• Journal of the Korean Society of Clothing and Textiles
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• v.36 no.11
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• pp.1237-1245
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• 2012

The effect of hydrophilicity and hydrophobicity of PET fabric on the detergency of particulate soil were investigated as functions of the concentration of hydrophilic and hydrophobic chemicals, surfactant concentration, ionic strength, adhesion and removal time, and pH. The detergency of the particulate soil was determined by the adhesion of particles to and their removal from fabric, the PET fabric and ${\alpha}-Fe_2O_3$ were used as textile materials and for the model of particulate soil, respectively. The hydrophilic and hydrophobic finish for PET fabric was treated with a polyester, silicone and fluorine organic compound of resin respectively. The adhesion of particulate soil to fabric treated with hydrophobic chemicals were slightly higher but its removal from fabric treated with hydrophobic chemicals was largely higher than fabric treated with a hydrophilic chemical regardless of solution conditions such as the concentration of hydrophilic and hydrophobic chemicals, surfactant concentration, ionic strength, adhesion and removal time, and pH. Therefore, hydrophobic treatment for fabric had a more positive effect than the hydrophilic treatment on the detergency of particulate soil.

• Environmental Analysis Health and Toxicology
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• v.23 no.2
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• pp.67-77
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• 2008

It has been observed that the linear relationship between the logarithm of bioconcentration factor (log BCF) of highly hydrophobic chemicals and their log $K_{ow}$ breaks when log $K_{ow}$ becomes greater than 6.0. Consequently, super hydrophobic chemicals were not thought to cause baseline toxicity as a single compound. Researchers often call this phenomenon as "hydrophobicity cutoff" meaning that bioconcentration or corresponding baseline toxicity has a certain cutoff at high log $K_{ow}$ value of hydrophobic organic pollutants. The underlying assumption is that the increased molecular size with increasing hydrophobicity prohibits highly hydrophobic compounds from crossing biological membranes. However, there are debates among scientists about mechanisms and at which log $K_{ow}$ this phenomenon occurs. This paper reviews three hypotheses to explain observed "cutoff": steric effects, kinetic or physiological limitations, and chemical activity cutoff. Although the critical molecular size that makes biological membranes not permeable to hydrophobic organic chemicals is uncertain, size effects in combination with kinetic limitation would explain observed non-linearity between log BCF and log $K_{ow}$. Chemical activity of hydrophobic chemicals generally decreases with increasing melting point at their aqueous solubility. Thus, there may be a chemical activity cutoff of baseline toxicity if there is a critical chemical activity over which baseline effects can be observed.

• Environmental Analysis Health and Toxicology
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• v.20 no.4 s.51
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• pp.351-358
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• 2005

The n -octanol/water partition coefficient (Pow) is one of the most important parameters employed for estimating a chemiral's environmental fate and toxicity. The shake-flask method, one direct experimental method, i.1 prone to experimental artifacts for highly hydrophobic compounds. Thus, a valid method for direct determination of the Pow of highly hydrophobic compounds is needed. The slow -stirring method has been demonstrated to provide reliable log Pow data to log Pow greater than 5. This study was performed to evaluate the accuracy of slow- stirring experiment for determination of log Pow, particularly for highly hydrophobic compounds. 1, 2, 3, 4-tetrachlorobenzene, hexachlorobezene, 2, 2', 3, 3', 5, 5', 6, 6'-octachlorobiphenyl, decachlorobiphenyl, and p, p'-DDT (4.5$\times$0.02, 5.41$\times$0.06, 7.26$\times$0.04, 7.87$\times$0.10, and 6.03$\times$0.06, respectively. The octanol/water partition coefficient by the slow-stirring method were very similar to the literature values. These results indicate that the slow- stirring method allows for reliable determination of log Pow of highly hydrophobic chemicals.

• Journal of Soil and Groundwater Environment
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• v.17 no.6
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• pp.59-68
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• 2012

This study provided sorption properties of chlorofluorocarbons (CFCs), and elucidated potential application of CFC sorption data in hydrogeochemistry. Prior sorption studies were reviewed for hydrophobic organic compounds similar to the CFCs, because there were only few CFC sorption studies. The CFCs are regarded as relatively conservative chemicals in groundwater environments based on their moderate hydrophobicity. However, thermally altered carbonaceous matter (TACM) can significantly increase sorption capacity and nonlinearity for hydrophobic organic compounds such as CFCs, compared to general soil organic matter. CFC sorption behavior are close to the sorption for reviewed organic chemicals. Therefore, the CFC sorption data can be used for determining hydrogeochemical properties and predicting transport of organic contaminants in TACM-containing aquifer environments.

• Membrane and Water Treatment
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• v.2 no.3
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• pp.137-145
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• 2011

Membrane processes are major breakthrough for the removal of organic pollutants in water remediation. The separations of solutes depend on nature of the membranes and solutes. The separation performance depends on the nature of the solutes (i.e., molecular volume, polarity, and hydrophobicity) for the same membrane. As 4-chlorophenol is of more dipolemoment compared to 2-chlorophenol, the orientation of the molecule enables it pass through the pores of the membrane, which is of negatively charged and thus separation order follows: 2-chlorophenol > 4-chlorophenol. Hydrophobicity factor also supports the order. Addition of sodium dodecyl sulfate (SDS) to chlorophenol solution shows remarkable increase in separation performance of the membrane. The improvement in separation is 1.8 and 1.5 times for 4- and 2- chlorophenol consecutively in case of 0.0082 M SDS (1cmc = 0.0082 M) in the solution. 4-chlorophenol has better attachment tendency with SDS because of its relatively more hydrophobic nature and thus reflects in performance i.e. the separation performance of 4-chlorophenol with SDS through the membrane is better compared to 2-chlorophenol.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.23 no.1
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• pp.31-36
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• 2013

Acetylated Cellulose Ether (ACE), cellulose-based amphiphilic polymer with hydrophilic and hydrophobic, was synthesized and investigated in terms of its solubility and wettability for organic solvents and water. Acetyl group was substituted to the cellulose ether in a hydrophilic polymer by esterification. As a result of FT-IR, the peak corresponding to the hydroxyl group decreased and carboxyl acid peak increased with increasing reaction time and temperature, which signified the increase in the degree of acetylation of the ACE. There were similar thermal decomposition behaviors before and after esterification reaction until $800^{\circ}C$ so that the reaction occurred without significant structural changes of cellulose backbones. The solubility parameter of the ACE had a range of 18.5~26.4, and its viscosity and turbidity were controlled according to the solubility parameter of organic solvents. The ACE showed the hydrophilicity because the contact angle of the ACE was higher than the cellulose ether. These results confirmed that the ACE had the hydrophobicity and hydrophilicity due to the ether which was glucosidic bonding between the glucose units and un-reacted hydroxyl functional groups in the ACE.

• Biomedical Science Letters
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• v.18 no.2
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• pp.175-179
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• 2012

It is desirable that a wound healing membrane acts as a barrier for coverage of a damaged skin and has the biological activities such as anti-inflammatory effects. In this study, we prepared the hydrogel film containing the propolis nanoparticles as a wound healing membrane. The propolis nanoparticles were prepared by incorporation of propolis into the hydrophobic core of ${\gamma}$-cyclodextrin. The incorporation efficiency of propolis in the nanoparticles was $50{\pm}2.3%$. Propolis nanoparticles observed by a scanning electron microscope (SEM) were spherical with the size of 30~40 nm. The swelling behaviors of the hydrogel film containing propolis nanoparticles showed a similar pattern with the hydrogel film without propolis nanoparticles. The cumulative amount of propolis released from the hydrogel film containing propolis nanoparticles in the buffer of pH 7.4 and 5.5 was $86.0{\pm}2.0%$ and $64.6{\pm}1.0%$ of total propolis loaded in the hydrogel film within 9 h, respectively. These results provide a rationale for studying wound healing application of the hydrogel film containing propolis nanoparticles in a clinical setting.

• Journal of Environmental Science International
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• v.24 no.11
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• pp.1541-1546
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• 2015

The objective of this research was to evaluate the toxicity of the industial xenobiotic Aroclor 1248 (A) and natural origin substances~elemental sulfur (S80) and oleic acid (OA) and their binary mixtures to V. fischeri bioluminescence during the prolonged exposure time (up to 60 min). The bioluminescence quenching test was used to determine the toxic effects. Full factorial experiment design and multiple regression analysis and the comparison of binary mixture effect with the sum of effects of individual chemicals were used for the evaluation of combined effects of toxicants. The analysis of general trend of mixture toxicity to bioluminescence showed that mixture toxic effects were reversible up to 60 min. Data analysis revealed different joint effects, which were depended on mixture composition. S80 enhanced toxic effect of A and acted additively with synergistic interaction. Hydrophobic OA in mixture with A acted antagonistically and in mixture with sulfur caused an additive effect with antagonistic component of interaction. It was concluded that low concentrations of natural toxic substances present in environmental samples as mixtures of chemicals can define the toxicodynamic character of industrial xenobiotics.

• Korea-Australia Rheology Journal
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• v.15 no.4
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• pp.179-185
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• 2003

Associating polymers act as flocculants in colloidal suspensions, because the hydrophobic groups (hydrophobes) can adsorb onto particle surfaces and create intermolecular cross-linking. The steady-shear viscosity and dynamic viscoelasticity were measured for suspensions flocculated by multichain bridging of associating polymers. The effects of surfactant on the suspension rheology are studied in relation to the bridging conformation. The surfactant molecule behaves as a displacer and the polymer chains are forced to desorb from the particle surfaces. The overall effect of surfactant is the reduction of suspension viscosity. However, the additions of a small amount of surfactant to suspensions, in which the degree of bridging is low, cause a viscosity increase, although the number of chains forming one bridge is decreased by the forced desorption of associating polymer. Since the polymer chains desorbed from one bridge can form another bridge between bare particles, the bridging density over the system is increased. Therefore, the surfactant adsorption leads to a viscosity increase. The surfactant influences the viscosity in two opposing ways depending on the degree of bridging.

• YAKHAK HOEJI
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• v.53 no.3
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• pp.114-118
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• 2009

Bioemulsifiers are those chemicals which are produced from microorganisms but which have both hydrophilic and hydrophobic groups. $\alpha$-Glucosidase inhibitor ($\alpha$-GI) produced from Bacillus lentimorbus B-6 (B-6) showed bioemulsifying activity. But $\beta$-glucosidase inhibitor produced from B-6 didn't show emulsifying activity. $\alpha$-GI was purified from supernatant of B-6 grown in minimal culture medium containing glucose and sodium glutamate by Sephadex G-100 column chromatography and isolated from $\beta$-GI by dialysis against water. Toluene was determined as the best substrate for emulsifying activity of $\alpha$-GI. $\alpha$-GI showed thermostability at $100^{\circ}C$ for 15 min, high salt tolerance up to 32% NaCl and wide range of pH-stability at pH $4\sim10$. Emulsifying character of $\alpha$-GI can be useful for the liposome formation for the treatment of diabetes mellitus.