• Journal of the Korean Applied Science and Technology
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• v.17 no.3
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• pp.158-166
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• 2000

A conductimetric study of foam formed from mixture of the protein, ${\beta}-lactoglobulin$, and the nonioinc surfactant, SML, revealed that their stability was reduced at concentrations of SML in the range $3{\sim}10mM$. The interaction of SML with ${\beta}-lactoglobulin$ was investigated by fluorimetry and a dissociation constant of $0.2{\mu}M$ was calculated for the complex. Surface tension studies confirmed the presence of interaction between the two components and provided evidence for the progressive displacement of ${\beta}-lactogloblin$ from the air/water interface with increasing SML concentration. Experiments using air-suspended microscopic thin liquid films revealed transitions in the chainage characteristics and thickness of the film at SML concentrations below that which resulted in destabilization of the foam. However, measurements of surface mobility of fluorescent-labeled ${\beta}-lactoglobulin$ by a photobleaching method identified that a transition to a mobile system occurred at a SML concentration which correlated with the onset of instability in the disperse phase. The results would indicate that maintenance of the viscoelastic properties of the surface is paramount importance in determining the stability of interfaces comprising mixtures of protein and surfactant.

• Applied Chemistry for Engineering
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• v.29 no.5
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• pp.620-625
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• 2018

Liquid detergent based on sodium lauryl ethoxy sulfate (SLES) as main ingredient sometimes met gelling film on the surface when it is opened in the air. It was assumed because of the change of phase diagram of micelle by concentration change of surfactant, major ingredient of detergent when the water of detergent is evaporated. SLES showed strong hexagonal liquid crystal (LC) in 30~60 wt%, and lamellar LC over 60 wt%. In this research surface gelling formation of liquid detergent which is based on SLES as main ingredient was because of water evaporation. As water of detergent was evaporated, concentration of surfactant became higher. It was checked that surface gelling was LC of mixed surfactant system. Conclusionally we applied alpha olefin sulfonate (AOS) having good solubility, Sodium secondary alkane sulfonate (SAS) preventing hexagonal LC and hydrotrope sodium xylene sulfonate (SXS) and PEG1500 in order to prevent gelling film in SLES based liquid detergent. Like this, improved formula 4 and 5 can prevent the formation of gelling film on the surface of liquid detergent when it is opened in the air.

• Journal of Korea Soil Environment Society
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• v.3 no.2
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• pp.115-125
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• 1998

The biodegradation of ($C^{14}$)phenanthrene was studied in water and soil-water systems with nonionic surfactants and biosurfactant : polyoxyethylene alkyl ester($C_{17}$$H_33$COO($C_2$$H_4$O)nH) and sophorolipid. The extents of so1ubilization and biodegradation were monitored by radiotracer technique. Experimental results showed that surfactant concentrations above the critical micelle concentration were toxic to the phenanthrene-degrading bacteria in soil or active sludge and the presence of surfactant micelles inhibited mineralization of PAHs. Solubility and bioavailibility of phenanthrene in water and soil-water system were enhanced by mixed surfactants system. The optimum water content and hydrogen concentration were 30% (w/v) , pH 7, respectively.

• Journal of the Korean Applied Science and Technology
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• v.38 no.3
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• pp.832-839
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• 2021

We tried to investigate the effects of substituent position, temperature, and additives such as NaCl and n-butanol on the solubilizations of cresol isomers by tetradecyltrimethylammonium bromide (TTAB), using the UV-Vis spectrophotometric method. The measured solubilization constants (K_s) values for each cresol isomer increased in the order o-cresolo and ∆H^o values for the solubilizations of cresols were all negative values but the ∆S^o values were all positive values within the measured ranges. The values of ∆G^o increased also with increasing the concentration of n-butanol but decreased with increasing the concentration of NaCl. From these facts, we could conclude that both the enthalpy and entropy changes contribute together for the solubilizations of cresols isomers by cationic surfactant of TTAB and they are solubilized in the polar palisade region or at the surface of micelle.

• Bulletin of the Korean Chemical Society
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• v.30 no.9
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• pp.2051-2056
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• 2009

The rate constants of alkaline fading of malachite green ($MG^+$) was measured in the presence of nonionic (TX-100), cationic (DTAB) and anionic (SDS) surfactants. This reaction was studied under pseudo-first-order conditions at 283∼303 K. The rate of fading reaction showed noticeable dependence on the electrical charge of the used surfactants. It was observed that the reaction rate constants were increased in the presence of TX-100 and DTAB and decreased in the presence of SDS. According to Hughs-Ingold rules for nucleophilic substitution reactions, the electric charge of MG/surfactant compound along with decrease in dielectric constant of $MG^+$ micro-environment in this compound varies the rate of fading reaction. Binding constants of surfactant molecules to $MG^+$ were calculated using cooperativity, pseudo-phase ion exchange and classical models and the related thermodynamic parameters were obtained by classical model. The results show that the binding of $MG^+$ to TX-100 is exothermic and binding of $MG^+$ to DTAB and SDS in some concentration ranges of the used surfactants is endothermic and in the other ones is exothermic.

• Journal of the Korean Chemical Society
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• v.39 no.3
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• pp.143-149
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• 1995

At low concentration a simplified model of organic dye-surfactant system has been used to evaluate. By applying the resultant three parameter equation to the experimental data, values for the equilibrium constants for the ion-pair formation $(K_O)$, surfactant molecule addition to aggregates $(K_S)$ and dye aggregation reactions $(K_D)$ could be calculated and changes of free energy have obtained from its values. $K_O$ and K_S$ values were larger than those expected electrostatic interaction indicatihng a hydrophobic contribution and the $K_D$ values were about 10~20 times higher than those found for association in pure aqueous solutions which can be ascribed to the screening effect of the electrostatic repulsion.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.215-218
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• 2004

The electrokinetically enhanced soil flushing had a great potential to improve the removal efficiency of polycyclic aromatic hydrocarbons (PAHs) from low permeable soils. A semi-pilot study of surfactant-enhanced electrokinetic process was investigated for the removal of phenanthrene from kaolinite. A nonionic surfactant, Tergitol 15-S-12 at 10 g/L was introduced as a flushing agent and 0.001M of sodium chloride was used as an electrolyte. When the constant voltage of 100 V was applied to the system for 25 days, only 0.66 kWh of electric power was consumed and the amount of electroosmotic flow was 6.9 L. The removal efficiency of phenanthrene was about 40 % and it can be improved by increasing the ion concentration of the flushing solution or the applied voltage.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.19 no.1
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• pp.127-138
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• 1993

This study was investigated optimal conditions which were necessary to prepare emulsion of four component systems by the Microfluidizer. Squalane, isopropyl myristate, PPG-15 stearyl benzoate ester were used as an oil and POE(20) sorbitan monolaurate, POE(20) sorbitan monopalmitate, POE(20) sorbitan monostearate, glycerine were selected as a cosurfactant and surfactant. The emulsion was affected by the operating pressure, the recycle frequency and oil, surfactant, cosurfactant phase. The operating pressure and recycle frequency increased, the droplet diameter of emulsion decreased and was constant later. In this study, the optimal pressure and recycle frequency were 1400 bar, 4 cycles. The droplet size was the smallest when the concentration of glycerine was 30 wt.%. As the oil phase is increased, the size is increased.

• Bulletin of the Korean Chemical Society
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• v.13 no.5
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• pp.486-491
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• 1992

The rate constants for the reactions of p-nitrophenyl acetate with 6 different aryloxides and 2 benzohydroxamates have been measured spectrophotometrically in water containing various concentrations of cetyltrimethylammonium bromide (CTAB). The reactivity of the nucleophiles has been demonstrated to be significantly enhanced as the concentration of the surfactant increases up to a certain point. When the basicities of the aryloxides are comparable, the rate enhancement is more prominent for the aryloxide having larger binding constant to the micellar aggregate. Benzohydroxamates exhibitis significantly large ${\alpha}$-effect in the absence of the surfactant, although, the ${\alpha}$-effect nucleophiles are considered to be more solvated in water than the corresponding normal nucleophile. Thus, the solvation effect does not appear to be solely responsible for the ${\alpha}$-effect. Interestingly, the large ${\alpha}$-effect disappears in the presence of the surfactant. Therefore, one might attribute the disappearance of the ${\alpha}$-effect to solvent effect. However, a structural change of the reactive ${\alpha}$ -effect nucleophile into unreactive ones would also be considered to be responsible for the absence of the ${\alpha}$-effect in the present system.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.150-155
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• 2006

Falling liquid plays a role in a wide variety of naturally occurring phenomena as well as in the operation of industrial process equipment where heat and mass transfer take place. In such cases, it is required that the falling film should spread widely on the surface forming thin liquid film to enlarge contact surface. An addition of surface active agent to a falling liquid film affects the flow characteristics of the falling film. In this study the heat transfer characteristics for a falling liquid film has been investigated by an addition of the surface active agents. The falling liquid film was formed on a vertical flat plate. As the mass flow rate of liquid falling film is increased, the wetted area is a little increased while the heat transfer rate as well as heat transfer coefficient is significantly increased. It is also found that both wetted area and heat transfer rate is substantially increased while heat transfer coefficient is a little increased with an increase in the surfactant concentration at a given mass flow rate.