• Polymer(Korea)
• /
• v.28 no.5
• /
• pp.374-381
• /
• 2004

Gas permeability of low density polyethylene (LDPE) film containing zeolite powder for $CO_2,\;O_2$ and $N_2$ were investigated. Zeolite powders modified by cations or surfactant were compounded with LDPE to produce $20 wt\%$ masterbatch. After blending the masterbatch with LDPE, zeolite filled films were prepared by the blown film process. Finally, the composite films containing zeolite loadings of 0, 3,5, and $10 wt\%$ were produced. A gas permeability apparatus based on the variable volume principle was designed to analyze the characteristics of films. Experiments showed a general trend that gas permeabilities first decreased and then increased as the zeolite content was increased. Surfactant modified zeolite showed a better interfacial adhesion with the matrix, but the film did not show a discernible difference in gas permeability compared with the other modified films. The difference of temperature dependences in the gas permeabilities of composite films was slightly smaller than that of LDPE film.

• Applied Chemistry for Engineering
• /
• v.5 no.1
• /
• pp.114-120
• /
• 1994

Esterolysis reactions of PNPDPP (p-nitrophenyldiphenylphosphate) by DCI ( dichloroisocyanuric acid sodium salt) in borate buffer pH8.0 micellar phase were studied. The rate of hydrolysis reaction was rapidly increased by adding cationic surfactants, CTAC (cetyltrimethylammonium chloride) or CTAB (cetyltrimethylammonium bromide), to the DCI solution. Especially in CTAB micellar system, the N-Cl bond of DCI was transformed to the N-Br bond during the reaction.

• Microbiology and Biotechnology Letters
• /
• v.19 no.3
• /
• pp.308-312
• /
• 1991

The delta-endotoxin from B. thuringiensis subsp. damstadienszs 73E10-2 was resistant to high concentration of salt (4M NaBr), organic solvents (50% acetone), denaturants (4 M urea), and neutral detergents (10% triton X-100). In contrast, the toxin was inactivated by treating with charged detergents as well as guanidine hydrochloride or carbon tetra-chloride. The delta-endotoxin is not a sulfhydryl activated toxin, but modification of the lysine side chains eliminated toxicity against mosquito larvae.

• Journal of Soil and Groundwater Environment
• /
• v.9 no.4
• /
• pp.24-31
• /
• 2004

A cold mix asphalt (CMA) treatment process was proposed as a tool to recycle soils contaminated with petroleum hydrocarbons. Experimental studies were conducted to characterize performances of the CMA process in treating soils contaminated with diesel or diesel compounds. From the screening experiments, it was found that performances of five types of asphalt emulsions that contained a cationic or an anionic or a nonionic surfactant were not substantially different. In consideration of higher affinity for soils and higher sorption coefficients obtained, an emulsion containing Lauryl Dimethyl Benzyl Ammonium Chloride (LDBAC) was selected as a promising asphalt emulsion for treating diesel-contaminated soils. When the asphalt emulsion LDBAC was applied to treat three compounds that originated from diesel, the removal efficiencies obtained in the order of decreasing efficiencies were as follows: docosane > pentadecane > undecane. Leaching experiments on the specimen formulated by the emulsion LDBAC found that the selected treatment method could treat soils with diesel concentrations as high as 10,000 mg/kg. Leaching of the diesel from the specimen was controlled by diffusion for the first four days and then leaching rate diminished substantially. The latter behavior was characterized as depletion, which represents that the contaminant released amounts to more than $50\%$ of the total amount of the contaminant that can be leached. The amounts of three diesel compounds leached from the specimen in the order of decreasing amount were undecane, pentadecane, and docosane. The curing of the soil contaminated with pentadecane was relatively slow.

• Journal of Korean Society of Water and Wastewater
• /
• v.28 no.4
• /
• pp.419-429
• /
• 2014

Recent studies have been reported the presence of Endocrine Disrupting Compounds, Pharmaceuticals and Personal Care Products (EDC/PPCPs) in surface and wastewater, which could potentially affect to the complicate behavior in coupled presence of nano-colloid particles and surfactants (adsorption, dispersion, and partitioning). In this study, the adsorption of EDC/PPCPs by Single Walled Carbon Nanotubes (SWNTs) as a representative of nano-particles in cationic surfactant solutions were investigated. Hydrophobic interactions (${\pi}-{\pi}$ Electron Donor-Acceptor) have been reported as a potential adsorption mechanisms for EDC/PPCPs onto SWNTs. Generally, the adsorptive capacity of the relatively hydrophobic EDC/PPCPs onto SWNTs decreased in the presence of cationic surfactant (Cetyltrimethyl Ammonium Bromide, CTAB). This study revealed that the competitive adsorption occurred between CTAB cations and EDC/PPCPs by occupying the available SWNT surface (CTAB adsorption onto SWNTs shows five-regime and maximum adsorption capacity of 370.4 mg/g by applying the BET isotherm). The adsorption capacity of $17{\alpha}$-ethinyl estradiol (EE2) on SWNT showed the decrease of 48% in the presence of CTAB. However, the adsorbed naproxen (NAP) surely increased by forming hemimicelles and resulted in a favorable media formation for NAP partition to increase SWNTs adsorption capacity. The adsorbed NAP increased from 24 to 82.9 mg/g after the interaction of CTAB with NAP. The competitive adsorption for EDC/PPCPs onto SWNTs is likely to be a key factor in the presence of cationic surfactant, however, NAP adsorption showed a slight competition through $CH_3-CH_3$ interaction by forming hemimicelles on SWNT surface.

• Applied Chemistry for Engineering
• /
• v.20 no.2
• /
• pp.145-153
• /
• 2009

The acute oral and genetic toxicity of ASCO EAQ80 was established in this study. ASCO EAQ80, a novel cationic surfactant produced by Aekyung Speciality Chemicals Co. LTD. is currently commercialized as a clear fabric softener. In acute oral toxicity study, the 50% lethal dose $(LD_{50})$ of ASCO EAQ80 was determined to be higher than 5000 mg/kg and this product could be classified as Category 5 or Unclassified by Globally Harmonized Classification System. Also, to establish the gene-toxicity of ASCO EAQ80, we performed bacterial reversion assay against Salmonella typhimurium TA98, TA100, TA1535, TA1537, Escherichia coli WP2uvrA, and in vitro chromosomal aberration assay against Chinese hamster lung cells in the presence and absence of S-9 metabolic activation system. From these experiments, ASCO EAQ80 revealed nonmutagenic potential in S. typhimurium TA98, TA100, TA1535, TA1537, and Escherichia coli WP2uvrA both in the absence and presence of metabolic activation system. No clastogenicity of ASCO EAQ80 was observed in chromosomal aberration assay in vitro.

• 한국생물공학회:학술대회논문집
• /
• 2002.04a
• /
• pp.313-316
• /
• 2002

Effect of Pluronic F-68, a nonionic surfactant, on the extracellular production of hGM-CSF in transgenic Nicotiαna tabacum cell suspension culture was investigated. The addition of 5 g/L Pluronic F-68 did not affect the cell growth but increased the extracellular production of hGM-CSF by two-fold. This may be due to the enhanced permeability of the cell membrane by the interaction between the Pluronic F-68 and the cell membrane.

• Korean Chemical Engineering Research
• /
• v.40 no.6
• /
• pp.769-777
• /
• 2002

Using four components - nonionic surfactants, water, hydrocarbon oil and an alcohol as cosurfactant, 12 types of cleaning agents were prepared, and their physical properties such as surface tension, viscosity, electroconductivity and phase stability were measured. As the formulated cleaning agents have low surface tensions(30.5-31.1 dyne/cm) and low viscosities (1.6-7.2 c.p.), they are satisfied with the general physical properties of water-in-oil(W/O) microemulsions for their industrial use. They showed a tendency that their temperature range for stable one-phase microemulsion decreased in accordance with the increase of alcohol/surfactant(A/S) ratio in the formulations. However, the temperature range of one-phase microemulsion was much more affected by hydrophilic lipophillic balance(HLB) value of the nonionic surfactant which increased its temperature range and it increased in accordance with the higher HLB value in the formulations. And the maximum content of water which can keep stable one-phase W/O microemulsion was measured at each sample. In addition, their temperature range for stable one-phase microemulsion was also measured. It was confirmed that the selection of surfactant type was very important for formulating a cleaning agent, since the W/O microemulsion system with the nonionic surfactant of the lower HLB value showed better cleaning efficacy that of the higher HLB value for abietic acid as a soil, which was used for preparing a rosin-type flux. In the formulated cleaning agents with the increase of A/S ratio in the formulations, however, there was no significant difference in cleaning efficacy. It was investigated that the differences of their cleaning efficacy was affected by the change of the condition of temperature and sonicating frequency as important factors in the industrial cleaning. That is, the higher, their cleaning temperature and the lower, their sonicating frequency, the more increased, their cleaning efficacy. Furthermore, using optical instruments like UV/Visable Spectrophotometer and FT-IR Spectrometer, their cleaning efficacy for abietic acid was measured. The removal of soil from the contaminated rinse water was measured by gravity separation method in the rinse bath. As a result, the cleaning agent system having the nonionic surfactant of HLB value 6.4 showed over 85% water-oil separation efficacy at over $25^{\circ}C$. Therefore, it was demonstrated in this work that the formulating cleaning agents were very effective for cleaning and economical in the possible introduction of water recycling system.

• Journal of the Korean Chemical Society
• /
• v.33 no.1
• /
• pp.3-10
• /
• 1989

In order to obtain a clue in understanding enzymatic hydrolysis in which the His-Cys moieties of papain protease is involved, we prepared cationic peptide-sufactants bearing histidyl, cysteinyl, and both histydyl and cysteinyl residues. Their catalytic efficiency toward the hydrolysis of PNPL were investigated in comicellar phases formed with $N^{+}C_{2}CysC_{12}$, $N^{+}C_{2}HisC_{12}$, $N^{+}C_{2}HisCysC_{12}$ increased markedly in the same order compared with that of $N^{+}C_{2}AlaC_{12}$. The markedly increased catalytic effects are attributed to the imidazole groups of $N^{+}C_{2}HisC_{12}$ and the thiol groups of $N^{+}C_{2}CysC_{12}$, and the large catalytic efficiency of $N^{+}C_{2}HisCysC_{12}$, is considered due to the interaction of the imidazole and the thiol groups. In order to investigate catalytic activities, rate constants for the functional groups, km* and dissociation constants, pKa have been determined. The results showed that $k^{\ast}_m$ and pKa of the imidazole groups were $7.91{\times}10^{-4}S^{-1}$ and 6.49, and those of the thiol groups were $6.00{\times}10^{-4}S^{-1}$ and 10.50. The catalytic effects of comicellar systems on the hydrolysis of p-nitrophenyl esters has increased according to the increasing size of the alkyl carbon number. Therefore, the catalytic effects have been increasing by the interaction of micellar hydrophobic parts and substrates as well as action of the functional groups.

• Microbiology and Biotechnology Letters
• /
• v.15 no.5
• /
• pp.334-339
• /
• 1987

Enzymatic conversion of pyruvic acid produced by microorganism to tryptophan was investigated. A luminescent bacteria. Beneckea sp., was used for the production of pyruvic acid. As a source of tryptophanase which synthesizes tryptophan from pyruvic acid, indole and ammonia, whole cells of Enterobacter aerogenes ATCC 10031 were used directly in the reaction mixture. To increase the production of tryptophan, nonionic detergents and nonaqeous organic solvents were used ms reserviors of indole in the reaction mixture. In the case of nonionic detergents, TritonX-100 was very effective. When 1.5% of Triton X-100 was used, 7.7g/$\ell$ of tryptophan was produced at 37$^{\circ}C$ for 48hr. In the case of nonaqueous solvents, 8.7g/$\ell$ of tryptophan was produced at 37$^{\circ}C$ for 48 hr, when 10% of benzene was used. This amount of tryptophan corresponds to conversion of 48% of Indole and 36% of pyruvic acid, respectively.