Addition Of Anionic Surfactant Research Articles

Surfactant assisted CaO-based sorbent synthesis and their application to high-temperature CO2 capture

The concern of carbon dioxide (CO2) emissions, a main contribution of greenhouse gases, has been emerged as an important issue for environmental impact. Adsorption of CO2 by porous solid materials is proven to be one of efficient techniques for CO2 capture technologies. In the present work, attempted has been made to improve property of porous solid materials, CaO-based sorbent, applied for high-temperature CO2 capture. CaCO3 and CaO-based alumina was synthesized using precipitation technique with the addition of sulfonic single chain (SDS) and gemini (12-carbon hydrophobic chains and 3-carbon alkyl spacer, 12-3-12) surfactants for controlling/modifying physical properties. Our studies showed that the addition of anionic surfactants affected phase formation and polymorph of CaCO3, where stronger effect was observed with gemini surfactant. The synthetic CaCO3 was derived to form CaO and applied for capturing CO2 at 600 °C, 15% v/v CO2 (N2 balanced). The results showed that CaO synthesized with adding gemini surfactant offered higher CO2 sorption capacity than single chain surfactant. By incorporating calcium with alumina using co-precipitation technique, the addition of gemini surfactant showed a good impact on CO2 capture performance as an increase in CO2 sorption capacity was observed. However, sintering effect was still not yet be resolved with the addition of gemini surfactant as CO2 sorption capacity decreased upon multiple cycles of CO2 capture.

Correction to "Role of Ion-Dipole Interactions in Nucleation of Gamma Poly(vinylidene fluoride) in the Presence of Graphene Oxide during Melt Crystallization".

The crystallization behavior and crystalline structure of poly(vinylidene fluororide) (PVDF) in the presence of graphene oxide (GO) platelets were investigated using time-resolved Fourier transformation infrared spectroscopy (FTIR), wide-angle X-ray diffraction (WAXD), as well as differential scanning calorimetry (DSC). It is shown that GO platelets induce the formation of γ phase when crystallizing from solution, but only α phase forms from melt crystallization. The crystallization kinetics of α phase is promoted due to heterogeneous nucleation ability of GO, which is probably originated from a weak π-dipole interaction between GO and PVDF. Intriguingly, after introduction of strong ion–dipole interactions between GO and PVDF by addition of an ionic surfactant (cetyltrimethylammonium bromide, CTAB), a significant amount of γ crystals are obtained during isothermal melt crystallization. Time-resolved FTIR results further provide a detailed evolution of the γ phase formation, and there are two distinct sta...

Investigating the improvement of Degradation Resistant with the Addition of SDBS Anionic Surfactant to PEO polymer

Polyethylene Oxide (PEO) is one of the most common drag reduction agents. However, its ability to reduce drag in turbulent flow decreases with the time due to the degradation of its molecules. Thus, the enhancement of its degradation resistance by the addition of Anionic surfactant is presented. The Polyethylene oxide (PEO) was used in different concentration ranges from 10 to 60 ppm and with addition of sodium dodecyl benzene sulfonate (SDBS) as the anionic surfactant with five concentrations between 100 to 500 ppm. The degradation measurements were done using rotating disk apparatus (RDA). The RDA results have shown a considerable improvement in the degradation resistance of PEO with the addition of surfactant to the polymer solution. The interaction between the polymer and the surfactant results in transferring the polymer chain from coil to straight-like body. Thus, enhance the polymer degradation resistant ability.

Study on the influence of addition of anionic surfactants on adhesion of ice

Study on the influence of addition of anionic surfactants on adhesion of ice

Influence of PAA on the Microstructure and Corrosion Resistance of Electrophoretically Deposited SiO2 and Ni/SiO2 Coatings on X2CrNiMo17-12-2 Steel

AbstractThe effect of anionic surfactant in the form of polyacrylic acid (PAA) on the electrophoretic deposition of the SiO2and Ni/SiO2coatings on X2CrNiMo17-12-2 stainless steel was examined. Parameters of the process, such as chemical composition of the suspensions, voltage between the electrodes and the deposition time were experimentally selected. Zeta potential measurements showed a beneficial effect of polyacrylic acid on the SiO2and Ni particles stability in ethanol. Scanning and transmission electron microscopy studies revealed that the microstructure of the coatings obtained from the suspensions containing polyelectrolyte is more homogenous and has less amount of desiccation cracks on the surface. The results of the polarization tests have shown that addition of anionic surfactant improves also corrosion resistance of the coatings in 3.5% NaCl solution.

Enhancement of thermoelectric properties of PEDOT:PSS thin films by addition of anionic surfactants

The thermoelectric properties of poly(3,4-ethylendioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) thin films were investigated following the introduction of the anionic surfactants sodium dodecyl sulfate (SDS) or sodium dodecylbenzene sulfonate (SDBS). The power factor of the PEDOT:PSS films were enhanced by approximately two orders of magnitude after the addition of either SDS or SDBS when compared with the control PEDOT:PSS film, which was a result of their improved electrical conductivity. Additionally, the wettability of the PEDOT:PSS solution towards a range of substrates was improved after the addition of SDS or SDBS. These results showed that the addition of anionic surfactants to a PEDOT:PSS solution is an effective way to improve both the thermoelectric properties of PEDOT:PSS thin films and the wettability of the solution. Importantly, this method allows for uniform film formation on a range of substrates using wet process coating.

Synthesis of nanosized composite powders via a wet chemical process for sintering high performance W-Y2O3 alloy

With the aim of preparing high performance oxide dispersion strengthened tungsten-based alloys by powder metallurgy, the W-Y2O3 composite nanopowders were prepared by an improved bottom-up wet chemical method. Ultrasonic treatment and anionic surfactant sodium dodecyl sulfate (SDS) addition were innovatively introduced into this wet chemical method in order to fabricate homogeneous, ultrafine W-Y2O3 composite nanopowders. As a result, the average tungsten grain size of 40–50nm was obtained for this composite nanopowders. For comparison, W-Y2O3 composite powders were also prepared by traditional mechanical milling. After that, spark plasma sintering (SPS) was employed to consolidate the powders prepared by either mechanical milling or wet chemical method to yield high density as well as suppress grain growth. It is found that the W-Y2O3 alloy prepared by wet chemical method and subsequent SPS possesses smaller grain size (0.76±0.17μm) and higher relative density (99.0%) than that prepared by mechanical milling and subsequent SPS. Moreover, the oxide nanoparticles (about 2–10nm) are dispersed within tungsten grains and at grain boundaries more uniformly in W-Y2O3 alloy prepared by wet chemical method and subsequent SPS. Due to the ultrafine grains, high sintering density and homogeneously distributed oxide nanoparticles, the Vickers microhardness of yttria dispersion strengthened tungsten-based alloy prepared in our work reaches up to 598.7±7.3HV0.2, higher than that reported in the previous studies. These results indicate that the improved bottom-up wet chemical method combined with ultrasonic treatment and anionic surfactant addition developed in our work is a promising way to fabricate high performance oxide dispersion strengthened tungsten-based alloys with ultrafine grain and high density.

Stabilising nanofluids in saline environments

Nanofluids (i.e. nanoparticles dispersed in a fluid) have tremendous potential in a broad range of applications, including pharmacy, medicine, water treatment, soil decontamination, or oil recovery and CO2 geo-sequestration. In these applications nanofluid stability plays a key role, and typically robust stability is required. However, the fluids in these applications are saline, and no stability data is available for such salt-containing fluids. We thus measured and quantified nanofluid stability for a wide range of nanofluid formulations, as a function of salinity, nanoparticle content and various additives, and we investigated how this stability can be improved. Zeta sizer and dynamic light scattering (DLS) principles were used to investigate zeta potential and particle size distribution of nanoparticle-surfactant formulations. Also scanning electron microscopy was used to examine the physicochemical aspects of the suspension.We found that the salt drastically reduced nanofluid stability (because of the screening effect on the repulsive forces between the nanoparticles), while addition of anionic surfactant improved stability. Cationic surfactants again deteriorated stability. Mechanisms for the different behaviour of the different formulations were identified and are discussed here.We thus conclude that for achieving maximum nanofluid stability, anionic surfactant should be added.

Effect of Surfactant Additives on Phase Inversion in Oil-Water Pipe Flow System

This research investigates the effect of surfactant additives on phase inversion point in the oil-water flow in horizontal pipe. Two types of surfactants were used in the experiments; anionic type (sodium lignosulfonate (SLS)) at 200 ppm and cationic type (hexadecyltrimethyl ammonium bromide (CTAB)) at 100 ppm. The experiments were carried at mixture velocities (0.8, 1, 1.9 and 2.3) m/s. The results showed that the phase inversion points are unaffected by surfactant addition or velocity at low mixture velocities while they shifted downward at high mixture velocities. The experiments show also that anionic surfactant addition caused a forward shifting in phase inversion point and downward shifting in the addition of cationic surfactant at high mixture velocities.

Interplay between bulk self-assembly, interfacial and foaming properties in a catanionic surfactant mixture of varying composition.

The self-aggregation, surface properties and foamability of the catanionic surfactant mixture cetyltrimethylammonium bromide (CTAB)/sodium octyl sulfonate (SOSo) have been investigated to obtain insight on the relation between bulk nanostructures, surfactant packing, and foam stability and aging. Light microscopy, SANS, cryo-TEM, DLS, surface tension, rheometry and direct photography were used to characterize mixtures with varying CTAB molar fraction, xCTAB. In the bulk, self-assembly is richer in the excess CTAB region than in the excess SOSo one. Starting from neat CTAB micelles and on addition of anionic surfactant, there is a change from small ellipsoidal micelles (1 < xCTAB ≤ 0.80) to large rodlike micelles (0.65 ≤ xCTAB ≤ 0.55) and then to vesicles (0 < xCTAB ≤ 0.50), with coexistence regions in between; SOSo-rich mixtures are thus dominated by vesicles. High size polydispersity for the micelles and vesicles is an intrinsic feature of this system. Foam stability is concomitantly impacted by xCTAB. SOSo is a small mobile molecule and so it disrupts foam stability, irrespective of the presence of vesicles. Foams are thus only stable in the CTAB-rich regions, and SANS shows that the shape of micelles and vesicles is unchanged inside the foam. Foam drainage is thereby mostly controlled by the presence of the elongated micelles through the solution viscosity, whereas coarsening is influenced by dense surfactant packing at the gas-liquid interfaces.

Effect of SDS on kinetics for Co-Cyanex 272 complex in a neutral micellar phase

Cobalt extraction by Cyanex 272, Bis(2,4,4-trimethylpentyl)phosphinic acid, (HR) in micellar solution has been shown to be a two-step reversible reaction and the reaction rate constants for the forward and reverse reactions have been obtained. In this investigation the influence of the addition of anionic surfactants, Sodium Dodecyl Sulphate (SDS), on the rate of extraction of cobalt from the aqueous phase by Cyanex 272 in the micelle phase was investigated. The anion surfactant (SDS) was found to increase the rate of extraction. This could be mainly ascribed to the increase in the local concentration of cobalt at the interface generated by the electrostatic surface potential with added surfactant. The effect of charge on the reaction rate has been modelled based on the electrostatic surface potential generated by the added surfactant.

Nanozirconia surface modification by anionic polyacrylamide in relation to the solid suspension stability — Effect of anionic surfactant addition

The turbidimetry and static light scattering methods were applied to specify the stability conditions of aqueous nanozirconia suspension. The stability coefficients and mean sizes of formed aggregates (flocks) were determined. The effects of solution pH (in the range 3–10), presence of anionic polyacrylamide (PAM), carboxyl groups content in its macromolecules (5–50%), as well as anionic surfactant (sodium dodecyl sulfate - SDS) addition were examined. The obtained changes in the system stability after the polymer (and surfactant) addition were explained based on adsorption (PAM adsorbed amount) and electrokinetic data (zeta potential). Analysis of the obtained results indicated that the simultaneous presence of the polymer and surfactant at pH6 has the greatest influence on the nanozirconia suspension stability. Under such conditions considerable improvement of the system stability takes place due to the electrosteric interactions between solid nanoparticles.

Surfactant-Triggered Fluorescence Turn "on/off" Behavior of a Polythiophene-graft-Polyampholyte.

Polythiophene-graft-polyampholyte (PTP) is synthesized using N,N-dimethylaminoethyl methacrylate and tert-butyl methacrylate monomers by grafting from polythiophene backbone, followed by hydrolysis. The resulting polymer exhibits aqueous solubility via formation of small-sized miceller aggregates with hydrophobic polythiophene at the center and radiating polyionic side chains (cationic or anionic depending on the pH of the medium) at the outer periphery. The critical micelle concentration of PTP in acidic solution (0.025 mg/mL, pH = 2.7) is determined from fluorescence spectroscopy. PTP exhibits reversible fluorescence on and off response in both acidic and basic medium with the sequential addition of differently charged ionic surfactants, repeatedly. The fluorescence intensity of PTP at pH 2.7 increases with the addition of an anionic surfactant, sodium dodecyl benzenesulfonate (SDBS), due to the self-aggregation forming compound micelles. The fluorescence intensity of these solutions again decreases on addition of a cationic surfactant, cetyltrimethylammonium bromide (CTAB), because of assembling of SDBS with CTAB, thus deassembling the PTP-SDBS aggregates. At pH 9.2, these turn on and turn off responses are also shown by PTP with the sequential addition of cationic surfactant (CTAB) and anionic surfactant (SDBS), respectively. This result shows that PTP has potential for surfactant-induced reversible fluorescence turn on and off using ionic surfactant (SDBS and CTAB) through self-assembling and deassembling of the ionic aggregates. The reversible aggregation and disaggregation process of PTP with the surfactants at both acidic and basic pH is supported from dynamic light scattering and Fourier transform infrared spectroscopy. The morphology of the above systems studied by transmission and scanning electron microscopy also supports the above aggregation and disaggregation process.

Organic phase addition of anionic/non-ionic surfactants to poly(paraphenyleneterephthalamide) thin film composite nanofiltration membranes

Thin-film composite (TFC) nanofiltration (NF) membranes containing poly (paraphenylene terephthalamide) skin layer on polyethersulfone (PES) support layer were prepared by in situ interfacial polymerization using p-phenylenediamine (PPD) in water and terephthaloyl chloride (TPC) in n-hexane. The effects of sodium lauryl ether sulfate (SLES), triethanolamine lauryl ether sulfate (TEA-LES) and disodium laureth sulfosuccinate (DSLS) as anionic surfactants as well as cocamide-MEA, polysorbate 20 and nonylphenol as non-ionic surfactants, in the organic phase on the properties of TFC membrane were investigated. The performance of prepared TFC membranes was investigated for the rejection of NaCl, Na2SO4 and MgSO4 ion solutions by dead-end filtration set-up. ATR-IR, SEM, AFM and zeta potential were applied to characterize the structure and morphology of the prepared TFC membranes. By addition of anionic surfactants in the organic phase, no significant change in the morphology and performance was observed; however, in the presence of non-ionic surfactants, the morphology and performance were changed and the salt rejections were increased. The structure of thin layer of membrane incorporated TEA-LES surfactant was not good and its surface had defect and micro crack. The highest salt rejections were obtained using nonylphenol in comparison with the other anionic/non-ionic surfactants.

Electrokinetic remediation of soil polluted with insoluble organics using biological permeable reactive barriers: Effect of periodic polarity reversal and voltage gradient

This study investigated the remediation of clay soil polluted with low-solubility organics (diesel hydrocarbons) using a combined electrochemical-biological technology. Electrokinetic soil flushing was used, coupled with a biological permeable reactive barrier, which was placed into soil away from electrodes to prevent the negative effects of the acidic and basic fronts on the viability of microorganisms. Three two-week long batch experiments were performed in a lab-scale installation specifically designed to evaluate the remediation of polluted soil. The primary variable under study was the electric field applied to the soil (0.5, 1.0 and 1.5Vcm−1), and the experimental procedure included daily polarity reversal of the electrodes and the addition of anionic surfactant in the electrode wells. The polarity reversal was observed to be a key strategy, which allowed adequate experimental conditions to be maintained in the soil (especially temperature and pH) for the success of the organic biodegradation process. The surfactant was evenly distributed across the soil, which helped the pollutant be transported. The biological activity was not limited to the barrier area but extended to the entire soil portion due to the microbial transport and growth far from the central barrier position. The voltage gradient did not have a strong influence on the measured experimental conditions (soil temperature, pH and moisture) but affected the electroosmotic flow. A higher diesel removal efficiency (36%) was observed when using the higher voltage gradient (1.5Vcm−1) after two weeks, which demonstrates a promising performance of the studied technology for a future real in-situ application.

Microwave-assisted Preparation of Copper Hydroxyphosphate and Characterization of Photocatalysis under Visible Light

Copper hydroxyphosphate (Cu2(OH)PO4) was quickly synthesized by microwave-assisted method at low temperature (< 100°C) and normal atmosphere pressure, then characterized by XRD, SEM and Raman spectra. The synthesis parameters were investigated by a series of controled experiments. It is found that molar ratio, initial concentration of CuCl2 and NaH2PO4, and surfactant species were crucial factors determining the formation and morphology of Cu2(OH)PO4. Cu2(OH)PO4 synthesized at different [PO4] (n(Cu)/n(P)=2) exhibited a various morphologies including grain-like, prism and long-prismatic. Addition of anionic surfactant and sodium dodecyl sulfate (SDS) greatly affects Cu2(OH)PO4 final morphology. The photocatalytic degradation of Cu2(OH)PO4 on methylene blue (MB) was evaluated with addition of H2O2 under visible light irradiation. The results showed that Cu2(OH)PO4 synthesized at conditions when n(Cu)/n(P)=2, [PO4]=0.0025 mol/L, 6.0 g urea and 0.10 g SDS, microwave heating at 80°C for 30 min exhibited best visible-light photo-degradation activity. The increase in HO· formation in the presence of Cu2(OH)PO4 and the inhibition of HO· generation by adding HO· scavengers (t-butanol) indicated that HO· generated 422 无 机 材 料 学 报 第 31 卷 in the reaction system was responsible for the enhanced MB decomposition. Cu2(OH)PO4 exhibited excellent stability and effectiveness after 5 consecutive runs in terms of photodegradation of MB.

Effect of Anionic Surfactant on the Growth of Anodic Nanoporous Aluminum Oxide

Nanoporous aluminum oxide film was prepared by anodizing Aluminum in a mixture of 0.3 M H3PO4 with the addition of varying concentration of Sodium Dodecyl Sulfate (SDS), which is an anionic surfactant. We found that addition of anionic surfactant during anodization of aluminum leads to the delay in dissolution of the formed pores as compared to those prepared without SDS surfactant. The results show that sufficient addition of SDS during anodization of aluminum oxide facilitates pore channel length, pore density and progress in chemical resistance. Morphology of nanoporous oxide with surfactant was confirmed by FE-SEM and EDS. Evaluation of pore diameter, interpore distance, pore density and porosity and uniformity of pores was done with the help of image-J software. Surface dissolution was observed when the concentration of SDS is more than 3.4 × 10−3 M (1g) after 2 hrs in one step anodization at 170 V which means that the optimum tolerance concentration against surface dissolution is less than 3.4 × 10−3 M (1g).

Influence of Ionic Surfactants on the Properties of Nanoemulsions Emulsified by Nonionic Surfactants Span 80/Tween 80

The instability of nanoemulsions were mainly due to Ostwald ripening. The droplet charge was influenced by the stability of nanoemulsions significantly. In this work, the properties of the shea butter oil-loaded nanoemulsions were investigated in detail with the addition of cationic surfactants (cetyl trimethyl ammonium chloride, 1631; octadecyl trimethyl ammonium chloride, 1831), anionic surfactants (alcohol ethoxysulfate, AES; dodecyl phosphate ester sodium salt, MAP), and zwitterionic surfactants (cocoamidopropyl betaine, CAB; dodecyl hydroxysulfobetaine, 20HD). By increasing the concentration of cationic surfactants, the positively charged nanoemulsions were prepared and the smallest droplets were being formed with 0.05% 1831. Upon the addition of anionic surfactants, a more negative value was obtained and the smallest droplets were being formed with 0.1% AES. The ionic surfactants by increasing the electrostatic interactions between droplets and incorporation into the oil phase improved the stability of the nanoemulsions via lowering the Ostwald ripening rate, and especially improved the high temperature stability. By increasing the concentration of zwitterionic surfactants, a less negative zeta potential was observed and the stability of the nanoemulsions did not improve. The results proved that the electrosteric repulsion had an appreciable impact on the stability of the nanoemulsions.

Anionic/Non-ionic Surfactants in Aqueous Phase of Thin Film Composite Poly(Paraphenylene Terephthalamide) Nanofiltration Membranes

In this work, the Interfacial interfacial polymerization (IP) technique was employed using terephthaloyl chloride (TPC) and p-phenylenediamine (PPD), as reactant monomers, to prepare poly(paraphenylene terephthalamide) thin film composite (TFC) nanofiltration on polyethersulphone (PES) support layer. The effects of six different anionic and non-ionic surfactants, in the aqueous phase on the morphology and performance of membranes were investigated. The performance of membranes was evaluated by the pure water flux (PWF) and the rejection of salt solutions. By addition of anionic surfactants, the morphology and performance were unaltered, while, in the presence of non-ionic surfactants, both morphology and performance were changed. Furthermore, the conditions for IP process were examined.

Surfactant assisted pulsed two-phase electromembrane extraction followed by GC analysis for quantification of basic drugs in biological samples

In this work, a simple and efficient surfactant assisted pulsed two-phase electromembrane extraction (SA-PEME) procedure combined with gas chromatography (GC) has been developed for the determination of alfentanil, sufentanil and methadone in various samples. It has been found that the addition of anionic surfactant causes the accumulation of the cationic analytes at the SLM/solution interface resulting in an easier transfer of the analytes into the organic phase. The method was accomplished with 1-octanol as the acceptor phase and supported liquid membrane (SLM) by means of an 80V pulsed electrical driving force and the extraction time of 20min. The model analytes were extracted from 3.0mL sample solution (pH 4.0) containing 0.02% w/v surfactant (sodium dodecyl sulfate). The duty cycle of 92% and frequency of 0.357Hz gave the best performance. Extraction recoveries in the range of 70.5–95.2% and satisfactory repeatability (7.6<RSD<13.7) were obtained. The limits of detection were 1.5, 1.5 and 0.6ngmL−1 for sufentanil, alfentanil and methadone, respectively. The method offers an acceptable linearity (2.0–1000.0ngmL−1) for each analyte with coefficient of determination higher than 0.998. Furthermore, the figures of merit of SA-PEME were compared with the results from the conventional two-phase EME which confirm the advantages of the proposed technique. The method was applied for the determination and quantification of the model compounds in the wastewater, plasma, breast milk and urine samples.