Cationic Surface-active Agents Research Articles

Control fouling and cleaning procedures of UF membranes by a streaming potential method

Abstract The impact of cleaning procedures on organic ultrafiltration (UF) membranes has been studied in terms of permeability, streaming potential (SP) and wettability. SP measurements of UF membranes are realised using a new design. This new design is more convenient to determine the SP for all kinds of modules (planar, hollow fiber, etc.). We used this design to control the efficiency of cleaning procedures. Furthermore, SP is used to determine the isoelectric points (IEPs) of two materials [polyethersulfone (PES) and cellulose triacetate (CTA)]. The IEPs were experimentally determined from SP variations with pH at a given ionic strength (0.001 mol l −1 ). The IEPs of both membranes studied are respectively 3.1 and 3.4. The study of the charge origin on the organic membranes showed that the adsorbing ions are those of water itself. In order to model the fouling with natural organic matter and to study the impact of cleaning procedures, the PES membrane was first modified by the surface adsorption of surface active agents (SAAs). For this purpose, a neutral (Triton X100, TX100) and a cationic [dodecyltrimethylammonium (DTAB)] SAA were studied. SAAs were used at a concentration in solution near that of CMC. The wettability of the fouled and virgin membranes was evaluated by means of contact angle measurements. An increase in the contact angle of a droplet deposited on the fouled membrane was correlated to a decrease in its permeability. Furthermore, the contact angle measurements show the acidic characteristic of the PES material at low pH. The use of β-cyclodextrin, a well-known host complexing agent for SAAs, was found to present a better efficiency to remove neutral SAAs than cationic SAAs, which are strongly bonded to the negatively charged PES membrane. The impact of cleaning procedures on CTA membranes fouled with Seine River water was evaluated in the light of these SP measurements. It appeared clearly that the streaming potential is a useful tool for the control of the membrane surface charge after cleaning procedures.

Composite Biosensor for Sulfite Assay: Use of Water-Insoluble Hexacyanoferrate(III) Salts as Electron-Transfer Mediators

Water-insoluble salts of hexacyanoferrate(III) and cationic surface active agents were synthetized and used as electron-mediators for sulfite oxidase. The biosensor was prepared from a composite consisting of modified graphite (50 % w/w) and n-eicosane (50 % w/w). Graphite was modified with mediators or with both mediator and sulfite oxidase for surface- and bulk-modified electrode, respectively. The main advantage of biosensors with insoluble mediators is the possibility to operate at a potential of 0 mV (vs. SCE), thus less interferences are expected, in comparison to soluble hexacyanoferrate(III) where a potential of +300 mV must be used. The maximum sensitivity 7.8 × 10−4 μA/μM was obtained for bulk-modified biosensor, prepared from graphite modified with 5 % w/w of hexadecyltrimethylammonium hexacyanoferrate(III) and 1.25 units/mg (of graphite) of sulfite oxidase. The sensitivity of the biosensor decreased to 24 % of the initial sensitivity after one month storage in dry state at ambient temperature. The use of trehalose as an enzyme stabilization agent has led to the improved stability: 40 % of the initial stability was retained after one month.

Cationic surfactants: new perspectives in medicine and biology

Analysis of present data about the chemical properties and uses of cationic surface-active agents in medicine and biology have shown that the biological action of these substances could be the variant of micellar catalysis in vivo. Use of physico-chemical phenomena is a good way of improving existing surfactants and creating new ones for use in pharmacology and biotechnology.

The effects of surface active agents on jet breakup in liquid‐liquid systems

AbstractAn experimental study has been made of the effects of anionic, cationic and nonionic surface active agents on jet length, jet contraction and drop size resulting from the formation and breakup of liquid jets in another immiscible liquid, while undergoing mass transfer.Correlations previously established for uncontaminated systems with various rates of mass transfer successfully fitted the present data, when used with the diminished value of interfacial tension caused by the surfactant. Variables included nozzle size, flow rate, and type and concentration of surfactant. Data were obtained from measurements on over 3,000 drops, plus jet lengths and jet diameters from 501 photographs.

Hydrophobic ligand-ligand interactions in multicomponent systems and their analytical significance

The presence of hydrophobic ligand-ligand interaction between chromophoric complexing ligands of the triphenylmethane series and cationic surface active agents (c-SAS) in M-R-c-SAS systems has been established. Hydrophobic interaction has been found to be the underlying principle of the formation of stable ionic associates R(c-SAS)n in aqueous solutions. Peculiarities of ion metal complexation in the systems and their importance for analysis have been revealed.

Stability of alumina dispersions in presence of surface active agents

In order to understand the suspension properties of concentrated alumina slips in presence of surface active agents, with particular reference on their flocculation behaviour, electrophoresis, rheology and sedimentation, experiments were carried out on a commercial alumina powder in three cationic surface active agents in the pH range 3–11. The results suggest that the alumina powder is associated with some acidic surface impurity and all three cationic additives are adsorbed on to the surface of alumina particles at all pH values investigated. While the rheological and sedimentation behavior of all slips prepared in water and the additive with the smallest polymer chain length depend upon the electrophoretic mobility, the surface charge appears to have no effect on the stability of alumina slips prepared in additive solutions containing longer polymer chain lengths.

Effect of the surface active agents on the rheology of aqueous alumina slips

In order to understand the properties of concentrated alumina slips with particular reference to their stability behavior, both electrophoresis and rheology experiments were carried out on three commercial alumina powders in three cationic surface active agents. The results suggest that all three commercial alumina powders used in this investigation are associated with some surface impurity that resembles sodium citrate and all three additives are adsorbed on the alumina particle surface. The net surface negative charge decreased with the addition of the additives for additive concentrations below 1% (wt), and above 1% (wt) it appears that the additive remains electrophoretically neutral. While the slips prepared in water and the additive solutions for concentrations above 1% (wt) were very stable, with low viscosity and Newtonian type fluid behavior, the alumina dispersions containing 0.5% (wt) additive solutions were flocculated and exhibited pseudo plastic fluid type properties. It appears that while at low additive concentrations, both the rheology of the slip and the electrophoretic mobility of the alumina particles is governed by the electrostatic interactions, steric effects are responsible for the state of the slip at high concentrations.

Analysis of Cationic Surface Active Agents Using DME and Its Relevance to Their Adsorption

The paper describes an application of dropping mercury electrode (DME) for analytical determination of certain cationic surface active agents and their mixtures and presents obtained thermodynamical data of adsorption of investigated substances.

ヨウ素の殺卵効果に及ぼす塩類および界面活性剤の影響

Ovicidal activity of iodine was observed in the acid solution of iodine and a 50% growth inhibtion dose (GID50) ranged from 9.4 to 16.8μg/ml. It was hardly observed in the alkaline soultion. In the test of an anion of various salts, an increase in activity of iodine was observed in the following increasing order: chioric, sulfuric acid, citric acid and phosphoric acid ion.ion. Moreover, an increase in activity of iodine was observed in the test of an anionic surface active agents, such as sodium lauryl sulfate, sodium lauryl benzenesulfonate and sodium dialkylsulfosuccinate, as well as in the test of the acid soultion. GID50 ranged from 18.0 to 22.0μg/ml. An increase in activity of iodine on Ascaris eggs was observed in the test of sorbitane mono laurate (T-20) and stearate succharose fatty acid ester 1570 of 15 nonionic surface active agents examined. No activity of iodine was observed on cationic surface active agents.

Interactions between large organic cations and cation exchange membranes

Interactions between cation exchange membranes and large organic cations have been studied; namely (1) adsorption and electrodialytic desorption of cationic surface active agents, and (2) change in transport properties of the membranes by adsorption.

Synthesis and bactericidal activity of cationic surface-active agents containing an asymmetric nitrogen atom

Synthesis and bactericidal activity of cationic surface-active agents containing an asymmetric nitrogen atom

Transposition of gentamicin resistance to staphylococcal plasmids encoding resistance to cationic agents.

Plasmid pWG115 isolated from a methicillin-resistant Staphylococcus aureus encodes resistance to cationic surface-active agents and trimethoprim. It has a molecular weight of ca 14.6 megadaltons and can be transferred to other strains of staphylococci in mixed-culture transfer with propamidine isethionate as a selective agent. Gentamicin resistance in Australian methicillin-resistant Staph. aureus isolates can be either chromosomal or plasmid-borne. The most common gentamicin resistance plasmid is 18.0 megadaltons and also encodes resistance to trimethoprim and cationic surface-active agents. This suggested that pWG115 was related to gentamicin resistance plasmids and that it may provide a target for the postulated gentamicin resistance transposon. This paper demonstrates that the chromosomal gentamicin resistance determinant from WG523 can transpose into pWG115 to generate an 18.0 megadalton plasmid, phenotypically indistinguishable from the naturally occurring gentamicin resistance plasmids such as pWG53. EcoR1 restriction enzyme analysis demonstrated that gentamicin resistance can transpose into at least two sites on pWG115. One of these sites generates EcoR1 restriction fragments identical to pWG53. The 5.2 kilobase pair (3.4 megadalton) element involved confers low-level resistance to gentamicin, cross resistance to tobramycin and kanamycin, and has been designated Tn3851.

Cationic surface active agents as fabric softeners

AbstractRinse cycle, wash cycle, and dryer type softeners are reviewed and their compositions discussed. Ashland’s conclusions are: (a) Rinse cycle softeners give the best performance from a softening and anti‐static point of view. They are, however, less convenient to use since they must be introduced into the final rinse, (b) Wash cycle softeners are convenient to use, but higher use levels are necessary to impart adequate softening and anti‐static properties making their use more expensive. They also tend to decrease the cleaning properties of the detergent used, (c) Dryer type softeners are convenient to use, but they impart less softening because of nonuniform deposition of softener on the fabric. The anti‐static properties, on the other hand, imparted by these softeners are very good.

The behaviour of dyes at oil/water interfaces

The adsorption of ionic dyes, the builder effect, and the interaction between ionic dyes and surface active agents were investigated by using the electrocapillarity at oil/water interfaces. The oil phase was the solution of tetra-butylammonium chloride, sodium cetylsulphate, cetylpyridinium chloride or stearylamine in methylisobutylketone, and the water phase contained various dyes in addition to the inorganic electrolyte. The interfacial tension decreased over the anodic (or cathodic) polarization range, when anionic (or cationic) dyes were added to the water phase, thus indicating the dye adsorption at the interface. The interfacial excess of dye ions was found to increase linearly with the cubic roots of dye concentration and of ionic strength of the water phase. The counterion binding took place at the oil/water interface between anionic (or cationic) dyes and positive (or negative) head groups of surface active agent ions adsorbed at the interface. It was found that the equilibrium constants of binding between anionic dyes and cationic surface active agents at the oil/water interface were of the same order of magnitude as, and a little larger than, those obtained at the water bulk phase.

The effect of surface active agents on the microelectrophoretic properties of a polystyrene latex dispersion. Microelectrophoretic studies

The effect of adding anionic (sodium alkyl sulphates), cationic (alkyltrimethylammonium bromides), and nonionic (polyoxyethylene glycol monoethers of n alkanols) surface active agents, and mixtures of these ionic and nonionic species, on the electrophoretic properties of a monodisperse polystyrene latex dispersion has been studied. The nonionic surfactants are probably adsorbed in a looped monolayer as shown by a plateau region in electrophoretic mobility versus concentration plots. With cationic surfactants adsorption is a two-stage process characterized by neutralization of negative charge followed by charge reversal. The free energy of adsorption is dependent on alkyl chain length, the adsorption process being controlled by the hydrophobic effect. Displacement of the reversal of charge concentration by nonionic surfactant depends on its concentration and the type of cationic surfactant. Adsorption of anionic surface active agents causes an increase in zeta potential. An estimate of the free energy of adsorption can be made from the slope of the zeta potential versus log concentration surfactant plot. Added nonionic surface active agents are found to complex with anionics, complexation being dependent on ethylene oxide chain length.

A test method for analyzing anionic or cationic surfactants in industrial water.

AbstractA general 2‐phase titration method is introduced for the quantitative identification of either anionic or cationic surface active agents commonly used in the domestic and industrial applications. Initially, an appropriate amount of quaternary ammonium compound is added to an unknown water sample to be analyzed and to ensure the treated sample contains excess amount of quaternary ammonium compound, and thus, is cationic in nature. The amount of excess quaternary ammonium compound is then quantitatively determined by titration with a standard anionic surfactant in the presence of methyl orange dye, buffer reagent, and chloroform. If the original surfactant in the tested sample is anionic, the anionic surfactant content (μM) is equal to the known amount (μM) of the added cationic quaternary ammonium compound minus the amount (μM) of standard anionic titrant spent in the neutralization reaction. If the original surfactant in the tested sample is cationic, the cationic surfactant content (μM) is equal to the amount (μM) of standard anionic titrant spent in the titration minus the known amount (μM) of the added cationic quaternary ammonium compound. The test procedure is simple and can be successfully completed within 5–7 min by a laboratory technician. For research or industrial application, a specific anionic or cationic surfactant to be used should be selected for the surfactant calibration. For the water quality control of unknown samples, the most common anionic surfactant, linear alkylate sulfonate, and the most common cationic surfactant, quaternary ammonium chloride, are selected as surfactant standards. The anionic surfactant concentration of a sample can be reported to be mg/liter as linear alkylate sulfonate while the cationic surfactant concentration of a sample can be reported to be mg/liter as cetyldimethylbenzylammonium chloride. Other alternatives for the use of the proposed general 2‐phase titration method are suggested. Effective elimination of the interference caused by the presence of oil in an industrial water is also discussed. The proposed method is limited in application to the measurement of free ionic surface active agents only.

Dynamic contact angles in mercury/carbon tetrachloride/solution systems. I. Factors affecting spreading

The impact, process of attachment and subsequent spreading of drops of carbon tetrachloride at mercury/solution interfaces have been recorded photographically. The effect of the history of the drop, prior to attachment at the interface, on the subsequent spreading phenomena is discussed. The reproducibility of dynamic contact angles is demonstrated. The influence of anionic and cationic surface-active agents on the spreading of carbon tetrachloride drops at a mercury/solution interface has been studied. The rate of change of contact angle with time depended on the magnitudes of the interfacial free energies involved, and these depended on the nature and concentration of the surface-active agent. The effects of various factors such as gravity, temperature and natures of the phases on the spreading process have been considered.

Dynamic contact angles in mercury/carbon tetrachloride/solution systems. III. The mechanism and kinetics of spreading

The surface areas ( A) per molecule of several typical anionic and cationic surface-active agents at carbon tetrachloride/water, and mercury/water interfaces have been determined by the application of Gibb's adsorption equation. Whereas a limiting value for A at the carbon tetrachloride/water interface was of the order 54 Å 2, values at the mercury/water interface were three to five times higher. This was probably due to the incomplete orientation of the molecules at the mercury/water interface. Spreading in the mercury/carbon tetrachloride/solution system was controlled by the magnitudes of the interfacial forces. Because of the rapid rate of establishment of equilibrium excesses at the interfaces, compared with the rate of interfacial expansion (or contraction) these forces were effectively constant. The spreading processes were exponential and followed first-order kinetics of the form: dθ dt = K(θ eq − θ t) , where θ eq is the value of θ at t ∞, θ t the value at time t, and K a constant only for a particular concentration of surface-active agent; it is proportional to the rate of the spreading process. The energy of activation of the spreading process was found to increase with increase in concentration of each surface-active agent. At a unique and reproducible “critical” concentration of each of the ionic surface-active agents, the mechanism of the spreading process changed abruptly, and the magnitude of the energy of activation then effectively remained constant, i.e., independent of concentration. At low surface concentrations of the ionic surface-active agents (apparently chemisorbed on the mercury surface) a mechanism is proposed in which these molecules are compressed ahead of the spreading drop. As the surface concentration increased, however, a situation was reached where this compression mechanism was no longer possible, due to the dense packing of surface-active molecules. After this stage, the drop proceeded to spread over the adsorbed layer of surface-active molecules. It has been shown that spreading coefficients can not only predict the position of the equilibrium stage but in some cases the speed of a spreading process as well. Better agreement may have been obtained if the difficulties involved in a change in mechanism of the spreading process had not occurred.

Cataracts induced by surface active agents

Intravitreally-administered anionic, cationic and neutral surface active agents are all capable of producing cataracts. The developing cataracts are characterized by increased hydration, loss of dry weight, progressive increases in Na + concentration, and progressive decreases in K + concentration. Glycolytic metabolism is only moderately decreased in the advanced stages of cataract. Surface active membrane damage is discussed in reference to the pathogenesis of cataract.

Influence of Surface Active Agents on Detergent Tolerance of Lipases

Although it has already been reported that anionic detergents (AD) strongly inhibited the activity of lipase, scarce data is available on their influence in the presence of surface active agents (PSA). This report deals the influence of PSA on detergent tolerance of lipases. Three microbial lipases of Achromobacter sp., Candida sp. and Mucor sp., and an animal lipase of hog pancreas were used. Anionic detergents included sodium dodecyl benzene sulfonate (DBS), sodium dodecyl sulfonate (SDS) and sodium stearate (SOAP). 12 kinds of surface active agents selected from cationic, nonionic and amphoteric surface active agents were tested for their protection of lipases. The influence of PSA were examined by assaying the residual lipase activity according to modified Dole's method after the contact of lipase solution with the mixture of AD and PSA. Results obtained were as follows : 1. The inhibition of microbial lipase activity by DBS and SDS was protected by the addition of nonionic PSA such as Tween and Emulgen (polyoxyethylene nonylphenylether), but in case of animal lipase, Ameate was the only PSA which was found to be effective to protect the activity. On the contrary, the inhibition of microbial lipase activity by SOAP was not protected by any PSA but most of the nonionic PSA protected animal lipase.2. This protective effect of PSA, with some exception, increased as concentration of lipase and PSA increased and decreased along the increse of the concentration of AD. The temperature and the time at the contract reversely affected to their protective effect.3. Lipases of Candida sp. and Mucor sp. were unstable in the presence of salts which are usually used as bilders, whereas lipases of hog pancreas and Achromobacter sp. were comparatively stable. Tolerance of lipase activity in commercial detergents also increased by the addition of PSA.