam stability tests were performed using sodium dodecyl sulfate(SDS)surfactant and SiO2 nanoparticles as foaming system at different asphaltene concentrations,and the half-life of CO_(2) foam was measured.The mechanism of foam stability reduction in the presence of asphaltene was analyzed by scanning electron microscope(SEM),UV adsorption spectrophotometric concentration measurement and Zeta potential measurement.When the mass ratio of synthetic oil to foam-formation suspension was 1:9 and the asphaltene mass fraction increased from 0 to 15%,the half-life of SDS-stabilized foams decreased from 751 s to 239 s,and the half-life of SDS/silica-stabilized foams decreased from 912 s to 298 s.When the mass ratio of synthetic oil to foam-formation suspension was 2:8 and the asphaltene mass fraction increased from 0 to 15%,the half-life of SDS-stabilized foams decreased from 526 s to 171 s,and the half-life of SDS/silica-stabilized foams decreased from 660 s to 205 s.In addition,due to asphaltene-SDS/silica interaction in the aqueous phase,the absolute value of Zeta potential decreases,and the surface charges of particles reduce,leading to the reduction of repulsive forces between two interfaces of thin liquid film,which in turn,damages the foam stability.

Sodium dodecyl sulfate (SDS) as an effective corrosion inhibitor for Mg-8Li-3Al alloy in aqueous NaCl: A combined experimental and theoretical investigation

The corrosion inhibition behavior of Mg-8Li-3Al alloy in NaCl solution with sodium dodecyl sulfate(SDS)was investigated by hydrogen analysis,scanning electron microscopy(SEM),electrochemical test,scanning Kelvin probe force microscopy(SKPFM)and computational methods.Results showed that the corrosion resistance of Mg-8Li-3Al alloy in NaCl solution was effectively improved with SDS.The SEM and SKPFM results confirmed a dense,200 nm-thick SDS-adsorbed layer had formed on the alloy surface.The separation energy ΔE_(gap) and adsorption energy E_(ads) of SDS on the Mg surface were calculated by density functional theory and molecular dynamics simulations,respectively.And the corrosion inhibition mechanism was hypothesized and described.

Enhancing the leaching effect of an ion-absorbed rare earth ore by ameliorating the seepage effect with sodium dodecyl sulfate surfactant

Ameliorating the problem of low leaching efficiency,long leaching period,and high agent consumption should be studied to efficiently exploit ion-absorbed rare earth ore resources.In this study,the surfactant sodium dodecyl sulfate(SDS) is used to enhance the leaching effect of an ion-absorbed rare earth ore by ameliorating the seepage effect for the first time.The effects of surfactant concentration,leaching agent dosage,solution flow velocity,and solution pH on the leaching rate were explored,and the mechanism of SDS was discussed.Under the optimum conditions,the addition of a small amount of SDS(mass fraction0.04%) can increase the leaching rate by about 5%,shorten the leaching period,and reduce the consumption of the leaching agent.SDS significantly ameliorates the seepage effect of the ore body by reducing the surface tension of the leaching agent and ameliorating the wettability of the mineral surface.This effect is the main factor that improves the leaching efficiency.DFT(density functional theory) calculation results show that SDS can react with rare earth ions,which reduces the adsorption strength on clay mineral surfaces.Hence,rare earth ions are easily exchanged by ammonium ions,and mass transfer is enhanced.

Effect of Addition of Sodium Dodecyl Sulfite on Physical Properties of Wheat Gluten Films

Films were made from the wheat glutens treated with 5%,10%,15%,20%,25% and 30%(wt% of gluten) of sodium dodecyl sulfite (SDS) in order to improve the properties of the films. Glycerol was used as a plasticizer.An addition of SDS in wheat glutens prior to forming films significantly increased the elongation at break(E) (P<0.05) and reduced notably the water vapor permeability(WVP) (P<0.05). In contrast,a decrease in the tensile strength(TS) of the films from gluten containing-SDS was found.Moreover,a significant decrease in P_(O_2) and P_(CO_2) of films from gluten treated with SDS was noticed. Although SDS-treated gluten film was slightly more yellow and darker than control one, it was not visually detrimental. It is indicated that the treatment with SDS prior to forming films greatly enhances the mechanical properties of wheat gluten films.The obivous improvement in water vapor permeability and extensibility of gluten films means that the use of SDS is a potential choice for improving properties of gluten films. The edible film was used to preserve tomatoes. The experimental results show that the shelf life of tomatoes coated with the edible film is extended, and the nutritional quality is kept well.

Molecular dynamics simulations of the effects of sodium dodecyl sulfate on lipid bilayer

Molecular dynamics simulations have been performed on the fully hydrated lipid bilayer with different concentrations of sodium dodecyl sulfate （SDS）. SDS can readily penetrate into the membrane. The insertion of SDS causes a decrease in the bilayer area and increases in the bilayer thickness and lipid tail order, when the fraction of SDS is less than 28%. Through calculating the binding energy, we confirm that the presence of SDS strengthens the interactions among the DPPC lipids, while SDS molecules act as intermedia. Both the strong hydrophilic interactions between sulfate and phosphocholine groups and the hydrophobic interactions between SDS and DPPC hydrocarbon chains contribute to the tight packing and ordered alignment of the lipids. These results are in good agreement with the experimental observations and provide atomic level information that complements the experiments.

The Electrooxidation of Tetracycline at Acetylene Black Electrode in the Presence of Sodium Dodecyl Sulfate

The electrooxidation of tetracycline (TC) at acetylene black electrode has been studied in the presence of sodium dodecyl sulfate (SDS). Tetracycline (TC) exhibited very sensitive oxidation peak in this system. The peak current was proportional to TC concentration, and the detection limit was 1.2×10-8 mol/L. The system was used to the determination of TC in Pharmaceuticals.

Effects of Sodium Dodecyl Sulfate on a Single Cavitation Bubble

Dynamics of a single cavitation bubble in sodium dodecyl sulfate（SDS） aqueous solutions is investigated experimentally and theoretically. The bubble pulsation is measured by a phase-locked integrated imaging technique,and the ambient radius is obtained by fitting the numerical calculation based on the Rayleigh–Plesset bubble dynamics model to the experimental data. The results show that, under the same driving condition, the ambient radius of the cavitation bubble decreases correspondingly with the increase of SDS concentration within the critical micelle concentration, while the compression ratio of the radius increases, which indicates that the addition of SDS decreases the internal molecular number of the cavitation bubble and increases the power capability of the cavitation bubble. In addition, bubble oscillation increases the concentration of the surfactant molecules on the bubble wall, so that the effect of SDS on a single cavitation bubble is reduced when the SDS concentration is greater than 0.8 m M.

Adsorption of Cr(III) from an Aqueous Solution by Chitosan Beads Modified with Sodium Dodecyl Sulfate (SDS)

This study is to prepare chitosan beads modified with sodium dodecyl sulfate (SDS) to effectively remove Cr(III) from an aqueous solution. The characterizations of SDS-chitosan by scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), Fourier transform-infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) proved the successful synthesis of the adsorbent. The adsorption of Cr(III) on the SDS material was investigated by varying experimental conditions such as pH, contact time and adsorbent dosage. The maximum adsorption capacity of SDS-chitosan for Cr(III) was estimated to be 3.42 mg?g-1. The results of adsorption kinetics and isothermal models show that the adsorption process conforms to the pseudo-second-order and Langmuir isotherm models, indicating that the adsorption is single-layer chemical adsorption. Thermodynamic analyses indicate that the adsorption of Cr(III) is an endothermic reaction. These results show that the new adsorbent has obvious application prospect to eliminate Cr(III).

Observations on the Function of Mucous Cells in the Epidermis of the Cat-fish Clarias batrachus Exposed to Sodium Dodecyl Sulfate

Response of mucous cells, in the epidermis of the catfish Clarias batrachus, to a sublethal concentration of sodium dodecyl sulfate was studied and correlated with the alteration in the status of their secretory activity after different durations of the treatment. At 4h, 8h, 24h,48h and 72h of the detergent treatment, most mucous cells attained voluminous dimensions and appeared closely approximating to or even overlapping the adjacent ones. At 12h, 36h, and 60h, in contrast, the mucous cells appeared small and slender, and seemed to be located at greater intervals. These changes in dimensions were responsible for the apparent increase or decrease in the density of mucous cells after different durations of detergent treatment. Statistically, however, no significant change was observed in the total number of the mucous cells throughout the experiment.The mucous cells appeared enlarged towards the end of the experiment signifying increased mucus production. This is considered as an adaptation, for protection, assisting the fish to adjust to the changed environment.A shift in the histochemical nature of the secretory contents at the middle and basal parts of the mucous cells, from a mixture of neutral and acid glycoproteins to neutral glycoproteins, during the early stages of the treatment suggests that acid moities could not simultaneously be synthesized as an immediate response to enhanced mucous secretion. The apical parts of the mucous cells, however, showed no histochemical change throughout the experiment.

Phase Behavior and Structural Transitions in Sodium Dodecyl Sulfonate Microemulsions

The forming mechanism of microemulsion of sodium dodecyl sulfonate, alcohols, water and isooctane was studied, with particular emphasis on the effect of molecular weight and concentration of alcohols. Phase diagram of the four components, alcohol, sodium dodecyl sulfonate, water and isooctane, was used as a means of study, through which the microemulsion regions were deter-mined. Phase diagram of sodium dodecyl sulfonate/n-pentanol/isooctane/water system at km = 2 (km = Wn-pentanol / WSDS ) is presented. The variation of conductivities of different microemulsion samples with water was measured. From the conductivities we investigated a change in structure from water droplets in oil (W/O) at low water content to liquid crystal at intermediate water content and a struc-ture of oil droplets in water (O/W) at high water content.

Molecular Dynamics Simulation of Effect of Salt on the Compromise of Hydrophilic and Hydrophobic Interactions in Sodium Dodecyl Sulfate Micelle Solutions

The presence of salt has a profound effect on the size,shape and structure of sodium dodecyl sulfate(SDS)micelles.There have been a great number of experiments on SDS micelles in the presence and absence of salt to study this complex problem.Unfortunately,it is not clear yet how electrolyte ions influence the structure of micelles.By describing the compromise between dominant mechanisms,a simplified atomic model of SDS in presence of salt has been developed and the molecular dynamics(MD)simulations of two series of systems with different concentrations of salt and charges of ion have been performed.Polydispersity of micelle size is founded at relatively high concentration of SDS and low charge of cation.Although the counter-ion pairs with head groups are formed,the transition of micelle shape is not observed because the charge of cation is not enough to neutralize the polar of micelle surface.

Interaction of ciprofloxacin hydrochloride with sodium dodecyl sulfate in aqueous/electrolytes solution at different temperatures and compositions

Interactions of ciprofloxacin hydrochloride(CPFH)with sodium dodecyl sulfate(SDS)were investigated by conductivity measurement in H2O/electrolyte solutions(NaCl,Na2SO4&Na3PO4)over 298.15–318.15 K temperature range(with 5 K interval)considering the human body temperature.In all cases,two critical micelle concentrations(c*)were observed which are increased in the presence of drug and decreased in the presence of salts enunciating the presence of interaction amongst the studied components.For(CPFH+SDS)system in the presence of salt,the c*values at 303.15 K and I=0.50 mmol·kg^-1 followed the order:CNaCl>CNa2SO4>CNa3PO4.TheΔG1,m0 andΔG2,m0values are found to be negative for all systems that show that the micellization process is thermodynamically spontaneous.For(CPFH+SDS)system in water,theΔHm0&ΔSm0 values reveal that the micellization processes is both entropy dominated in almost all cases.In the occurrence of electrolytes,ΔHm0 andΔSm0 values indicate that micellization processes are both entropy&enthalpy restricted at upper temperature but it becomes totally entropy dependent at higher temperature.The higher positiveΔSm0 values indicate the enhanced hydrophobic interaction in presence of salts.The enthalpy-entropy compensation was determined from the linear relationship betweenΔHm0 andΔSm0 values in every state.Different transfer energies as well as compensation temperature and intrinsic enthalpy were also evaluated and the behaviors were comparable to other biological system.

Determination of Trace Amounts of Zinc, Iron and Copper by Flame Atomic Absorption after Their Preconcentration Using Sodium Dodecyl Sulfate (SDS) Coated Alumina Nanoparticles Modified with 3-Mercapto-D-Valin from Environmental Samples

A sensitive and simple solid phase extraction method for the simultaneous determination of trace and toxic metals in environmental samples has been reported. The method is based on the adsorption of Zinc, Iron and Copper on SDS-coated alumina nanoparticles, which is also modified with 3-mercapto-D-valine. The retained analyte ions on modified solid phase were eluted using 5 mL of 4 mol·L﹣1 HNO3. The analyte determination was carried out by flame atomic absorption spectrometry. The influences of some metal ion and anions on the recoveries of understudy analyte ion were investigated. The influences of the analytical parameters including pH, ligand and SDS amount, eluting solution (type and concentrations) and sample volume on metal ions recoveries were investigated. The extraction efficiency was > 98% with relative standard deviation lower than 3% the method has been successfully applied for the extraction and determination of these ions content in some real samples. Prepared adsorbent was characterized by SEM and FT-IR measurements.

Effect of β-Cyclodextrin Upon the Sol-gel Transition of Methylcellulose Solutions in the Presence of Sodium Dodecyl Sulfate

methylcellulose ( MC )的大音阶的第五音胶化转变温度答案面对象 SDS 和 -cyclodextrin 的混合物一样的钠 dodecyl 硫酸盐( SDS )(-CD)被测量，并且二个竞争相互作用的效果，在 SDS 和 MC 之间的恐水病的相互作用和在在 MC 答案的大音阶的第五音胶化转变之上的 SDS 和-CD,之间的包括相互作用被学习。在 SDS 和 CD 之间的包括相互作用比在 SDS 和 MC 之间的恐水病的相互作用大得多，这被发现了。作为结果，在 SDS 和 -CD, 的共存， MC 答案的大音阶的第五音胶化转变温度把一样的值放在，独立于在解决方案的 SDS 的集中在 SDS 的集中是不到 CD 条件下。我们的试验性的结果不仅建议在 MC 答案的大音阶的第五音胶化转变之上的 SDS 的效果能被 CD 完全屏蔽而且显示到 CD 的 SDS 的包括比率能是由使用 rheological 测量的坚定的份量上。到 CD 的 SDS 的包括比率是 1:1 ，它 poly 在对到 CD 的 SDS 的包括比率的好同意面对( vincyl pyrrolidone )由粘性测量决定了但是面对由使用 rheological 测量的相对地控告的聚合电解质与到 CD 的 SDS 的包括比率极其不同，主要由于在 SDS 和 MC 之间的相互作用的机制与在 SDS

Experimental and Quantum Chemical Studies of the Inhibition of Copper with Sodium Dodecyl Sulphate (SDS) in Acidic Medium

This work investigates the inhibitive properties of sodium dodecyl sulphate (SDS) on the corrosion of copper (Cu) in nitric acid using gasometric methods. The inhibition efficiency increases with time and concentration of SDS. The corrosion rate of copper decreases as concentration of SDS increases. Adsorption of the SDS on the surface obeyed the Langmuir adsorption isotherm. The high negative values of the kinetic parameter B suggest that the inhibitor’s effectiveness increases with temperature. The equilibrium constant and the free energy of adsorption of SDS to copper are negative and large. This observation implies that the adsorption mechanism maybe chemisorption. The quantum chemical calculation of copper dodecyl sulphate shows that the energy change in the HOMO-LUMO energy of the moiety is positive and small. This observation implies that the SDS is an efficient inhibitor. The high dipole moment obtained implies that corrosion inhibition of Cu is enhanced by adsorption of SDS and this observation correlates with the observed experimental inhibition efficiency.

Cytotoxic effects of sodium dodecyl benzene sulfonate on human keratinocytes are not associated with proinflammatory cytokines expression

Background Keratinocytes play a crucial role in the biological function of skin barrier.The relationship between sodium lauryl sulfate （SLS） and keratinocytes has been studied.However,the cytotoxicity and effects of sodium dodecyl benzene sulfonate （SDBS）,a common detergent similar to SLS,on keratinocytes are still not known.This study aimed to investigate the effects of SDBS on cytotoxicity and expression of proinflammatory cytokines in cultured human keratinocytes.Methods This study was carried out using the keratinocytes cell line,HaCaT cells.The cytotoxicity of SDBS on HaCaT cells was evaluated with cell counting kit-8 （CCK-8） and phase-contrast microscopy.After exposure to different concentrations of SDBS,the total RNA of the HaCaT cells was extracted for evaluating the relative mRNA expression of IL-1α,IL-6,IL-8,and TNF-α by qPCR.The supernatants of cells were collected for measuring the levels of IL-6 and IL-8 by enzyme-linked immunosorbent assay （ELISA）.Results SDBS at concentrations of 20 Jg/ml and over showed direct cytotoxicity and induced morphological changes of the HaCaT cells.The mRNA expressions of IL-1a,IL-6,IL-8,and TNF-α in different concentrations of SDBS at different time were comparable with that of controls.SDBS at concentrations of 5,10,and 15 μg/ml had no significant effects on IL-6 and IL-8 excretion from HaCaT cells after 24-hour exposure.Moreover,no significant effects on the IL-6 and IL-8 excretion were found after 10 and 15 μg/ml S DBS stimulations for 6,12,and 24 hours,respectively.Conclusion SDBS at higher concentrations had cytotoxicity on HaCaT cells but had no effects on the mRNA expression of IL-1α,IL-6,IL-8,and TNF-α,that was different from SLS.

Investigation on Molecular Non-covalent Interaction in the Sodium Dodecyl Benzene Sulfonate-polychrome Blue B-protein Replacement Reaction

The molecular non-covalent interaction often originates from the electrostatic attraction and accords with the Langmuir isothermal adsorption. The sodium dodecyl benzene sulfonate (SDBS)-polychrome blue B (PCB)-protein [bovine serum albumin (BSA), ovalbumin (OVA) and myoglobin (MB)] ternary reaction has been investigated at pH 3.88. Protein to replace PCB from the PCB-SDBS binding product was used to characterize the assembly of an invisible-spectral compound, SDBS, on proteins by measuring the variation of PCB light-absorption by the microsurface adsorption-spectral correction (MSASQ technique. The effect of ionic strength and temperature on the aggregation was studied. Results showed that the aggregates SDBS(92)(.)BSA, SDBS(58)(.)OVA and (SDBS15MB)-M-. at 30 degreesC and SDBS(83)(.)BSA, SDBS(39)(.)OVA and (SDBS10MB)-M-. at 50 degreesC are formed.

Atomic force microscopy imaging of dialyzed single-walled carbon nanotubes dispersed with sodium dodecyl sulfate

The existence of excess sodium dodecyl sulfate(SDS)molecules in a single-walled carbon nanotube(SWNT)solution dispersed by hybridization with SDS leads to unstable atomic force microscopy(AFM)imaging.In this study,we demonstrate sequential dialysis against pure water in order to remove excess SDS molecules from an SDS-SWNT hybrid dispersion.A 1:102 volume ratio of SDS-SWNT dispersion to water in the dialysis was found to be effective in realizing stable AFM observations of the SDS-SWNT hybrids despite imperfect filtering of SDS via dialysis.On the other hand,the SDS-SWNT hybrids were stable even when this volume ratio was 1:106.Further,the SDS-SWNT hybrids were present in the solution even when the dialyzed samples were stored for 14 days.Our results reveal that dialysis under optimal conditions enables improved handling of SDS-SWNT hybrids,particularly for stable AFM observations.

Preparation of Polystyrene/Fe3O4 Nanoparticles in Triton X-100/ Sodium Dodecyl Benzenesulfonate Mixed Surfactant System

有壳核心结构的 polystyrene/Fe3O4 的合成 nanoparticles 在三重氢核 X-100 和 SDBS 的混合系统被准备。合成 nanoparticles 的壳被 Fe3O4 nanoparticles 被聚苯乙烯和核心形成。Fe3O4 nanoparticles 的直径是大约 10 nm 和合成 nanoparticles 25-35 nm 的。XRD 系列和 FTIR 系列证明与 Fe3O4 nanoparticles 聚苯乙烯包是成功的。

Formation and aggregation number of sodium dodecyl sulphonate-polyvinylpyrrolidone aggregates

THE interaction of surfactants with water-soluble polymers has been an active subject for manyyears. Early investigations were mainly concerned with the effect of synthetic detergents onnatural proteins, such as gel. These studies were motivated by observations of biologicalphenomena involving surfactants and proteins such as the inactivation of bacterial