Adsorption Of Sodium Dodecyl Sulfate Research Articles

Removal of cadmium ion using micellar-enhanced ultrafiltration (MEUF) and activated carbon fiber (ACF) hybrid processes: adsorption isotherm study for micelle onto ACF

Micellar-enhanced ultrafiltration (MEUF) was applied to remove cadmium ion from wastewater using sodium dodecyl sulfate (SDS) as a micelle in this study. Investigations were carried out on operational parameters such as initial permeate flux, retentate pressure, initial cadmium concentration, pH solution, molecular weight cut-off (MWCO), and molar ratio of cadmium to SDS. Removal efficiency of cadmium increased with increase in retentate pressure, pH solution, and molar ratio of cadmium to SDS and decreased with increase in initial permeate flux. Higher removal efficiency of cadmium was achieved using lower MWCO. In optimized experimental condition, cadmium removal efficiency reached 75% within an hour. With MEUF–ACF hybrid process, removal efficiencies of cadmium and SDS were found to be over 99 and 90%, respectively. Freundlich isotherm equation fitted better with experimental results on adsorption of SDS by ACF than Langmuir isotherm equation. Overall SDS removal efficiency of ACF unit in series was 90%.

Adsorption capacity of NH4Cl-induced activated carbon for removing sodium dodecyl sulfate from water

Surfactants are a very important group of compounds that are used extensively in modern life and have adverse effects on human health and aquatic life. The aim of this study was to evaluate the adsorption characteristics of sodium dodecyl sulfate (SDS) on standard activated carbon (SAC) and NH4Cl-induced activated carbon (NAC). It was found that, in the batch experiment conducted at 50 mg/L initial concentration of SDS, pH of neutral, and adsorbent dose of 1 g/L, SAC and NAC could remove up to 81 and 99% of SDS from the solution. The removal of SDS by both adsorbent followed the pseudo-second-order reaction kinetics. Results of the equilibrium experiments revealed that the adsorption of SDS onto SAC and NAC was better fitted by the Langmuir model. The maximum adsorption capacity of SDS onto SAC and NAC was 117.2 and 178.6 mg/g, respectively. The results suggested that NAC is suitable as a sorbent for the adsorption of SDS from aqueous solutions in view of its effectiveness and high capacity.

New Surfactant Delivery System for Controlling Surfactant Adsorption onto Solid Surfaces. Part I: Static Adsorption Tests

Chemical enhanced oil recovery processes (EOR) are effective if the injected chemical slugs propagate through the oil reservoir. With surfactant flooding, the loss of surfactant to adsorption onto rock surfaces significantly affects the effectiveness of the chemical flooding. Therefore, the adsorption of surfactant onto solid surfaces is a major issue that makes the process uneconomical. In this paper, the first of a series of three, a new approach to preventing surfactant adsorption onto rock surfaces is studied. A novel surfactant delivery system based on inclusion complexes between sodium dodecyl sulfate (SDS) and β‐cyclodextrin was evaluated. The adsorption of SDS in free‐ and complex‐state onto solid surfaces was investigated through static adsorption tests. Different mixtures of solid materials (sandstone, oil shale, and kaolinite) were used as adsorbents. The adsorption of the surfactant was quantified through analysis of total organic carbon (TOC). Qualitative experiments through bottle testing were also conducted to visualize the effectiveness of the surfactant delivery system. Experimental results demonstrate that the surfactant delivery system effectively minimizes the adsorption of surfactant (SDS) onto solid surfaces, with reductions of surfactant adsorption ranging from 64–76%. Likewise, the release of the surfactant hydrophobic tail from the β‐CD cavity was qualitatively verified through bottle testing. Therefore, this novel surfactant delivery system shows great potential for chemical EOR flooding applications.

Coarse-grained molecular dynamics simulation of self-assembly and surface adsorption of ionic surfactants using an implicit water model.

We perform coarse-grained molecular dynamics simulations for sodium dodecyl sulfate (SDS) surfactant using a modification of the Dry Martini force field (Arnarez et al. 2014) with implicit water. After inclusion of particle mesh Ewald (PME) electrostatics, an artificially high dielectric constant for water (ε(r) = 150), and reparameterization, we obtain structural and thermodynamic properties of SDS micelles that are close to those obtained from the standard Martini force field with explicit water, which in turn match those of atomistic simulations. The gains in computational efficiency obtained by removing explicit water allow direct simulations of the self-assembly of SDS in solution. We observe surfactant exchange among micelles and micelle fission and fusion and obtain realistic, equilibrated micelle size distributions at modest computational cost, as well as a transition to cylindrical micelles at high surfactant concentration or with added salt. We further apply this parametrized force field to study the adsorption of SDS onto hydrophobic surfaces and calculate the adsorption kinetics and equilibrium adsorption isotherm. The greatly increased speed of computation of surfactant self-assembly made possible by this Dry Martini method should allow future simulation of competitive adsorption of multiple surfactant species to surfaces, as well as simulation of micellar shape transitions.

Effects of sodium dodecyl sulfate on structures of poly(N-isopropylacrylamide) at the particle surface.

The effect of sodium dodecyl sulfate (SDS) on the poly(N-isopropylacrylamide) (PNIPAM) tethered to nanoparticles was experimentally investigated using dynamic light scattering below the lower critical solution temperature. A mean-field analytical model was used to calculate the parameters of interfacial PNIPAM-SDS complexes. Particularly, the magnitude of SDS adsorption energy obtained decreases with decreasing excluded volume parameter, implying that the partially collapsed PNIPAM brush virtually favors the adsorption of SDS onto the PNIPAM chains. A self-consistent field theory (SCFT) model was used to get a detailed quantitative description of monomer density distribution. By lowering the solvent quality, a number of phenomena related to the noncontinuity of monomer density are revealed. These phenomena are either referred to as the vertical phase separation or as its precursor, which can be delayed and eventually eliminated as the SDS coverage is increased. The distribution of free chain ends was calculated using the SCFT model. Increasing the SDS coverage gives rise to a broader and more asymmetric distribution of free chain ends, accompanied by a considerable expansion of the dead zone (below which the free chain ends do not exist), but lowering the solvent quality has opposite influences. The relative thickness of the dead zone can be scaled to a master curve, regardless of SDS coverage.

MnO2 as ink material for the fabrication of supercapacitor electrodes

With the objective of the formulation of ready-to-print stable water-based inks of supercapacitive MnO2, selected surfactants have been used as reactants for the synthesis of manganese oxide powders. The presence of sodium dodecylsulfate (SDS), caffeic acid and Triton TX100 in the reaction medium drastically impacts on the characteristics of the resulting material at crystal and molecular levels, on particle shape and size, on the Mn oxidation state as well as on the electrochemical behavior of the corresponding electrodes. With caffeic acid and Triton TX100, resulting oxides are mixtures of amorphous MnO2 and Mn2O3 with limited electrochemical performances. Showing, in contrast, strong similarities with birnessite-type MnO2, surfactant-free powders and those prepared in presence of SDS, both show attractive electrochemical performances with capacitances up to 164F/g for the latter. The excess of particle surface charges upon SDS adsorption is pointed out for a better stability of the corresponding ink formulation as well as for a better dispersibility of the powder at dry state, which result in a more homogeneous composite electrode.

Influence of short chain alcohols on adsorption of sodium dodecylsulfate and Triton X-100 mixture at solution–air interface

Measurements of the surface tension of the aqueous solutions of sodium dodecylsulfate (SDDS) and p-(1,1,3,3-tetramethylbutyl)phenoxypoly(ethylene glycol) (Triton X-100 or TX-100) mixture with methanol, ethanol or propanol were carried out in the whole range of alcohol concentration and in the range of the surfactant mixture concentration from 1×10−5 to 5×10−3M. On the basis of the obtained results the surface excess concentration of the surfactant mixture and alcohol was determined and compared to the surface excess concentration of the particular components of the solution. Taking into account the values of the surface excess concentration of the surfactant mixture and alcohol obtained on the basis of the surface tension values of the aqueous solutions of the TX-100 and SDDS mixture with alcohol as well as the surface excess concentration of individual TX-100, SDDS and alcohol from their aqueous solutions, the mutual influence of the surfactant mixture and alcohol on their adsorption at the solution–air interface was considered. Therefore the alcohol activity at the solution–air interface was calculated by using the Sprow and Prausnitz equation. The mutual behavior of TX-100 and SDDS in the presence of alcohol was determined on the basis of Rosen's theory of regular solutions. The influence of the particular components of the water+alcohol solutions of the TX-100 and SDDS mixture was discussed in the light of the Gibbs surface free energy of adsorption of these components at the solution–air interface. This energy was determined by different methods and it appeared that the equation of Gu and Zhu proposed for the surfactant adsorption at the solid–solution interface was also useful for determination of the standard free energy of adsorption of alcohols at the solution–air interface.

Stick–Slip Friction of Stainless Steel in Sodium Dodecyl Sulfate Aqueous Solution in the Boundary Lubrication Regime

The objective of this study is to correlate the mass and structure of the adsorbed sodium dodecyl sulfate (SDS) on stainless steel surface in aqueous solution with the boundary lubrication behavior, especially the stick–slip phenomenon of the ZrO2/stainless steel friction pair. Surface tension measurement, quartz crystal microbalance (QCM) technique and ball-on-flat friction test were performed in this study. The adsorption isotherm of SDS on stainless steel surface in SDS aqueous solution was measured by QCM, and four-stage adsorption behavior was found at the solid/liquid interface. As the SDS concentration increases, the mass of the adsorbed SDS molecules increases, while the structure of the adsorbed layer changes from monomers to hemimicelles. Tribological properties of ZrO2/stainless steel friction pair in SDS aqueous solution were verified with an UMT-3 tester. Boundary lubrication was emphasized as water-based lubrication easily fails in hydrodynamic lubrication due to its low viscosity. Stick–slip phenomenon was observed in the boundary lubrication of the adsorbed SDS film under certain loading and sliding conditions. Both the static and kinetic friction coefficients were analyzed with respect to the SDS concentration and sliding velocity. The stick–slip phenomenon is related to both of the adsorbed mass and adsorption structure of the SDS boundary film.

Adsorption of anionic surfactant sodium dodecyl sulfate onto alpha alumina with small surface area

Adsorption of sodium dodecyl sulfate (SDS) onto large α-alumina beads was systematically analyzed as functions of pH and NaCl concentration. The maximum adsorption density of SDS onto α-Al2O3 increases with decreasing pH due to the increase in equilibrium surface charge. Adsorption isotherms at different salt concentrations demonstrated a common intersection point (CIP) corresponding to charge neutralization. The obtained comprehensive data clarified the applicability of two-step adsorption and four-region models to describe the adsorption isotherms of SDS onto α-Al2O3 beads. Also, proton adsorption isotherms upon SDS uptake onto α-Al2O3 can be fitted by two-step adsorption model with almost the same parameters of surfactant adsorption for 0.001 and 0.01 M NaCl. Our finding indicates that proton adsorption takes place onto the adsorbed SDS. After passing through CIP, proton adsorption onto α-Al2O3 increases at low ionic strength while the amount of proton adsorption does not change for 0.1 M NaCl. Adsorption amount of proton as a function of SDS adsorption shows that only hemimicelles are plausible for case of low ionic strength. The increase in the proton adsorption is not significant at high ionic strength, suggesting the presence of admicelles on the surface of α-Al2O3 beads.

Adsorption Mechanism of Sodium Dodecyl Sulfate on Coagulating Precipitate in Treatment of Vat Dark Blue BO by Coagulation and Air-Flotation

Vat dark blue BO simulated wastewater was treated by Dissovled air flolation (DAF), the interaction of sodium dodecyl sulfate (SDS) and precipitate in the DAF process was investigated by thermodynamic methods. The adsorption isotherms of SDS on precipitate at pH 5.00 were determined at 30,35,40 and 45°C. The isosteric heat of sorption was calculated by the Clausius-Clapeyron equation. The results show that the isotherm of SDS on coagulation precipitate is not the normal style, the adsorption of SDS on precipitate is exothermic in nature and the isosteric heat of adsorption decreases with a increase in the equilibrium uptake of SDS on precipitate. The isosteric heat of sorption varies between-16.266 and-21.719kJ/mol as surface loading is between 3 and 11 mg/g. The values of isosteric heat of adsorption proves the primary adsorption of SDS on precipitation is physisorption.

Electrokinetic potential of multilayer carbon nanotubes in aqueous solutions of electrolytes and surfactants

The effect of electrolytes with single-, double- and triple-charged counterions, as well as cationic (cetyltrimethylammonium bromide) and anionic (sodium dodecyl sulfate) surfactants, on the electrokinetic potential of multiwall carbon nanotubes prepared via catalytic pyrolysis of propylene in a gas phase according to the CCVD technology has been studied. It has been shown that the influence of different electrolytes on the electrophoretic mobility of the nanotubes does not differ essentially from their effect on the behavior of well-studied inorganic dispersed particles; i.e., the dependence of the absolute values of the ζ-potential on the concentration of a 1: 1 electrolyte passes through a maximum and the introduction of double-charged counterions dramatically reduces the ζ-potential, while the addition of triple-charged cations and a cationic surfactant causes charge reversal of the nanotube surface. The adsorption of sodium dodecyl sulfate in a neutral medium increases the negative ζ values; this effect evens out in the presence of an alkali due to a rise in the electrostatic repulsion between surfactant anions and nanotube surface, which bears a high negative charge resulting from the dissociation of surface functional groups.

Recovery of streptomycin sulfate from the wastewater using foam fractionation coupled with adsorption separation for reusing sodium dodecyl sulfate

AbstractBACKGROUNDSurfactants are always used as collectors to form complexes with the hazardous materials of wastewaters in foam fractionation. An important topic is how to reuse the surfactants in the process of recovering the hazardous materials. In this work, a novel technology of foam fractionation coupled with adsorption separation was developed for separating streptomycin sulfate (SS) from its simulated wastewater and reusing the collector sodium dodecyl sulfate (SDS).RESULTSD152 resin had a high SS adsorption capacity and a low SDS adsorption capacity using adsorption separation. A high SS desorption percentage of 96.0% was obtained while SDS was not desorbed. The desorbed resin still had the same high SS adsorption capacity as a fresh one and SDS was not adsorbed. From the coupling technology, the SS recovery percentage reached as high as 94.1% which was better than foam fractionation or adsorption separation, respectively and 93.7% of SDS was reused.CONCLUSIONIt was effective for the coupling technology not only to separate SS from the wastewaters, but also to reuse SDS in foam fractionation. The coupling technology gave a novel and effective method for treating wastewaters. © 2014 Society of Chemical Industry

Infrared Spectroscopy of Thin Organic Films Adsorbed at a Gold Electrode Surface

This lecture will review our research involving IR spectroscopy at the solid –liquid interface. After a brief review of basic principles of IR spectroscopy and the laws of reflection of light at interfaces, three methods of Infrared Reflection Absorption Spectroscopy (IRRAS) will be described. The first is subtractively normalized interfacial Fourier transform infrared spectroscopy (SNIFTIRS) or in short potential difference IR spectroscopy. This technique finds application to study reversible adsorption of soluble molecules at electrode surfaces. The methods of optimisation of the SNIFTIRS experiment will be discussed. Its application will be illustrated by the case of adsorption of a soluble surfactant such as sodium dodecyl sulphate (SDS) at a gold electrode surface.1 The second technique to measure IR spectra at interfaces is the photon polarization modulation infrared reflection absorption spectroscopy (PM IRRAS). This technique is used to study films of insoluble molecules a various interfaces. I will discuss application of this technique to study model biological membranes supported at a gold electrode surface.2 The third technique is the surface enhanced infrared reflection absorption spectroscopy (SEIRAS). It is performed using attenuated total internal reflection (ATR) element covered by nanoparticles of gold. The intensity of the IR signal is then enhanced by a factor of 100. In addition, since the film of metal nanoparticles is conductive it is used to study phenomena at electrified interfaces. I will describe application of this technique to study structure of water in model biological membrane supported at a gold electrode surface.3 I will emphasize complementarity of SEIRAS and PMIRRAS in application to bio-electrochemical research.Literature1.Jay Leitch, John Collins, K. Andreas Friedrich, Ulrich Stimming, John R. Dutcher, Jacek Lipkowski “Infrared Studies of the Potential Controlled Adsorption of Sodium Dodecyl Sulfate at the Au(111) Electrode Surface”, Langmuir, 2012,28,2455-2464.2. Jacek Lipkowski, “Building model biomimetic membrane at a gold electrode surface”, Phys. Chem. Chem. Phys., 2010,12,13874-13887.3. Taro Uchida, Masatoshi Osawa and Jacek Lipkowski, “SEIRAS studies of water structure at the gold electrode surface in the presence of supported lipid bilayer”, J.Electroanal.Chem. DOI:10.1016/j.jelechem.2013.10.015

An Experimental Examination of Adsorption Phenomenon in Foamassisted Water Alternative Gas: The Effect of Injection Rate

The main factor affecting the economics of foam-ass isted water alternative gas (FAWAG) process is the loss of foaming agent by adsorption onto reserv oir rocks. In this study, the effects of phases, surfactant concentration, salinity, adsorbents, and sacrificial agent on adsorption density were investigated by special adsorption experiments. Mor eover, a series of FAWAG tests were performed to examine the effect of injection rates on final a dsorption density and adsorption variation during t he test. A clean and fast spectrophotometric method wa s used for the determination of sodium dodecyl sulfate (SDS) concentration based on the formation of an ion-pair, SDS-Safranin O. Higher SDS adsorption was observed at the first cycle of FAWAG flooding. FAWAG injection rate had no noticeable effect on the adsorption density. Howeve r, using high injection rate decreased the possibility that gas faces surfactant, and thereby reducing the ultimate oil recovery. The presence of CLS increases the ultimate oil recovery slightly, w hile it decreases the adsorption density of SDS by

Effect of electrolyte on adsorption of polyallyl amine hydrochloride/sodium dodecyl sulphate at water/tetradecane interface

The adsorption from mixed aqueous solutions of polyallyl amine hydrochloride (PAH)/sodium dodecyl sulphate (SDS), both in absence and presence of the inorganic electrolyte NaCl, at the solution/tetradecane interface is studied experimentally by drop profile analysis tensiometry. The results are discussed in terms of a competitive adsorption of PAH+SDS complexes and unbound SDS molecules. A thermodynamic model, developed originally for the adsorption of protein/surfactant mixtures, is modified such that it takes into account the formation of PAH+SDS complexes and the influence of the SDS concentration on their surface activity. It is shown that at low SDS concentrations the properties of the adsorbed monolayer are determined mostly by the adsorption of complexes, while at high SDS concentrations the properties are determined mostly by the SDS adsorption and the effect of the PAH+SDS complexes is negligibly small. The proposed modified model demonstrates good agreement with the experimental data.

The Origin of the “Snap‐In” in the Force Curve between AFM Probe and the Water/Gas Interface of Nanobubbles

The long-range attractive force or "snap-in" is an important phenomenon usually occurring when a solid particle interacts with a water/gas interface. By using PeakForce quantitative nanomechanics the origin of snap-in in the force curve between the atomic force microscopy (AFM) probe and the water/gas interface of nanobubbles has been investigated. The snap-in frequently happened when the probe was preserved for a certain time or after being used for imaging solid surfaces under atmospheric conditions. In contrast, imaging in liquids rarely induced a snap-in. After a series of control experiments, it was found that the snap-in can be attributed to hydrophobic interactions between the water/gas interface and the AFM probe, which was either modified or contaminated with hydrophobic material. The hydrophobic contamination could be efficiently removed by a conventional plasma-cleaning treatment, which prevents the occurring of the snap-in. In addition, the adsorption of sodium dodecyl sulfate onto the nanobubble surface changed the water/gas interface into hydrophilic, which also eliminated the snap-in phenomenon.

Preparation of magnesium hydroxide from leachate of dolomitic phosphate ore with dilute waste acid from titanium dioxide production

A novel method for the removal of magnesium from dolomitic phosphate ores by using dilute waste acid (DWA) from titanium dioxide pigment production was experimentally studied in this work. The pH of liquid phase and particle size of granulized phosphate ore have been found to be crucial to the efficient removal of magnesium from phosphate ore. Operating under the optimum leaching conditions, a 98.31% removal of Mg with 0.02% P2O5 loss was obtained. It was demonstrated that dolomite can be selectively dissolved by H+ in the DWA and the ability of H+ to attack the apatite is inhibited by the strong interionic strength of DWA. By using the solubility differences of corresponding elements, a two-step precipitation process was presented to remove Fe selectively from Mg. A process for further purifying the synthetic leachate by a precipitation/leaching method and oxidation was also investigated. Subsequently, magnesium hydroxide (Mg(OH)2) was prepared by precipitation from the refined solution with ammonia as the precipitant and sodium dodecyl sulfate (SDS) as the modifier. The phase structure and morphology of Mg(OH)2 were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. The prepared nanoparticles of Mg(OH)2 were found to exhibit a column-shaped structure, demonstrating that the anions of DS− adsorbed onto the surface of Mg(OH)2 nucleus contribute to the stacking of Mg(OH)2 regular-hexagon platelets along the c-axis perpendicular to the [001] plane. The adsorption of SDS on the surface of Mg(OH)2 was supported by Fourier transform infrared spectroscopy (FTIR).

EFFECT OF SDS ON THE DISPERSION STABILITY OF YSZ PARTICLES IN AN ELECTROLESS NICKEL SOLUTION

Optimum particle dispersion is an essential feature for composite coatings carried out on the autocatalytic electroless nickel plating platform. In this regard, the potential influence of an anionic surfactant, sodium dodecyl sulphate (SDS), on the dispersion stability of a ceramic, yttria stabilized zirconia (YSZ), in an acidic electroless nickel solution of pH 4.9 has been assessed in this study. Ultra violet-visible spectrophotometry was used in accordance with the Beer-Lambert law (–log (I 1/I 0) = A) to evaluate the rate of YSZ particle sedimentation in electroless nickel solutions with and without surfactant. Measurement of the particles' zeta potential at each surfactant concentration was conducted in parallel with the UV-vis tests with the aim of establishing the interaction among the surfactant, YSZ particles, and electroless nickel solution. A slight increase in the negative magnitude of the particles' zeta potential indicated the adsorption of SDS onto the particles' surface and a possibility of contributing to its stability. However, the surfactant's inability to counteract an electroless nickel solution–induced particle accretion resulted in the observation of poor YSZ particle stabilities at all the investigated surfactant concentrations.

Real-time monitoring the adsorption of sodium dodecyl sulfate on a hydrophobic surface using dual polarization interferometry

The adsorption process of sodium dodecyl sulfate (SDS) at a hydrophobic layer was investigated by dual polarization interferometry (DPI), which provided the real-time information at solid/liquid interface. In dilute solution, the molecules adsorb at the surface as isotropic layer. With the increase in concentration, the molecules aggregate to form hemimicelles and the critical hemimicelles concentration (HMC) is 1mM. The adsorption of SDS at C18 surface obeys two-step process. The competitive formations of micelles in solution and hemimicelles on C18 surface lead to particular adsorption behavior in higher concentration. We also proposed a four-stage adsorption model of SDS at C18 surface according to bulk concentration.

Adsorption Ability of SDS Intercalated ZnAL-LDH and MgFe-LDH on Simulated Organic Amine

Hexadecyl trimethyl ammonium bromide (CTAB) was used as simulated substance of organic amine wastewater, the adsorption of sodium dodecyl sulfate (SDS) intercalated ZnAl-LDH and MgFe-LDH [ZnAl (SDS)-LDH and MgFe (SDS)-LDH] on it are studied. These two kinds of LDHs all have good adsorption ability on CTAB, the COD removal degree of ZnAl (SDS)-LDH and MgFe (SDS)-LDH on CTAB can be high up to 94% and 96% due to the static electric attraction and the hydrophobic interaction between the SDS and CTAB.