Amount Of Anionic Surfactant Research Articles

ZSM-5@MCM-41 composite porous materials with a core-shell structure: Adjustment of mesoporous orientation basing on interfacial electrostatic interactions and their application in selective aromatics transport

A series of hierarchically porous materials with core-shell structures have been successfully fabricated through a modified Stöber method. The interfacial growth of mesoporous silica with adjustable mesochannel orientation on the surface of ZSM-5 nanocrystal results in the formation of a core-shell structure. The zeta potentials of ZSM-5 nanocrystals have been carefully adjusted through interfacial assembly with a certain amount of anionic surfactants, thus inducing different electrostatic interactions with positively charged cetyltrimethylammonium bromide micelles. The alignment of the outer silicate mesopores around the ZSM-5 nanocrystals transforms from parallel into vertical relative to the zeolite surface, so that the orientation effect of interfacial interactions is experimentally confirmed to be effective in the epitaxial growth of mesoporous shell on the surface of nano-zeolite. The adsorption capacities of the composite porous materials have been dramatically improved after the epitaxial growth of mesoporous shells. Moreover, the materials demonstrate different diffusion efficiencies for organic molecules on the basis of their mesochannel alignments.

Effect of adsorption of catanionic surfactant mixtures on wettability of quartz surface

The adsorption behaviors of dodecyl trimethyl ammonium bromide (C12TAB) and the catanionic mixtures of C12TAB with sodium dodecyl sulfate (SDS), sodium dodecyl sulfonate (SDDS) and sodium dodecanoate (DAS) on quartz surface have been investigated. Physicochemical parameters such as the critical micelle concentration (CMC), surface tension, contact angle, adhesional tension and work of adhesion have been estimated. At the interface of quartz and aqueous solution of catanionic mixture, there is a competition between anionic surfactants and quartz surface in attracting cationic surfactants. SDDS and DAS fail to inhibit the adsorption of C12TAB because of the smaller size and less negative charge of the head-groups, even the amount of anionic surfactants well surpasses that of C12TAB. Instead the anionic surfactants are dragged by cationic surfactants to quartz surface and form a mixed monolayer on the quartz surface. The insert of anionic surfactants reduces the repulsion between the cationic molecules and results in closer packing of molecules in adsorption layers. Thus, SDDS-C12TAB and DAS-C12TAB have displayed stronger hydrophobic modification at quartz surface than pure C12TAB. However, the electrostatic attraction between excessive SDS and C12TAB is strong enough to constrain C12TAB and decreases the adsorption on quartz surface. Only a small amount of catanionic complexes with the structure like zwitterionic surfactant adsorb on quartz through the interaction between the positive sites of surfactant complexes and negative sites of quartz. Over CMC, bilayers are formed on quartz surface in the systems of SDDS-C12TAB and DAS-C12TAB, while micelle structures are adsorbed on quartz surface for SDS-C12TAB.

Small-angle neutron scattering study of the structure of mixed micellar solutions based on heptaethylene glycol monotetradecyl ether and cesium dodecyl sulfate

The micellization in mixed aqueous systems based on a nonionic surfactant, heptaethylene glycol monotetradecyl ether (C14E7), and an anionic surfactant, cesium dodecyl sulfate, has been investigated by small-angle neutron scattering. Preliminary data on the behavior of the C14E7 aqueous solutions (with three concentrations, 0.17, 0.5, and 1%) mixed with a small amount of anionic surfactant, cesium dodecyl sulfate, are reported.

Experimental observation on the mixing systems and ways to significantly enhance the conductivity of PEDOT-sulfonated poly(imide) aqueous dispersion

Conductive poly(3,4-ethylenedioxythiophene):sulfonated polyimide (PEDOT:SPI) films were successfully developed by decreasing the particle size along with the addition of anionic surfactant leading to potential applications in electronic devices. By varying the mixing system (magnetic bar at 1000rpm, mechanical at 1000rpm and mechanical at 4000rpm), we observed significant conductivity and thermal stability enhancement of the obtained PEDOT-SPI films by using designed stir shaft with high-speed mechanical mixing systems allowing for smaller particle sizes of PEDOT:SPI about 43nm averaging. In addition, the further conductivity enhancement and thermal stability of PEDOT:SPI was achieved by adding various amounts of anionic surfactant into the aqueous polymer suspension because of the resulting conformational changes. The highest conductivity, 9.5Scm−1, was achieved at 1wt% SDS in PEDOT:SPI (6FDA) film which increased by a factor of 5 from the PEDOT:SPI without addition of SDS. Moreover, using a high-speed mechanical mixing system and addition of anionic surfactant also improved the thermal stability of conductive films, which was verified by TGA analysis. Due to the combination of using high-speed mechanical mixing and adding of anionic surfactant, superior dispersion stability, high conductivity and good thermal stability PEDOT:SPI films were achieved.

Fluorimetric Method to Determine Trace Anionic Surfactants Using a Novel Triazene Reagent

Although widely applied in many industries, anionic surfactants (AS) have been shown to contaminate the natural environment. Therefore, the detection of trace amounts of AS in environmental samples is of great interest. Here, we report a novel fluorescence quenching method for the determination of trace AS, specifically, sodium dodecyl sulfate (SDS), using 1-(5-naphthol-7-sulfonic acid) -3-(4-pheny-lazophenyl)-triazene (NASAPAPT). Under optimum conditions, the degree of fluorescence quenching is linearly proportional to the concentration of SDS from 2.08×10-8 to 8.67×10-7mol L-1 with a detection limit of 8.35×10-9mol L-1. The proposed method exhibits high sensitivity and selectivity, yet it avoids the use of toxic organic solvents and tedious solvent extraction procedures. It has been applied to the determination of trace SDS in both natural water and industrial samples with recoveries between 99.04 and 103.58%. Results indicated that the hydrogen bonds formed between NASAPAPT and SDS played an important role in the detection process and that the π→π* transition was crucial for fluorescence of the NASAPAPT complex.

Electrochemical assembly of [Ru(bpy)2tatp]2+ associated with surfactants on the MWNTs/GC electrode

The electrochemical assembly of [Ru(bpy)2tatp]2+ (where bpy = 2,2′-bipyridine, tatp = 1,4,8,9-tetra-aza-triphenylene) on the multi-walled carbon nanotubes-modified glassy carbon electrode (MWNTs/GC) in the presence of anionic and cationic surfactants has been investigated. A diffusion-controlled wave and three prewaves are exhibited on the differential pulse voltammogram of [Ru(bpy)2tatp]2+. The formal potential of the prewaves is found to be much negative than that of the diffusion-controlled wave. An appropriate amount of anionic surfactants including dihexadecyl phosphate (DHP) and deoxyribonucleic acid (DNA) can prompt the assembly of [Ru(bpy)2tatp]2+ on the MWNTs/GC electrode by using the method of repetitive voltammetric sweeping. In contrast, cationic surfactant such as hexadecyl trismethyl ammonium chrolide (HTAC) dispersed on the MWNTs surface is found to inhibit the assembly of [Ru(bpy)2tatp]2+. Meanwhile, the assembled principle of [Ru(bpy)2tatp]2+ on the MWNTs/GC electrode with the participation of surfactants is discussed in detail.

Resonance light scattering method for the determination of anionic surfactant with acridine orange

The resonance Rayleigh scattering (RRS), second-order scattering (SOS) and frequency-double scattering (FDS) spectra of sodium dodecylbenzene sulfonate (SDBS) (anionic surfactant (AS)) with acridine orange (AO) system were studied. Experimental results showed that when λ em = λ ex = 537 nm, the RRS peak of AO was greatly enhanced with the increase of SDBS concentration at a pH range of 1.8–4.0. The linear range of the calibration curve for SDBS was 0.028–8.71 mg L −1 with a detection limit of 8.36 μg L −1 when the AO concentration was 2.5 × 10 −5mol L −1. The method has been applied to the determination of trace amount of AS in environmental water samples with satisfactory results. In addition, when λ em = 321 nm and λ ex = 642 nm, the intensity of FDS was proportional to the SDBS concentration ranging from 0.014 to 8.71 mg L −1 and the correlation coefficient was 0.993 with a detection limit of 4.31 μg L −1; when λ em = 642 nm and λ ex = 321 nm, the intensity of SOS was proportional to the SDBS concentration ranging from 0.050 to 8.71 mg L −1, and the correlation coefficient was 0.993 with a detection limit of 14.9 μg L −1.

A look at surfactant partitioning in polymeric latexes using conductivity measurements

An attempt was made to analyse the partitioning of anionic surfactants in a mixed surfactant system using surface tension and conductivity measures. This last technique gives us access to the quantity of free ions in solution, and thus a measure of the amount of anionic surfactant available in the aqueous phase. The range of surfactant concentrations studied here is such that the global surface coverage (assuming that the totality of the emulsifier is at the particle surface) varies around 100%.

96/01388 Rheological characteristics of coal-water mixture fuel and pressure losses in pipe flow

The rheological characteristics of coal-water mixture(CWN) fuel, based on the power law model, were investigated using the Haake rotational viscometer, which produced shear rates from 0.1 to . Test results showed that all the slurries exhibited non-Newtonian properties of shear-thinning behavior, i.e., pseudoplastic or yield-pseudoplastic. The slurries become more viscous as the temperature, the mean particle size, and the amount of anionic surfactant were lowered. Furthermore, the yield stress measured in the case of no additive varied with the solid volume fraction and the coal particle size. The CWMs displayed a higher degree of pseudoplasticity with an increase in coal content and with a decrease in the mean size of the coal particles, the amount of additive, and the temperature. The pressure loss data obtained in the CWM test loop were coincided with the calculated values from the correlation based on the power law constants. Also, the generalized Reynolds number()-friction factor(f) relationship could be applied to the laminar flow of CWM fuel.

Rheological behaviour of coal-water mixtures. 2. Effect of surfactants and temperature

The rheological characteristics of coal-water mixture (CWM) were investigated, including the effects of surfactant type and concentration, presence of added electrolytes and slurry temperature. The slurryability of coal could be enhanced considerably by the addition of surfactants and some electrolytes and the slurries almost exhibited shear-thinning behaviour, i.e. were pseudoplastic with n < 1, which is a desirable rheological characteristic for CWM. The slurry viscosity increased as the temperature, the amount of anionic surfactant and electrolyte, and the HLB value of non-ionic surfactant decreased. The addition of nonylphenol non-ionic surfactants also enhanced the resistance of CWM to sedimentation, and this effect was more pronounced, the greater the number of ethylene oxide groups in the surfactant molecule. The CWMs displayed a higher degree of pseudoplasticity with decreasing amount of surfactant and temperature. The effect of temperature on the slurry viscosity could be described by the simple Andrade equation, but the rate of reduction of apparent viscosity associated with the temperature rise began to decrease above a certain temperature which seems to mark the onset of an adverse effect of temperature.