• Journal of Conservation Science
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• v.32 no.3
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• pp.321-331
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• 2016

Textiles damage caused by acetaldehyde($CH_3CHO$) is not clear as compared to other materials. Total 20 specimens were prepared using 4 different materials (silk, cotton, ramie, hemp) after dyed with 4 colors (undyed, red, yellow, blue, black). The specimens were exposed to $CH_3CHO$ gas in the test chamber. First, textile specimens' damage by differert concentration of acetaldehyde(0.1, 0.5, 1, 10, 100, 500, 1000 ppm) was tested. Second, accelerared damage to the textile specimens were tested according to the temperature and humidity conditions at the damage levels. Third, damage of deliberately degraded textile specimens were examined at the damage levels. After the exposure, optical, chemical, and physical evaluation was carried out. As a result, at 1000 ppm/day, the color difference of cotton_yellow has increased. At the condition of $25^{\circ}C-80%$, $30^{\circ}C-50%$, $30^{\circ}C-80%$, the color difference of yellow specimens has increased and grey scale rating has decreased. At $30^{\circ}C-80%$, acetate of cotton_undyed increased and the pH of silk_undyed decreased. In the case of deliberately degraded textile specimens, actetate concentration of black specimens increased. In conclusion, damage to the traditional fabric by acetaldehyde is not impact. However, it is expected that yellow specimens will be bleach and black specimens' actetate concentration will be increase.

• Journal of the Korean Chemical Society
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• v.46 no.6
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• pp.502-508
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• 2002

We have used PET chemosensors in the determination of N-carbamoylglycine. When N-carbam-oylglycine reacts with complex already made by the fluorophore and metal ion, the luminescence intensity can be changed and this phenomenon can be utilized in quantification. We used three metal ions, $Zn^{2+}$, $Ni^{2+}$, $Cu^{2+}$ and in order to investigate selectivity an acetic acid was used. $Ni^{2+}$ ion showed change in the eT mechanism by the anions. $Cu^{2+}$ ion showed the ability to distinguish N-carbamoylglycine from an acetic acid and it is noteworthy that $Zn^{2+}$ ion can change luminescence sensitively according to concentration.

• Korean Chemical Engineering Research
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• v.44 no.5
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• pp.476-482
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• 2006

This paper studied the recovery of organic acid from organic acid salt by using bipolar membrane electrodialysis. Acetic acid and lactic acid was used as for organic acid. Organic acid concentration, sodium hydroxide concentration and pH values were measured at various current density. Organic acid salt was effectively converted to organic acid and sodium hydroxide. Based on the experimental results, mathematical models were developed, in which time changes in ion balance were considered. Model predictions of organic acid concentration, sodium hydroxide concentration and pH values were in good agreement with the experimental data.

• Membrane Journal
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• v.1 no.1
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• pp.44-54
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• 1991

Sulfonated polystyrene-divinylbenzene(PS-DVB) copolymer membranes were prepared using different diluents (toluene, cyclohexane, cyclohexanol), various diluent ratio and DVB contents. And initial fluxes of organic acids were investigated by varying pH and initial concentration. As a results, water content and ion-exchange capacity decreased with increasing DVB concetration. Among used diluents, cyclohexanol was the most efficient for building up the highest water content and ion-exchange capacity. In the experiment of permeation, carboxylic acid such as formic acid and acetic acid showed higher fluxes when pH was lower than pKa and amino add such as L-alanine showed minimum flux when pH was isoelectric value. The relationaship between initial fluxes and initial concentrations has been expressed by saturation kinetics.

• Applied Chemistry for Engineering
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• v.10 no.3
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• pp.477-485
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• 1999

The grafting of 2,3-epoxypropylmethacrylate (GMA) onto polypropylene fabric was carried out by the $\gamma$-ray preirradiation grafting technique. Subsequently, the GMA-grafted polypropylene fabric was reacted with iminodiacetic acid (IDA) in different mixed solvents to prepare the fibrous metal adsorbent. The grafting extent was found to be dependent on the reaction time, temperature, preirradiation dose and dose rate. The effects of various mixed solvents on the IDA amination onto GMA-grafted polypropylene fabric were investigated. Compared with other mixed solvents, the extent of amination was highest in the dimethylsulfoxide (DMSO)/water, but the reaction did not occur in the water. The adsorption characteristics of various metal ions by the prepared adsorbent were examined when it was immersed in the 100 ppm metal ion solution. The amount of adsorption followed the order:$Pb^{2+}>Co^{2+}>Fe^{2+}$.

• Journal of the Korean Wood Science and Technology
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• v.21 no.3
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• pp.22-29
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• 1993

나뭇잎으로부터 발생되는 저분자량 유기산을 이온크로마토그래피를 이용하여 분석하였다. 이 방법은 자연상태의 나뭇잎 (needle litter)을 유기용매의 추출 없이 그대로 이용할 수 있어서 사용하기에 편리하다. 본 논문에서는 이온 크로마토그래피의 사용방법과 침엽수잎(Pacific Silver Fir)의 부후정도에 따른 유기산의 종류와 농도의 변이를 간략하게 소개한다. 초기의 침엽수잎 여과액으로부터는 $C_2$에서 $C_4$까지의 아세트산(acetic acid), 프로피온산(propionic acid), 옥살산(oxalic acid) 그리고 포름산(formic acid) 등이 주종을 이루지만 부후정도가 커짐에 따라 방향핵을 가진 방향핵 유기산(aromatic organic acid)이 발생한다.

• Korean Chemical Engineering Research
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• v.43 no.2
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• pp.266-271
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• 2005

This paper studied succinic acid recovery from organic acid mixture by using mono-polar membrane electrodialysis. Current efficiency, solute recovery efficiency, energy consumption, and separation factor were measured at various pHs and concentration ratios. The separation factor of succinic acid could be interpreted in terms of ionization degree, molecular weight, ionic conductance, average charge, and initial feed composition.

• Korean Chemical Engineering Research
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• v.56 no.5
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• pp.679-686
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• 2018

Reverse osmosis (RO) concentration of sodium chloride, sodium acetate, and sodium citrate solutions has been performed by polyamide RO membrane. Concentration polarization phenomena was also studied by changing pressure, solute kinds, and initial solution concentration. Pressure effect on permeation flux was that the increase of flux was accompanied by the increase of pressure. Flux increase was observed by the decrease of initial solution concentration. Surface concentration on the RO membrane increases and so flux declines due to the concentration polarization. In the later phase of concentration, concentration polarization effect was decreased by the back diffusion of solute from the polariztion layer. In case of sodium citrate, its large ion size and charge density resulted in the discrepancy between theory and experimental data of concentration polarization. It may be due to electric repulsion on the membrane surface.

• Journal of Applied Biological Chemistry
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• v.64 no.2
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• pp.159-164
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• 2021

Heavy metals exist in soils in various chemical forms including free metal ions and organo-metal complexes. The ratio of free metal ions has been known to be highly associated with the plant absorption of heavy metals. This study aims to understand the effect of free ions and organo-metal complexes on the absorption of lead (Pb) and cadmium (Cd) by plants. For this, lettuce grown in a hydroponic system for 28 days was consequently grown another 48 hours using Pb and Cd solutions. The ratios of free ion to organo-metal complexes in the solutions were adjusted at 100:0, 90:10, 70:30, 60:40 by four different organic acids (citric, oxalic, acetic, and humic acid). After that, the concentration of Pb and Cd in lettuce were analyzed. The Pb and Cd absorption by lettuce was more relied on the types of organic acids treated and the type of metals rather than the ratio of free metal ions. For example, citric acid increased the Pb absorption while it decreased the Cd absorption by lettuce. There was no significant relationship between free metal ion ratios and both Pb and Cd uptake by lettuce. It could be explained that citric acid, a relatively higher molecular weight organic acid, has higher ion binding capacity, so it forms organo-Pb complex easily due to the higher affinity of Pb on the binding site in comparison with Cd. Consequently, this complexation would assist Pb uptake by lettuce.

• Journal of the Korean Chemical Society
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• v.29 no.6
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• pp.615-622
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• 1985

The chemical species formed by uranium and vanadium and their equilibria have been investigated in the various concentrations of oxalic and acetic acids by the ion exchange chromatography and UV-Vis spectrophotometry. Uranyl and vanadyl ions seem to be form the complex as $UO_2(C_2O_4)_2=$, $UO_2(C_2O_4)_3^{4-}$ and $VO_2(C_2O_4)-2^{3-}$ respectively in the concentration range of 0.005∼0.05M oxalic acid concentration. In the case of acetic acid the equilibria of $UO_2^{2+}+3Ac^-=UO_2(Ac)_3^-$ and $VO_2^++2Ac^-=VO_2(Ac)_2^-$ were existed individually according to the increase of acetic acid concentration.