• Journal of Photoscience
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• 제10권3호
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• pp.219-223
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• 2003

Phloxine B (2,4,5,7-tetrabromo-4,5,6,7-tetrachlorofluorescein disodium salt), also referred as D&C red dye no. 28, is phototoxic to many insects such as Tephritidae fruit flies. Sunlight photolysis of phloxine B in aqueous solutions was a first order kinetic reaction at low concentrations. But it turned to be more complex reactions with the increase of phloxine B concentration. The half-lives of phloxine B (6-120 ${\mu}$M) were 18-41 and 52-289 hours in oxygenated and deaerated distilled water, respectively. The photolysis rate constants increased as the phloxine B concentrations increased. The singlet oxygen formation positively correlated with the concentrations of phloxine B and humic acid in oxygenated distilled water. The formation of singlet oxygen did not stop even after the complete degradation of phloxine B, which suggested an involvement of photoproduct-mediated reactions. The results showed that singlet oxygen mediated photooxidation was a dominant reaction for phloxine B dissipation in an aqueous solution, and the self-sensitized and photoproduct-mediated reactions were also involved at the higher concentrations. Iodide and bromide ions significantly decreased phloxine B photolysis rate constants, which were in relation to the decrease of singlet oxygen formation.

• Macromolecular Research
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• 제11권6호
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• pp.488-494
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• 2003

We have fabricated gelatin-immobilized polyurethane foams (PUFG) by dipping polyurethane foam (PUF) in an aqueous solution containing gelatin and by subsequent reaction with glutaraldehyde after freeze-drying. Gelatin aqueous solutions of different concentrations were used as the dipping solutions to control the amount of immobilized gelatin. The average pore size of PUF decreased with an increase in gelatin concentration. It was found from the hepatocyte adhesion experiment that the amount of hepatocytes seeded on PUFG1, prepared by using a 1% aqueous gelatin solution, was higher than that on other PUFGs. The hepatocytes inoculated in PUFG1, were slightly aggregated as the incubation time increased. The cells inoculated in PUFG1 showed higher ammonia removal ability than those monolayer-cultured on a gelatin-immobilized polystyrene dish (PSG) after 1 and 4 days of incubation time. The inoculated cells exhibited higher albumin secretion relative to monolayer-cultured hepatocytes on PSG. Albumin secretion by hepatocytes seeded on PUFG1 was increased by the presence of serum and was further increased by both the presence of serum and cytokines. The results obtained from a 3-(3,4-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) assay indicated that PUFG can provide a better microenvironment for hepatocyte culture along with nutrition and metabolite transfer through the high porosity of PUF.

• 한국농공학회논문집
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• 제55권1호
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• pp.49-57
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• 2013

The present study was conducted to investigate phosphate removal from aqueous solution using industrial wastes, red mud (RM), acid treated red mud (ATRM) and converter furnace steel slag (CFSS). The chemical composition of adsorbents was analyzed using X-ray fluorescence (XRF). Batch experiments and elution experiments using water tank were performed to examine environmental factors that influences on phosphate removal. Kinetic sorption data of RM, ATRM, and CFSS were described well by the pseudo second-order kinetic sorption model, and equilibrium sorption data of all adsorbents obeyed Freundlich isotherm model. The adsorption capacities of adsorbents followed order: ATRM (7.06 mg/g)>RM (4.34 mg/g)>CFSS (1.88 mg/g). Increasing pH from 3 to 11, the amount of adsorbed phosphate on all RM, ATRM, and CFSS were decreased. The presence of sulfate and carbonate decreased the phosphate removal of RM and ATRM but did not influence on the performance of CFSS. The phosphate removal of RM, ATRM, and CFSS was greater in seawater than deionized water, resulting from the presence of cations in seawater. The water tank elution experiments showed that RM capping blocked the elution of phosphate effectively. It was concluded that the adsorbents can be successfully used for the removal of the phosphate from the aqueous solutions.

• Bulletin of the Korean Chemical Society
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• 제32권9호
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• pp.3443-3447
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• 2011

The spectroscopic behavior of catechin (5,7,3',4'-tetrahydroxyflavan-3-ol), has been studied in the presence and the absence of air using UV-vis absorption spectrophotometry and fluorescence spectroscopy. The UV-vis absorption spectrum of catechin shows a very sharp and strong absorption maximum peak at 275 nm in deaerated water. New absorption maximum peaks appeared in aerated water, as well as in basic aqueous solution, caused by the oxidation of catechin. The absorbances in the UV-vis absorption spectrum of catechin decreased when the solution was left in the dark for a long time. The fluorescence emission spectrum of catechin after a long time period differs markedly from that in freshly prepared solution; the fluorescence maxia shifted as time passes after adding catechin to the solutions. When the deaerated basic catechin solutions were left in the dark for a long time, their fluorescence quantum yields were found to be nearly zero. This suggests that the oxidized catechin molecules were seen to have slowly undergone successive chemical reactions in basic buffer solution.

• Archives of Pharmacal Research
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• 제25권3호
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• pp.381-386
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• 2002

The objective of this study was to link conformational changes of proteins at a water/methylene chloride interface to their destabilization upon emulsification. When 4 aqueous protein solutions (bovine serum albumin, $\beta$-lactoglobulin, ovalbumin, or ribonuclease) were emulsified in methylene chloride, considerable proportions of all the proteins became water insoluble aggregates. There were also noticeable changes in the compositions of their water-soluble species. A series of water/methylene chloride interfacial reactions upon the proteins was considered a major cause of the phenomena observed. Based on this supposition, the interfacial tension was determined by a Kruss DVT-10 drop volume tensiometer under various experimental conditions. It substantiated that the interfacial tension was high enough to cause the adsorption of all the proteins. Under our experimental conditions, their presence in the aqueous phase resulted in reductions of the interfacial tension by the degrees of 8.5 - 17.1 mN $m^{-1}$. In addition, dynamic changes in the interfacial tension were monitored to compare relative rates at which the adsorbed proteins underwent conformational, structural rearrangements at the interface. Such information helped make a prediction about how easily proteins would denature and aggregate during emulsification. Our study indicated that emulsifying aqueous protein solutions in organic solvents should be handled with care, due to adverse interfacial effects.

• 대한화학회지
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• 제54권5호
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• pp.603-610
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• 2010

수용액으로부터 3개 양이온 염료(메틸렌 블루 MB, 중성래드 NR, 녹공작석 옥살산염MG)를 제거하는 Maghnia 점토의 흡착제로서의 가능성을 알아보기 위해 접촉시간, pH, 초기 염료 농도, 흡착제 사용량등을 변화시키면서 조사하였다. 적절한 pH는 NR의 경우 6이었고, MB와 MG의 경우 7로 나타났다. 90% 이상의 최대 염료 흡착은 약 60분내에 이루어졌으며, 염료 흡착은 유사 2차반응속도식을 따랐다.

• Membrane and Water Treatment
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• 제10권5호
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• pp.373-379
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• 2019

One of the real issues of the recent years is water contamination because of harmful synthetic dyes. Liquid Membranes (LM) resemble a promising alternative to the current separation processes, demonstrating various points of interest as far as effectiveness, selectivity, and operational expenses. The improvement of various Liquid Membranes designs has been a matter of examination by few researchers, particularly for the expulsion of dyes from aqueous solutions. The choice of organic surfactants plays an essential role in the efficiency of the dye removal. In LM design, the most significant step towards productivity is the decision of the surfactant type and its concentration. Liquid emulsion membrane (LEM) was used to remove safranin from aqueous solutions in which the emulsion was made with the help of D2EHPA as carrier, kerosene was used as a diluent and Span 80 (Sorbiton monooleate) was used as an emulsifying agent or surfactant. Various sorts of internal stages were utilized, to be specific sulphuric acid and sodium hydroxide. The impact of parameters influencing extraction efficiency such as pH of feed solution, concentrations of surfactant and emulsifying agent in membrane phase, volume ratio of internal phase to membrane phase, internal phase concentration, agitation speed and time of extraction were analyzed.

• 대한화학회지
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• 제33권1호
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• pp.97-105
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• 1989

CTABr 미셀용액 속에서의 2-alkylbenzimidazole(R-BI) 및 sodium 2-alkylbenzimidazole-5-sulfonate(R-BISO$_3$Na)에 의해 추진되는 p-nitrophenyl carboxylic esters(p-NPCE)들의 가수분해반응에 대한 미셀효과를 다루었다. 이들 반응은 각각 BI 및 BISO$_3$Na에 의해 추진되는 반응의 속도보다 현저히 감소하고, 알킬기가 methyl에서 heptyl로 길어질수록 감소의 정도가 더욱 크다. 이것은 CTABr을 포함하지 않는 수용액속에서의 BISO$_3$Na와 R-BISO$_3$Na에 의한 가수분해 반응속도가 별차이가 없음을 감안 할 때, 미셀의사층(micellar pseudophase) 내에서 이들 친핵체의 알킬기가 입체장해(steric hindrance)로 작용하기 때문이다. 이것은 수용액과 미셀용액 속에서의 반응의 측정된 홀성화에너지(${\Delta}H{\neq},\;{\Delta}G{\neq}$ 및 ${\Delta}S{\neq}$)의 값과도 정성적으로 일치하고 있다. 한편, nonyl기에서 pentadecyl기까지의 긴 알킬기를 갖고 있는 R-BISO$_3$Na는 그것의 imidazole 부분(BI moiety)이 친핵체로 작용할 뿐 아니라, 이들은 CTABr을 포함하지 않는 수용액속에서 미셀을 형성하고, 그 결과 기질인 p-NPCE를 쉽게 수용하여 반응속도를 촉진시키는 것으로 판단된다. R-BISO$_3$Na에 의한 이들 p-NPCE들의 가수분해반응의 mechanism을 알기위하여 중수소 동위원소효과(kinetic isotope effect)를 측정하였다. $k'_{H_2O}/K'_{D_2O}$값이 약 2.5∼3.2의 범위로서, 이 값은 R-BISO$_3$Na가 친핵체로만 작용한다고 보기에는 너무 높고, 일반염기로 작용한다고 보기에는 너무 낮다. 따라서 CTABr 미셀용액 속에서의 이 반응은 이 두 mechanism에 의해 동시적으로 진행된다고 생각된다.

• 한국환경농학회지
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• 제14권3호
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• pp.296-301
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• 1995

약제, 계면활성제, 수용성 유기용매, 증류수의 조성을 가지는 농약스크리닝용 약제용액중에서 각 성분들의 역할을 명확히 이해하는 동시에 약제용액에 보다 우수한 성질을 부여할 수 있는 계면활성제를 선발하기 위하여 Tween 20을 포함한 6종의 비이온성 계면활성제 수용액의 제초제 원제 18종에 대한 용매성, 벼와 콩에 대한 전착력 및 약해를 시험하고 평가하였다. 제초제 원제에 대한 계면활성제-아세톤 수용액의 용매성은 아세톤의 첨가비에 의존하였으며, 이에 대한 비이온 계면활성제의 역할은 미미하였다. 시험한 계면활성제중 polyoxyethylene nonylphenyl ether HLB 16.0(NP-16.0)을 함유하는 아세톤 수용액이 약간 더 양호한 용매성을 보였다. 콩잎에 대한 전착력은 모든 계면활성제 수용액이 고르게 양호하였으나, 벼에 대한 전착력은 polyoxyethylene lauryl ether HLB 13.6(LE-13.6)를 함유하는 아세톤 수용액만이 양호하였다. 대부분의 계면활성제 수용액이 벼에 대해서는 약해를 유발하지 않았으나, 콩잎에 대해서는 Tween 20 0.1%, LE-13.6 0.01% 및 NP-16.0 0.01% 수용액만이 약해를 유발하지 않았다. 약제에 대한 유화성, 식물체에 대한 전착력 및 약해 안전성을 모두 만족시킬 수 있는 계면활성제는 찾지 못하였으나 시험한 계면활성제중에서는 LE-13.6이 가장 적당하였다.

• Journal of Pharmaceutical Investigation
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• 제19권4호
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• pp.213-217
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• 1989

To formulate the stable preparation of Gingko extract injection and to evaluate the stability of the preparation, Gingko extract aqueous solutions having various pH values were prepared and the stability of ginskoflavonglycoside (GFG) was investlfated by high performance liquid chromatography. The stability of GFG decreased as pH increased, while the water solubility of Gingko extract decreased as pH decreased. The optimal pH of the Gingko extract aqueous solution was found to be pH 6.5. The shelf life $(T_{90%})$ of the Gingko extract aqueous solution of pH 6.5 at $20^{\circ}C$ was extrapolated to be four years.