Influence Of Surfactant Addition Research Articles

PHYSICOCHEMICAL PROPERTIES OF SULPHATE WASTE LIQUOR AFTER SOAP EXTRACTION IN THE PRESENCE OF SURFACTANTS

During the wood delignification a multicomponent spent liquor (black liquor) is formed. Depending on the type of wood, black liquor is enriched with valuable extractives. The isolation of extractives from processing liquors and their conversion into biologically active substances, tall products is according to development trend of pulp and paper industry. It includes the introduction of scientific based technologies in manufacturing processes with reference to modern environmental protection requirements. Now the extraction efficiency of sulphate soap does not exceed 75–80% whereby the quality of obtained soap is low. Sulphate soap, especially extracted after hardwood cooking, contains a large amount of impurities. This complicates the process of soap treatment into valuable biologically active substances (beta-sitosterol, etc.). 
 In the present work the addition of demulsifying and coagulating substances into the black liquor is proposed to intensify the hardwood sulphate soap extraction. The chemical colloidal characteristics of the obtained sulphate soap were investigated. Two critical micelle concentration (CMC) were found on the surface tension isotherms. The second critical micelle concentration (CMC2) in the concentration range of 0.9–1.0% CMC2 indicates the restructuring of micelles into a spherocylindrical shape. A comparative qualitative and quantitative analysis of the composition of sulfate soap obtained in industrial conditions and in the presence of selected additives in laboratory was carried out. Surfactants promote the extraction of phytosterol from black liquor obtained from hardwood species cooking. The influence of surfactant addition on the main physical and colloidal chemical characteristics of black liquor before and after isolation of sulphate soap is investigated. A decrease in viscosity and a de foaming of a black liquor solution is observed as a result of the addition of surfactant additives.

Influence of Surfactant Additives on Photochemical Synthesized Silver Nanoparticles using UV Pulsed Laser Irradiations in Aqueous Silver Nitrate Solution

The effect of different additives on the AgNPs formation process was explored in this study. AgNPs were synthesized in an aqueous solution of silver nitrate-containing surfactants by photoreduction of silver ions. The concentration dependency of AgNPs formation suggested that stability was induced by the equilibrium of AgNPs adsorbed by surfactants with higher carbon chain molecules such as SDS and AOT. These results open up a new window both for structural control and the development process. It also indicated that different additives had an impact on the morphology of NPs. The hydrocarbon chain influenced the growth process and demonstrated that <10 carbon chain surfactants such as SMS, SOS, did not constitute the CGC and had a minor effect on the mechanism of growth. However, the NPs formation begun at a lower limit indicated as CGC. It was observed only with hydrocarbon chains of > 10 carbon atoms such as AOT, SDS. Fluorescence results confirmed that after laser irradiation, hemi-micelle formation after the development of AgNPs.

Influence of Surfactant Additives on the Electrolyte Flow Velocity and Insoluble Gas Bubbles Behavior within a Lead-Acid Battery

Improving the flooded-electrolyte batteries performance in fast charging and discharging processes has attracted many researchers. Due to electrochemical reactions during charging and discharging process in these batteries, many insoluble gas bubbles are produced within the electrolyte. These bubbles have a major effect on the performance of the electrodes and the rate of electrochemical reactions. On the other hand, the electrolyte flow rate plays an important role on the performance of the battery. In the present investigation, the effect of surface tension on the production of insoluble bubbles and velocity of electrolyte flow have been investigated experimentally when different types of surfactants are added to the electrolyte. In addition, a Particle Image Velocimetry setup has been used in order to measure the velocity of electrolyte flow and the behavior of bubbles. The results declared that the capacity of battery enhances about 16% and 10% by adding Triton X100 and SDS surfactants, respectively. Hence, the averaged electrolyte velocities during charging process reduces about 11% and 13% when Triton X100 and SDS, repectively; are used as surfactants. Also, the effect of adding different amounts of SDS surfactant on the mean diameter, rising velocity and production rates of bubbles have been illustrated comprehensively.

Wavelet analysis on the drag-reducing characteristics of turbulent channel flow with surfactant additive based on experimental data

Two-dimensional velocity fields for turbulent channel flows of water and 50 ppm CTAC/NaSal (cetyltrimethyl ammonium chloride/sodium salicylate) solution were experimentally obtained by particle image velocimetry. Multi-scale decompositions of the fluctuating velocity signals were performed by two-dimensional binary orthogonal discrete wavelet to analyze the influence of surfactant additives on the multi-scale characteristics of turbulent channel flow. From the results of wavelet multi-scale decompositions, it can be observed that the quantity of coherent structures near the wall in CTAC solution flow is decreased obviously. The results of the flatness factor show that the addition of drag-reducing additives inhibits the intermittency in turbulence. By analyzing the distribution of local intermittence measure and local Reynolds shear measure, it is found that the intermittency mainly concentrates near the wall, and the intermittent region distinctly reduces in CTAC solution flow compared with that in water flow. By combining the analysis of the motion of coherent structures in turbulent channel flow, it is shown that surfactant additives mainly and distinctly impact the coherent structures near the wall, especially in the viscous layer.

Role of Anionic Surfactants in the Synthesis of Smart Microgels Based on Different Acrylamides.

We investigated the influence of two anionic surfactants, namely, sodium dodecyl sulfate and sodium decyl sulfate, on acrylamide-based microgels consisting of N-n-propylacrylamide. In this context, the main focus was on the influence of surfactant addition on the size of the microgels. The surfactant was added to the reaction mixture before or during the polymerization at different points in time. Microgels were characterized via photon correlation spectroscopy and atomic force microscopy. All results were compared to those for other more common acrylamide-based microgels consisting of N-isopropylacrylamide and N-isopropylmethacrylamide. A significant difference between the three microgels and a strong dependence on the surface activity of the surfactant was found.

Growth of anatase and rutile phase TiO2 nanoparticles using pulsed laser ablation in liquid: Influence of surfactant addition and ablation time variation

Titanium dioxide (TiO2) nanoparticles were grown using nanosecond pulsed laser ablation of Ti target in DI water and in 0.001M sodium dodecyl sulfate (SDS) surfactant aqueous solution. Growth was carried out with varying ablation times i. e. 30min, 60min and 90min. The objective of our study was to investigate the influence of variations in liquid ambience conditions on the growth of the nanoparticles in a pulsed laser ablation in liquid (PLAL) process. Size, composition and optical properties of the grown TiO2 nanoparticles were investigated using transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), optical absorption, photoluminescence (PL) spectroscopy and X-ray diffraction (XRD) studies. The obtained nanoparticles of TiO2 were found almost spherical in shape and polycrystalline in nature in both the liquid mediums i.e. DI water and aqueous solution of surfactant. Nanoparticles number density was also found to increase with increasing ablation time in both the liquid mediums. However crystalline phase of the grown TiO2 nanoparticles differs with the change in liquid ambience conditions. Selected area electron diffraction (SAED), PL and XRD studies suggest that DI water ambience is favorable for the growth of anatase phase TiO2 nanoparticles for all ablation times. While Surfactant added water ambience is favorable for the growth of rutile phase TiO2 nanoparticles but for shorter ablation times of 30min and 60min only, for longer ablation time of 90min anatase phase was also observed along with the rutile phase TiO2 nanoparticles. The formation of anatase phase in DI water and rutile and anatase phase in aqueous solution of surfactant is explained on the basis of varying thermodynamic conditions with the two different liquid ambiences and different ablation times.

Surfactant-enhanced biohydrogen production from organic fraction of municipal solid waste (OFMSW) via dry anaerobic digestion

Abstract The influence of surfactant addition on the hydrogen fermentative of the organic fraction of municipal solid waste was extensively investigated under thermophilic conditions (55 ± 2 °C) in batch cultures. The addition of Tween 80® (T80) and polyethylene glycol (PEG 6000®) substantially improved hydrogen yields (HYs) resulting in 109.9 ± 7.1 and 113.8 ± 7.7 mlH2/gCarb.initial at T80 and PEG 6000® concentrations not exceeding 2.8% and 16.7 g/L, respectively. A combination of 2.8% T80 with 1.7 g/L PEG 6000® achieved slightly higher HYs of 116.7 ± 5.2 mlH2/gCarb.initial. An artificial neural network model reliably represented the relationship between the surfactant concentration and hydrogen production with a correlation coefficient (R2) of 0.980. Microbial community analysis of the batches supplemented with 2.8% T80 and 1.7 g/L PEG 6000® showed the dominance of the hydrogen-producing bacteria Enterobacter, Escherichia, Buttiauxella, and Pantoea. The study confirms the potential of surfactant addition for H2 production from wastes containing organics in a particulate form.

Electroanalytical Method for Determining Pyrogallol in Biodiesel in the Presence of a Surfactant

AbstractA sensitive, straightforward electroanalytical method for determining pyrogallol (PY) in biodiesel in the presence of a surfactant was developed using a voltammetric technique and screen‐printed electrodes. The influence of surfactant addition (sodium dodecyl sulfate (SDS), Triton X‐100 (TX‐100), cetyltrimethylammonium bromide (CTAB), tetrabutylammonium iodide (TBAI), tetrabutylammonium bromide (TBAB), or tetraethylammonium bromide (TEAB)) on the supporting electrolyte (0.04 mol L−1 BrittonRobinson buffer) was evaluated. Only CTAB significantly increased the oxidation peak current. Under optimal conditions, the method demonstrated linearity over the concentration range of 0.8–9.0×10−6 mol L−1, with limits of detection and quantification of 4.9×10−7 and 1.5×10−6 mol L−1, respectively. The results were satisfactory, relative to those obtained using high‐performance liquid chromatography (HPLC).

Improvement of Biodegradable Biocide’s Activity of Peroxyacetic Acid Basis Using Surfactants: Characterization and Stability

This paper deals with the study of the kinetics decomposition reaction of the peroxyacetic acid under influence of surfactant additives. The peroxyacetic acid shows a decomposition rate of 1.70×10−3 h−1and its activation energy is 66 kJ mol−1. The influence of temperature on the reaction of spontaneous decomposition of peroxyacetic acid was studied at two seasonal periods. Peroxyacetic acid standard and four prototypes of biocide samples with known concentration of peroxyacetic acid and hydrogen peroxide were studied. Finally, a factorial analysis ANOVA was carried out to establish significant differences (p<0.003) between the four biocide samples over time with respect to peroxyacetic acid and hydrogen peroxide concentration. From the study carried out, it can be concluded that the biocide with surfactant substances in its composition offers the best stability and its difference versus the other biocides may guarantee a better behaviour.

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Phase change material: Optimizing the thermal properties and thermal conductivity of myristic acid/palmitic acid eutectic mixture with acid-based surfactants

In this study the addition of surfactant to fatty acids as phase change materials (PCMs) for solar thermal applications is proposed. The incorporation of surfactant additives into a eutectic mixture of fatty acids can significantly increase the value of latent heat storage and can suppress undercooling. We report the preparation of myristic acid/palmitic acid (MA/PA) eutectic mixture as Phase Change Material (PCM) with addition of 0, 5, 10, 15, and 20% sodium myristate (SM), sodium palmitate (SP), and sodium stearate (SS), the influence of surfactant additives on thermal properties and thermal conductivity of eutectic mixtures. It was found that the addition of 5% SM, 5% SP, and 5% SS to MA/PA eutectic mixture is very effective in depressing the liquid/solid phase change temperature, reducing the undercooling and increasing the amount of latent heat of fusion as well as thermal conductivity of eutectic PCM compared to eutectic PCM without surfactants. Furthermore MA/PA + 5%SS has the highest latent heat of fusion of 191.85 J g−1, while MA/PA + 5%SM showed the least undercooling of 0.34 °C and the highest thermal conductivity of 0.242 W m−1 K−1.

Influence of surfactant addition on rheological behaviors of injection-molded ultrafine 98W-1Ni-1Fe suspension

Ultrafine 98W-1Ni-1Fe powder injection molding was studied. The influence of ball milling and stearic acid (SA) addition on ultrafine powder characteristics and feedstock rheological behavior was investigated systematically. Results show that ball milling and SA addition can effectively increase powder loading of feedstock. SA addition can also avoid surface interactions between powder and binder during feedstock preparation, thus shortening the mixing time. SA addition is effective in reducing feedstock viscosity, but this effect decreases with increasing temperature and becomes disadvantageous when temperature is higher than 125 °C. SA addition can also reduce the temperature required for injection molding. The feedstock of powder with SA addition gets its best shear stability and lowest viscosity at 115 °C, while the feedstock of powder without SA addition obtains its best shear stability and lowest viscosity at 135 °C. Meanwhile, the former has lower temperature sensitivity and better comprehensive rheology than the latter, so the former is more suitable for ultrafine 98W-1Ni-1Fe injection molding.

Influence of surfactant addition for the texture etching process on multi-crystalline silicon wafer

This study investigates the effects of different recipes and concentrations of surfactant on the texture and reflectance of a multi-crystalline silicon wafer surface. The morphology of the surface was examined and photographed using a field emission scanning electronic microscope. The reflectance of the surface was measured and analyzed using a self-designed optical system. The results of this study show that a higher hydrocarbon-surfactant (CH-surfactant) concentration in the etchant resulted in a slower reaction time. The optimum concentration of CH-surfactant was 1%. However, there were many white bubbles in the etching process. The optimum recipe for surfactant included fluoride 2% to diminish these bubbles. The reflectance was less than 22% in visible light. This cost effective acid chemical etching method is suitable for texturing silicon surfaces on 50 nm nanostructures. This is a critical criterion for determining the optimum recipe for surface texturing of acidic etching in solar cells.

TiO<sub>2</sub> Hollow Spheres Obtained under Autogenic Pressure at Elevated Temperature

Carbon/TiO2 composites were prepared via the reaction under Autogenic Pressure at Elevated Temperature (RAPET) using alkoxides as precursor, and then porous TiO2 hollow spheres were derived after removing the carbon ingredient by calcination at 600°C. The influence of surfactant additives, including the addition ratio and the nature of the surfactants, on the morphology and the structures of the Carbon/TiO2 composites and the derived TiO2 were also studied with scanning electron microscopy (SEM), X-ray diffraction (XRD), UV-Vis diffuse reflectance spectrophotoscopy (DRS) and nitrogen adsorption-desorption measurements. The results revealed that the morphology of the products turned to spherical and then fusiform and the structures turned from hollow to solid with the increasing of surfactant additive. The BET surface area of the hollow TiO2 was modified from 12m2/g to 57m2/g after calcinations. The XRD investigation indicates that the phases of the TiO2 in both the carbon/TiO2 composites and the derived TiO2 hollow spheres are anatase.

Vertical two-phase flow regimes and pressure gradients under the influence of SDS surfactant

Two-phase gas/liquid flows in vertical pipes have been systematically investigated. Water and SDS surfactant solutions at various concentrations were used as the working fluids. In particular, we focus our work on the influence of surfactant addition on the flow regimes, the corresponding pressure gradients, and the bubble sizes and velocity. Adding the surfactant lowers the air critical Reynolds numbers for the bubble–slug flow and the slug flow transitions. The pressure gradients of SDS solutions are lower than those of pure water especially in the slug flow and the slug–churn flow regimes, implying turbulent drag reduction. At low Re air, the bubble sizes of the surfactant solution are lower than those of pure water due to the increase in viscosity. With increasing and at high Re air, the bubble sizes of the SDS solution become greater than those of pure water which is attributed to the effect of surface tension.

Influence of Surfactant Additives on the Intensity of Acoustic Causative Agents of Ultrasonic Cleaning in Water Solutions

SUMMARYAddition of a surfactant to an aqueous cleaning solution lowers the intensity of ultrasonic cavitation. The present investigation was aimed at determination of the degree of lowering of cavitation intensity in water with surfactant additive, and of the influence of the surfactant on the intensity of movements of the liquid resulting from the activity of ultrasound pressure

Removal of nonylphenol ethoxylates by electrochemically-generated coagulants

This study investigated the behaviour of aluminium and carbon steel electrodes in the presence and absence of nonylphenol ethoxylates (NPnEO, where n is the number of ethoxylate groups in the molecule) and NPnEO removal by electrochemically-generated coagulants. The electrode processes were studied by potentiodynamic polarization measurements to determine the influence of surfactant addition (ethylene oxide units and organic load), inorganic composition and pH. The polarization curves showed the extent of the involvement of NPnEO in the electrode processes. Their influence appeared clearly in the range of anodic activation, depending on the number of ethoxylate groups. Removal of NPnEO from simulated wastewaters was carried out in two electrocoagulation cells with vertical and horizontal electrodes, respectively. The removal efficiencies calculated from the chemical oxygen demand before and after treatment were 30–50% for NP16EO and NP40EO, and 40–80% for NP4EO. The hydrophilic-lipophilic balance number for NP4EO indicated a relative ratio of polar and non-polar groups lower than for the other two surfactants, which was in favour of better NP4EO removal. The experiments showed the processes in the bulk (bridging of electrochemically-generated polymeric species and adsorption of surfactants) were predominant over the involvement of NPnEO in the electrode processes, which were only responsible for the electrogeneration of coagulants.

Influence of surfactant addition on the rheological properties of aqueous Welan matrices

In the present work the effects produced by the presence of two different surfactants (Abil B 8842 and Triton N 101) on the rheological properties of aqueous welan matrices are studied, both in steady and in oscillatory shear conditions. Welan is an acidic microbial polysaccharide having high thermal, pH, and salt stability. At sufficiently low concentrations it forms aqueous weak gel matrices which can be profitably used to regulate the rheological properties of disperse systems and improve their stability. Different systems are examined, having the same polysaccharide concentration (0.25 wt%) and different surfactant concentrations (up to 40 wt%, far beyond the range of practical interest for emulsion preparation). All the systems exhibit marked shear-thinning properties which can be described quite satisfactorily by the Cross equation. The concentration dependence of the zero-shear-rate viscosity as well as the mechanical spectra confirm that, in the concentration range considered, the aqueous welan systems are typically weakly structured fluids. The influence of both surfactants is examined in detail by comparing the behavior of the different classes of systems. Both surfactants reduce the polymer contribution at low shear, whereas an opposite action is exerted at high concentration and shear. These contrasting effects are ascribed to the different structural features of the polymer matrix under low stresses and high shear conditions, respectively.

Influence of surfactant addition on the stability of concentrated alumina dispersions in water

The goal of this study was to assess the effects of surfactant addition on the stability and viscosity of concentrated alumina dispersions. The stabilizing effects of several candidate surfactants were investigated for concentrated dispersions of two different pseudoboehmite aluminas at pH 4 and 7. The stabilities of concentrated alumina dispersions treated by pH adjustment alone and by pH adjustment combined with surfactant addition were compared to assess the degree to which the surfactant enhanced stability. The initial rate of mass removal from a sedimenting alumina dispersion was used as a measure of stability. The anionic surfactants Surfine WNT-A and DOWFAX 3B2 were identified as effective in enhancing the stability of concentrated alumina dispersions. The optimal doses of these surfactants for stabilizing 15% by weight VERSAL™ 250 alumina dispersions at pH 4 were determined to be about 4.6 × 10−5 mol g−1 for both surfactants. On the basis of the initial rate of mass removal, surfactant-stabilized 15 wt.% suspensions were found to be approximately 2.5 and 10.6 times more stable than similar dispersions stabilized electrostatically by pH adjustment alone. These more stable dispersions exhibited lower viscosities than observed for the alumina dispersions not subjected to surfactant addition. The results indicate that the stability of concentrated alumina dispersions can be enhanced by anionic surfactant addition, and that such surfactants may therefore help to control the rheology of concentrated dispersions of alumina in water.

Influence of some organic compounds on the corrosion mechanism of carbon steel (XC 38) in 3% NaCl I. dodecyl sodium phosphonate (C10H21PO3Na2) and n-undecylimidazole (C14H26N2) surfactants

The electrochemical behaviour of carbon steel (XC38) in stirred and aerated 3% NaCl solution has been investigated using a rotating disc electrode. Steady-state and transient measurements have been carried out. The influence of surfactant additives on the corrosion process is reported.