• Resources Recycling
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• v.26 no.5
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• pp.77-84
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• 2017

White and black dross are resulted from the recycling of aluminum. There are no established processes to recover valuable materials from black dross. Hydrometallurgical processes seem to be suitable for the treatment of aluminum dross. The salts in the black dross are recovered by dissolving with water. The residues are treated by either alkaline or acid leaching. Although the leaching rate of alumina by NaOH is lower than that by acid, its intermediates are more suitable to the production of alumina-based materials. The future direction for the treatment and recovery of valuable materials from aluminum dross is discussed.

• Applied Chemistry for Engineering
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• v.25 no.5
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• pp.526-530
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• 2014

Polystyrene-poly(etheramic acid) core-shell particles were prepared by dispersion polymerization of styrene using poly(etheramic acid) obtained by the reaction of 2,2'-bis[4-(3,4-dicarboxyphenoxy) phenyl]propane dianhydride and 3,5-diamniobenzoic acid as a stabilizer. 4-Vinylbenzyltrimethylammonium chloride was used as a comonomer to increase the binding efficiency of poly(etheramic acid). When the ethanol-water mixture (7 : 3) was used as a reaction medium, particles were stabilized well and the size distribution of particles was fairly narrow. The particle size increased with the amount of styrene. The particles polymerized in the dimethylformamide-water mixture had a broad size range. Polystyrene-poly(etheramic acid) core-shell particles were transformed to polystyrene-polyetherimide core-shell particles by the chemical imidization of shells.

• Resources Recycling
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• v.25 no.3
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• pp.11-19
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• 2016

A fundamental study to recycle a Si-Sludge and waste copper nitrate solution acid solution generated by domestic electronic industries was carried out. The waste copper nitrate solution was used as the lixiviant to leach the metals like Cu, Ca, Fe, etc. from the sludge leaving Si in the residues. The effect of reaction temperature, time and pup density on the metals leaching from the sludge was investigated. To enhance the extractability of Fe, the effect of HCl, $HNO_3$ and $H_2O_2$ introduced additionally during the leaching was also examined. Considering the leaching efficiency of Fe along with Cu, the leaching conditions comprising of 200 ~ 225 g/L pulp density and $90^{\circ}C$ temperature for 30 min were optimized. Under this condition, 98.27 ~ 99.17% Cu could be dissolved in the leach liquor with the obtained purity of Si in the residues as 98.69 ~ 98.86 %. The study revealed that the leaching of Cu contained in the Si-Sludge with the waste copper nitrate solution is a plausible approach by which the obtained leach liquor can further be treated suitably to recover Cu as the high pure value-added products.

• The Korean Journal of Nuclear Medicine
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• v.9 no.2
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• pp.23-28
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• 1975

Glucose tolerance, insulin and growth hormone responses following glucose or amino acids administration by means of parenteral or oral load were studied in patients with far advanced gastric cancer. Hormone responses following nutrients load showed in patients with gastric cancer were compared to those of healthy subjects. Results were as follows: 1. Blood sugar appearance following oral glucose administration was diminished in patients with far advanced gastric cancer. 2. The insulin responses of gastric cancer following oral glucose were also diminished as compared to that of normal subjects and were identical with parenteral route. 3. Parenteral administration of glucose or amino acids to patients with gastric cancer result ed in a increase of plasma growth hormone level. 4. Lower insulin response to amino acids was observed on parenteral administration in patient with gastric cancer as in healthy subjects. 5. Author discussed that the low insulin response after oral glucose administration showed in gastric cancer, and any additional insulin requirement arise when longer periods of parenteral amino acid administration are necessary, as in the patient with malnutritions.

• Resources Recycling
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• v.30 no.5
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• pp.38-48
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• 2021

In this study, we determine the optimal process conditions for selectively recovering Si from a solar cell surface by removal of impurities (Al, Zn, Ag, etc.). To selectively recover Si from solar cells, leaching is performed using HCl solution and an ultrasonic cleaner. After leaching, the solar cells are washed using distilled water and dried in an oven. Decompression filtration is performed on the HCl solution, and ICP-OES (Inductively Coupled Plasma Optical Emission spectroscopy) full scan analysis is performed on the filtered solution. Furthermore, XRD (X-ray powder diffraction), XRF (X-ray fluorescence), and ICP-OES are performed on the dried solar cells after crushing, and the purity and recovery rate of Si are obtained. In this experiment, the concentration of acid solution, reaction temperature, reaction time, and ultrasonic intensity are considered as variables. The results show that the optimal process conditions for the selective recovery of Si from the solar cells are as follows: the concentration of acid solution = 3 M HCl, reaction temperature = 60℃, reaction time = 120 min, and ultrasonic intensity = 150 W. Further, the Si purity and recovery rate are 99.85 and 99.24%, respectively.

• Analytical Science and Technology
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• v.30 no.6
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• pp.303-311
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• 2017

A new method for obtaining the photoluminescence of footwear impression by using 1,2-indandione (1,2-IND) solution, which is a latent fingerprint-developing reagent, was studied. A binary complex of DL-alanine and 1,2-IND was prepared by spraying a DL-alanine solution and the 1,2-IND solution (an amino acid sensitive reagent) onto dry or wet origin footwear impression deposited on the surface of printed A4 paper. This binary complex reacts with the trace metal component in the footwear impression to form a ternary complex that exhibits photoluminescence. However, when 5-methylthioninhydrin (5-MTN) solution was used instead of 1,2-IND, no consistent photoluminescence was observed even under identical treatment conditions. In addition, when footwear impressions treated with DL-alanine and 1,2-IND solutions were stored under various temperature conditions (30, 40 and $50^{\circ}C$) and various humidity conditions (30 %, 40 %, 50 % and 60 % RH), the contrast between the footwear impression and the background decreased. Optimal footwear impression photoluminescence was obtained when the footwear impressions treated with DL-alanine and 1,2-IND solutions were stored at $30^{\circ}C$ and 30 % RH for 1 h. The sensitivity of the developed method was ccompared with the sensitivities of three known methods - black gelatin lifting, 2,2'-dipyridyl treatment, and 8-hydroxyquinoline treatment. The results showed that the sensitivity of the developed method was worse than that of the black gelatin lifting method but better than that of 2,2'-dipyridyl or 8-hydroxyquinoline treatment method.

• 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.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10b
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• pp.163-164
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• 2003

키토산은 셀룰로오스 다음으로 자연계에 많이 존재하는 천연 고분자인 키틴을 탈아세틸화 시킨 것으로서, 많은 아민기를 가지고 있는 것이 특징이다[1]. 키토산은 아민기에 의한 항균성이 뛰어나기 때문에 섬유제품의 항균 가공제로 이용되고 있다. 그러나 키토산은 다른 천연고분자와 마찬가지로 용융가공성이 없기 때문에 섬유, 멤브레인 등으로의 성형은 묽은 산 수용액으로 만든 용액을 가공하는 방법을 이용하고 있다. (중략)

• Journal of Chest Surgery
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• v.29 no.10
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• pp.1066-1075
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• 1996

To compare the efficacy of cardiac preservation, we examined purine metabolites during 24 hours of cold storage($0^{\circ}C$) of the Korean ongrel dog hearts after using three different types of cardioplegic solutions. The hypothermic arrest with total cardiopulmonAry bypass method was employed in 51. Thomas solution(575) and blood cardioplegic solution(BCPS) preservation cases. Specimens were analyzed for levels of adenine nucleotides and their precursors by high performance liquid chromatography. The ATP content in the UW(University of Wisconsin) solution group tends to be higher than that of the combined hypothermic arrest group(575 and BCPS groups) after 2,4,8, and 12 hours of preservation respectively, but there were no significant differences between 575 and BCPS groups. The ADP contents in the UWS and BCPS groups were higher than that of the 575 group at 4,8, 12, and 24 hours, but the difference was not statistically significant between UWS and BCPS groups. The AMP contents did not change significantly in the three groups. The adenosine, Inosine, and hypoxanthine concentrations increased progressively, but the lev l of xanthine was very low in the three groups.

• Analytical Science and Technology
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• v.6 no.5
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• pp.435-442
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• 1993

Carboxymethylated polyamine-polyurea resin loaded with rubeanic acid (RCCPPI resin) was obtained by 1 step chemical reaction between chlorocarboxymethylated polyamine-polyurea(CCPPI) resin as matrix polymer and rebeanic acid. This resin was confirmed with infrared spectrometry, elemental analysis, and thermal analysis(DSC). The adsorption characteristics of the heavy metal's on the resin were studied by measuring distribution coefficient($K_d$) with changing pH of the solutions and frontal chromatography. The enrichment, recovery, and analysis of trace heavy metals, such as cadmium, cerium, copper, nikel, lead, and zinc, in the presence of high concentrations of sodium, calcium, and acetate salts was possible quantitatively by a column packed with the resin at each optimum pH. Preconcentration factors were more than 25. To elute the adsorbed heavy metals on the resin, 0.025M EDTA solution(pH 9.0) was used.