• 공업화학
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• 제30권5호
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• pp.639-642
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• 2019

본 연구에서는 침전법을 이용하여 양이온성 계면활성제인 hexadecyltrimethylammonium chloride (CTAC)를 도입한 수산화인회석을 합성하였다. X-선 회절 분석법과 투과전자현미경, 비표면적 분석기를 이용하여 수산화인회석과 CTAC을 도입한 수산화인회석의 결정성, 형태, 비표면적을 분석하였다. 열처리 후, HAP와 CTAC-HAP는 열처리 전과 비교하여 비표면적이 감소하였다. 또한 열처리는 뾰족한 막대 모양에서 종횡비가 감소한 둥근 모양으로의 CTAC-HAP의 형태변화를 유도하였다. 이러한 형태의 변화는 순수한 HAP에서도 관찰되었다. 그러므로 형태 변화와 열처리 후의 비표면적 감소는 열처리 중 CTAC의 제거로 생성된 기공들이 형태 변화로 인해 유지되지 않는 것으로 판단된다.

• Bulletin of the Korean Chemical Society
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• 제26권4호
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• pp.548-552
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• 2005

The interaction between ionic surfactants and different nonionic molecules and polymers are studied using ion surfactant selective electrode. From the experimental data, critical concentrations of the interaction and binding process are evaluated. The interaction between hexadecyltrimethylammonium bromide (HTAB) with polyethylene glycol (PEG) in three molecular weights (1000, 10000 and 100000) and also schiff-bases, 2-[2-carboxyphenyl nitrilomethylidyne]-phenol (ortho CNP), 2-[3-carboxyphenyl nitrilomethylidyne]-phenol (meta CNP)and 2-[4-carboxyphenyl nitrilomethylidyne]-phenol (para CNP) with the potentiometric method were investigated using HTAB membrane selective electrode. In the case of PEG with increasing molecular weights more interaction to HTAB occurs. The electromotive force (EMF) data also showed that interaction between para CNP with HTAB is more than the other schiff-bases. It seems this case related to less space interference of COOH group for that compound. The onset of binding ($T_1$) of course is the same for three schiffbase molecules.

• 대한화학회지
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• 제35권6호
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• pp.612-616
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• 1991

Sodium dodecyl sulfate(SDS), chondroitin sulfate 그리고 L-${\alpha}$-lecithin vesicle의 각각의 수용액에서 methylene blue (MB)의 metachromatic 성질을 $18^{\circ}$C에서 $52^{\circ}$C까지 흡수분광법으로 측정했다. MB는 지질이 고농도일 때 vesicle 매트릭스에 뭉치를 형성했다. MB의 metachromasy는 vesicle의 상전이 온도에 무관하게 나타났으며, 이것은 색소가 vesicle의 친수성 표면에서 회합함을 의미한다. Vesicle에서 MB의 metachromasy 현상은 hexadecyltrimethylammonium bromide(CTAB)를 첨가할 때보다 SDS를 첨가할 때 매우 약하게 관측되었다. 이것은 vesicle 표면에서 계면활성제들의 끼어드는 위치가 다른 것으로 보이며, CTAB가 SDS보다 색소뭉치 사이에 더욱 잘 끼어드는 것으로 사료된다.

• 한국광물학회지
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• 제15권4호
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• pp.305-314
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• 2002

HDTMA로 표면개질된 몬모릴로나이트의 탈수현상을 X-선 회절분석기와 시차주사열량측정 기(DSC)로 조사하였다 열에 의한 HDTMA-몬모릴로나이트의 탈수작용은 유기점토의 팽창거동에 영향을 주었다. HDTHA-몬모릴로나이트의 기저d(001)두께/온도변화 곡선은 크기가 다른 2개의 팽창피크를 보여주었다. 이것은 일차적으로 계면활성제의 정렬에 의한 점토광물의 층간팽창이 10$0^{\circ}C$ 부근에서 발생하고 알킬고리의 이차적인 수직배열에 의한 층간팽창이 20$0^{\circ}C$ 부근에서 일어났음을 가리킨다. 따라서, 이러한 결과는 유기점토의 탈수작용에 의해 점토 규산염층에 상대적으로 수직적인 알킬고리의 배열이 활성화되며, 소규모의 층간팽창을 야기한다는 것을 지시한다.

• 한국환경과학회지
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• 제16권2호
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• pp.143-149
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• 2007

The effect of precoating of silica with polyamine surfactants on the adsorption of five model compounds containing asphalt-like functionalities was studied. Hexadecyltrimethylammonium chloride (HDTMA) and 1-hexadecylamine were used for silica precoating. The model compounds representing five asphalt functionalities were benzoic acid, phenol, benzylbenzoate, benzophenone, and quinoline. All the adsorption isotherms conformed well to the Langmuir adsorption model. All the model compounds showed decreased adsorption with the HDTMA precoating. However, two acidic compounds, benzoic acid and phenol, showed enhanced adsorption on the silica precoated with 1-hexadecylamine. In aqueous solutions, the adsorption of the acidic compounds were in the following order: silica precoated with 1-hexadecylamine > silica precoated with HDTMA > uncoated silica.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2001년도 총회 및 춘계학술발표회
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• pp.15-18
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• 2001

Sorption/desorption studies were conducted to determine sorption/desorption characteristics of phenolic compounds (phenol and 4-chlorophenol) in organically modified natural bentonite. The cationic exchange capacity (CEC) of bentonite was exchanged with a cationic surfactant, hexadecyltrimethylammonium (HDTMA), to enhance the removal capacity of organic phenol contaminants dissolved in aqueous solution. This modification produces a change of the surface property of bentonite from hydrophilic to organophilic. The single-solute and bi-solute competitive adsorptions were performed In batch mode to investigate the removal of two toxic organic Phenols, chlorophenol and 4-chlorophenol on the HDTMA-bentonite. The adsorption affinity of the 4-chlorophenol was higher than phenol due to higher octanol:water partition coefficient (Kow). The single-solute and bi-solute competitive desorptions were also performed investigate the competitive desorption of the phenolic compounds from HDTMA-bentonite. Freundlich model was used to analyze the single-solute adsorption/desorption results, while the IAST model predicted the hi-solute adsorption/desorption equilibria. The IAST model well predicted hi-solute competitive adsorption/desorption behaviors.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2001년도 총회 및 춘계학술발표회
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• pp.168-171
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• 2001

Organobentonite modified with hexadecyltrimethylammonium (HDTMA) was used to quantify an adsorption of heavy metals. Based on preliminary experiments, optimal soil/solution ratio, a range of pH, and electrolyte were selected. Adsorption experiments of cadmium and lead were conducted to quantify an adsorption selectivity to bentonite and organobentonite. Adsorption of cadmium and lead to bentonite was increased with increasing a soil/solution ratio. Adsorption of cadmium and lead to bentonite was increased with increasing a soil/solution ratio. Adsorptions of heavy metal to organobentonite were slightly reduced relative to bentonite. This study used the principle of hard-soft-acid-base (HBAB) to interpretate an adsorption mechanism. Because of competition between cadmium and lead. adsorption of cadmium and lead was reduced in mixture of heavy metals. Adsorption selectivity.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 추계학술발표회
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• pp.67-70
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• 2002

Remediation of groundwater contaminated with chlorinated organics, nitro aromatics, and heavy metals using zero valent iron (ZVI) filings has paid considerable attention in recent years. When the contaminants of high concentration leaked abundantly in subsurface environment, permeable reactive barrier technology using iron filing is taken a long time for the remediation of contaminated groundwater, The problem of contaminant shock is able to be solved using surfactant (hexadecyltrimethylammonium, HDTMA) modified bentonite (SMB) as immobilizing material. Therefore, the purpose of this research was to develop the combined remediation technology using conventional permeable reactive and immobilizing barrier for the enhanced decontamination of chlorinated compounds. Four column experiments were conducted to assess the performance of the mixed reactive materials with Ottawa sand, iron filing, and HDTMA-bentonite for trichloroethylene (TCE) removal under controlled groundwater flow conditions. TCE reduction rates with sand/iron filing/HDTMA-bentonite were highest among four column due to dechlorination of TCE by iron filing and sorption of TCE by SMB.

• Journal of Microbiology
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• 제43권3호
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• pp.272-276
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• 2005

Bacillus subtilis ATCC 6633 was grown in BHIB medium supplemented with $Mn^{2+}$ for 96 h at $37^{\circ}C$ in a shaker incubator. After removing the microbial biomass, a lipopeptide biosurfactant was extracted from the supernatant. Its structure was established by chemical and spectroscopy methods. The structure was confirmed by physical properties, such as Hydrophile-Lipophile Balance (HLB), surface activity and erythrocyte hemolytic capacity. The critical micelle concentration (cmc) and erythrocyte hemolytic capacity of the biosurfactant were compared to those of surfactants such as SDS, BC (benzalkonium chloride), TTAB (tetradecyltrimethylammonium bromide) and HTAB (hexadecyltrimethylammonium bromide). The maximum hemolytic effect for all surfactants mentioned was observed at concentrations above cmc. The maximum hemolytic effect of synthetic surfactants was more than that of the biosurfactant produced by B. subtilis ATCC 6633. Therefore, biosurfactant would be considered a suitable surface-active agent due to low toxicity to the membrane.

• Bulletin of the Korean Chemical Society
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• 제24권1호
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• pp.23-26
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• 2003

Titanium acetylacetonate was used in the construction of a PVC-based membrane electrode. This sensor shows very good selectivity for iodide ion over a wide variety of common inorganic and organic anions. It exhibits Nernstian behavior with a slope of 59.1 mV per decade. The working concentration ranges of the sensor are with a detection limit of $3.0\;{\times}\;10^{-6}\;M$. The response time of the sensor is very fast (<8 s), and can be used for at least twelve weeks in the pH range of 4.0-9.2. The best performance was obtained with a membrane composition of 30% PVC, 65% dibutylphthalate, 3% titanium acetylacetonate and 2% hexadecyltrimethylammonium bromide. The proposed sensor was successfully applied as an indicator electrode for titration of iodide with silver ion.