Types Of Surface-active Agents Research Articles

Effect of the Surface modification of Cellulose nanofibers on the Mechanical Properties and Disintegrability of Specific PLA/Cellulose Composites

Abstract PLA/nanofibrillar cellulose (NFC) composite films were produced by solution casting. Before use, the cellulose fibers were modified with various types of surface active agents – cationic, anionic and non-ionic surfactants. The structure and morphology of samples of the cellulose fillers and composite films with polymer were analyzed by means of scanning electron microscopy and PXRD diffraction. Thermal parameters of the composite films were characterized by differential scanning calorimetry and thermogravimetric analysis. The tensile strength and elongation at break of the films were evaluated in mechanical tests. The ability to disintegrate of all PLA/NFC composites under composting conditions was also determined and compared.

EFFECTS OF SURFACTANT ON LIFT COEFFICIENT OF ELLIPSOIDAL BUBBLES IN THE VISCOUS-FORCE DOMINANT REGIME

Effects of surfactants on lift coefficients, <i>C<sub>L</sub></i>, of single ellipsoidal bubbles rising through linear shear flows were investigated. Two types of surface-active agents, Triton X-100 and 1-octanol, were used. The liquid properties except for the surface tension were identical to those in a clean system of logM = -5.5, where M is the Morton number. The range of the bubble Reynolds number was 0.1 < Re < 70. Bubble shapes were either spherical or ellipsoidal. Comparing with clean bubbles, less deformation of contaminated bubbles was confirmed. A shape correlation without taking the dimensionless shear rate into account gave good evaluations of the bubble aspect ratio, which means that the shear rate is not a dominant factor causing the change of shape deformation. However, drag coefficients were affected by the shear rate. A new correlation of drag coefficients was deduced, which agreed well with the experimental data. Both clean and contaminated <i>C<sub>L</sub></i> data showed a similar tendency: after a drastic decrease in <i>C<sub>L</sub></i>, <i>C<sub>L</sub></i> slightly increases and then decreases to a negative value while increasing the bubble Reynolds number, Re. A difference in concentration of Trion X-100 resulted in only a slight change in <i>C<sub>L</sub></i> at high Re regime. Different types of surfactant resulted in noticeably different values of <i>C<sub>L</sub></i> especially at low Re. The <i>C<sub>L</sub></i> of small bubbles in contaminated systems could be reproduced by a correlation for solid particles, supporting that fully contaminated spherical bubbles behave like solid spheres. For deformed bubbles, <i>C<sub>L</sub></i> can be expressed by relating the negative lift force due to shape deformation with the drag force.

ANALYTICAL METHOD FOR THE IDENTIFICATION OF OIL SPILL DISPERSANT COMPOSITION

Chemical dispersants are often used to disperse spilled oils, which threaten to pollute shoreline areas. In Indonesia all dispersants produced or marketed should undergo the toxicity test with regand to certain types of fish to determine the threshold limit, LC-50. The type of surface-active agent (surfactants) and the solvent used in the dispersants, which determine the dispersing quality, might be toxic to the marine species and bacteria.

Upgradation of Iron Ore Fines and Slime by Selective Flocculation Using Surface-Active Agents, Settling Study, and Characterization of the Beneficiation Waste for Value Addition

Washing of iron ore fines and slime (10% and 25% w/v, slurry concentrations) with two types of surface-active agents (sodium humate (synthesized) and AD 200 (commercial)) at varying concentrations at pH 8 was conducted for ascertaining the efficacy of dispersants in beneficiating the low-grade iron ores. The beneficiation process follows the “selective dispersion-cum-settling technique.” The process results in the formation of a dispersed phase rich in gangue minerals and a settled phase of predominantly active hematite mineral. The stability of dispersed phase (DP) was evaluated by determination of the percentage solid content in the DP. Settling tests were performed. First-order kinetic models have been applied to the dispersion-cum-settling behaviour of both the samples, and evaluated kinetic parameters were found to have good agreement with experimental data. Removal of gangue minerals from iron ore depends on the pH of the slurry, concentration of the slurry, and concentration of the surface-active agent used. The surface-active agents at pH 8 produce ∼1.2–1.5 times more stable suspension in the case of iron ore fines and slimes than that of without surface-active agent. They significantly remove gangue minerals and increase the iron value ∼2–7% with ∼58–74% recovery depending on the experimental conditions. The concentrates collected satisfy the required specifications (Al203/Fe < 0.05 and Al203/Si02 < 1). The gangues in the dispersed phase as characterised by “SEM-EDXA” are mostly clay-bearing minerals like kaolinite, goethite, chlorite, and alumina-silicate minerals. Heat treatment causes distortion of clay minerals present in the dispersed phase and also indicates the complex nature of the gangue minerals.

Sonochemical synthesis, characterization and investigation of the electrochemical hydrogen storage properties of TlPbI3/Tl4PbI6 nanocomposite

Hydrogen storage is an important technology for the promotion of fuel cell and hydrogen technologies in applications such as transportation, portable power, and stationary power. Hydrogen possesses the most energy per mass of each fuel; despite its low room temperature density leads to a low energy per unit volume, since demanding the improvement of high-level storage techniques that possess the potential for higher energy density. For this regard, novel nanocomposite (TlPbI3/Tl4PbI6) has been fabricated for electrochemical hydrogen storage by the importance of the optimum state to obtain higher efficiency. TlPbI3/Tl4PbI6 nanocomposite was prepared by a facile and low-cost sonochemical pathway. The sonochemical method performs a significant figure in the synthesis of nanostructures with large surface area and tiny crystal size, characteristics that are useful for electrochemical hydrogen storage. The influence of multiple factors, including stoichiometric ratios, types of surface-active agents, time, and power of sonication was studied on the structure, purity, shape, size, and uniformity of the samples. The electrochemical characteristics of the TlPbI3/Tl4PbI6 were examined via charge-discharge chronopotentiometry procedures in an alkaline medium. The discharge capacity of TlPbI3/Tl4PbI6 with particle shape was evaluated 61.45 mAhg−1 after 15 cycles. The discharge capacity nanocomposite with rod-like structure was calculated 99.06 mAhg−1. The results confirm that the hydrogen storage capacity for rod-like samples is higher than particle shape nanocomposite, and the capacity reduces by enhancing the diameters of rods.

Surface-active biopolymers from marine bacteria for potential biotechnological applications

Surface-active agents are amphiphilic chemicals that are used in almost every sector of modern industry, the bulk of which are produced by organo-chemical synthesis. Those produced from biological sources (biosurfactants and bioemulsifiers), however, have gained increasing interest in recent years due to their wide structural and functional diversity, lower toxicities and high biodegradability, compared to their chemically-synthesised counterparts. This review aims to present a general overview on surface-active agents, including their classification, where new types of these biomolecules may lay awaiting discovery, and some of the main bottlenecks for their industrial-scale production. In particular, the marine environment is highlighted as a largely untapped source for discovering new types of surface-active agents. Marine bacteria, especially those living associated with micro-algae (eukaryotic phytoplankton), are a highly promising source of polymeric surface-active agents with potential biotechnological applications. The high uronic acids content of these macromolecules has been linked to conferring them with amphiphilic qualities, and their high structural diversity and polyanionic nature endows them with the potential to exhibit a wide range of functional diversity. Production yields (e.g. by fermentation) for most microbial surface-active agents have often been too low to meet the volume demands of industry, and this principally remains as the most important bottleneck for their further commercial development. However, new developments in recombinant and synthetic biology approaches can offer significant promise to alleviate this bottleneck. This review highlights a particular biotope in the marine environment that offers promise for discovering novel surface-active biomolecules, and gives a general overview on specific areas that researchers and the industry could focus work towards increasing the production yields of microbial surface-active agents.

Synthesis of novel white flake polyaniline

A novel polyaniline have been successfully prepared by in situ emulsion polymerization using KIO3 as an oxidant. White polyaniline was observed after 3h the color of the polyaniline is usually black or green. This change in polyaniline color has led to an interest in its use for display devices, packaging and other applications. Scanning electron microscopy was used to characterize the morphology of polyaniline. The chemical structure of products was determined by Fourier Transform Infrared Spectroscopy (FTIR) and UV–vis spectroscopy. The results show that the type of surface active agent affects the intensive of peaks. This process leading to white flake polyaniline plate with 0.015–140μm particle size and approximate yield of 40%.

Effects of Contaminants on the Mass‐Transfer Characteristics of a Two‐Impinging‐Streams Gas‐Liquid Reactor

AbstractThe mass‐transfer characteristics of a new type of two‐impinging‐streams reactor (TISR) was studied by means of sodium sulfite solution as the liquid phase and air as the gas phase, in the presence and absence of various types of surface‐active agents (SAAs). The influences of anionic, cationic, and nonionic SAAs on the specific interfacial area and overall volumetric mass‐transfer coefficient obtained in the TISR were investigated. It was found that the presence of a little amount of the above‐mentioned contaminants increases the specific interfacial area and decreases the overall volumetric mass‐transfer coefficient. On the basis of the experimental results obtained for various types of SAAs, correlations were derived for the interfacial area as well as the Sherwood number for the liquid phase in terms of Froude, Reynolds, Schmidt, and Morton numbers.

Effects of surface active agents on hydrodynamics and mass transfer characteristics in a split-cylinder airlift bioreactor with packed bed

The effects of three types of surface active agents (containing SDS, HCTBr and Tween 40) with various concentrations (0–5ppm) on the hydrodynamic and oxygen mass transfer characteristics in a split-cylinder airlift bioreactor with and without packing were investigated. It was observed that in the surfactant solutions, surface tension of the liquid decreased and smaller bubbles were produced in comparison with pure water. So, surfactants presence strongly enhanced mixing time and gas hold-up although oxygen mass transfer coefficient and the liquid circulation velocity reduced. Furthermore, the packing installation enhanced the overall gas–liquid volumetric mass transfer coefficient by increasing flow turbulency and Reynolds number compared to an unpacked column. The packing increased gas hold-up and decreased bubbles size and liquid circulation velocity.

Retarding Effect of Contaminants on the Performance of a Two‐Impinging‐Jets Liquid‐Liquid Extraction Contactor

AbstractIn industrial liquid‐liquid extraction processes, the feed is not clean liquid but there are various kinds of contaminants in the feed entering the extractors. In this regard, a two‐impinging‐jets contacting device (TIJCD) was tested through the standard test system recommended by the European Federation of Chemical Engineering (EFCE), namely toluene‐acetone‐water, in the presence and absence of various types of surface‐active agents (SAAs). The influences of anionic, cationic, and nonionic SAAs such as sodium dodecyl sulfate (SDS), dodecyl trimethyl ammonium chloride (DTMAC), and octylphenol decaethylene glycol ether (Triton X‐100), respectively, on the extraction efficiency and overall volumetric mass transfer coefficient of a TIJCD were investigated. It was found that the presence of a little amount of the above named contaminants greatly decreases the performance capability of the TIJCD. On the basis of the experimental results obtained for various types of surfactants, the overall volumetric mass transfer coefficients obtained have satisfactorily been correlated in terms of Weber (We) and Eötvös (Eö) numbers.

Influence of coexisting surface-active agents on leachability of dioxins in raw and treated fly ash from an MSW incinerator

The leaching behavior of dioxins from raw and treated fly ash (FA) under the coexistence of several types of surface-active agents (SAAs) was examined by batch leaching tests to obtain significant information not only for evaluating leachability of dioxins as hydrophobic organic pollutants (HOPs) under the severe environment in which SAAs coexist, but also for evaluating the reduction efficiency of dioxin-leachability from the treated FA. Enhancement of dioxin-leachability by sufficient addition of SAAs was observed in the leaching test, whereas addition of a smaller quantity depressed the leachability. The higher the degree of chlorination in PCDDs/PCDFs homologues, the more effectively the SAAs enhanced the leachability. Moreover, there was a large difference in the potential for leachability enhancement due to each surface activity, based on critical micelle concentration (CMC) of the SAAs although Aldrich humic acid enhanced the leachability at a much lower concentration than CMC. A comparison of the leachability in FA treated by several methods showed a difference in the reduction efficiency of leachability, depending on the adsorption of SAAs by each treated FA.

Study of the microstructure of o/w creams with thermal and rheological methods

Thermogravimetric and rheological investigations of oil/water (o/w) creams prepared with different types of surface-active agents (non-ionic, non-ionic POE-free, ionic) were carried out. Thermogravimetry was aimed at the indirect study of the water bond mechanism in o/w creams and the influence of the composition, type and concentration of the mixed emulsifier on the binding of water incorporated in the structure (interlamellar, bulk) and on the binding proportions. The microstructural changes during application were studied with respect to the stability of the lamellar bilayer.

Drop size distributions in high holdup fraction dispersion systems: effect of the degree of hydrolysis of PVA stabilizer

Although turbulence-stabilized dispersions are of considerable industrial importance, their behaviour is generally not well understood, especially for the high dispersed phase volume fractions encountered in suspension polymerization reactors. The dispersion is formed by two dynamic processes, namely, drop breakage and coalescence. Breakage mainly occurs in regions of high shear stress near the impeller or as a result of turbulent velocity and pressure fluctuations along the surface of a drop. Droplet coalescence is prevented by the combined action of turbulent agitation and the addition of protective colloids such as poly(vinyl alcohol) (PVA). Depending on the combination of the degree of agitation and the concentration and type of surface active agent, the average droplet size can exhibit a U-shaped variation with respect to the impeller speed or the degree of hydrolysis of the PVA stabilizer. This U-type behaviour has been confirmed both experimentally and theoretically and has been attributed to a manifestation of the balance between breakage and coalescence rates of the monomer drops. Both processes are related to the interfacial tension and its variation with time as a result of the varying polymer concentration and conformation at the monomer/water interface. In the present study, a series of experiments were carried out with a model system of 50% n-butyl chloride in water in the presence of PVA with varying degrees of hydrolysis at different agitation rates. A generalized numerical algorithm incorporating the most comprehensive models describing the breakage and coalescence processes has been used for simulating the steady-state drop size distributions in a high holdup liquid—liquid dispersion system in order to elucidate the breakage and coalescence mechanisms as a function of the droplet interfacial characteristics. It is shown that the model simulations are in satisfactory agreement with measurements of the drop size distributions over the whole range of the experimental conditions investigated.

The formation of particle clusters near an interfacial meniscus

A study of the behaviour of particles in dilute liquid suspensions in the proximity of a gas-liquid interface has been carried out. The experiments were performed in a thin channel, the liquid was allowed to evaporate so that a meniscus between the suspension and the vapour was formed. As this receded into the liquid, particles were concentrated in a close-packed band adjacent to the meniscus. As the number of particles in this band increased, the meniscus became unstable and bifurcated. This resulted in the particles from the band being depositied in complex patterns, the development of which was shown to be a strong function of the particle size. Where the meniscus bifurcated, a thin filament of suspension was formed. When the particles in the original suspension were small, mean diameter d ⩽ 10 μm, the liquid subsequently evaporated from the filament to produce a final deposit of particles as ordered chains. In experiments with larger partices d ⩾ 13 μm, the filaments ruptured leave “islands”. As the liquid evaporated from these, particles reassembled under the action of capillary forces to form compact discs. Using spherical particles, precipitates of copper oxalate or glass ballotini, the particles in the discs assumed a structure close to that of the lowest configurational entropy. Various parameters were studied in relation to the above-described particle ordering phenomenon. Particle distribution, concentration and morphology, surface free energy, surface tension and the presence of various types of surface-active agents were all studied. In systems where the deposit formed ordered chains, successive bifurcations of the meniscus produced branched structures, the patterns of which were shown to be reproducible. These patterns resembled river drainage nets and other similar phenomena. The analysis of the patterns showed them to be fractal structrues with a fraction dimension of 1.31.

Inhibition of Streptococcus mutans Adherence to Hydroxyapatite with Combinations of Alkyl Phosphates and Nonionic Surfactants

Seven alkyl phosphate derivatives and three nonionic surfactants were examined for their ability to inhibit the adherence of 3H-labelled cells of Streptococcus mutans to hydroxyapatite (HA) treated with buffer (BHA) or parotid saliva (SHA). None of the compounds alone hindered binding of bacteria to BHA or SHA effectively. A combination of certain of the alkyl phosphates, notably a disodium phosphate of 1-octadecanol, and nonionic surfactant at a 1:1 molar ratio gave a strong inhibition of S. mutans adherence. Treatment of SHA with this combination resulted in 98% reduction of adherence. Adsorption of the two types of surface-active agents alone and in combinations was studied using 14C-labelled agents. Electrophoretic measurements revealed that surfaces treated with only alkyl phosphate became highly negatively charged, while surfaces treated with the combination had a zeta-potential of around zero. The results suggest that treatment with surfactants might be used to interfere with bacterial adherence on the tooth surface.

界面活性剤の魚に対する作用

When fish were exposed to a solution containing RSO3-, RSO4-type surfactants, these surfactants were particularly adsorbed on to the surface of fish gills, causing increased numbers of red blood cells in the treated fish. Death caused by these types of surface active agents was delayed by the addition of protein to the surfactant solution.These results suggest that the toxicity of RSO3-, RSO4-type surfactants for fish might be due to the formation of a surfactant-protein complex upon contact with gill protein.

Separation and determination of mixtures of anionic surface-active agents by salting-out chromatography

The optimum chromatographic conditions for the separation and determination of mixtures of anionic surface-active agents by salting-out chromatography were determined. The conditions finally adopted were as follows: column, 25 mm I.D. and 410 mm long; resin, Amberlite CG-50 (200-400 mesh); eluent, aqueous 30% isopropanol-0.2 M sodium chloride solution; column temperature, 40.0°. The elution behaviour of various types of surface-active agents was examined under these conditions and the surfactants were classified by their elution volumes in order to establish separable combinations.

General Dispersant Theory

Abstract Chemical dispersants have a role in the cleanup of oil spills. However, neither dispersion nor any other current technique is a panacea for this purpose. There are situations where dispersants can be used for the benefit of our natural resources; but there are also instances where they should not be used. Similarly, there are conditions under which they are effective, as well as limits where they become ineffective. These aspects of the subject, as well as the mechanism of and basis for dispersing oil slicks, will be discussed. An understanding of the mechanism of dispersency is of prime importance in order to appreciate the behavior and variation in effectiveness of various generic types of surface active agents in promoting oil-in-water dispersions. In this regard, the presence of naturally occurring surfactants in crude oil and their properties are discussed. Even for the same chemical agent, its efficiency can vary due to the influence of many factors such as method of application, degree of mixing, type of oil, temperature of water, amount of circulation in the body of water, etc. Some chemicals can be more sensitive to a specific factor than others. Therefore, an appreciation of mechanism and the effect of environmental and application factors is necessary in order to assess the appropriate scope of application for dispersants as a tool for the handling of oil spills.

Absorption and Excretion of Drugs. XXIX. Effect of Surface-active Agents on Rectal Absorption of Sulfisoxazole from Oily Base

Effect of various types of surface-active agents on the rectal absorption of sulfisoxazole from cocoa butter was investigated by the blood level determination with rabbits. Blood levels were in general increased with increase of surface-active agent, and decreased by addition of the large amount. Surface-active agent accelerated the release of the drug from the base to dissolution medium. On the other hand, surface-active agent reduced the absorption rate of the drug from aqueous solution. These results suggest that the increase of the drug absorption at the low concentrations of surface-active agents is due to release acceleration, but the reduction effect on drug absorption in their higher concentrations is due to predominance of absorption reduction over release acceleration. Cetyltrimethyl ammonium bromide especially stimulated the drug absorption in the very low concentrations.

Germicidal Effect of Several Types of Surface Active Agents

The germicidal effects of nonionic, anionic, cationic and amphoteric surface active agents were tested. Escherichia coli, Bacillus subtilis and Staphylococcus aureus were used as the test organisms. The results were as follows:1) A nonionic surface active agent, Liponox NA, showed no germicidal activities to the test organisms.2) An anionic surface active agent, Anion P-105, inhibited the growth of Staphylococcus and B. subtilis at the concentration of 1/1920, but did not inhibit the growth of E. coli.3) A cationic surface active agent, Bionol, inhibited the growth of Staphylococcus and B. subtilis at the concentration of 1/30720.4) The concentration of Lipomin COH, an amphoteric surface active agent, which inhibited the growth of B. subtilis was 1/960.5) The mixture consisted of 10 percent nonionic, 10 percent cationic and 1 percent amphoteric surface active agents showed the phenol coefficient of 170 to E. coli. Increase in 15 percent of the contents of amphoteric surface active agent did not show any perceptible effect on the phenol coefficient.