Typical Anionic Surfactants Research Articles

Interactions between kaolinite clay and AOT

Interactions between kaolinite (KGa-2) and a typical anionic surfactant bis(2-ethylhexyl) sulfosuccinate sodium (AOT) have been study to obtain a better knowledge of this system. Firstly, adsorption isotherms of AOT on kaolinite are realized as a function of pH. Stability experiments have been performed between the surfactant and the clay mineral and the bed sediments structure have been studied with Small Angle X-ray Scattering (SAXS).In acidic media, the shape of the adsorption isotherm leads to the following suggestions: firstly, for surfactant concentration below the CMC a surfactant monolayer is adsorbed on the positively charged edge surfaces, and then, for surfactant concentrations above the CMC, a bilayer is adsorbed on the edge surfaces. Consequently, in the first case, the surface becomes hydrophobic and in the second case, the surface becomes hydrophilic and this assumption is verified with hydrophobicity tests. Under alkaline conditions no surfactant is adsorbed on surfaces confirming the adsorption on the edge surfaces in acidic conditions. Significant stabilization of kaolinite suspensions can be observed in the presence of high surfactant concentration, in both pH conditions. Finally, structural studies by SAXS provide data about the organization of particles in the bed sedimentation.

Solubility Enhancement of Polycyclic Aromatic Hydrocarbons by an Eco-Friendly Ester-Linked Gemini Surfactant and its Mixtures with Conventional Surfactants

AbstractThe present study deals with the solubility enhancement of the two polycyclic aromatic hydrocarbons (PAHs) anthracene and pyrene in the aqueous micellar system of the cationic ester-containing cleavable gemini surfactant ethane-1,2-diyl-bis(N,N-dimethyl-N-tetradecylammoniumacetoxy) dichloride (14-E2-14 = C14H29(CH3)2N+(CH2COOCH2)2N+(CH3)2C14H29 · 2Cl−)), and its equimolar binary mixtures with some typical conventional cationic, anionic and non-ionic surfactants. The surface tension and conductivity measurements were used to evaluate the physicochemical parameters such as the critical micelle concentration (CMC), the interaction parameter (βm) and Gibbs excess free energy of micellization (ΔGexm) of the systems. The extent of solubilization of the micellar systems towards PAHs has been quantified in terms of molar solublization ratio (MSR), micellar/water partition coefficient (ln Km) and the standard Gibbs free energy of solubilization (ΔGs0). Above the CMC, all studied single as well as binary gemini-conventional surfactant systems show an increase in solubilization of the PAHs. For pure systems, the MSR value of Brij 58 was found to be significantly higher than that of the other amphiphiles. Amongst the mixed surfactant systems, the solubility enhancement of anthracene is found to be maximum in the 14-E2-14 + SDS/SDBS system whereas the system14-E2-14 + Brij 58 shows a higher solubility for pyrene.

Surfactant effect on phase-controlled synthesis and photocatalyst property of TiO2 nanoparticles

The influence of surfactant type on phase-controlled synthesis of titanium dioxide (TiO2) was investigated by varying pH, temperature and method. Typical anionic, cationic and nonionic surfactants (SDS, CTAB and TritonX-100) with the two methods of hydrothermal and emulsion preparation were selected. The phase composition and size of synthesized TiO2 nanoparticles were characterized by XRD and FE-SEM, respectively. The photocatalytic activity of synthesized TiO2 was investigated by methylene blue (MB) degradation. Moreover, BET was used to measure the specific surface area for more understanding of the photocatalytic performance using synthesized TiO2 catalyst. Results indicated the stability, size, and shape of surfactant micelles were the main factors to determine TiO2 phase. Anatase phase was found when the micelle was small and stable. On the other hand, rutile phase occurred when the micelle lost stability and expanded in size, leading to more TiO2 aggregation around micelle. The pure anatase and pure active site rutile {1, 1, 1} TiO2 with smaller nanoparticles exhibited more effective MB photodegradation overall, although mixed phase samples showed higher degradation per unit BET area. The greater the anatase phase formed in the mixed phase TiO2, the greater the MB degradation. The highest degradation of the mixed phase was at the optimum ratio of two phases according to the synergistic effect. From this study, photocatalytic activity was affected by all factors so that one needed to consider simultaneously phase, synergistic effect of mixed phase and particle size. No one factor was deemed the most effective.

The effects of anionic and non-ionic surfactant on anaerobic co-digestion of sludge, food wastes and green wastes

Surfactants are widely used and discharged into wastewater treatment plants, which might influence the anaerobic digestion (AD) treatment of municipal waste. In this study, the effects of typical anionic surfactants sodium dodecyl benzene6 sulfonate (SDBS) and non-ionic surfactants APG, on mesophilic anaerobic co-digestion of sludge, food waste, and green waste were investigated. Results indicated that at 5 mg/g, the biogas production was inhibited in SDBS supplemented systems while stimulated in APG-added reactors, with the methane yield of 146.58 L/g VS consumed. At 15 mg/g, the biogas production in both SDBS and APG supplemented reactors was both inhibited. It means the negative or positive effect of APG on AD depends on the dose of APG supplementation. The 16S rRNA gene analysis demonstrated the microbial community structure in the digester was changed due to the addition of surfactant. Bacteroidia significantly increased with the addition of APG and SBDS, while the increase of Clostridia only occurred in APG-added system. The variation of microbial Communities’ structure in APG and SDBS-added digesters might give an explanation for the different efficiencies in these two systems. Thus, the effects of surfactants on the efficiency of AD should be considered during the disposal of municipal organic waste.

Influence of sodium dodecyl sulfate coating on adsorption of methylene blue by biochar from aqueous solution

Biochar is regarded as a promising new class of materials due to its multifunctional character and the possibility of effectively coupling different properties. With increasing introduction into the environment, environmental chemicals such as surfactants will load onto the released biochar and change its physicochemical characteristics and adsorption behavior toward pollutants. In this study, sodium dodecyl sulfate (SDS), as one type of anionic surfactant, was coated onto biochar with different loading amounts. The influence of SDS loading onto biochar's physicochemical properties were investigated by Fourier transform infrared (FT-IR) spectroscopy, elemental analysis, zeta potential and Brunauer–Emmett–Teller (BET) surface area and pore size distribution analysis. Results showed that the pore size of the biochar decreased gradually with the increase of SDS loading because of the surface-adsorption and pore-blocking processes; the pH of the point of zero charge (pHPZC) decreased with increasing SDS loading. Although surface-coating with SDS decreased the pore size of the biochar, its adsorption capacity toward Methylene Blue (MB) significantly increased. The biochar-bound SDS introduced functional groups and negative charges to the biochar surface, which could thus enhance the adsorption of MB via hydrogen bonding and electrostatic interaction. The results can shed light on the underlying mechanism of the influence of anionic surfactants on the adsorption of MB by biochar.

Micelle-mediated transport disturbance providing extracellular strategy for alleviating n-butanol stress on Escherichia coli.

One barrier inhibiting further progress in biofuel production is the toxicity of biofuels towards their producers. It is promising to apply gene-based intracellular techniques to engineer better strains with higher organic solvent tolerance. These methods are, however, complex. In the present study, we developed a simple, manageable, and commercial extracellular prototypal strategy to alleviate n-butanol (n-BuOH) stress on Escherichia coli via a micelle-mediated transport disturbance. When the concentration of sodium dodecyl sulfate, a typical anionic surfactant, is high enough to form micelles, n-BuOH will be trapped into/onto the micelles, and the negative charge prevents the n-BuOH from approaching the cells. Our study provides an extracellular strategy to relieve the stress from n-BuOH, and it also exhibits a new angle to advance microbial factories through extracellular routines.

In situ growth of hollow Cu2O spheres using anionic vesicles as soft templates

Geometrically optimizing anionic vesicles were fabricated using two types of anionic surfactants with antipodal molecular configuration. The influence of counterions on the anionic vesicles was systematically investigated to maintain electrostatic interaction between the anionic vesicles and the precursors, as well as to ensure the structural integrity of the vesicle templates. The transcription from vesicles to hollow Cu2O spheres was achieved through an in situ reduction approach. The obtained hollow Cu2O spheres were assembled by abundant nanoparticles around the vesicle interface and showed preferable adsorption capacity for methyl orange in the dark compared with the solid Cu2O spheres synthesized without any surfactants.

Biosafety Evaluation of Three Sodium Lauryl N‐Amino Acids Synthesized from Silk Industrial Waste in Mice

AbstractIn this study, three amino acid mixtures recovered from silk industry waste were reacted with lauryl chloride to synthesize three sodium laurel N‐amino acid surfactants. The three types of anionic surfactants are referred to as silk fibroin surfactant, silk sericin surfactant, and silkworm pupae surfactant. All three surfactants showed good surface properties. To evaluate biological safety, we added these three surfactants to the normal diet of mice for 8 weeks. Blood indices, blood lipid, antioxidant capacity (GSH‐PX, MDA, T‐AOC, and T‐SOD), and lipid metabolism key enzyme mRNA (PPAR‐γ, SREBP, FASN, and C/EBP‐α) levels in the liver were measured. No evident histopathological changes were found in the liver and kidney. The results showed no significant difference in their indexes between the surfactant‐fed and normal diet‐fed mice. Thus, the three amino acid surfactants are biologically safe and can be used in daily chemical cleaning products. These surfactants will not only help to reduce wastage of resources and damage to the environment, but also yield economic benefits to the silk industry in the future.

Effects of twelve sodium dodecyl sulfate (SDS) on electro-catalytic performance and stability of PbO2 electrode

To improve the electro-catalytic performance and stability of PbO2 electrode in organic wastewater treatment, sodium dodecyl sulfate (SDS, a typical anionic surfactant) modified PbO2 electrode was successfully synthesized by electro-deposition method. The morphology, crystal phase, electro-catalytic performance, safety assessment and stability were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD), Acid red G (ARG) degradation, inductively coupled plasma atomic emission spectroscopy (ICP-AES) detection and the accelerated life test, respectively. In addition, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS) were applied. The results showed that SDS could obviously refine the coating particles, increase the oxygen evolution potential (OEP) and accelerate charge transfer. After modified with SDS, the electro-catalytic performance and stability of PbO2 electrode were greatly improved. The PbO2 electrode modified at 5.0 vt% volume fractions of SDS (PbO2-SDS(5.0)) exhibited the highest ARG decolorization rate of 83.5% and the largest COD removal rate of 53.9%, respectively, which could be attributed to the highest OEP and massive adsorbed hydroxyl oxygen (Oad). Besides, PbO2-SDS(5.0) electrode showed a high reusability for ARG degradation and the accelerated service life could reach 348 h, which was almost 3.6 times longer than that of PbO2 electrode (96 h).

Photodecomposition of surfactants using Ti(IV)-doped calcium hydroxyapatite particles

The decomposition of surfactants under UV irradiation was carried out using Ti(IV)-doped calcium hydroxyapatite (TiHap) particles with various Ti/(Ca+Ti) atomic ratios (XTi). The typical cationic, anionic, and nonionic surfactants, namely, cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS), and polyoxyethylene nonylphenyl ether (NP-15, which has 15 oxyethylene units on average), respectively, were used. CTAB readily decomposed in the presence of TiHap particles with XTi values of 0.10 and 0.20. The plot of CTAB concentration versus time for the decomposition was fitted with a first-order reaction rate equation, and rate constants (k) were obtained. k values for the CTAB system were independent of the XTi values of TiHap particles, that is, TiHap particles facilitated the decomposition of CTAB under UV irradiation. A considerable amount of the hydrocarbon chains in CTAB molecules decomposed because the percentage of CO2 produced (PCP) increased to 55–70% after UV irradiation for 240 h. We also obtained k values for the SDS system using the first-order reaction equation, although the fit was slightly inferior to that observed with the CTAB system. This result may be explained by the electrostatic repulsive force between negatively charged SDS and TiHap particles. In addition, the PCPs after UV irradiation for 120 h slowly increased to 20–35%, which are less than those obtained for CTAB. Nevertheless, few NP-15 molecules (15%) decomposed after UV irradiation for 240 h. The decomposition rates for the three surfactants followed the order CTAB > SDS >> NP-15.

Effect of Temperature on Foaming Ability and Foam Stability of Typical Surfactants Used for Foaming Agent

AbstractFoam has extensive applications in a wide range of industrial fields. Some surfactants are used as foaming agents in the preparation of foam. The performance of the foaming agent directly affects the application of the foam. In this paper, experiments were designed and conducted to reveal the influence of temperature on foaming performance of 10 typical anionic, cationic, nonionic, and amphiprotic surfactants. They were exposed to different temperature conditions to measure the foaming capacity (FC), foaming expansion (FE), and foam's half‐life. FC and FE represent foaming ability (FA), and half‐life represents foam stability (FS). The results show that the FC increased at elevated foaming temperature, while FS decreased with rising temperature. Anionic surfactants are less affected by temperature and have better FA and longer FS. It seems that 20–30 °C is an ideal foaming temperature. This study lays an important foundation for the efficient preparation and utilization of foam in industrial fields.

Effect of anionic surfactant inhibition on sewage treatment by a submerged anaerobic membrane bioreactor: Efficiency, sludge activity and methane recovery

The effect of linear alkylbenzene sulfonate (LAS), a typical anionic surfactant, on the sewage treatment by a submerged anaerobic membrane bioreactor (SAnMBR) was investigated by a 243days operation. The changes of treatment efficiency, methane recovery and sludge activity due to the presence of LAS in sewage was studied in detail. Compared with control (96.8% and 2.87L/d), lower COD removal (95.2%) and biogas production rate (2.11L/d) were found at a LAS dosage of 5mg/L. Besides, LAS was removed by adsorption rather than degradation on the sludge (30–70%). Its adsorption can lead to significant loads in sewage sludge, which then decrease the methane production activity. The recovery efficiency of potential bioenergy was decreased by 20% and 26% at LAS of 2.5mg/L and 5.0mg/L, respectively. The results indicated that LAS had a more negative effect on the acetoclastic methanogens than acidogenic microbiota and the LAS inhibition to methanogen activity was responsible for the decrease of SAnMBR performance. Moreover, LAS caused a higher membrane fouling rate than the control experiment due to the microbial self-protection behavior in coping with the LAS in sewage. SAnMBR was hence not suitable to dispose LAS containing sewage with higher concentration.

A novel approach for the preparation of nanosized Gd2O3 structure: The influence of surface force on the morphology of ball milled particles

This work investigates the effect of inter-particle forces arising from adsorbed typical cationic and anionic surfactants on the morphology of ball milled gadolinium oxide (Gd2O3). The experimental outcomes are interpreted in terms of stabilization and interaction mechanisms of fine washed Gd2O3 particles (size diameter <1μm) in aqueous medium under the variation of surface forces arising of adsorbed surfactant. After ball milling and washing, the point of zero charge or isoelectric point (IEP) of Gd2O3 particles suspension is at pH 11 where its maximum yield stress is observed. Because of hydrophobic interaction, the maximum yield stress increases by 30 times by adsorbed sodium dodecyl sulfate (SDS) and its IEP shifts slightly to a lower pH. By cetyl trimethyl ammonium bromide (CTAB), the yield stress also increases by a much smaller extent (3 times) and shifts to a higher pH of ⿼12.5. Without surfactants, the microstructure of dried Gd2O3 displays the coarse particles of various shapes, i.e. rod, spherical and cubic shapes. This indicates that the milled particles remain agglomerated in dispersion. In the presence of adsorbed anionic SDS, the particles are refined together with numerous 2D nanowire or nano-rod particles at pH⿼8. In contrast, coarser particles with absence of nano-rods are found when cationic CTAB is used to modify the Gd2O3 surface at a pH of about 12.5. The SDS-modified suspension exhibits a much higher yield stress, which results from finer particles in suspension. This is invoked from an organic shell formed by the high adsorbability of negatively charged heads of SDS into the bare positive charge density of the particle. The organic SDS shell prevents the fine particles from re-welding during the dispersing and annealing route. This work develops an inexpensive ball-milling approach with assisted SDS surfactant for mass production of nanosized Gd2O3 from bulky gadolinium material.

Arsenic retention and transport behavior in the presence of typical anionic and nonionic surfactants

The massive production and wide use of surfactants have resulted in a large amount of surfactant residuals being discharged into the environment, which could have an impact on arsenic behavior. In the present study, the influence of the anionic surfactant sodium dodecyl benzene sulfonate (SDBS) and nonionic surfactant polyethylene glycol octylphenyl ether (Triton X-100) on arsenic behavior was investigated in batch and column tests. The presence of SDBS and Triton X-100 reduced arsenic retention onto ferrihydrite (FH), enhanced arsenic transport through FH coated sand (FH-sand) columns and promoted arsenic release from the FH surface. With coexisting surfactants in solution, the equilibrium adsorbed amount of arsenic on FH decreased by up to 29.7% and the adsorption rate decreased by up to 52.3%. Pre-coating with surfactants caused a decrease in the adsorbed amount and adsorption rate of arsenic by up to 15.1% and 58.3%, respectively. Because of the adsorption attenuation caused by surfactants, breakthrough of As(V) and As(III) with SDBS in columns packed with FH-sand was 23.8% and 14.3% faster than that in those without SDBS, respectively. In columns packed with SDBS-coated FH-sand, transport of arsenic was enhanced to a greater extent. Breakthrough of As(V) and As(III) was 52.4% and 43.8% faster and the cumulative retention amount was 44.5% and 57.3% less than that in pure FH-sand column systems, respectively. Mobilization of arsenic by surfactants increased with the increase of the initial adsorbed amount of arsenic. The cumulative release amount of As(V) and As(III) from the packed column reached 10.8% and 36.0%, respectively.

Solubilization of naphthalene and octafluoronaphthalene in ionic hydrocarbon and fluorocarbon surfactants

The solubilization abilities of various kinds of surfactants are clarified through a systematic solubilization study. Naphthalene and octafluoronaphthalene have similar molecular structures and can be used as solubilizates in hydrocarbon and fluorocarbon surfactant systems. The solubilizaton quantities are measured for typical anionic, cationic, and cationic gemini surfactants with different alkyl chain lengths (nine hydrocarbon and six fluorocarbon surfactants). The maximum solubilization quantities of naphthalene and octafluoronaphthalene in aqueous solutions of hydrocarbon or fluorocarbon surfactant are measured as a function of surfactant concentration at 318.2K. There are four solubilization systems regarding hydrocarbons and fluorocarbons. Judging from the molar solubilization ratio (MSR), naphthalene is solubilized most in typical gemini surfactant solution (12-2-12), whereas hardly any naphthalene is solubilized in fluorocarbon surfactants. On the other hand, the maximum MSR of octafluoronaphthalene is found for the gemini type of fluorocarbon surfactant, whereas the minimum value is recorded in the C9H19COONa system. Therefore, gemini surfactants reveal excellent solubilization abilities in homogeneous combination systems. The solubilization stability can be analyzed by estimating the Gibbs free energy change (ΔG°) for the transfer of solubilizate molecules to the aggregate phase. The largest negative value of ΔG° is estimated to be −34.8kJmol−1 for the homogeneous system of octafluoronaphthalene and the gemini-type fluorocarbon surfactant, whereas smaller values are obtained for the heterogeneous systems of naphthalene and fluorocarbon surfactants. These results indicate that fluorocarbon surfactants are not generally suitable for the solubilization of naphthalene.

Buffering colour fluctuation of purple sweet potato anthocyanins to acidity variation by surfactants

Anthocyanins are intriguing natural pigments with beneficial bioactivities and their colour is extremely susceptible to acidity variation. Minimisation of colour fluctuation is essential to maintain quality consistency in food industry. A new strategy employing surfactants to mimic encapsulation was attempted with typical anionic, cationic and nonionic surfactants and proved effective although the traditional copigmentation method was inactive. The exceptional colour fluctuation buffering effect of anionic surfactants especially sodium dodecyl sulphate (SDS) was revealed and then carefully analysed by colorimetric and spectroscopic methods. The outstanding activity of SDS presumably resulted from effective shielding of anthocyanins from external acidity through strong interaction with the positively charged flavylium cations owing to its anionic nature. These results suggest SDS is a valuable additive for buffering colour fluctuation of anthocyanins. The strategy of surfactant will be useful for buffering colour fluctuation of natural colourants.

Synergy between Polyamine and Anionic Surfactant: A Bioinspired Approach for Ordered Mesoporous Silica

A novel bioinspired approach for ordered mesoporous silica was developed on the basis of the synergic coassembly between polyamine and an anionic surfactant as a template. With the help of cationic polyamine, anionic surfactant micelles could be utilized as a mesostructure template, whereas with the aid of the anionic surfactant micelles the cationic polyamine chains underwent aggregation to exert their ability to induce silica condensation. Mesoporous silicas with well-ordered mesostructure of Fd-3m symmetry and 3D hexagonal close-packed mesostructure (hcp) were fabricated. Because of the abundant types of anionic surfactants and polyamines, the synthesis approach can be regarded as a general method for anionic-surfactant-templated mesoporous silica, and new mesostructures and morphologies are expected.

Drag Reducing Flow of water in forced closed loop circulation system by using Sodium dodecyl sulfate additive

The turbulent flow friction of a water solution with a small amount of surfactant additive is dramatically reduced when compared to that of pure water. This effect offers a significant reduction in pumping power and energy consumption. Commercial implementation of drag reducing fluids have proved successful for oil pipeline transportation, district heating and cooling systems, fire fighting, sewer throughput, jet cutting, etc. The investigation was carried out on a facility with a forced closed loop for pressure drop measurements. A type of anionic surfactant (Sodium dodecyl sulfate) mixed with same weight of counter ion material (Sodium nitrate) was used as a drag reducing additive to tap water at a mass concentration ranged from 50 to 2000 ppm. Pressure drop data was collected over a 1668 mm flow pipe of carbon steel with 15.8 and 26.6 mm internal diameter and different solution flow rate (up to 8 m3/h) at constant temperature of 30 ̊C (ambient temperature). The paper focused on calculation of friction factor from experimental data. It was found that the friction factor values lies near Blasuis asymptote for pure solvent, while they positioned towards maximum drag reduction asymptotes when surfactant is added. A maximum drag reduction percent of about 66% was obtained by using 2000 ppm surfactant – counter ion aqueous solution. Also, it was concluded that there is a critical Reynolds number equals to about 96000 not to be exceeded because any further increasing leads to decrease in drag reduction. In addition, a correlation equation was found to correlate wall shear stress as a function of bulk mean fluid velocity. This correlation equation is of value in scale up of results obtained in small laboratory equipments to larger diameter pipes and different operating conditions. Another objective was to investigate the mechanism behind a possible drag reduction.

Effluent as Surfactant for Enhanced Oil Recovery

This investigation considers black liquors (BL) as candidates for chemical enhanced oil recovery (EOR) process. These BLs were effluents from paper mills. The main constituent of BL is sodium lignosulfonate, an anionic surfactant. Results show that these anionic surfactants may be the preferred candidates for EOR as they may be effective in creating low interfacial tension (IFT) at dilute concentrations without requiring an alkali or a co-surfactant. Some of the formulations exhibit a low IFT at high salinity, and hence may be suitable for use in high saline reservoirs. Adsorption tests were conducted on core samples whichindicate that the loss of these formulated surfactants may be comparable to other types of anionic surfactants. Evaluation of surfactants performance was done in oil recovery by core flood tests. Selected formulations recovered about 20-30% of the waterflood residual oil saturation even with dilute concentration of 0.18 wt% surfactant concentrations from core samples.

Formation of High Aspect Ratio Macropore Array on N-Type Silicon

The fabrication of high aspect ratio macropore silicon arrays (MSA) on n-type silicon under optimum photo-electrochemical (PEC) etching (anodization) conditions was demonstrated. The depth of the MSA can reach 350 μm with an aspect ratio of more than 100. With the presence of AOS (a type of anionic surfactant) in the electrolyte, the pore walls solution is slowest, and is more suitable for the preparation of high aspect ratio n-type MSA. The etching voltage is critical for the formation of high aspect ratio MSA on n-type silicon. The relative spectral response curve was measured for silicon photo-electrochemical etching. An IR-LEDs (850 nm) array was proposed as light source for illumination of whole silicon wafers, which was proved available.