Surfactant Sodium Lauryl Sulfate Research Articles

Electrophilic Reactivity of Sulfated Alcohols in the Context of Skin Sensitization.

The surfactant sodium lauryl sulfate (SLS), although consistently positive in the murine local lymph node assay (LLNA) for skin sensitization, shows no evidence of being a human sensitizer and is often described as a false positive, lacking structural alerts for sensitization. However, there is evidence of the cinnamyl sulfate anion being the metabolite responsible for the sensitization potential of cinnamyl alcohol to humans and in animal tests. Here, manufacturing chemistry data and physical organic chemistry principles are applied to confirm that SLS is not reactive enough to sensitize, whereas sensitization to cinnamyl alcohol via cinnamyl sulfate is plausible. Sensitization data for several other primary alcohols, including geraniol, farnesol, and possibly hydrocortisone, are also consistent with this mechanism. It seems possible that biosulfation may play a wider role than has previously been recognized in skin sensitization.

In Vitro Drug Release Testing Method For Nepafenac Ophthalmic Suspension

In vitro release test (IVRT) method is important to monitor batch-to-batch quality variations during pharmaceutical manufacturing and also to show the pharmaceutical equivalence of a generic product with the innovator. To fulfil regulatory requirements for approval of a generic ophthalmic suspension product, in vitro release study is required. No compendial or non-compendial method is available for IVRT of nepafenac ophthalmic suspension. Current research is aimed to screen various approaches using different conventional and non-conventional instruments to suggest the most suitable technique appropriate for nepafenac ophthalmic suspension followed by optimization of method parameters and validation. The trials used the paddle apparatus (USP Type-2) with dialysis sacs, the flow-through cell apparatus (USP Type-4), the rotating bottle apparatus, and the Franz diffusion cell apparatus. With the USP Type-4 apparatus drug release was found to be ∼ 83% in the simulated tear fluid (STF) of pH 7.4 in 120 min that increased to ∼ 97% upon the addition of surfactant sodium lauryl sulfate (SLS). With USP Type-2 and Franz diffusion cell apparatus, the drug release was either slow or not reaching close to the complete release. Whereas, in the case of the rotating bottle apparatus, a burst release profile was observed. The estimation of the drug release was done by the HPLC method and all the method validation parameters like specificity, accuracy, linearity, and precision were found to be within acceptance criteria.

Assaying the effects of some essential oils on Root-knot Nematode [Meloidogyne javanica (Treub 1885) Chitwood 1949] in the laboratory

Nematodes are man’s faceless enemy whose activities encourage hunger and poverty. This study was conducted to determine the efficacy of selected plant oil extract in the control of root knot Nematode [Meloidogyne javanica] in the laboratory. The experimental design used was Complete Randomized Design (CRD) with fourteen treatments, replicated three times. Egg hatch inhibition test on M. javanica eggs and juvenile mortality test were separately performed by exposing the eggs and juveniles to different dosage of the essential oils. Neem seed oil statistically proved effective in inhibiting egg hatch followed closely by Garlic clove oil and then Moringa seed oil. All the essential oil treatments were more effective than carbofuran treatment. The surfactant Sodium Lauryl Sulphate was shown to have nematicidal properties as it also recorded zero egg hatching at all the doses applied. The second stage juveniles of M. javanica recorded a higher mortality rate (100%), when they were treated with Neem seed oil, closely followed by Garlic clove oil and then Moringa seed oil. All Surfactant treatments caused 100% juveniles’ mortality. The higher the doses of the essential oils, the higher the juvenile mortality rate. Neem seed oil at all the dosage proved effective in controlling Meloidogyne javanica causing high rate of juvenile mortality and suppressing M. javanica egg hatch. The nematicidal characteristics exhibited by the essential oils might be due to the phytochemicals present in the oils.

Oil displacement properties of surfactin: a comparative study

Abstract Biosurfactants are amphiphilic compounds synthesized from plants and microorganisms and are known for their high biodegradability, low toxicity, and eco-friendliness. They have diverse applications in industrial and environmental fields, including oil recovery, bioremediation, and cleaning up hydrocarbons from polluted areas. Surfactin is a potent lipopeptide biosurfactant produced by Bacillus subtilis bacteria. In this study, we produced surfactin by B. subtilis using cassava wastewater as the fermentation medium. This production was monitored by high performance liquid chromatography (HPLC). Approximately 600 mg L−1 of surfactant was produced. The oil displacement test was then performed to evaluate the effectiveness of crude and purified surfactin compared to a synthetic surfactant and a biosurfactant. Three types of surfactants were tested: the synthetic surfactant sodium lauryl sulfate (SDS), the commercial biosurfactant rhamnolipid (Rh), and surfactin in its crude form and purified one – after acid precipitation. The analysis results indicated that surfactin, in both its crude and purified forms, was more effective at dispersing oil than the other surfactants tested, even at lower concentrations. This suggests that biosurfactants have great potential as a more sustainable and effective alternative to petroleum-derived synthetic surfactants. Surfactin can be applied without the need for downstream processes.

The Composite TiO2-CuOx Layers Formed by Electrophoretic Method for CO2 Gas Photoreduction.

This study demonstrates the ability to control the properties of TiO2-CuOx composite layers for photocatalytic applications by using a simple electrophoretic deposition method from isopropanol-based suspension. To obtain uniform layers with a controlled composition, the surfactant sodium lauryl sulfate was used, which influenced the electrophoretic mobility of the particles and the morphology of the deposited layers. The TiO2-CuOx composite layers with different CuOx contents (1.5, 5.5, and 11 wt.%) were obtained. It is shown that the optical band gap measured by UV-VIS-NIR diffuse reflectance spectra. When CuOx is added to TiO2, two absorption edges corresponding to TiO2 and CuOx are observed, indicating a broadening of the photosensitivity range of the material relative to pure TiO2. An open-circuit potential study shows that by changing the amount of CuOx in the composite material, one can control the ratio of free charge carriers (n and p) and, therefore, the catalytic properties of the material. As a result, the TiO2-CuOx composite layers have enhanced photocatalytic activity compared to the pure TiO2 layer: methanol yield grows with increasing CuOx content during CO2 photoreduction.

DESIGN, OPTIMIZATION, AND CHARACTERIZATION OF A NOVEL AMORPHOUS SOLID DISPERSION FORMULATION FOR ENHANCEMENT OF SOLUBILITY AND DISSOLUTION OF TICAGRELOR

Objective: The study aims to enhance the solubility and dissolution of ticagrelor by formulating an amorphous solid dispersion using the hot melt extrusion technique. Methods: Solubility of ticagrelor is very limited in water and buffers of pH 1.2 to 6.8, which is one of the prime reasons for its low oral bioavailability. Amorphous solid dispersions were prepared using the Hot Melt Extrusion technique using different polymers, plasticizers, and surfactants. The formulation is optimized based on the level of polymer in the formulation. The final formulation of Ticagrelor Amorphous Solid Dispersion is made with a drug-polymer ratio of 1:3, keeping the plasticizer level at 10% of the polymer along with a surfactant Sodium Lauryl Sulfate. Results: The formulation showed an increase in solubility of 193.95-times in water, 50.71-times in 0.1 N HCl, 332.74-times in pH 4.5 acetate buffer, and 85.20-times in pH 6.8 phosphate buffer as compared to the pure drug. The drug release of the final formulation was found to be 70.0±4.4%, 55.4±1.1%, 35.5±2.1%, and 30.0±0.8% at 90 min, while the reference product showed a release of 9.4±1.1%, 20.7±0.5%, 8.4±0.3%, and 7.8±0.2% at 90 min in water, 0.1 N HCl, pH 4.5 acetate buffer and pH 6.8 Phosphate Buffer respectively. The drug release of the final formulation was found to be 99.1±3.8% at 60 min in 0.2% w/v Polysorbate-80 in water. Conclusion: In the present study, the amorphous solid dispersion of the poorly-soluble drug ticagrelor was successfully prepared. The polymer, Plasdone S630, is considered the most suitable with ticagrelor for formulating amorphous solid dispersion using Hot Melt Extrusion technology to increase the solubility and dissolution of the drug.

Combined effects of temperature rise and sodium lauryl sulfate in the Mediterranean mussel

Personal care products (PCPs) are those compounds used daily (e.g., soaps, shampoos, deodorants, and toothpaste), explaining their frequent detection in aquatic systems. Still, scarce information is available on their effects on inhabiting wildlife. Among the most commonly used PCPs is the surfactant Sodium Lauryl Sulfate (SLS). The present study investigated the influence of temperature (CTL 17 ºC vs 22 ºC) on the effects of SLS (0 mg/L vs 4 mg/L) in the mussel species Mytilus galloprovincialis. Mussels’ general health status was investigated, assessing their metabolic and oxidative stress responses. Higher biochemical alterations were observed in SLS-exposed mussels and warming enhanced the impacts, namely in terms of biotransformation capacity and loss of redox homeostasis, which may result in consequences to population maintenance, especially if under additional environmental stressors. These results confirm M. galloprovincialis as an excellent bioindicator of PCPs pollution, and the need to consider actual and predicted climate changes.

Pillarization of Sumatera Bentonite by Sodium-assisted As Effective Adsorbent of Anionic Surfactants Sodium Lauryl Sulphate (SLS) Waste

In this work, the Sumatera bentonite was sodium-pillarized in a new low-temperature and restricted time preparation route and then applied in anionic surfactant sodium lauryl sulphate removal. Structure characterization used Fourier Transform Infra Red (FT-IR), Scanning Electron Microscope - Energy Dispersive X-ray (SEM-EDX), X-ray Diffraction (XRD), and Brunauer–Emmett–Teller (BET) analysis. A strong peak at 22° and 35.66° in XRD analysis was detected as Sodium-pillar that increased crystallinity, then the functional changes of dehydration in lattice structure were detected in 1013 cm−1 by FTIR analysis. The morphology and compositional transformation were analyzed by SEM-EDX and BET analysis, denoted by increasing particle shape and sodium intercalant composition homogeneity. Moreover, the surface area increased from 61.791 to 66.086 m2/g. The sodium lauryl sulphate adsorption by bentonite-Na reached maximum capacity at 8.403 mg/g, which is higher than the pristine bentonite (5.747 mg/g) under the optimum condition. The adsorption mechanism is feasible, endothermic, and conformed to the pseudo-second-order and Freundlich adsorption model. The new route proposed for sodium intercalation effectively improves the Sumatera bentonite adsorption ability to remove sodium lauryl sulphate waste. Copyright © 2023 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Effect of Sodium Lauryl Sulfate on Sorption of Cells of the Electrogenic Bacterium Strain Micrococcus luteus on Carbon Cloth.

Results of a study into the effect of anionic surfactant sodium lauryl sulfate on the sorption of cells of the electrogenic bacteria strain Micrococcus luteus 1-I on the surface of carbon cloth used as electrodes in microbial fuel cell (MFC) technology are presented. Investigations using spectrophotometry, microscopy and microbiology revealed an increase in the degree of sorption of microbial cells on carbon cloth under the action of sodium lauryl sulfate at concentrations of 10 and 100mg/l. The sorption of cells did not significantly differ from the control at a surfactant content of 200, 400 and 800mg/l. It had no negative effect on bacterial growth in the concentration range from 10 to 800mg/l. Due to the fairly high resistance of the electrogenic strain M. luteus 1-I to sodium lauryl sulfate, a widespread component of wastewater, it may be considered as a prospective bioagent for the treatment of domestic wastewater using MFC technology.

Unravelling the mechanisms of drugs partitioning phenomena in micellar systems via NMR spectroscopy

Despite extensive use of micelles in materials and colloidal science, their supramolecular organization as well as host–guest interactions within these dynamic assemblies are poorly understood. Small guest molecules in the presence of micelles undergo constant exchange between a micellar aggregate and the surrounding solution, posing a considerable challenge for their molecular level characterisation. In this work we reveal the interaction maps between small guest molecules and surfactants forming micelles via novel applications of NMR techniques supported with state-of-the-art analytical methods used in colloidal science. Model micelles composed of structurally distinct surfactants (block non-ionic polymer Pluronic® F-127, non-ionic surfactant Tween 20 or Tween 80, and ionic surfactant sodium lauryl sulphate, SLS) were selected and loaded with model small molecules of biological relevance (i.e. the drugs fluconazole, FLU or indomethacin, IMC) known to have different partition coefficients. Molecular level organization of FLU or IMC within hydrophilic and hydrophobic domains of micellar aggregates was established using the combination of NMR methods (1D 1H NMR, 1D 19F NMR, 2D 1H–1H NOESY and 2D 1H-19F HOESY, and the multifrequency-STD NMR) and corroborated with molecular dynamics (MD) simulations. This is the first application of multifrequency-STD NMR to colloidal systems, enabling us to elucidate intricately detailed patterns of drug/micelle interactions in a single NMR experiment within minutes. Importantly, our results indicate that flexible surfactants, such as block copolymers and polysorbates, form micellar aggregates with a surface composed of both hydrophilic and hydrophobic domains and do not follow the classical core–shell model of the micelle. We propose that the magnitude of changes in 1H chemical shifts corroborated with interaction maps obtained from DEEP-STD NMR and 2D NMR experiments can be used as an indicator of the strength of the guest-surfactant interactions. This NMR toolbox can be adopted for the analysis of broad range of colloidal host–guest systems from soft materials to biological systems.

Synthesis and application of treated activated carbon for cationic dye removal from modelled aqueous solution

Use of activated carbon (AC) prepared from rice husk and treated with anionic surfactant is investigated to eliminate cationic dye crystal violet (CV) using modelled dye solution. AC modified with anionic surfactant sodium lauryl sulfate (ACSLS) and other two surfactant namely sodium dodecyl sulfonate and hexadecyl trimethyl ammonium bromide were used for the analysis. Optimum ACSLS was analyzed and characterized using BET, XRD, SEM accompanied with XEDS, FTIR, HR-TEM and zeta potential, which confirms the sorption of CV onto ACSLS. Influence of pH, dose of adsorbent, concentration of initial dye, contact time, additive salts as well as actual water samples were investigated. Presence of NH4+, Ca2+, Mg2+, Na2+, Ca2+and K+cations in dye solution were having negligible (less than 4 %) influence on dye removal capacity. Study of mass transfer parameters revealed intra particle diffusion and film diffusion both played their part, whereas other kinetic studies has shown that experimental data fitted best with Pseudo 2nd order rate. Isotherm studies accompanied with error analysis revealed that Langmuir isotherm controls the adsorption equilibrium with highest capacity of CV adsorption with optimum operating conditions as pH = 6, temperature = 318 K, adsorbent dose = 100 mg/L and dye concentration = 30–60 mg/L. Study of thermodynamics and temperature analysishave shown that the sorption reaction was favourable and spontaneous with rise in temperature and endothermic in nature. Column studies are reported for varying rate of flow, depth of bed and dye concentrations along with analysis of column experimental data with various models like Yoon-Nelson, Thomas, Bohart-Adam and Clark model. Reusability (no. of cycles) of used adsorbent was studied using regeneration experiments. Analysis inferred that AC modified using surfactants can be a useful technique for enhanced adsorption capacity of dyes from aqueous solution andnot much work has been reported on use of anionic surfactant modified AC for dye removal process.

Experimental Study on the Influence of Coal Fracture Surface Roughness on Water Injection Seepage.

Coal seam water injection has a significant effect on downhole dust resistance. However, during the operation of coal seam water injection, the seepage of the solution in the coal fractures is impacted by the roughness of coal fractures. Therefore, in this study, distilled water and a sodium lauryl sulfate surfactant were used as seepage solutions, kennel coal was used as the research subject, and four coal samples with different roughness coefficients were prepared for seepage experiments. After the analysis and discussion of the experimental results, it is found that the surface roughness of coal fractures hinders the seepage effect of coal seam water injection. The greater the surface roughness of coal fractures, the smaller the permeability coefficient. Furthermore, increasing the injection pressure and fracture aperture can reduce the influence of coal fracture surface roughness on the permeability coefficient. In addition, after sodium lauryl sulfate is added, the permeability coefficient of the coal sample is reduced. This further reveals the seepage of water injection into coal seams and provides certain guidance for the development of coal seam water injection technology.

KARAKTERISASI SIFAT FISIKOKIMIA SABUN CUCI PADAT BERBASIS LERAK (Sapindus rarak DC)

Lerak (Sapindus rarak DC.) is one of the fruits with a main active compound called saponin. Saponins function as natural surfactants with foaming and emulsifying properties. Lerak in Indonesia is widely used as a traditional detergent. Using lerak essence as a detergent, batik washing can be done well without fading colors and is more environmentally friendly. Lerak essence can be applied as an additional component in preparing solid laundry soap. Adding lerak essence is to replace the anionic surfactant Sodium Lauryl Sulfate (SLS). Therefore, the risk of pollution can be lowered, as well as keep batik cloth from easily fading out. This study was conducted using Randomized Block Design (RBD) with two factors, including the concentration of lerak essence (10%, 7.5%, and 5%) and NaOH molecules (0.5 mol and 0.375 mol). This study aimed to analyze the effect of variation in lerak essence concentration and NaOH molecular on the physicochemical properties of solid laundry soap. The results showed that the higher the concentration of lerak essence and NaOH molecules, the more it reduces the water content in solid laundry soap. Concentrations of 10% lerak essence and 0.5 mol NaOH molecules have the highest value for foam stability and the lowest value for moisture content. Among the tensile strength, pH, brightness level and yellowness level, the highest value was in the concentration of 7.5% lerak essence and 0.5 mol NaOH molecules. Treatments of the variation of lerak essence concentrations significantly affect pH, while the treatment of NaOH molecular variation significantly affects pH, tensile strength, foam stability, brightness level (L*) and yellowness level (b*).

Antiradical activity, base-catalyzed hydrolysis and partition coefficients of some surfactants

Antiradical activity and some environmental characteristics such as biodegradability and bioavailability of several coconut oil derived surfactants have been studied by photometry and UV–Vis absorption spectroscopy. The effects of polar group size and type were revealed using non-ionic surfactants cocamide monoethanolamine, cocamide diethanolamine, amphoteric surfactant cocamidopropyl betaine, and anionic surfactants sodium lauryl sulfate and sodium alfa olefin sulfonate. Free radical scavenging properties were examined by determination of rate constant of the reaction with hydroxyl radicals. To calculate the rate constant the competitive reaction between hydroxyl radicals and p-nitroso-N,N-dimethyl aniline was investigated. The results show pronounced antioxidant activity of surfactants. To confirm the environmentally friendly character of mentioned surfactants the biodegradability and accumulation were studied using base-catalyzed hydrolysis and partition coefficient between n-octanol/water layers. The obtained results show that type of head group and the carbon chain structure have major effect on these properties.

Effect of sodium lauryl sulfate-mediated gelation on the suppressed dissolution of crystalline lurasidone hydrochloride and a strategy to mitigate the gelation

In dissolution test, the surfactant sodium lauryl sulfate (SLS) is usually added to increase the dissolution of insoluble drugs and achieve the sink condition. However, the current study found that 0.1 % SLS would significantly decrease the dissolution of crystalline lurasidone hydrochloride (LH, a BCS Ⅱ drug). The aim of this study was to clarify the mechanism of this unexpected phenomenon and explore a strategy for mitigating the negative effect of SLS on the dissolution of LH. Sample characterizations (such as PLM, DSC, PXRD, IR and NMR) confirmed that the insoluble single-phase amorphous LH-SLS complex (with a single Tg at 35.2 °C) formed during dissolution in 0.1 % SLS aqueous solution via electrostatic interaction, tetrel bond interaction, and hydrophobic effect. Due to the plasticization effect of water, the transition of amorphous LH-SLS from its glassy state to viscous supercooled liquid state led to the gel formation, and suppressd the dissolution of LH. Meanwhile, the solubility curve of LH in SLS aqueous solution at various concentrations exhibited an unusual V-shaped feature, with the CMC value of SLS serving as the inflection point, since the gel degree was attenuated due to the micelle solubilization of SLS. Additionally, an innovative strategy was developed to alleviate the inhibiting effect of SLS on LH dissolution based on the potential competitive interactions. This study not only enriches the internal mechanism of surfactant-inhibited drug dissolution but also informs an effective strategy to mitigate the gelation.

Synthesis of Surfactant-Modified Activated Carbon (SMAC) Above Critical Micelle Concentration as Cr(VI) Ion Adsorbent

The synthesis of surfactant-modified activated carbon (SMAC) has been widely studied. However, no research has been conducted to study SMAC concentrations higher than the critical micellar concentration. Therefore, in this study, SMAC was synthesized using anionic and cationic surfactants above CMC (Critical Micelle Concentration) and compared with SMAC below CMC and coconut husk-based activated carbon. This study aimed to determine the surface profile of SMAC and the characteristics and mechanism of metal ion adsorption by SMAC. The selected metal ions were Cr(VI) cations and NH4+ cations as a reference. SMAC was prepared by modifying coconut shell-based activated carbon with anionic surfactant SLS (Sodium Lauryl Sulfate) and cationic surfactant HDTMA-Br (Hexadecyl Trimethyl Ammonium Bromide). Modification of SMAC was performed by three different methods: (a) activated carbon was added gradually with SLS followed by HDTMA-Br, (b) activated carbon was added with HDTMA-Br followed by SLS, (c) activated carbon was mixed with SLS and HDTMA-Br simultaneously. All synthesized SMAC were characterized using FTIR, GSA (Gas Sorption Analyzer), and zeta potential. The FTIR analysis results showed that the synthesized SMAC comprised S=O and (CH3)3N+ groups derived from surfactants. GSA analysis revealed that SMAC has a surface area of 36.790 m2/g, and it was more stable than activated carbon according to the zeta potential result. In this study, the efficiency of SLS and HDTMA-Br in synthesizing SMAC was 99.98% and 95.85%, respectively. SMAC synthesis using method c resulted in Cr(VI) adsorption efficiency of 93.50% and NH4+ adsorption efficiency of 87.37%. In comparison, SMAC below CMC has adsorption capacities of 93.41% for Cr(VI) and 85.05% for NH4+, respectively, whereas Cr(VI) adsorption efficiency by coconut shell-based activated carbon was 99.98%.

Polyisoprenes obtained from jackfruit latex (Artocarpus heterophyllus L.): Extraction and characterization

AbstractJackfruit latex is a residue from the agricultural production of this fruit, which does not have an application in the food or pharmaceutical industry. The objectives of the study were to (1) extract the polyisoprenes from jackfruit latex using the surfactant sodium lauryl sulfate, and (2) characterize their physicochemical and techno‐functional properties. The chemical composition, foaming and emulsifying capacity, and thermal behavior. According to the proximal chemical analysis of the extracts, the major content were lipophilic compounds (89%), including polyisoprenes. Regarding the emulsifying properties, the concentrates extracts showed intermediate values for the emulsifying activity index (32–59 m2/g) and stability times from 15 to 95 min. The thermal analysis showed endothermic events (50–65°C) associated with the melting of the concentrate, as well as exothermic events related to the crystallization of the polyisoprenes. The FTIR spectra indicates the presence of the polyisoprenes in the extracts, the stretching of the C═C bonds in 1704 at 1712 cm−1 are characteristic of cis‐1,4 polyisoprene bonds, and at 980 cm−1 the CH bending. The physicochemical and techno‐functional properties of polyisoprene extracts indicate that they could be used in emulsions or electrohydrodynamic encapsulation processes.

Physical Evaluation and Hedonic Test of Sandalwood Oil (Santalum album L.) Cream as an Anti-Inflammatory

Inflammation is the body's defense response used to fight agents that cause cell damage in an organism. One source of natural ingredients whose content can be developed as an anti-inflammatory with low side effects is Sandalwood (Santalum album L.). The pharmaceutical preparation chosen for the development of Sandalwood oil as an anti-inflammatory is a cream, because of its several advantages, namely, it is more convenient, practical, easy to use, not sticky, and easy to wash with water so it is easy to clean. The purpose of this study was to determine the physical quality of sandalwood oil cream using two variant concentrations of surfactant sodium lauryl sulfate 1.5% (F1) and 2.5% (F2) as an emulsifying agent, as well as to determine consumer perceptions of sandalwood oil cream. In ensuring pharmaceutical quality, the preparations made must meet several physical parameters including organoleptic tests, homogeneity tests, pH tests, mechanical stability tests, dispersibility tests, and hedonic tests. To find out whether there is a significant difference between F1 and F2, statistical data processing of cream physical quality was performed using SPSS 20 with an unpaired T-test if the data were normally distributed, and if the data were not normally distributed, the Mann-Whitney test was performed. The results of the research that has been carried out show that overall the two cream formulas have good physical quality and are quite liked by the panelists. From the results of the organoleptic test, homogeneity test, and pH test, it is known that F1 and F2 have no difference, and the results of the dispersion test and hedonic test show that there is no significant difference between F1 and F2.

Experimental analysis of saturated pool boiling of acetone and isopropanol with added surfactant sodium lauryl sulfate over aluminum surface

AbstractThe present article reports a detailed experimental study to know the effect of adding surfactants to different base fluids. For this purpose, an aqueous solution of different concentrations of surfactant with base fluids was formed and then heated at varying heat flux in a pool boiling apparatus. Acetone and isopropanol have been used as base/boiling fluids with anionic surfactant sodium lauryl sulfate (SLS) of 200, 400, 600, 800, and 1000 PPM concentration. The data obtained by heating surfactant‐based fluids has been compared to the data of heating pure base fluids to establish the role of surfactants and the importance of surfactant concentration, that is, critical micelle concentration (CMC) in pool boiling augmentation. CMC value was found in the case of pool boiling of acetone with an SLS concentration of 400 PPM. However, the CMC value is found to be a lower value of SLS concentration of 200 PPM in the pool boiling process of isopropanol. Therefore, it is interesting to investigate the possible causes of such heat transfer phenomena with different values of surfactant concentration. Variations in heat flux change the degree of superheat of the aluminum heater substrate. The heat transfer performance is studied, and finally, a semi‐empirical correlation is proposed to know the heat transfer coefficient and its dependency over the concentration of surfactant.

Methodological approaches to assessing the toxicity of compounds by changing the behavioral response of soil oligochaetes

The methodological aspects of assessing the toxicity of surface-active substances (SAS) by changing the behavioral response of avoiding the substrate by earthworms Eisenia fetida andrei Bouche, 1972 were studied. The conditions for biotesting were selected, under which the method is more sensitive to the tested pollutants. In this method, 30 worms. placed in a Petri dish with a substrate unfavorable for worms (dry sand). Around it, Petri dishes with test samples of moistened sand contaminated with individual toxicants in various concentrations and their mixtures were placed radially. A control sample (wet sand) was also placed among the prototypes. When the worms selected the most favorable of the tested contaminated substrate samples, their movement from dry sand was observed. After 4 h from the start of the experiment, the number of worms in each of the compartments was counted. The toxic effect of the cationic surfactant cetyltrimethylammonium bromide (CTAB) was manifested when its content in the soil sample was from 0.001 g / kg; nonionic surfactant Tween-80 – from 1 ml / kg; anionic surfactant sodium lauryl sulfate – from 20 mg / kg.