• Analytical Science and Technology
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• v.24 no.4
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• pp.298-303
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• 2011

Selenium is one of the interesting elements in human body, because it's important micro-nutrient for human health as the essential biological tissue in protein. Selenite ($SeO_3^{2-}$) and selenate ($SeO_4^{2-}$) are the dominant dissolved selenium species in natural water, and their toxicity and chemical properties are very different each other. Thus it is necessary to separate the two selenium species for understanding selenium behaviors in natural waters. Some reported methods, using an alumina-filled column and an ion chromatography, to separate the selenite and selenite may be difficult to directly apply to the natural water. Therefore magnetite selectively adsorbs selenite and selenate according to pH of solution, the separation of selenite and selenate using a magnetite-filled column was successfully obtained at weak alkali solutions. Moreover, the influence of dissolved anions in natural water at the selenite sorption onto magnetite was also investigated because they could hinder the sorption of selenite onto magnetite. In other to directly apply to the natural water, reactive sites of magnetite should be considered because dissolved silicate in natural water can hinder the adsorption of selenite onto magnetite.

• Applied Chemistry for Engineering
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• v.8 no.4
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• pp.679-684
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• 1997

The major constituents in spent FCC catalysts are Si, Al, Fe, Ti, alkali metals and some others. The spent catalyst is also composed small amounts of rare metals such as Ce, Nd, Ni and V. The selective adsorption and concentration of Ce and Nd from the leaching solution of spent FCC catalysts with sulfuric acid($0.25mol/dm^3$) were carried out by the column method with a chelate resin having a functional group of aminophosphoric acid type. Ce and Nd were separated from eluate liquor containing Al, Nd and V by the precipitation process with oxalic acid. Vanadium is purified from chloride ion coexistance by solvent extraction, employing tri-n-octyl phosphine oxide as extractant with Al in the raffinate solution. Rare metals with the purity of 99 percent were obtained from the spent FCC catalyst.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.259-263
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• 2001

There are several steps such as slicing, lapping, chemical etching and mechanical polishing in the silicon wafer production process. The chemical etching step is necessary to remove damaged layer caused In the slicing and lapping steps. The typical etching liquor is the acid mixture comprising nitric acid, acetic acid and hydrofluoric acid. At present, the waste acid is treated by a neutralization method with a high alkali cost and balky solid residue. A solvent extraction method is applicable to separate and recover each acid. Acetic acid is first separated from the waste liquor using 2-ethlyhexyl alcohols as an extractant. Then, nitric acid is recovered using TBP(Tri-butyl phosphate) as an extractant. Finally hydrofluoric acid is separated with the TBP solvent extraction. The expected recovered acids in this process are 2㏖/l acetic acid, 6㏖/1 nitric acid and 6㏖/l hydrofluoric acid. The yields of this process are almost 100% for acetic acid and nitric acid. On the other hand, it is important to recover and reuse the metal values contained in various industrial wastes in a viewpoint of environmental preservation. Most of industrial products are made through the processes to separate impurities in raw materials, solid and liquid wastes being necessarily discharged as industrial wastes. Chemical methods such as solvent extraction, ion exchange and membrane, and physical methods such as heavy media separation, magnetic separation and electrostatic separation are considered as the methods for separation and recovery of the metal values from the wastes. Some examples of the application of solvent extraction to the treatment of wastes such as Ni-Co alloy scrap, Sm-Co alloy scrap, fly ash and flue dust, and liquid wastes such as plating solution, the rinse solution, etching solution and pickling solution are introduced.

• Journal of Electrochemical Science and Technology
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• v.11 no.1
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• pp.60-67
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• 2020

In this study, copper (II) oxide powder for electroplating was prepared by recovering CuCl₂ from NaClO₃ type etching wastes via recovered non-sintering two step chemical reaction. In case of alkali copper carbonate [mCuCo₃·nCu(OH)₂], first reaction product, CuCo₃ is produced more than Cu(OH)₂ when the reaction molar ratio of sodium carbonate is low, since m is larger than n. As the reaction molar ratio of sodium carbonate increased, m is larger than n and Cu(OH)₂ was produced more than CuCO₃. In the case of m has same values as n, the optimum reaction mole ratio was 1.44 at the reaction temperature of 80℃ based on the theoretical copper content of 57.5 wt. %. The optimum amount of sodium hydroxide was 120 g at 80℃ for production of copper (II) oxide prepared by using basic copper carbonate product of first reaction. At this time, the yield of copper (II) oxide was 96.6 wt.%. Also, the chloride ion concentration was 9.7 mg/L. The properties of produced copper (II) oxide such as mean particle size, dissolution time for sulfuric acid, and repose angle were 19.5 mm, 64 second, and 34.8°, respectively. As a result of the hole filling test, it was found that the copper oxide (II) prepared with 120 g of sodium hydroxide, the optimum amount of basic hydroxide for copper carbonate, has a hole filling of 11.0 mm, which satisfies the general hole filling management range of 15 mm or less.

• Journal of the Korean Applied Science and Technology
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• v.32 no.1
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• pp.116-126
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• 2015

The present study utilized a shuttle mechanism of wet chemical absorption using MEA. In addition, industrial by-products containing a large amount of inorganic alkali substances were utilized for wet carbonization process. Chemical pretreatment of industrial by-products extracted calcium ions. ICP result of calcium ion was obtained up to 17,900 ppm(17.9%) by acidic substance. And also, In this work, 94% of recovery rate was obtained using wet MEA absorption process from $CO_2$ flow at the ambient condition. Through the liquid carbonation process, a sludge was fixed with rate of 0.175 mg of $CO_2$ per mg of sludge. It was found from XRD results that the structure of final product was composed of a calcite structure which is general structure of $CaCO_3$.

• Textile Coloration and Finishing
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• v.11 no.1
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• pp.16-24
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• 1999

The effects of two-step fixation of steaming and baking on the dischargeability of cotton fabrics dyed with C.I. Reactive Black 5(Bl-5) were investigated when the concentrations of $K_2CO_3$ and benzaldehyde sodium bisulfite(BASB) were increased over 120/kg. Remarkably increased dischargeability resulted from baking for 3 min or more at 160t after steaming for 8 min or more at $102^\circ{C}$, but 120g/kg or more amounts of $K_2CO_3$ and BASB(50%) had little influence on dischargeability. Therefore the discharge mechanism can be suggested that covalent bonds between cellulose and Bl-5 undergo $S_N2$ attack by hydroxide ion formed by the reaction of $K_2CO_3$ and water in steaming at $102^\circ{C}$ first and then, through transition states they are cleavaged in baking at 160t to yield hydrolyzed Bl-S and compounds of BASB and Bl-5 isolated from fiber, which are undyeable and removed by washing. The effect of urea, one of the hydrotrope agents, on discharge printing was also studied. The result which dischargeability was greatly improved by increasing the steaming time from 8 min to 15 min at $102^\circ{C}$ or by increasing the amount of urea obviously shows that water in steaming and urea in print paste play an important role in discharge printing. And as an increase of the baking time from 5 min to 7 min at $160^\circ{C}$ makes it possible to improve dischargeability, it is once more confirmed that high temperature of about 160t is exactly required to discharge the dyed Bl-5. The colored discharge printing demands a more amount of urea because urea contributes to the putting color fixation as well as the discharge reaction.

• Journal of Microbiology and Biotechnology
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• v.16 no.2
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• pp.247-255
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• 2006

Yeast cell wall matrix particles are composed entirely of mannoprotein and ${\beta}-glucan$. The mannoproteins of yeast cell wall can systemically enhance the immune system. We previously purified and analyzed alkali-soluble ${\beta}-glucans$ [${\beta}$-(1,3)- and ${\beta}$-(1,6)-glucans] [10]. In the present study, a wild-type strain was first mutagenized with ultraviolet light, and the cell wall mutants were then selected by treatment with 1.0 mg/ml laminarinase (endo-${\beta}$-(1,3)-D-glucanase). Mannoproteins of Saccharomyces cerevisiae were released by laminarinase, purified by concanavalin-A affinity and ion-exchange chromatography. The results indicated that the mutants yielded 3-fold more mannoprotein than the wild-type. The mannoprotein mass of mutant K48L3 was 2.25 mg/100 mg of yeast cell dry mass. Carbohydrate analysis revealed that they contained mannose, glucose, and N-acetylglucosamine. Saccharomyces cerevisiae cell wall components, mannoproteins, are known to interact with macrophages through receptors, thereby inducing release of tumor necrosis factor alpha ($TNF-{\alpha}$) and nitric oxide. Mannoprotein tractions in the present study had a higher macrophage activity of secretion of $TNF-{\alpha}$ and nitric oxide and direct phagocytosis than positive control ($1{\mu}g$ of lipopolysaccharide). In particular, F1 and F3 fractions in mannoproteins of K48L3 enhanced and upregulated the activity of nitric oxide secretion and macrophage phagocytosis by approximately two- and four-fold, respectively.

• Korean Journal of Pharmacognosy
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• v.1 no.3
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• pp.93-99
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• 1970

There have been reported by several workers for the isolation and determination of the amine derivatives as Metbylephedrine Hydrochloride and Ephedrine Hydrochloride adopting neutralization method, steam distillation method, non-aqous titration method, ion-exchange resin method, titration method after acetylation, colorimetric method, gravimetric method, iodine titration method and gas chromatography. Those methods mentioned in above, can be practically applied for the sample which is not mixed one mith the other amine compounds. Presently, it has not shown on the isolative determination of the mixed sample of amine derivatives. In this paper, it is discussed on the isolative determination of Methylephedrine Hydrochloride as the tertiary amine compound and Ephedrine Hydrochloride as the secondary amine compound. According to the results of the experiment, it could be summarized as follows: 1. There is no time-variation on the color reaction of Methylephedrine Hydrochloride and Ephedrine Hydrochloride with the color reagent, bromcresolgreen. And Methylephedrine Hydrochloride and Ephedrine Hydrochloride, respectively, can be determined spectrophotometrically by means oft his color reaction. 2. For the isolation of Methylephedrine Hydrochloride and Ephedrine Hydrochloride from the mixed sample, Methylephedrine Hydrochloride can be eluted by chloroform, while Ephedrine Hydrochloride by the mixed solvent of chloroform and ethylalcohol (2:1), from the celite column adsorbed at pH6.4 followed by extraction with ether undersodium hydroxide alkali re action. 3. When the sample is mixed with quinine hydrochloride, dihydrocodeine bitartate, and noscapine, these mixed compounds can be eliminated by means of stram distillation. 4. When the sample is mixed with chlorpheniramine maleate, dextromethorphan hydrobromide and diphenhydramine hydrochloride, the mixed compounds can be eliminated by means of steam distillation and celite adsorption column chromatography, In conclusion, the isolative determination method for Methylephedrine Hydrochloride and Ephedrine Hydrochloride studied in this paper, indicates with the excellent reproducibility and accuracy.

• Analytical Science and Technology
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• v.8 no.4
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• pp.675-682
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• 1995

Thin films of buckminsterfullerene($C_{60}$) formed by solution drop casting on Pt foil electrode surfaces were studied by cyclic voltammetry(CV) in acetonitrile(MeCN) containing quaternary ammonium or alkali-metal salts as supporting electrolyte. The electrochemical behaviors of $C_{60}$ films are found to be strongly dependent on the nature of the supporting electrolytes, especially with tetrabutyl ammonium perchlorate (TBAP, $NBu_4ClO_4$), and tetrabutyl ammonium tetrafluoroborate ($TBABF_4$, $NBu_4BF_4$). Reasonably stable films are formed into which electrons can be injected. The interaction of $C_{60}$ film with the quaternary ammonium cation may produce the fulleride salts $(TBA^+)(C{_{60}}^-)$ and $(TBA^+)_2(C{_{60}}^{2-})$. The bulk electroreduction with a controlled potential to generate the soluble $C{_{60}}^{3-}$ anions(dark red-brown color) is followed by electrooxidative deposition to produce a neutral $C_{60}$ film on the surface. The peak currents($I_{pc}$ and $I_{pa}$) of these thin film were dramatically decreased with repetitive potential scanning. These results could be explained by the adsorption-desorption phenomena and ion pairing interaction of reduced species($C{_{60}}^-$, and $C{_{60}}^{2-}$) onto the electrode surface. The peak current changes and peak potential shifts of the thin $C_{60}$ film in cyclic voltammograms formed from solution were observed by varying scan rates.

• Economic and Environmental Geology
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• v.29 no.4
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• pp.483-493
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• 1996

The tectonic environment and source characteristics of the Daebo granitic batholith in the central Ogcheon Belt were investigated based upon major and trace element geochemistry. The batholith is comprised of three granite types; a biotite granite (DBBG), K-feldspar megacryst-bearing biotite granite (DBKG), and a more mafic granodiorite (DBGD). The variations of Na and K in the granites can not be explained by simple fractional crystallization from the same primary magma. The irregular behavior of these alkali elements indicates a variety of source materials or incomplete mixing of different source materials. The large ion lithophile (LIL) element enrichment and low Ta/Hf ratios of the granites are typical characteristics of normal, calc-alkaline continental arc granitoids. Based upon REE patterns of the granites, it seems to be unreasonable to regard the felsic DBBG as a late stage differentiate formed by residual melts after the fractionation of major constituent minerals of the more mafic DBGD. Inconsistent variations in ${\varepsilon}_{Nd}(t)$ and LIL element concentrations of the granites preclude a mixing model between primitive melt and LIL element-enriched upper crustal materials. The irregular geochemical variation of the granites is taken to be largely inherited from an already heterogeneous source region.